View Filing Data

$ 3.3

$ 109.3

^[1]

87.6

67.3

^[1]

Other receivables

0.3

0.5

^[1]

Other current assets

4.7

3.3

^[1]

Total current assets

95.9

180.4

^[1]

Equity investments

107.8

67.3

^[1]

Long-term receivable—affiliate

3,010.1

2,735.3

^[1]

1.2

1.3

^[1]

Deferred tax asset

^[2]

49.8

12.9

6.9

^[1]

3,277.7

2,991.2

^[1]

Accounts payable—affiliate

30.6

18.6

^[1]

47.9

15.8

^[1]

Current maturities of long-term debt

88.7

85.6

^[1]

^[1]

11.3

Other current liabilities

8.9

6.8

^[1]

176.1

138.1

^[1]

Long-term debt

1,753.5

969.8

^[1]

16.0

7.2

^[1]

1,945.6

1,115.1

^[1]

General partner

^[1]

14.9

Accumulated other comprehensive income

131.1

516.8

^[1]

Noncontrolling interest

1,200.6

2,194.1

^[1]

0.4

1.2

^[1]

Net parent investment

^[1]

(836.0)

1,332.1

1,876.1

^[1]

3,277.7

2,991.2

^[1]

Class A Shares

Common Unitholders - Public

$ 131.1

Common Unitholders - Affiliate

^[1]

357.1

Subordinated Unitholders - Affiliate

^[1]

39.5

Statement Of Income And Comprehensive Income [Abstract]

^[1]

$ 105.3

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.
[2]	Represents components of deferred tax assets and liabilities for Hess Midstream LP.

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

^[1]

Dec. 31, 2017

Changes in fair value of cash flow hedges

$ 317.7

$ 325.5

$ 242.0

^[1]

Other comprehensive income

^[1]

3.3

Effect of hedge (gains) losses reclassified to income

(0.8)

(0.4)

(1.7)

^[1]

Total other comprehensive income

(0.8)

(0.4)

1.6

^[1]

Comprehensive income

316.9

325.1

243.6

^[1]

Less: Comprehensive income (loss) attributable to net parent investment

(55.6)

(47.2)

27.0

^[1]

Less: Comprehensive income (loss) attributable to noncontrolling interest

302.6

301.5

175.4

^[1]

Comprehensive income attributable to Hess Midstream LP

$ 69.9

$ 70.8

$ 41.2

^[1]

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Accrued Liabilities - Schedule of Accrued Liabilities (Detail) - USD ($)
$ in Millions

Dec. 31, 2019

Dec. 31, 2018

Accrued Liabilities Current [Abstract]

Accrued capital expenditures

$ 34.7

$ 52.4

Accrued interest

18.7

16.9

Other accruals

35.3

16.3

Total

$ 88.7

$ 85.6

^[1]

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Income Taxes - Summary of Difference between the Effective Income Tax Rate and U.S. Statutory Rate (Detail)

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Effective Income Tax Rate Continuing Operations Tax Rate Reconciliation [Abstract]

U.S. statutory rate

21.00%

^[1]

21.00%

^[2]

35.00%

^[2]

Non-taxable income from pre-Restructuring period

(21.40%)

^[1]

(20.60%)

^[2]

(37.60%)

^[2]

Change in enacted tax laws

^[2]

(1.70%)

Noncontrolling interest in partnership

^[1]

0.40%

Valuation allowance

^[2]

(0.40%)

4.30%

[1]	Represents effective income tax rate reconciliation for Hess Midstream LP.
[2]	Represents effective income tax rate reconciliation for the pre-Restructuring period, inclusive of stand-alone income tax provision for Hess Water Services.

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Adjustments to reconcile net income to net cash provided by (used in) operating activities:

$ 317.7

$ 325.5

^[1]

$ 242.0

^[1]

(Gain) loss on sale of property, plant and equipment

142.5

126.9

^[1]

116.5

^[1]

^[1]

(0.6)

(4.7)

(Gain) loss on interest rate swaps

(0.8)

(0.4)

^[1]

(1.7)

^[1]

(Income) loss from equity investments

(3.4)

(Increase) decrease in capitalized interest

(4.1)

Equity-based compensation expense

5.1

5.0

^[1]

3.8

^[1]

1.5

0.9

^[1]

0.2

^[1]

Deferred income tax expense (benefit)

(0.1)

(19.5)

(6.3)

^[1]

(16.9)

^[1]

(1.4)

1.9

^[1]

1.2

^[1]

11.5

4.0

^[1]

(16.7)

^[1]

3.7

(6.4)

^[1]

7.5

^[1]

18.6

17.3

^[1]

3.2

^[1]

Net cash provided by (used in) operating activities

(0.6)

(0.9)

^[1]

2.1

^[1]

470.7

466.9

^[1]

336.5

^[1]

Payments for equity investments

Acquisitions

(89.2)

(33.0)

(67.3)

^[1]

Proceeds from sale of property, plant and equipment

^[1]

1.6

12.8

Net cash provided by (used in) investing activities

(306.4)

(241.9)

^[1]

(144.2)

^[1]

(497.5)

(307.6)

^[1]

(131.4)

^[1]

Proceeds from (repayments of) bank borrowings - revolver

32.0

(153.0)

^[1]

Borrowings

210.0

Repayments

(7.5)

(2.5)

^[1]

(385.0)

^[1]

Proceeds from issuance of senior notes

550.0

800.0

^[1]

(20.4)

(1.0)

^[1]

(22.9)

^[1]

^[1]

365.5

Distributions to HESM limited partners

(349.5)

Cash offering costs

^[1]

(2.1)

(85.4)

(74.1)

^[1]

(31.7)

^[1]

Cash consideration paid related to Restructuring

(601.8)

Net cash provided by (used in) financing activities

^[1]

(6.1)

27.6

(79.2)

(405.7)

^[1]

148.9

^[1]

(106.0)

(246.4)

^[1]

354.0

^[1]

^[1]

109.3

355.7

1.7

Supplemental disclosure of non-cash investing and financing activities:

3.3

109.3

^[1]

355.7

^[1]

(Increase) decrease in accrued capital expenditures and related liabilities

(10.7)

(29.4)

^[1]

25.9

^[1]

Recognition of deferred tax asset

49.7

Removal of historical capitalized offering costs

^[1]

8.6

Hess and GIP

Distributions to Hess and GIP

^[1]

(349.5)

^[1]

$ (322.0)

$ (100.0)

Hess

Acquisitions

(68.9)

Capital distribution to Hess associated with acquisitions

$ (156.1)

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Segments - Additional Information (Detail)	12 Months Ended
Segments - Additional Information (Detail)	Dec. 31, 2019 Segment Railcar mi	Dec. 31, 2018 Railcar	Jan. 25, 2018	Jan. 24, 2018
Segment Reporting Information [Line Items]
Number of reportable segments \| Segment	3
Number of crude oil rail cars	550
McKenzie County
Segment Reporting Information [Line Items]
Crude oil pipeline length \| mi	6
Minimum
Segment Reporting Information [Line Items]
Number of crude oil rail cars, operate as unit trains		100
Maximum
Segment Reporting Information [Line Items]
Number of crude oil rail cars, operate as unit trains		110
LM4
Segment Reporting Information [Line Items]
Percentage of ownership in joint venture			50.00%	50.00%

Related Party transactions - Revenue from Contracts with Customers on Disaggregated Basis (Detail) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

$ 847.6

$ 712.0

^[1]

$ 579.5

^[1]

0.7

^[1]

Oil and Gas Gathering Services

$ 253.5

$ 214.9

$ 190.3

$ 189.6

$ 185.9

$ 183.8

$ 176.5

$ 166.5

848.3

712.7

^[1]

579.5

^[1]

Water Gathering and Disposal Services

345.6

324.9

271.6

Processing and Storage Services

77.3

50.3

13.9

Terminaling and Export Services

294.7

251.4

227.3

Debt and Interest Expense

$ 130.0

$ 85.4

$ 66.7

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Debt and Interest Expense

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Note 7. Debt and Interest Expense

Total long-term debt is as follows:

	December 31, 2019			December 31, 2018
(in millions)
Fixed-rate senior notes:
5.625% due 2026	$	800.0		$	800.0
5.125% due 2028		550.0			-
Total fixed-rate senior notes		1,350.0			800.0
Term Loan A facility		400.0			197.5
Revolving credit facility		32.0			-
Total Borrowings		1,782.0			997.5
Unamortized deferred financing costs and discounts		(28.5	)		(16.4	)
Total debt		1,753.5			981.1
Less: current maturities of long-term debt		-			11.3
Total long-term debt	$	1,753.5		$	969.8

As of December 31, 2019, the maturity profile of total debt, excluding deferred financing costs and discounts, is as follows:

(in millions)	Total		2020		2021		2022		2023		2024		2025 and thereafter
Fixed-rate senior notes	$	1,350.0	$	-	$	-	$	-	$	-	$	-	$	1,350.0
Term Loan facility		400.0		-		10.0		20.0		30.0		340.0		-
Revolving credit facility		32.0		-		-		-		-		32.0		-
Total debt (excluding interest)	$	1,782.0	$	-	$	10.0	$	20.0	$	30.0	$	372.0	$	1,350.0

Fixed‑Rate Senior Notes

In November 2017, HIP issued $800.0 million of 5.625% fixed‑rate senior notes due 2026 to qualified institutional investors. In December 2019, in connection with the Restructuring, the Partnership, Hess Midstream Operations LP, a consolidated subsidiary of the Company, assumed the $800.0 million of outstanding HIP senior notes in a par-for-par exchange for newly issued 5.625% senior notes due 2026 of the Partnership and paid approximately $2.0 million of exchange consent fees. The notes are guaranteed by certain subsidiaries of the Partnership. Interest is payable semi‑annually on February 15 and August 15.

In December 2019, the Partnership issued $550.0 million of 5.125% fixed‑rate senior notes due 2028 to qualified institutional investors. The notes are guaranteed by certain subsidiaries of the Partnership. Interest is payable semi‑annually on June 15 and December 15. The Partnership used the net proceeds to finance the acquisition of HIP, including to repay borrowings under HIP’s credit facilities, and pay related fees and expenses.

Each of the indentures for the 2026 and 2028 senior notes contains customary covenants that restrict our ability and the ability of our restricted subsidiaries to (i) declare or pay any dividend or make any other restricted payments; (ii) transfer or sell assets or subsidiary stock; (iii) incur additional debt; or (iv) make restricted investments, unless, at the time of and immediately after giving pro forma effect to such restricted payments and any related incurrence of indebtedness or other transactions, no default has occurred and is continuing or would occur as a consequence of such restricted payment and if the leverage ratio does not exceed 4.25 to 1.00. As of December 31, 2019, we were in compliance with all debt covenants under the indentures.

In addition, the covenants included in the indentures governing the senior notes contain provisions that allow the Company to satisfy the Partnership’s reporting obligations under the indenture, as long as any such financial information of the Company contains information reasonably sufficient to identify the material differences, if any, between the financial information of the Company, on the one hand, and the Partnership and its subsidiaries on a stand-alone basis, on the other hand and the Company does not directly own capital stock of any person other than the Partnership and its subsidiaries, or material business operations that would not be consolidated with the financial results of the Partnership and its subsidiaries. The Company is a holding company and has no independent assets or operations. Other than the interest in the Partnership and the effect of federal and state income taxes that are recognized at the Company level, there are no material differences between the consolidated financial statements of the Partnership and the consolidated financial statements of the Company.

Credit Facilities

In December 2019, in connection with the Restructuring, both HIP and the Partnership retired their existing senior secured revolving credit facilities, HIP retired its senior secured Term Loan A facility and the Partnership entered into new senior secured credit facilities (the “Credit Facilities”) consisting of a $1,000.0 million 5-year revolving credit facility and a fully drawn $400.0 million 5-year Term Loan A facility, receiving cash of $210.0 million at closing. Facility fees accrue on the total capacity of the revolving credit facility. Borrowings under the 5-year revolving credit facility will generally bear interest at LIBOR plus the applicable margin ranging from 1.275% to 2.000%, while the applicable margin for the 5-year syndicated revolving credit facility ranges from 1.275% to 2.000%. Pricing levels for the facility fee and interest-rate margins are based on the Partnership’s ratio of total debt to EBITDA (as defined in the Credit Facilities). If the Partnership obtains an investment grade credit rating, the pricing levels will be based on the Partnership’s credit ratings in effect from time to time. At December 31, 2019, borrowings of $32 million were drawn under the Partnership’s revolving credit facility, and borrowings of $400 million, excluding deferred issuance costs, were drawn under the Partnership’s Term Loan A facility.

The Credit Facilities can be used for borrowings and letters of credit for general corporate purposes. The Credit Facilities are guaranteed by each direct and indirect wholly owned material domestic subsidiary of the Partnership, and are secured by first priority perfected liens on substantially all of the presently owned and after-acquired assets of the Partnership and its direct and indirect wholly owned material domestic subsidiaries, including equity interests directly owned by such entities, subject to certain customary exclusions. The Credit Facilities contain representations and warranties, affirmative and negative covenants and events of default that the Partnership considers to be customary for an agreement of this type, including a covenant that requires the Partnership to maintain a ratio of total debt to EBITDA (as defined in the Credit Facilities) for the prior four fiscal quarters of not greater than 5.00 to 1.00 as of the last day of each fiscal quarter (5.50 to 1.00 during the specified period following certain acquisitions) and, prior to the Partnership obtaining an investment grade credit rating, a ratio of secured debt to EBITDA for the prior four fiscal quarters of not greater than 4.00 to 1.00 as of the last day of each fiscal quarter. As of December 31, 2019, the Partnership was in compliance with these financial covenants.

At December 31, 2018, HIP had $800 million of senior secured syndicated credit facilities maturing in 2022, consisting of a $600 million 5-year revolving credit facility and a drawn $200 million 5-year Term Loan A facility. In addition, the Partnership had a $300.0 million 4-year senior secured revolving credit facility maturing in 2021. In connection with the Restructuring, the Partnership entered into new Credit Facilities, as described above. The proceeds from the new Credit Facilities were used to finance the acquisition of HIP, including to repay borrowings under HIP’s credit facilities, and pay related fees and expenses.

Fair Value Measurement

At December 31, 2019, our total long-term debt had a carrying value of $1,753.5 million and had a fair value of approximately $1,820.1 million, based on Level 2 inputs in the fair value measurement hierarchy. The carrying value of the amounts under the Term Loan A facility and revolving credit facility at December 31, 2019, approximated their fair value. Any changes in interest rates do not impact cash outflows associated with fixed rate interest payments or settlement of debt principal, unless a debt instrument is repurchased prior to maturity.

Interest Paid

The total amount of interest paid on all credit facilities, including facility fees, during the years ended December 31, 2019, 2018 and 2017 was $60.8 million, $42.7 million and $18.8 million, respectively.

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Estimated remediation liabilities included in accrued liabilities	$ 700,000	$ 600,000
Estimated remediation liabilities included in other noncurrent liabilities	2,100,000	2,000,000
Accrued liabilities for legal contingencies	0	$ 0
Discounted lease amount recognized	$ 600,000
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent
Unconditional purchase obligation, due in next fiscal year	$ 65,000,000
Unconditional purchase obligation, due thereafter	$ 0

Debt and Interest Expense - Summary of Total Long-term Debt (Detail) - USD ($)
$ in Millions

Dec. 31, 2019

Dec. 31, 2018

Unamortized deferred financing costs and discounts

$ 1,782.0

$ 997.5

(28.5)

(16.4)

Total debt

1,753.5

981.1

Less: current maturities of long-term debt

^[1]

11.3

Total long-term debt

1,753.5

969.8

^[1]

Term Loan A Facility

Revolving Credit Facility

400.0

197.5

32.0

Fixed-Rate Senior Notes

Fixed-Rate Senior Notes | 5.625% Fixed Rate Senior Notes due 2026

1,350.0

800.0

Fixed-Rate Senior Notes | 5.125% Fixed Rate Senior Notes due 2028

800.0

$ 800.0

$ 550.0

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Segments - Total Assets for Reportable Segments (Detail) - USD ($)
$ in Millions

Dec. 31, 2019

Dec. 31, 2018

$ 3,277.7

$ 2,991.2

^[1]

Interest and Other

Gathering Opco | Operating Segments

67.0

118.4

Processing and Storage | Operating Segments

1,844.9

1,544.0

Terminaling and Export | Operating Segments

^[2]

1,055.1

1,008.6

$ 310.7

$ 320.2

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.
[2]	Includes $107.8 million of investment in equity investees.

Subsequent Events

12 Months Ended

Dec. 31, 2019

Subsequent Events [Abstract]

Subsequent Events

Note 16. Subsequent Events

On January 27, 2020 the board of directors of our general partner declared a quarterly cash distribution of $0.4258 per Class A Share for the quarter ended December 31, 2019, an increase of 15% compared with the quarter ended December 31, 2018. The distribution was paid on February 14, 2020 to shareholders of record as of the close of business on February 6, 2020.

Acquisitions - Consolidated Balance Sheet (Parenthetical) (Detail) - shares	Dec. 31, 2019	Dec. 31, 2018
Common Unitholders - Public
Business Acquisition [Line Items]
Common and subordinated units issued	0	17,014,377
Common and subordinated units outstanding	0	17,014,377
Common Unitholders - Affiliate
Business Acquisition [Line Items]
Common and subordinated units issued	0	10,282,654
Common and subordinated units outstanding	0	10,282,654
Subordinated Unitholders - Affiliate
Business Acquisition [Line Items]
Common and subordinated units issued	0	27,279,654
Common and subordinated units outstanding	0	27,279,654

Commitments and Contingencies - Schedule of Future Undiscounted Minimum Lease Payments (Detail) $ in Millions	Dec. 31, 2019 USD ($)
Commitments And Contingencies Disclosure [Abstract]
Total	$ 1.1
2020	0.2
2021	0.1
2022	0.1
2023	0.1
2024	0.1
2025 and thereafter	$ 0.5

Income Taxes

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Income Taxes

Note 15. Income Taxes

Prior to the Restructuring on December 16, 2019, the Partnership was not a separate taxable entity for U.S. federal and state income tax purposes; therefore, we did not recognize income tax expense or benefit in those periods. Each partner was subject to income taxes on its share of the Partnership’s earnings. As a result of the Restructuring, the Company holds a 6.32% controlling interest in the Partnership and is subject to federal and state income taxes on its share of the Partnership’s earnings. Although the Company is a Delaware limited partnership, it is subject to corporate income tax, because of our election to be treated as a corporation for U.S. federal and state income tax purposes in connection with the Restructuring.

In connection with the Restructuring, we became a partial owner of the Partnership and recognize income tax expense or benefit on our allocable share of the Partnership’s income or loss subsequent to the Restructuring. For the period from December 16, 2019 through December 31, 2019, we recognized a deferred tax benefit of $0.1 million and we did not have any current income tax expense. As part of the Restructuring, we recognized a deferred tax asset of $49.8 million for the temporary differences related to our investment in the Partnership. The effect of recognizing the deferred tax asset was included in Class A shareholders’ equity balance in the accompanying consolidated statement of changes in partners’ capital due to the Restructuring being characterized as a transaction among or with shareholders.

On March 1, 2019, HIP acquired Hess Water Services (see Note 3, Acquisitions). For the periods prior to March 1, 2019, Hess Water Services was included in the consolidated income tax returns of Hess. The provision for Hess Water Services’ income taxes and income tax assets and liabilities were determined as if it were a standalone taxpayer for all periods presented and is included in our retrospectively recast financial statements.

The difference between the effective income tax rate and the U.S. statutory rate is reconciled below:

	Year Ended December 31,
	2019 ⁽¹⁾				2018 ⁽²⁾				2017 ⁽²⁾
U.S. statutory rate		21.0		%		21.0		%		35.0		%
Non-taxable income from pre-Restructuring period		(21.4	)			(20.6	)			(37.6	)
Change in enacted tax laws		-				-				(1.7	)
Noncontrolling interest in partnership		0.4				-				-
Valuation allowance		-				(0.4	)			4.3
Effective rate		-		%		-		%		-		%
(1) Represents effective income tax rate reconciliation for Hess Midstream LP.
(2) Represents effective income tax rate reconciliation for the pre-Restructuring period, inclusive of stand-alone income tax provision for Hess Water Services.

The components of deferred tax assets and liabilities are as follows:

	December 31,
	2019⁽¹⁾		2018⁽²⁾
(in millions)
Deferred tax liabilities
Investments	$	0.2	$	-
Property, plant and equipment		-		10.7
Total deferred tax liabilities		0.2		10.7
Deferred tax assets
Investments		49.8		-
Net operating loss carryforwards		0.2		16.9
Asset retirement obligations		-		0.2
Total deferred tax assets		50.0		17.1
Valuation allowance		-		(6.4	)
Total deferred tax assets, net of valuation allowance		50.0		10.7
Net deferred tax assets (liabilities)	$	49.8	$	-
(1) Represents components of deferred tax assets and liabilities for Hess Midstream LP.
(2) Represents components of deferred tax assets and liabilities for Hess Water Services.

The 2019 deferred tax position presented in the schedule above primarily represents our deferred tax asset for temporary differences related to our investment in the Partnership. The 2018 deferred tax position presented in the table above represents the results of Hess Water Services as if it were a stand-alone entity for the period. The related activity was included in Hess’s federal and state income tax returns and the related attributes are not available on income tax filings of HIP and its partners. Hess Water Services was in a three-year cumulative loss position at the end of 2018, which constitutes objective negative evidence to which accounting standards require we assign significant weight relative to subjective estimates, such as income projections. As a result, a full valuation allowance was maintained against the net deferred tax assets of Hess Water Services at December 31, 2018.

We have no unrecognized tax benefits or interest and penalties related to tax liabilities recorded in the financial statements. For the years presented, we earned all net income before taxes in the United States. We file income tax returns in the U.S. and various states. We are not subject to examinations by income tax authorities for years prior to 2019.

Related Party Transactions - Summary of Classification of Charges between Operating and Maintenance Expenses and General and Administrative Expenses (Detail) - Hess - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Operating and maintenance expenses	$ 53.1	$ 50.2	$ 57.3
General and administrative expenses	15.5	7.8	6.7
Total	$ 68.6	$ 58.0	$ 64.0

Debt and Interest Expense - Summary of Maturity Profile of Total Debt, Excluding Deferred Financing Costs and Discounts (Detail) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total debt (excluding interest)	$ 1,782.0	$ 997.5
2021	10.0
2022	20.0
2023	30.0
2024	372.0
2025 and thereafter	1,350.0
Fixed-Rate Senior Notes
Debt Instrument [Line Items]
Total debt (excluding interest)	1,350.0	$ 800.0
2025 and thereafter	1,350.0
Term Loan Facility
Debt Instrument [Line Items]
Total debt (excluding interest)	400.0
2021	10.0
2022	20.0
2023	30.0
2024	340.0
Revolving Credit Facility
Debt Instrument [Line Items]
Total debt (excluding interest)	32.0
2024	$ 32.0

Debt and Interest Expense - Additional Information (Detail) - USD ($)	1 Months Ended		12 Months Ended
	Dec. 31, 2019	Nov. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt covenant, leverage ratio			550.00%
Ratio of debt to EBITDA			500.00%
Secured leverage ratio - Maximum			400.00%
Debt instrument covenant, description			The Credit Facilities contain representations and warranties, affirmative and negative covenants and events of default that the Partnership considers to be customary for an agreement of this type, including a covenant that requires the Partnership to maintain a ratio of total debt to EBITDA (as defined in the Credit Facilities) for the prior four fiscal quarters of not greater than 5.00 to 1.00 as of the last day of each fiscal quarter (5.50 to 1.00 during the specified period following certain acquisitions) and, prior to the Partnership obtaining an investment grade credit rating, a ratio of secured debt to EBITDA for the prior four fiscal quarters of not greater than 4.00 to 1.00 as of the last day of each fiscal quarter.
Total long-term debt	$ 1,753,500,000		$ 1,753,500,000	$ 981,100,000
Line of credit interest paid on credit facilities, including facility fees			60,800,000	$ 42,700,000	$ 18,800,000
Carrying Value
Debt Instrument [Line Items]
Total long-term debt	1,753,500,000		1,753,500,000
Level 2
Debt Instrument [Line Items]
Total long-term debt fair value	$ 1,820,100,000		1,820,100,000
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility - Term	5 years
Maximum borrowing capacity	$ 1,000,000,000		1,000,000,000
Borrowings	$ 32,000,000		32,000,000
Revolving Credit Facility \| Hess Infrastructure Partners LP
Debt Instrument [Line Items]
Credit facility - Term				5 years
Maximum borrowing capacity				$ 600,000,000
Revolving Credit Facility \| Minimum
Debt Instrument [Line Items]
Interest rate applicable margin	1.275%
Revolving Credit Facility \| Maximum
Debt Instrument [Line Items]
Interest rate applicable margin	2.00%
Term Loan A Facility
Debt Instrument [Line Items]
Credit facility - Term	5 years
Maximum borrowing capacity	$ 400,000,000		400,000,000
Cash received	210,000,000
Borrowings	$ 400,000,000		$ 400,000,000
Term Loan A Facility \| Hess Infrastructure Partners LP
Debt Instrument [Line Items]
Credit facility - Term				5 years
Maximum borrowing capacity				$ 200,000,000
Syndicated Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility - Term	5 years
Syndicated Revolving Credit Facility \| Minimum
Debt Instrument [Line Items]
Interest rate applicable margin	1.275%
Syndicated Revolving Credit Facility \| Maximum
Debt Instrument [Line Items]
Interest rate applicable margin	2.00%
Senior Secured Syndicated Credit Facilities \| Hess Infrastructure Partners LP
Debt Instrument [Line Items]
Debt instrument due year				2022
Maximum borrowing capacity				$ 800,000,000
Senior Secured Revolving Credit Facility \| Hess Infrastructure Partners LP
Debt Instrument [Line Items]
Debt instrument due year				2021
Credit facility - Term				4 years
Maximum borrowing capacity				$ 300,000,000
Fixed-Rate Senior Notes
Debt Instrument [Line Items]
Debt covenant, leverage ratio			425.00%
5.625% Fixed Rate Senior Notes due 2026
Debt Instrument [Line Items]
Debt instrument interest rate	5.625%		5.625%
Debt instrument due year			2026
5.625% Fixed Rate Senior Notes due 2026 \| Hess Infrastructure Partners LP
Debt Instrument [Line Items]
Fixed-rate senior notes		$ 800,000,000
5.625% Fixed Rate Senior Notes due 2026 \| Hess Midstream Operations LP
Debt Instrument [Line Items]
Fixed-rate senior notes	$ 800,000,000		$ 800,000,000
5.625% Fixed Rate Senior Notes due 2026 \| Fixed-Rate Senior Notes
Debt Instrument [Line Items]
Debt instrument due year			2026
5.625% Fixed Rate Senior Notes due 2026 \| Fixed-Rate Senior Notes \| Hess Infrastructure Partners LP
Debt Instrument [Line Items]
Debt instrument interest rate		5.625%
Debt instrument due year		2026
5.625% Fixed Rate Senior Notes due 2026 \| Fixed-Rate Senior Notes \| Hess Midstream Operations LP
Debt Instrument [Line Items]
Debt instrument interest rate	5.625%		5.625%
Debt instrument due year	2026
Exchange consent fee	$ 2,000,000
Frequency of periodic interest payment			semiannually
Interest payment terms			Interest is payable semiannually on February 15 and August 15
5.125% Fixed Rate Senior Notes due 2028
Debt Instrument [Line Items]
Fixed-rate senior notes	$ 550,000,000		$ 550,000,000
Debt instrument interest rate	5.125%		5.125%
Debt instrument due year			2028
5.125% Fixed Rate Senior Notes due 2028 \| Fixed-Rate Senior Notes
Debt Instrument [Line Items]
Debt instrument interest rate	5.125%		5.125%
Debt instrument due year	2028		2028
Frequency of periodic interest payment			semiannually
Interest payment terms			Interest is payable semiannually on June 15 and December 15.

Acquisitions - Consolidated Statements of Cash Flows (Detail) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Adjustments to reconcile net income to net cash provided by (used in) operating activities:

$ 75.1

$ 87.4

$ 74.4

$ 80.8

$ 78.9

$ 86.1

$ 82.8

$ 77.7

$ 317.7

$ 325.5

^[1]

$ 242.0

^[1]

(Gain) loss on sale of property, plant and equipment

142.5

126.9

^[1]

116.5

^[1]

^[1]

(0.6)

(4.7)

(Gain) loss on interest rate swaps

(0.8)

(0.4)

^[1]

(1.7)

^[1]

5.1

5.0

^[1]

3.8

^[1]

Unit-based compensation

1.5

0.9

^[1]

0.2

^[1]

(19.5)

(6.3)

^[1]

(16.9)

^[1]

(1.4)

1.9

^[1]

1.2

^[1]

11.5

4.0

^[1]

(16.7)

^[1]

3.7

(6.4)

^[1]

7.5

^[1]

18.6

17.3

^[1]

3.2

^[1]

Net cash provided by (used in) operating activities

(0.6)

(0.9)

^[1]

2.1

^[1]

470.7

466.9

^[1]

336.5

^[1]

Payments for equity investments

(33.0)

(67.3)

^[1]

Proceeds from sale of property, plant and equipment

^[1]

1.6

12.8

Net cash provided by (used in) investing activities

(306.4)

(241.9)

^[1]

(144.2)

^[1]

(497.5)

(307.6)

^[1]

(131.4)

^[1]

Proceeds from (repayments of) bank borrowings - revolver

32.0

(153.0)

^[1]

Repayments of bank borrowings - term loan

(2.5)

(385.0)

Proceeds from issuance of fixed-rate senior notes

550.0

800.0

^[1]

(20.4)

(1.0)

^[1]

(22.9)

^[1]

^[1]

365.5

Distributions to Hess and GIP

(349.5)

Cash offering costs

^[1]

(2.1)

(322.0)

(100.0)

Distributions to HESM limited partners

(85.4)

(74.1)

^[1]

(31.7)

^[1]

Net cash provided by (used in) financing activities

^[1]

(6.1)

27.6

(79.2)

(405.7)

^[1]

148.9

^[1]

(106.0)

(246.4)

^[1]

354.0

^[1]

^[1]

109.3

355.7

109.3

355.7

1.7

Partnership as Previously Reported

$ 3.3

109.3

^[1]

3.3

109.3

^[1]

355.7

^[1]

Adjustments to reconcile net income to net cash provided by (used in) operating activities:

372.3

284.8

123.0

113.1

1.0

0.6

Unit-based compensation

0.9

0.2

(3.2)

(15.2)

1.6

(1.7)

3.1

(16.6)

(6.7)

34.4

2.7

(1.9)

Net cash provided by (used in) operating activities

(1.1)

2.2

493.6

399.9

Payments for equity investments

(67.3)

Net cash provided by (used in) investing activities

(235.6)

(136.4)

(302.9)

(136.4)

Cash distributions to parent prior to the IPO on April 10, 2017

(95.3)

Cash contributions from parent prior to the IPO on April 10, 2017

67.1

(3.9)

365.5

(349.5)

Cash offering costs

(2.1)

Contributions from noncontrolling interests

(199.2)

(244.6)

57.3

78.5

Distributions to HESM limited partners

(74.1)

(31.7)

Distributions to HESM general partner

(1.6)

(0.6)

Net cash provided by (used in) financing activities

(217.6)

(216.6)

(26.9)

46.9

20.3

47.2

20.3

47.2

0.3

Restatement Adjustment | Acquisition of HIP

20.3

47.2

Adjustments to reconcile net income to net cash provided by (used in) operating activities:

(46.8)

(42.8)

(Gain) loss on sale of property, plant and equipment

3.9

3.4

(0.6)

(4.7)

(Gain) loss on interest rate swaps

(0.4)

(1.7)

4.0

3.2

(3.1)

(1.7)

0.3

2.9

0.9

(0.1)

0.3

(26.9)

14.6

5.1

Net cash provided by (used in) operating activities

0.2

(0.1)

(26.7)

(63.4)

Proceeds from sale of property, plant and equipment

1.6

12.8

Net cash provided by (used in) investing activities

(6.3)

(7.8)

(4.7)

5.0

Cash distributions to parent prior to the IPO on April 10, 2017

95.3

Cash contributions from parent prior to the IPO on April 10, 2017

(67.1)

Proceeds from (repayments of) bank borrowings - revolver

(153.0)

Repayments of bank borrowings - term loan

(2.5)

(385.0)

Proceeds from issuance of fixed-rate senior notes

800.0

Distributions to Hess and GIP

(1.0)

(19.0)

(322.0)

(100.0)

Contributions from noncontrolling interests

199.2

244.6

(57.3)

(78.5)

Distributions to HESM general partner

1.6

0.6

Net cash provided by (used in) financing activities

(6.1)

27.6

(188.1)

365.5

(219.5)

307.1

$ 89.0

$ 308.5

$ 89.0

308.5

1.4

Percentage of ownership interest

$ 89.0

$ 308.5

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Earnings per Share/Limited Partner Unit - Additional Information (Detail)	Dec. 16, 2019
Hess and GIP \| Common Class A
Limited Partners Capital Account [Line Items]
Conversion of Class B units and Class B shares into Class A shares	100.00%

Income Taxes - Additional Information (Detail) - USD ($)

12 Months Ended

Dec. 31, 2019

Dec. 16, 2019

Dec. 31, 2019

Income Tax Disclosure [Abstract]

6.32%

Deferred tax benefit

$ 100,000

Current income tax expense

Deferred tax asset

^[1]

49,800,000

Unrecognized tax benefits

$ 0

[1]	Represents components of deferred tax assets and liabilities for Hess Midstream LP.

Earnings per Share/Limited Partner Unit

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Earnings per Share/Limited Partner Unit

Note 10. Earnings per Share/Limited Partner Unit

Earnings per limited partner unit prior to the Restructuring on December 16, 2019, were computed by dividing the respective limited partners’ interest in net income attributable to Hess Midstream Partners LP by the weighted average number of common and subordinated units outstanding. Because we had more than one class of participating securities, we used the two‑class method when calculating earnings per limited partner unit. The classes of participating securities included common units, subordinated units, general partner interest and incentive distribution rights. Our net income includes earnings related to businesses acquired through transactions between entities under common control for periods prior to their acquisition by us. We have allocated these pre-acquisition earnings to Net income attributable to net parent investment.

Subsequent to the Restructuring, we calculate earnings per Class A Share and we do not have any other participating securities. Class B Units of the Partnership together with the equal number of Class B Shares of the Company are convertible to Class A Shares of the Company on a one-for-one basis. In addition, our restricted equity-based awards may have a dilutive effect on our earnings per share. Diluted earnings per Class A Share are calculated using the “treasury stock method” or “if-converted method”, whichever is more dilutive.

		Year Ended December 31,
(in millions, except per share amounts)	2019		2018		2017
Net income	$	317.7	$	325.5	$	242.0
Less: Net income attributable to net parent investment		(55.0)		(46.8)		25.4
Less: Net income attributable to noncontrolling interest		302.6		301.5		175.4
Net income attributable to Hess Midstream LP		70.1		70.8		41.2
Less: General partner's interest in net income prior to the Restructuring		3.4		1.7		0.8
Limited partners' interest in net income	$	66.7	$	69.1	$	40.4
Common unitholders' interest in net income attributable to Hess Midstream LP			$	34.6	$	20.2
Subordinated unitholders' interest in net income attributable to Hess Midstream LP			$	34.5	$	20.2
Net income attributable to Hess Midstream LP per Class A Share/limited partner unit*:
Basic:	$	1.21
Diluted:	$	1.20
Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):
Common			$	1.27	$	0.75
Subordinated			$	1.27	$	0.75
Weighted average Class A Shares outstanding subsequent to the Restructuring (basic and diluted):		18.0
Weighted average limited partner units outstanding prior to the Restructuring
Basic:
Common		27.3		27.3		26.9
Subordinated		27.3		27.3		26.9
Diluted:
Common		27.5		27.4		26.9
Subordinated		27.3		27.3		26.9

*Net income attributable to Hess Midstream LP per Class A Share/limited partner unit was calculated by combining net income per limited partner unit (common and subordinated) for the period prior to the Restructuring on December 16, 2019, and net income per Class A Share for the period subsequent to the Restructuring.

Related Party Transactions - Additional Information (Detail) - USD ($)

12 Months Ended

Jan. 24, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Jan. 25, 2018

Earnings from equity investments

$ 847,600,000

$ 712,000,000

^[1]

$ 579,500,000

^[1]

$ 3,400,000

LM4

Percentage of gas processing plant capacity

16 years

Agreement description

The agreement has a 16-year initial term, after which it is automatically renewed for subsequent one-year terms unless terminated by either party.

50.00%

Percentage of ownership in joint venture

50.00%

Expenses incurred under gas processing agreement

$ 6,300,000

Earnings from equity investments

$ 3,400,000

Credit Concentration Risk | Revenue

Revenues attributable to fee based commercial agreements

100.00%

Hess

Minimum volume shortfall fee payments earned

$ 8,300,000

$ 47,500,000

$ 61,600,000

Expenses incurred under gas processing agreement

53,100,000

50,200,000

57,300,000

Hess | Rail Transportation Costs

Hess | Water Trucking and Disposal Costs

40,200,000

16,800,000

17,000,000

57,700,000

36,500,000

5,100,000

Hess | Electricity Fees

Hess | Credit Concentration Risk | Revenue

$ 32,200,000

$ 27,200,000

$ 24,900,000

Revenues attributable to fee based commercial agreements

100.00%

Hess | Amended and Restated Commercial Agreement

Number of rights to extend the term of agreement

10 years

Agreement description

Each of our commercial agreements with Hess retains its initial 10year term (“Initial Term”) and we have the unilateral right to extend each commercial agreement for one additional 10year term (“Secondary Term”). Initial Term for the water services agreements is 14 years and the Secondary Term is 10 years.

one

Secondary term of agreement

10 years

Hess | Amended and Restated Water Services Agreements

Secondary term of agreement

14 years

10 years

Hess | Amended and Restated Agreement for Certain Gas Gathering Sub-system

Secondary term of agreement

15 years

Agreement description

The amended and restated gas gathering agreement also extends the Initial Term of the gathering agreement with respect to a certain gathering sub-system by 5 years to provide for a 15-year Initial Term and decreases the Secondary Term for that gathering sub-system by 5 years to provide for a 5-year Secondary Term.

5 years

Initial term to extend by period

5 years

Secondary term to reduce by period

5 years

Targa Resources Corp. | LM4

Percentage of ownership in joint venture

50.00%

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Property, Plant and Equipment

12 Months Ended

Dec. 31, 2019

Property Plant And Equipment [Abstract]

Property, Plant and Equipment

Note 5. Property, Plant and Equipment

Property, plant and equipment, at cost, is as follows:

	Estimated useful lives	December 31, 2019			December 31, 2018
(in millions, except for number of years)
Gathering assets
Pipelines	22 years	$	1,352.7		$	1,098.1
Compressors, pumping stations and terminals	22 to 25 years		725.9			558.9
Gas plant assets
Pipelines, pipes and valves	22 to 25 years		460.0			460.0
Equipment	12 to 30 years		428.2			428.2
Buildings	35 years		182.3			182.3
Processing and fractionation facilities	25 years		188.6			185.5
Logistics facilities and railcars	20 to 25 years		385.5			385.8
Storage facilities	20 to 25 years		19.5			19.5
Other	20 to 25 years		13.0			11.4
Construction-in-progress	N/A		149.3			158.5
Total property, plant and equipment, at cost			3,905.0			3,488.2
Accumulated depreciation			(894.9	)		(752.9	)
Property, plant and equipment, net		$	3,010.1		$	2,735.3

Segments

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

Segments

Note 13. Segments

Our operations are located in the United States and are organized into three reportable segments: (i) gathering, (ii) processing and storage and (iii) terminaling and export. Our reportable segments comprise the structure used by our Chief Operating Decision Maker (“CODM”) to make key operating decisions and assess performance. These segments are strategic business units with differing products and services. The accounting policies of the segments are identical to those described in Note 2, Summary of Significant Accounting Policies and Basis of Presentation. Our CODM evaluates the segments’ operating performance based on multiple measures including Adjusted EBITDA, defined as net income (loss) before interest expense, income tax (benefit), depreciation and amortization, and our proportional share of depreciation of our equity affiliates as further adjusted for other non‑cash, non‑recurring items, if applicable.

Gathering. Our gathering segment consists of the following assets:

•

Natural Gas Gathering and Compression. A natural gas gathering and compression system located primarily in McKenzie, Williams and Mountrail Counties, North Dakota connecting Hess and third‑party owned or operated wells to the Tioga Gas Plant, Little Missouri 4 gas processing plant, and third‑party pipeline facilities. The system also includes the Hawkeye Gas Facility, which was placed into service in 2017.

•

Crude Oil Gathering: A crude oil gathering system located primarily in McKenzie, Williams, and Mountrail Counties, North Dakota, connecting Hess and third‑party owned or operated wells to the Ramberg Terminal Facility and the Johnson’s Corner Header System. The system also includes the Hawkeye Oil Facility that was placed into service in 2017.

•

Produced Water Gathering and Disposal. A produced water gathering system and disposal facilities located primarily in Williams and Mountrail Counties, North Dakota.

Processing and Storage. Our processing and storage segment consists of the following assets:

•

Tioga Gas Plant (TGP). A natural gas processing and fractionation plant located in Tioga, North Dakota.

•

Mentor Storage Terminal. A propane storage cavern and rail and truck loading and unloading facility located in Mentor, Minnesota.

•

Equity Investment in LM4 Joint Venture. The Partnership’s 50% equity method investment in LM4 joint venture that owns a natural gas processing plant located in McKenzie County, North Dakota, which was placed in service in the third quarter of 2019.

Terminaling and Export. Our terminaling and export segment consists of the following assets:

•

Ramberg Terminal Facility. A crude oil pipeline and truck receipt terminal located in Williams County, North Dakota that is capable of delivering crude oil into an interconnecting pipeline for transportation to the Tioga Rail Terminal and to multiple third‑party pipelines and storage facilities.

•

Tioga Rail Terminal. A crude oil and NGL rail loading terminal in Tioga, North Dakota that is connected to the Tioga Gas Plant, the Ramberg Terminal Facility and our crude oil gathering system.

•

Crude Oil Rail Cars. A total of 550 crude oil rail cars, constructed to the most recent DOT‑117 safety standards, which we operate as unit trains consisting of approximately 100 to 110 crude oil rail cars.

•

Johnson’s Corner Header System. An approximately six‑mile crude oil pipeline header system located in McKenzie County, North Dakota that receives crude oil by pipeline from Hess and third parties and delivers crude oil to third‑party interstate pipeline systems. The Johnson’s Corner Header System commenced operations in 2017.

The following tables reflect certain financial data for each reportable segment. The acquisition of HIP, which included Hess Water Services caused a change in composition of reportable segments and, as a result, the corresponding items of segment information for earlier periods have been restated.

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated
(in millions)
For the Year Ended December 31, 2019
Revenues and other income	$	422.9	$	295.3	$	130.1	$	-		$	848.3
Net income (loss)		186.0		176.1		54.8		(99.2	)		317.7
Net income (loss) attributable to Hess Midstream LP		34.6		34.6		10.5		(9.6	)		70.1
Depreciation expense		81.6		44.7		16.2		-			142.5
Proportional share of equity affiliates' depreciation		-		2.0		-		-			2.0
Income from equity investments		-		3.4		-		-			3.4
Interest expense, net		-		-		-		62.4			62.4
Income tax expense (benefit)		-		-		-		(0.1	)		(0.1	)
Transaction costs		-		-		-		26.2			26.2
Adjusted EBITDA		267.6		222.8		71.0		(10.7	)		550.7
Capital expenditures*		373.6		42.5		0.2		-			416.3
	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated
(in millions)
For the Year Ended December 31, 2018
Revenues and other income	$	375.2	$	251.4	$	86.1	$	-		$	712.7
Net income (loss)		199.6		148.8		36.1		(59.0	)		325.5
Net income (loss) attributable to Hess Midstream LP		38.4		30.7		7.3		(5.6	)		70.8
Depreciation expense		67.2		43.9		15.8		-			126.9
Interest expense, net		-		-		-		53.3			53.3
Gain on sale of property, plant and equipment		-		-		-		0.6			0.6
Adjusted EBITDA		266.8		192.7		51.9		(6.3	)		505.1
Capital expenditures		257.0		10.0		4.3		-			271.3

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated
(in millions)
For the Year Ended December 31, 2017
Revenues and other income	$	285.5	$	227.3	$	66.7	$	-		$	579.5
Net income (loss)		132.1		123.8		14.4		(28.3	)		242.0
Net income (loss) attributable to Hess Midstream LP		23.3		18.8		2.4		(3.3	)		41.2
Depreciation expense		57.8		43.6		15.1		-			116.5
Interest expense, net		-		-		-		25.8			25.8
Gain on sale of property, plant and equipment		-		-		-		4.7			4.7
Adjusted EBITDA		189.9		167.4		29.5		(7.2	)		379.6
Capital expenditures		77.8		15.9		24.6		-			118.3
*Includes acquisition, expansion and maintenance capital expenditures.

Total assets for reportable segments are as follows:


	December 31, 2019		December 31, 2018
(in millions)
Gathering	$	1,844.9	$	1,544.0
Processing and Storage⁽¹⁾		1,055.1		1,008.6
Terminaling and Export		310.7		320.2
Interest and Other		67.0		118.4
Total assets	$	3,277.7	$	2,991.2

⁽¹⁾	Includes $107.8 million of investment in equity investees.

Accrued Liabilities

12 Months Ended

Dec. 31, 2019

Accrued Liabilities Current [Abstract]

Accrued Liabilities

Note 6. Accrued Liabilities

Accrued liabilities are as follows:

	December 31, 2019		December 31, 2018
(in millions)
Accrued capital expenditures	$	34.7	$	52.4
Accrued interest		18.7		16.9
Other accruals		35.3		16.3
Total	$	88.7	$	85.6

Supplemental Quarterly Financial Information (Unaudited) - Schedule of Supplemental Quarterly Financial Information (Detail) - USD ($)
$ / shares in Units, $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

^[1]

Dec. 31, 2017

^[1]

Quarterly Financial Information [Line Items]

$ 253.5

$ 214.9

$ 190.3

$ 189.6

$ 185.9

$ 183.8

$ 176.5

$ 166.5

$ 848.3

$ 712.7

$ 579.5

90.3

99.3

91.2

95.8

92.1

99.0

96.3

90.8

376.6

378.2

263.1

75.1

87.4

74.4

80.8

78.9

86.1

82.8

77.7

317.7

325.5

242.0

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

$ 16.1

$ 19.1

$ 16.8

$ 18.1

$ 17.2

$ 18.8

$ 17.8

$ 17.0

$ 70.1

$ 70.8

$ 41.2

Common Class A

Net income attributable to Hess Midstream Partners per limited partner unit

$ 0.28

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

$ 0.33

$ 0.29

$ 0.32

$ 0.31

$ 0.34

$ 0.32

$ 0.30

$ 1.27

$ 0.75

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

$ 0.33

$ 0.29

$ 0.32

$ 0.31

$ 0.34

$ 0.32

$ 0.30

$ 1.27

$ 0.75

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Debt and Interest Expense - Summary of Total Long-term Debt (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2019
5.625% Fixed Rate Senior Notes due 2026
Debt Instrument [Line Items]
Debt instrument interest rate	5.625%
Debt instrument due year	2026
5.125% Fixed Rate Senior Notes due 2028
Debt Instrument [Line Items]
Debt instrument interest rate	5.125%
Debt instrument due year	2028

Description of Business - Additional Information (Detail) $ in Millions					12 Months Ended
	Dec. 16, 2019 USD ($) shares	Dec. 15, 2019	Oct. 03, 2019	Apr. 10, 2017 shares	Dec. 31, 2019 Segment shares	Dec. 31, 2018 shares	Jan. 25, 2018 MMcf	Jan. 24, 2018
Description Of Business [Line Items]
Number of operating segments \| Segment					3
Percentage of ownership interest	6.32%
LM4
Description Of Business [Line Items]
Percentage of ownership in joint venture							50.00%	50.00%
Gas processing plant capacity \| MMcf							200
LM4 \| Targa Resources Corp.
Description Of Business [Line Items]
Percentage of ownership in joint venture							50.00%	50.00%
Common Class A
Description Of Business [Line Items]
Common and subordinated units issued					17,960,655	0
Number of units hold in partnership					17,960,655	0
Class B Shares
Description Of Business [Line Items]
Common and subordinated units issued					266,416,928	0
Number of units hold in partnership					266,416,928	0
Hess and GIP
Description Of Business [Line Items]
Stock exchange ratio	100.00%
Hess and GIP \| Common Class A
Description Of Business [Line Items]
Conversion of Class B units and Class B shares into Class A shares	100.00%
Hess and GIP
Description Of Business [Line Items]
Percentage of noncontrolling economic interest	93.68%				93.68%
Percentage of indirect ownership interest	100.00%
Cash consideration \| $	$ 601.8
Hess and GIP \| Common Class A
Description Of Business [Line Items]
Number of units hold in partnership	898,000
Hess and GIP \| Class B Shares
Description Of Business [Line Items]
Number of units hold in partnership	266,416,928
Common Units \| Hess Infrastructure Partners LP
Description Of Business [Line Items]
Common and subordinated units issued				10,282,654
Subordinated Units \| Hess Infrastructure Partners LP
Description Of Business [Line Items]
Common and subordinated units issued				27,279,654
Hess North Dakota Pipelines Operations Limited Partnership
Description Of Business [Line Items]
Percentage of noncontrolling economic interest			80.00%
Hess T G P Operations Limited Partnership
Description Of Business [Line Items]
Percentage of noncontrolling economic interest			80.00%
Hess North Dakota Export Logistics Operations Limited Partnership
Description Of Business [Line Items]
Percentage of noncontrolling economic interest			80.00%
Hess Water Services Holdings Limited Liability Company
Description Of Business [Line Items]
Percentage of ownership interest	100.00%		100.00%
Hess Midstream Partners GP Limited Partner
Description Of Business [Line Items]
Percentage of ownership interest			100.00%
Hess Infrastructure Partners LP \| IPO
Description Of Business [Line Items]
Percentage of ownership interest				20.00%
Hess Mentor Storage Holdings Limited Liability Company \| IPO
Description Of Business [Line Items]
Percentage of ownership interest				100.00%
Hess Infrastructure Partners Limited Partnership Joint Interest Assets
Description Of Business [Line Items]
Percentage of ownership interest	80.00%
Hess Water Services and Hess Midstream Partners GP Limited Partner
Description Of Business [Line Items]
Percentage of ownership interest	100.00%	100.00%
Public Limited Partners
Description Of Business [Line Items]
Percentage of ownership interest	95.00%
Percentage of indirect ownership interest	6.00%
Percentage of voting interest	6.00%
Hess and GIP
Description Of Business [Line Items]
Percentage of ownership interest	5.00%
Percentage of indirect ownership interest	94.00%
Percentage of voting interest	94.00%

Earnings per Share/Limited Partner Unit (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Schedule of Earnings per Share Limited Partner Unit

		Year Ended December 31,
(in millions, except per share amounts)	2019		2018		2017
Net income	$	317.7	$	325.5	$	242.0
Less: Net income attributable to net parent investment		(55.0)		(46.8)		25.4
Less: Net income attributable to noncontrolling interest		302.6		301.5		175.4
Net income attributable to Hess Midstream LP		70.1		70.8		41.2
Less: General partner's interest in net income prior to the Restructuring		3.4		1.7		0.8
Limited partners' interest in net income	$	66.7	$	69.1	$	40.4
Common unitholders' interest in net income attributable to Hess Midstream LP			$	34.6	$	20.2
Subordinated unitholders' interest in net income attributable to Hess Midstream LP			$	34.5	$	20.2
Net income attributable to Hess Midstream LP per Class A Share/limited partner unit*:
Basic:	$	1.21
Diluted:	$	1.20
Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):
Common			$	1.27	$	0.75
Subordinated			$	1.27	$	0.75
Weighted average Class A Shares outstanding subsequent to the Restructuring (basic and diluted):		18.0
Weighted average limited partner units outstanding prior to the Restructuring
Basic:
Common		27.3		27.3		26.9
Subordinated		27.3		27.3		26.9
Diluted:
Common		27.5		27.4		26.9
Subordinated		27.3		27.3		26.9

Acquisitions - Additional Information (Details) - USD ($) $ in Millions						12 Months Ended
	Dec. 16, 2019	Dec. 15, 2019	Oct. 03, 2019	Mar. 22, 2019	Mar. 01, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Cash paid for business acquisition, net of cash acquired						$ 89.2
Restructuring costs						$ 26.2
Hess Infrastructure Partners LP Acquisition
Business Acquisition [Line Items]
Percentage of ownership interest	80.00%
Cash consideration	$ 601.8
Stock split conversion ratio	1
Hess Infrastructure Partners LP Acquisition \| Common Class A
Business Acquisition [Line Items]
Units representing noncontrolling limited partner interests	898,000
Hess Infrastructure Partners LP Acquisition \| Class B Shares
Business Acquisition [Line Items]
Units representing noncontrolling limited partner interests	266,416,928
Hess Water Services Holdings Limited Liability Company
Business Acquisition [Line Items]
Percentage of ownership interest	100.00%		100.00%
Hess Water Services and Hess Midstream Partners GP Limited Partner
Business Acquisition [Line Items]
Percentage of ownership interest	100.00%	100.00%
Hess Infrastructure Partners LP
Business Acquisition [Line Items]
Percentage of membership interest acquired					100.00%
Cash paid for business acquisition, net of cash acquired					$ 225.0
Hess
Business Acquisition [Line Items]
Business combination consideration transferred in excess of book value of net assets acquired as capital distribution					$ 156.1
Tioga System Acquisition
Business Acquisition [Line Items]
Percentage of membership interest acquired				100.00%
Cash paid for business acquisition, net of cash acquired				$ 89.2
Potential contingent payments, subject to certain future performance metrics				$ 10.0
Hess Infrastructure Partners LP Acquisition
Business Acquisition [Line Items]
Stock split conversion ratio	1
Restructuring costs	$ 26.2
Hess Infrastructure Partners LP Acquisition \| Common Class A
Business Acquisition [Line Items]
Units representing noncontrolling limited partner interests	898,000
Hess Infrastructure Partners LP Acquisition \| Class B Shares
Business Acquisition [Line Items]
Units representing noncontrolling limited partner interests	266,416,928
Cash consideration	$ 601.8

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2019	Feb. 10, 2020	Jun. 28, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	HESM
Entity Registrant Name	Hess Midstream LP
Entity Central Index Key	0001789832
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock Shares Outstanding		17,960,655
Entity Public Float			$ 321.7
Entity Interactive Data Current	Yes
Title of 12(b) Security	Class A shares representing limited partner interests
Security Exchange Name	NYSE
Entity File Number	001-39163
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	84-3211812
Entity Address, Address Line One	1501 McKinney Street
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77010
City Area Code	713
Local Phone Number	496-4200
Document Annual Report	true
Document Transition Report	false

Debt and Interest Expense (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Summary of Total Long-term Debt

Total long-term debt is as follows:

	December 31, 2019			December 31, 2018
(in millions)
Fixed-rate senior notes:
5.625% due 2026	$	800.0		$	800.0
5.125% due 2028		550.0			-
Total fixed-rate senior notes		1,350.0			800.0
Term Loan A facility		400.0			197.5
Revolving credit facility		32.0			-
Total Borrowings		1,782.0			997.5
Unamortized deferred financing costs and discounts		(28.5	)		(16.4	)
Total debt		1,753.5			981.1
Less: current maturities of long-term debt		-			11.3
Total long-term debt	$	1,753.5		$	969.8

Summary of Maturity Profile of Total Debt, Excluding Deferred Financing Costs and Discounts

As of December 31, 2019, the maturity profile of total debt, excluding deferred financing costs and discounts, is as follows:

(in millions)	Total		2020		2021		2022		2023		2024		2025 and thereafter
Fixed-rate senior notes	$	1,350.0	$	-	$	-	$	-	$	-	$	-	$	1,350.0
Term Loan facility		400.0		-		10.0		20.0		30.0		340.0		-
Revolving credit facility		32.0		-		-		-		-		32.0		-
Total debt (excluding interest)	$	1,782.0	$	-	$	10.0	$	20.0	$	30.0	$	372.0	$	1,350.0

Commitments and Contingencies

12 Months Ended

Dec. 31, 2019

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 12. Commitments and Contingencies

Environmental Contingencies

The Company is subject to federal, state and local laws and regulations relating to the environment. As of December 31, 2019, our reserve for estimated remediation liabilities included in Accrued liabilities and Other noncurrent liabilities was $0.7 million and $2.1 million, respectively. As of December 31, 2018, we had $0.6 million and $2.0 million, respectively.

Legal Proceedings

As of December 31, 2019, and 2018, we did not have accrued liabilities for any legal contingencies. Based on currently available information, we believe it is remote that the outcome of known matters would have a material adverse impact on our financial condition, results of operations or cash flows.

Lease and Purchase Obligations

We enter into certain lease and purchase commitments in connection with ongoing business activities. The following table presents our future undiscounted minimum lease payments (in millions). The discounted amount recognized on our accompanying consolidated balance sheet as of December 31, 2019, is $0.6 million included within other noncurrent liabilities.

Total

2020

2021

2022

2023

2024

2025 and

thereafter

Operating leases

1.1

0.2

0.1

0.5

In addition, as of December 31, 2019, we have unconditional purchase commitments of $65.0 million for the year ending December 31, 2020 and none for the years thereafter.

CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Dec. 31, 2019	Dec. 31, 2018
Common Class A
Common and subordinated units issued	17,960,655	0
Common and subordinated units outstanding	17,960,655	0
Class B Shares
Common and subordinated units issued	266,416,928	0
Common and subordinated units outstanding	266,416,928	0
Common Unitholders - Public
Common and subordinated units issued	0	17,014,377
Common and subordinated units outstanding	0	17,014,377
Common Unitholders - Affiliate
Common and subordinated units issued	0	10,282,654
Common and subordinated units outstanding	0	10,282,654
Subordinated Unitholders - Affiliate
Common and subordinated units issued	0	27,279,654
Common and subordinated units outstanding	0	27,279,654

CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL (UNAUDITED) (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Distributions to unitholders - per unit		$ 1.3578	$ 0.5810
Prior To Restructuring
Distributions to unitholders - per unit	$ 1.5616

Supplemental Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Schedule of Supplemental Quarterly Financial Information (Unaudited)

Supplemental quarterly financial information is as follows:

	2019
	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
(in millions, except per share/unit amounts)
Revenues and other income	$	189.6	$	190.3	$	214.9	$	253.5
Income from operations	$	95.8	$	91.2	$	99.3	$	90.3
Net income	$	80.8	$	74.4	$	87.4	$	75.1
Net income attributable to Hess Midstream LP	$	18.1	$	16.8	$	19.1	$	16.1
Net income attributable to Hess Midstream LP per Class A Share/limited partner unit (basic and diluted):
Class A Share	$	-	$	-	$	-	$	0.28
Common unit	$	0.32	$	0.29	$	0.33	$	-
Subordinated unit	$	0.32	$	0.29	$	0.33	$	-

	2018
	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
(in millions, except per share/unit amounts)
Revenues and other income	$	166.5	$	176.5	$	183.8	$	185.9
Income from operations	$	90.8	$	96.3	$	99.0	$	92.1
Net income	$	77.7	$	82.8	$	86.1	$	78.9
Net income attributable to Hess Midstream LP	$	17.0	$	17.8	$	18.8	$	17.2
Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):
Common	$	0.30	$	0.32	$	0.34	$	0.31
Subordinated	$	0.30	$	0.32	$	0.34	$	0.31

Amounts in the tables above have been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP, which was accounted for as an acquisition of a business under common control. See Note 3, Acquisitions. No other adjustments have been made to the quarterly financial information as previously reported by Hess Midstream Partners LP.

Supplemental Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Supplemental Quarterly Financial Information (Unaudited)

Supplemental quarterly financial information is as follows:

	2019
	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
(in millions, except per share/unit amounts)
Revenues and other income	$	189.6	$	190.3	$	214.9	$	253.5
Income from operations	$	95.8	$	91.2	$	99.3	$	90.3
Net income	$	80.8	$	74.4	$	87.4	$	75.1
Net income attributable to Hess Midstream LP	$	18.1	$	16.8	$	19.1	$	16.1
Net income attributable to Hess Midstream LP per Class A Share/limited partner unit (basic and diluted):
Class A Share	$	-	$	-	$	-	$	0.28
Common unit	$	0.32	$	0.29	$	0.33	$	-
Subordinated unit	$	0.32	$	0.29	$	0.33	$	-

	2018
	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
(in millions, except per share/unit amounts)
Revenues and other income	$	166.5	$	176.5	$	183.8	$	185.9
Income from operations	$	90.8	$	96.3	$	99.0	$	92.1
Net income	$	77.7	$	82.8	$	86.1	$	78.9
Net income attributable to Hess Midstream LP	$	17.0	$	17.8	$	18.8	$	17.2
Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):
Common	$	0.30	$	0.32	$	0.34	$	0.31
Subordinated	$	0.30	$	0.32	$	0.34	$	0.31

Equity-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Equity-based Award Activity

Equity‑based award activity for the year ended December 31, 2019 was as follows:

		Weighted Average
		Award Date
	Number of Shares	Fair Value
Outstanding and unvested shares/units at December 31, 2018	114,237	$21.06
Granted	74,528	22.76
Forfeited	(4,427)	21.36
Vested	(48,278)	21.15
Outstanding and unvested shares at December 31, 2019	136,060	$21.95

(in millions)	2019		2018		2017
Fair value of shares granted	$	1.7	$	1.9	$	1.0
Fair value of shares vested	$	1.0	$	0.4	$	-

Equity-Based Compensation

12 Months Ended

Dec. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Equity-Based Compensation

Note 9. Equity-Based Compensation

In 2017, the Partnership adopted the Hess Midstream Partners LP 2017 Long‑Term Incentive Plan. Pursuant to the Restructuring, the Company assumed the Hess Midstream Partners LP 2017 Long-Term Incentive Plan and all obligations with respect to outstanding awards thereunder. The Company amended and restated the Hess Midstream Partners LP 2017 Long-Term Incentive Plan to, among other things, change the plan’s name to Hess Midstream LP 2017 Long-Term Incentive Plan (the “LTIP”) and to reflect the Company’s assumption of the plan. Awards under the LTIP are available for officers, directors and employees of our general partner or its affiliates, and any individuals who perform services for the Company. The LTIP provides the Company with the flexibility to grant restricted share awards, restricted shares, phantom shares, share options, share appreciation rights, distribution equivalent rights, profits interest shares and other equity‑based awards. The LTIP limits the number of shares that may be delivered pursuant to vested awards to 3,000,000 Class A Shares.

Under the LTIP, we granted restricted share awards with distribution equivalent rights to certain officers, employees and directors. These restricted shares and distribution equivalent rights vest ratably over a three‑year period for officers and employees, and vest after one year for directors. Each restricted share represents the right to receive one Class A Share upon vesting (or an equivalent amount of cash). Cash distributions on the restricted shares accumulate and are paid upon vesting. Fair value of restricted shares is based on the fair value of the Company’s Class A Shares on the grant date.

Equity‑based award activity for the year ended December 31, 2019 was as follows:

		Weighted Average
		Award Date
	Number of Shares	Fair Value
Outstanding and unvested shares/units at December 31, 2018	114,237	$21.06
Granted	74,528	22.76
Forfeited	(4,427)	21.36
Vested	(48,278)	21.15
Outstanding and unvested shares at December 31, 2019	136,060	$21.95

(in millions)	2019		2018		2017
Fair value of shares granted	$	1.7	$	1.9	$	1.0
Fair value of shares vested	$	1.0	$	0.4	$	-

During the year ended December 31, 2019, we recognized compensation expense related to the outstanding awards of $1.5 million (2018: $0.9 million, 2017: 0.2 million). As of December 31, 2019, $1.7 million of compensation cost related to our unvested restricted shares awarded under the LTIP remains to be recognized over an expected weighted‑average period of 1.8 years.

Summary of Significant Accounting Policies and Basis of Presentation (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Consolidation	Consolidation. The consolidated financial statements include our accounts and the accounts of entities over which we have a controlling financial interest through our ownership or the majority voting interests of the entity. We consolidate the activities of the Partnership, and prior to the Restructuring the activities of Gathering Opco, HTGP Opco and Logistics Opco, each as a variable interest entity (“VIE”) under U.S. Generally Accepted Accounting Principles (“GAAP”). We have concluded that we are the primary beneficiary of the VIE, as defined in the accounting standards, since we have the power, through our ownership, to direct those activities that most significantly impact the economic performance of the Partnership. This conclusion was based on a qualitative analysis that considered the Partnership’s governance structure and the delegation of control provisions, which provide us the ability to control the operations of the Partnership. All financial statement activities associated with the VIE are captured within gathering, processing and storage, and terminaling and export segments (see Note 14, Segments). Our noncontrolling interest represents the 93.68% interest in the Partnership retained by Hess and GIP. Prior to the Restructuring, our noncontrolling interest represented the 80% interest in the Joint Interest Assets retained by HIP. All intercompany transactions and balances have been eliminated.
Use of Estimates	Use of Estimates. We prepare our consolidated financial statements in conformity with the U.S. GAAP, which require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the years presented. Changes in facts and circumstances may result in revised estimates and actual results could differ from those estimates.
Common Control Transactions	Common Control Transactions. Assets and businesses acquired from Hess and its subsidiaries are accounted for as common control transactions whereby the net assets acquired are combined with net assets of the Company at Hess’ historical carrying value. If any recognized consideration transferred in such a transaction exceeds the carrying value of the net assets acquired, the excess is treated as a capital distribution to Hess, similar to a dividend. To the extent that such transactions require prior periods to be retrospectively adjusted, historical net equity amounts prior to the transaction date are reflected in “Net Parent Investment.” Cash consideration up to the carrying value of net assets acquired is presented as an investing activity in our consolidated statement of cash flows. Cash consideration in excess of the carrying value of net assets acquired is presented as a financing activity in our consolidated statement of cash flows.
Cash and Cash Equivalents	Cash and Cash Equivalents. Cash equivalents consist of highly liquid investments, which are readily convertible into cash and have maturities of three months or less when acquired.
Accounts Receivable	Accounts Receivable. We record affiliate accounts receivable upon performance of services to affiliated companies. Generally, we receive payments from affiliated companies on a monthly basis, shortly after performance of services. There were no doubtful accounts written off, nor have we provided an allowance for doubtful accounts, as of December 31, 2019 and 2018.
Property, Plant and Equipment	Property, Plant and Equipment. Property, plant and equipment are stated at the lower of historical cost less accumulated depreciation subject to the results of impairment testing. We capitalize all construction-related direct labor and material costs, as well as indirect construction costs. Indirect construction costs include general engineering, taxes and the cost of funds used during construction. Costs, including complete asset replacements and enhancements or upgrades that increase the original efficiency, productivity or capacity of property, plant and equipment, are also capitalized. The costs of repairs, minor replacements and other projects, which do not increase the original efficiency, productivity or capacity of property, plant and equipment, are expensed as incurred.
Capitalization of Interest	Capitalization of Interest. Interest charges from borrowings are capitalized on material projects using the weighted average cost of outstanding borrowings until the project is substantially complete and ready for its intended use. Capitalized interest is depreciated over the useful lives of the assets in the same manner as the depreciation of the underlying assets.
Impairment of Long-Lived Assets	Impairment of Long‑Lived Assets. We review long-lived assets for impairment whenever events or changes in business circumstances indicate the net book values of the assets may not be recoverable. Impairment is indicated when the undiscounted cash flows estimated to be generated by those assets are less than the assets’ net book value. Undiscounted cash flows are based on identifiable cash flows that are largely independent of the cash flows of other assets and liabilities. If impairment occurs, a loss is recognized for the difference between the fair value and net book value. Such fair value is generally determined by discounting anticipated future net cash flows, an income valuation approach, or by a market-based valuation approach, which are Level 3 fair value measurements. Factors that indicate potential impairment include a significant decrease in the market value of the asset, operating or cash flow losses associated with the use of the asset, and a significant change in the asset’s physical condition or use. No impairments of long‑lived assets were recorded during the years ended December 31, 2019, 2018 and 2017.
Leases	Leases. We determine if an arrangement is a lease at inception. Operating lease right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The operating lease right-of-use asset includes any initial direct costs and excludes lease incentives received. The lease term used in measurement of our lease obligations may include periods covered by an option to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected not to recognize lease assets and lease liabilities for leases with a term of 12 months or less for all classes of underlying assets. Our lease agreements may include lease and non-lease components, which are generally accounted for separately. As of December 31, 2019, we had $0.8 million of operating lease right-of-use assets included within other noncurrent assets on our consolidated balance sheet. Operating lease liabilities were $0.2 million and $0.6 million included within other current liabilities and other noncurrent liabilities, respectively, on our consolidated balance sheet. As of December 31, 2019, we did not have any finance leases.
Equity Investments	Equity Investments. We account for our investment in LM4 under the equity method of accounting, as we do not control, but have a significant influence over, its operations. As of December 31, 2019, we contributed $100.3 million of cash for our gross interest in LM4 and capitalized $4.1 million of interest expense associated with our investment in LM4. Difference in the basis of the investment and the underlying net asset value of the equity investee is amortized into net income over the remaining useful lives of the underlying assets. Earnings from equity investments represent our proportionate share of net income generated by the equity investee. We classify distributions received from equity method investees on the basis of the nature of the activity of the investee that generated the distribution as either a return on investment classified as cash inflows from operating activities or a return of investment classified as cash inflows from investing activities when such information is available to us.
Deferred Financing Costs	Deferred Financing Costs. We capitalize debt issuance costs and fees incurred related to the procurement of our credit facilities. We amortize such costs as additional interest expense over the life of the credit agreement using the straight-line method, which approximates the effective interest method. Unamortized deferred financing costs related to our revolving credit facility are presented in Other noncurrent assets (2019: $12.2 million, 2018: $6.9 million) and unamortized deferred financing costs related to our fixed-rate senior notes and our term loan are presented as a direct reduction to the Long-term debt (2019: $28.5 million, 2018: $16.5 million) in the accompanying consolidated balance sheets.
Asset Retirement Obligations	Asset Retirement Obligations. We record legal obligations to remove and dismantle long-lived assets. We recognize a liability for the fair value of legally required asset retirement obligations associated with long-lived assets in the period in which the retirement obligations are incurred if the liability can be reasonably estimated. The associated asset retirement costs are capitalized as part of the carrying amount of the long-lived assets. Accretion expense is included in Depreciation expense in the consolidated statement of operations. We have not incurred significant asset retirement obligations.
Net Parent Investment	Net Parent Investment. Net parent investment represents HIP’s historical activity as well as Hess’ historical investment in Hess Water Services prior to its acquisition by HIP, the accumulated net operating results through the date when we obtained control of HIP, and the net effect of transactions between HIP and the Sponsors, and between Hess and Hess Water Services. Retrospectively adjusted financial information from prior to the acquisition of HIP is included in Net parent investment.
Revenue Recognition	Revenue Recognition—Contracts with Customers. We earn substantially all of our revenues by charging fees for gathering, compressing and processing natural gas and fractionating NGLs; gathering, terminaling, loading and transporting crude oil and NGLs, gathering and disposing produced water, and storing and terminaling propane. We do not own or take title to the volumes that we handle. Effective January 1, 2014, we entered into i) gas gathering, ii) crude oil gathering, iii) gas processing and fractionation, iv) storage services, and v) terminal and export services fee‑based commercial agreements with certain subsidiaries of Hess, and effective January 1, 2019, we entered into water gathering and disposal services fee-based agreements with certain subsidiaries of Hess. In 2018 and partial year 2017, Hess Water Services had documented intercompany arrangements with certain subsidiaries of Hess pursuant to which it provided produced water gathering and disposal services and charged agreed-upon fees per barrel for the services performed. Our responsibilities to provide each of the above services for each year under each of the commercial agreements are considered separate, distinct performance obligations. We recognize revenues for each performance obligation under our commercial agreements over‑time as services are rendered using the output method, measured using the amount of volumes serviced during the period. The minimum volume commitments are subject to fluctuation based on nominations covering substantially all of Hess’ production and projected third-party volumes that will be purchased in the Bakken. As the minimum volume commitments are subject to fluctuation, and these commercial agreements contain fee inflation escalators and fee recalculation mechanisms, substantially all of the transaction price, as this term is defined in ASC 606, is variable at inception of each of the commercial agreements. As the variability is resolved prior to the recognition of revenue, we do not apply a constraint to the transaction price at the inception of the commercial agreements. We elected the practical expedient to recognize revenue in the amount to which we have a right to invoice as permitted under ASC 606. Due to this election and as the transaction price allocated to our unsatisfied performance obligations is entirely variable, we have elected the exemption provided by ASC 606 from the disclosure of revenue recognizable in future periods as our unsatisfied performance obligations are fulfilled. There are no significant financing components in any of our commercial agreements. The minimum volumes that Hess provides to our assets under our commercial agreements include dedicated production covering substantially all of Hess’ existing and future owned or controlled production in the Bakken and projected third-party volumes owned or controlled by Hess through dedicated third-party contracts. If Hess delivers volumes less than the applicable minimum volume commitments under our commercial agreements during any quarter, Hess is obligated to pay us a shortfall fee equal to the volume deficiency multiplied by the related gathering, processing and/or terminaling fee, as applicable. Our responsibility to stand-ready to service a minimum volume over each quarterly commitment period represents a separate, distinct performance obligation. Currently, and for the remainder of the Initial Term of each commercial agreement as described in Note 4, volume deficiencies are measured quarterly and recognized as revenue in the same period, as any associated shortfall payments are not subject to future reduction or offset. During the Secondary Term of each commercial agreement as described in Note 4, Hess will be entitled to receive a credit, calculated in barrels or Mcf, as applicable, with respect to the amount of any shortfall fee paid by Hess, which will initially be reported in deferred revenue. Hess may apply such credit against the fees payable for any volumes delivered to us under the applicable agreement in excess of Hess’ nominated volumes up to four quarters after such credit is earned. Unused credits by Hess will be recognized as revenue when they expire after four quarters. However, Hess will not be entitled to receive any such credit with respect to crude oil terminaling services under our terminal and export services agreement Our revenues also included pass‑through third‑party rail transportation costs, third-party produced water trucking and disposal costs, and electricity fees for which we recognize revenues in an amount equal to the costs.
Depreciation Expense	Depreciation Expense. We calculate depreciation using the straight-line method based on the estimated useful lives after considering salvage values of our assets. Depreciation lives range from 12 to 35 years. However, factors such as maintenance levels, economic conditions impacting the demand for these assets, and regulatory or environmental requirements could cause us to change our estimates, thus impacting the future calculation of depreciation.
Equity-Based Compensation	Equity‑Based Compensation. Equity‑based compensation issued to the officers, directors and employees of our general partner is recorded at grant‑date fair value. Expense is recognized on a straight‑line basis over the vesting period of the award and is included in General and administrative expenses in the accompanying consolidated statements of operations. Forfeitures are recognized as they occur.
Income Taxes	Income Taxes. Deferred income taxes are determined using the liability method and reflect temporary differences between the financial statement carrying amount and income tax basis of assets and liabilities recorded using the statutory income tax rate. Regular assessments are made of the likelihood of those deferred tax assets being realized. If it is more likely than not that some or all of the deferred tax assets will not be realized, a valuation allowance is recorded to reduce the deferred tax assets to the amount expected to be realized. Prior to the Restructuring on December 16, 2019, we were not a separate taxable entity for U.S. federal and state income tax purposes; therefore, we did not provide for income tax benefit or expense. Each partner was subject to income taxes on its share of the Partnership’s earnings. On March 1, 2019, HIP acquired Hess Water Services (see Note 3, Acquisitions). For the periods prior to March 1, 2019, Hess Water Services was included in the consolidated income tax returns of Hess. The provision for Hess Water Services’ income taxes and income tax assets and liabilities were determined as if it were a standalone taxpayer for all periods presented. For the period from March 1, 2019 through the Restructuring date of December 16, 2019, Hess Water Services was not taxable itself and was not part of a separate taxable entity; therefore, no income tax provision was recognized.
Net Income per Limited Partner Unit	Net Income Per Limited Partner Unit. Prior to the Restructuring, we identified the general partner interest and IDRs as participating securities and computed income per unit using the two‑class method under which net income per unit was calculated for common units and participating securities considering both distributions declared and participation rights in undistributed earnings as if all such earnings had been distributed during that period. Net income per unit applicable to limited partners, including subordinated unitholders, was computed by dividing limited partners' interest in net income, after deducting the general partner's 2% interest and IDRs, by the weighted‑average number of outstanding common and subordinated units.
Environmental and Legal Contingencies	Environmental and Legal Contingencies. We accrue and expense environmental costs on an undiscounted basis to remediate existing conditions related to past operations when the future costs are probable and reasonably estimable. In the ordinary course of business, the Company is from time to time party to various judicial and administrative proceedings. We regularly assess the need for accounting recognition or disclosure of these contingencies. In the case of a known contingency, we accrue a liability when the loss is probable and the amount is reasonably estimable. If a range of amounts can be reasonably estimated and no amount within the range is a better estimate than any other amount, then the minimum of the range is accrued.
Fair Value Measurements	Fair Value Measurements. We measure assets and liabilities requiring fair value presentation using an exit price (i.e., the price that would be received to sell an asset or paid to transfer a liability) and disclose such amounts according to the level of valuation inputs under the following hierarchy: Level 1: Quoted prices in an active market for identical assets or liabilities. Level 2: Inputs other than quoted prices that are directly or indirectly observable. Level 3: Unobservable inputs that are significant to the fair value of assets or liabilities. The classification of an asset or liability within the fair value measurement hierarchy is based on the lowest level of input significant to its fair value. There were no nonrecurring fair value measurements during the years ended December 31, 2019 and 2018. We had other short‑term financial instruments, primarily cash and cash equivalents, accounts receivable and accounts payable, for which the carrying value approximated their fair value as of December 31, 2019 and 2018.
Derivatives	Derivatives. We may utilize derivative instruments for financial risk management activities. In these activities, we may use futures, forwards, options and swaps, individually or in combination, to mitigate our exposure to fluctuations in interest rates. All derivative instruments are recorded at fair value in our consolidated balance sheet. Our policy for recognizing the changes in fair value of derivatives varies based on the designation of the derivative. The changes in fair value of derivatives that are not designated as hedges are recognized in earnings. Derivatives may be designated as hedges of expected future cash flows or forecasted transactions (cash flow hedges). Changes in fair value of derivatives that are designated as cash flow hedges are recorded as a component of other comprehensive income (loss). Amounts included in Accumulated other comprehensive income (loss) for cash flow hedges are reclassified into earnings in the same period that the hedged item is recognized in earnings.
New Accounting Pronouncements	New Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, Financial Instruments – Credit Losses. This ASU makes changes to the impairment model for trade receivables, net investments in leases, debt securities, loans and certain other instruments. The standard requires the use of a forward-looking "expected loss" model compared with the current "incurred loss" model. We will adopt this ASU in the first quarter of 2020 when the standard becomes effective and it is not expected to have a material impact on our consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, as a new Accounting Standards Codification (“ASC”) Topic, ASC 842. We adopted ASC 842 on January 1, 2019 using the modified retrospective method. Accordingly, comparative financial statements for periods prior to the adoption date of ASC 842 were not affected. In addition, we have elected to apply the ‘package’ of practical expedients allowing us to avoid reassessing whether existing contracts are (or contain) leases, whether the lease classification for existing leases would differ under ASC 842, and whether initial direct costs incurred for existing leases are capitalizable under ASC 842. Finally, we have elected to apply the practical expedient allowing us to avoid reassessing land easements that were not previously accounted for as leases under ASC 840. We have not elected the ‘hindsight’ practical expedient when determining lease term. As a result, no cumulative effect adjustment to Partners’ capital was recognized. The adoption of ASC 842 did not have a material impact on our consolidated financial statements.

Partners' Capital and Distributions

12 Months Ended

Dec. 31, 2019

Partners Capital Notes [Abstract]

Partners' Capital and Distributions

Note 8. Partners’ Capital and Distributions

Prior to the Restructuring, our partners’ capital included common and subordinated units representing limited partner interests in the Partnership. Pursuant to the Restructuring, 17,062,655 public common units of the Partnership outstanding as of December 16, 2019, were converted into Class A Shares of the Company (economic and voting) on a one-for-one basis, the Sponsors received 898,000 Class A Shares of the Company, 266,416,928 Class B Units representing noncontrolling limited partner interests in the Partnership and a cash consideration of $601.8 million. In addition, our general partner purchased 266,416,928 Class B Shares of the Company (non-economic voting only) for a cash amount equal to $0.0001 per Class B Shares. Class B Units of the Partnership together with the equal number of Class B Shares of the Company are convertible to Class A Shares of the Company on a one-for-one basis.

Our partnership agreement requires that, within 45 days after the end of each quarter, we distribute all of our available cash to shareholders/unitholders of record on the applicable record date. The following table details the distributions declared and/or paid for the periods presented:

Period	Record Date	Distribution Date	Distribution per Common and Subordinated Unit/Class A Share
First Quarter 2018	May 4, 2018	May 14, 2018	$0.3333
Second Quarter 2018	August 2, 2018	August 13, 2018	$0.3452
Third Quarter 2018	November 5, 2018	November 13, 2018	$0.3575
Fourth Quarter 2018	February 4, 2019	February 13, 2019	$0.3701
First Quarter 2019	May 3, 2019	May 14, 2019	$0.3833
Second Quarter 2019	August 5, 2019	August 13, 2019	$0.3970
Third Quarter 2019	November 4, 2019	November 13, 2019	$0.4112
Fourth Quarter 2019⁽¹⁾	February 6, 2020	February 14, 2020	$0.4258

(1)

For more information, see Note 16, Subsequent Events.

The following table details distributions paid by HIP to Hess and GIP prior to the Restructuring (in millions):

Type of Distributions	Period	Distribution to Hess Corporation		Distribution to GIP		Total Distributions
HIP LP Distributions	Second Quarter 2017		27.1		22.9	$	50.0
HIP LP Distributions	Third Quarter 2017		25.0		25.0	$	50.0
HIP LP Distributions	Fourth Quarter 2018		160.0		162.0	$	322.0

In the second quarter of 2017, we also made a special distribution of $349.5 million, distributed 50/50 to Hess and GIP from the proceeds of the Partnership’s initial public offering.

Financial Risk Management Activities

12 Months Ended

Dec. 31, 2019

Derivative Instruments And Hedging Activities Disclosure [Abstract]

Financial Risk Management Activities

Note 14. Financial Risk Management Activities

In the normal course of our business, we are exposed to market risks related to changes in interest rates. Financial risk management activities include transactions designed to reduce risk by reducing our exposure to interest rate movements. Interest rate swaps may be used to convert interest payments on certain long‑term debt.

As of December 31, 2019 and 2018, there were no outstanding interest rate swaps designated as cash flow hedges. At December 31, 2019, deferred income in Accumulated other comprehensive income in connection with the settled instruments was $0.4 million, of which $0.4 million will be reclassified into earnings during the next 12 months.

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)
shares in Millions, $ in Millions

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Revenues

$ 847.6

$ 712.0

^[1]

$ 579.5

^[1]

hesm:AffiliateServicesMember

^[1]

hesm:AffiliateServicesMember

^[1]

$ 0.7

^[1]

848.3

712.7

^[1]

$ 579.5

^[1]

Operating and maintenance expenses (exclusive of depreciation shown separately below)

276.8

193.5

^[1]

186.0

^[1]

142.5

126.9

^[1]

116.5

^[1]

52.4

14.1

^[1]

13.9

^[1]

471.7

334.5

^[1]

316.4

^[1]

Income from equity investments

376.6

378.2

^[1]

263.1

^[1]

3.4

62.4

53.3

^[1]

25.8

^[1]

Income before income tax expense (benefit)

^[1]

0.6

4.7

317.6

325.5

^[1]

242.0

^[1]

Income tax expense (benefit)

(0.1)

Less: Net income (loss) attributable to net parent investment

317.7

325.5

^[1]

242.0

^[1]

(55.0)

(46.8)

^[1]

25.4

^[1]

Less: Net income (loss) attributable to noncontrolling interest

302.6

301.5

^[1]

175.4

^[1]

Less: General partner's interest in net income prior to the Restructuring

70.1

70.8

^[1]

41.2

^[1]

3.4

1.7

^[1]

0.8

^[1]

$ 66.7

$ 69.1

^[1]

$ 40.4

^[1]

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

^[1]

$ 1.27

$ 0.75

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

26.9

Weighted average limited partner units outstanding prior to the Restructuring, Basic:

Units outstanding prior to the Restructuring, Basic

27.3

^[1]

26.9

^[1]

Weighted average limited partner units outstanding prior to the Restructuring, Diluted:

Units outstanding prior to the Restructuring, Diluted

27.5

27.4

^[1]

26.9

^[1]

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

^[1]

$ 1.27

$ 0.75

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

26.9

Weighted average limited partner units outstanding prior to the Restructuring, Basic:

Units outstanding prior to the Restructuring, Basic

27.3

^[1]

26.9

^[1]

Weighted average limited partner units outstanding prior to the Restructuring, Diluted:

Units outstanding prior to the Restructuring, Diluted

27.3

^[1]

26.9

^[1]

Common Class A

Net income attributable to Hess Midstream LP per Class A share/limited partner unit:

Net income attributable to Hess Midstream LP per Class A share/limited partner unit, Basic

$ 1.21

Net income attributable to Hess Midstream LP per Class A share/limited partner unit, Diluted

$ 1.20

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

18.0

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Partners' Capital and Distributions - Schedule of Distributions Declared and Paid (Detail)

12 Months Ended

Dec. 31, 2019

$ / shares

First Quarter 2018

Distribution Made To Limited Partner [Line Items]

May 04, 2018

Distribution per Common and Subordinated Unit/Class A Share

May 14, 2018

$ 0.3333

Second Quarter 2018

Distribution Made To Limited Partner [Line Items]

Aug. 02, 2018

Distribution per Common and Subordinated Unit/Class A Share

Aug. 13, 2018

$ 0.3452

Third Quarter 2018

Distribution Made To Limited Partner [Line Items]

Nov. 05, 2018

Distribution per Common and Subordinated Unit/Class A Share

Nov. 13, 2018

$ 0.3575

Fourth Quarter 2018

Distribution Made To Limited Partner [Line Items]

Feb. 04, 2019

Distribution per Common and Subordinated Unit/Class A Share

Feb. 13, 2019

$ 0.3701

First Quarter 2019

Distribution Made To Limited Partner [Line Items]

May 03, 2019

Distribution per Common and Subordinated Unit/Class A Share

May 14, 2019

$ 0.3833

Second Quarter 2019

Distribution Made To Limited Partner [Line Items]

Aug. 05, 2019

Distribution per Common and Subordinated Unit/Class A Share

Aug. 13, 2019

$ 0.3970

Third Quarter 2019

Distribution Made To Limited Partner [Line Items]

Nov. 04, 2019

Distribution per Common and Subordinated Unit/Class A Share

Nov. 13, 2019

$ 0.4112

Fourth Quarter 2019

Distribution Made To Limited Partner [Line Items]

Feb. 06, 2020

^[1]

Distribution per Common and Subordinated Unit/Class A Share

Feb. 14, 2020

^[1]

$ 0.4258

^[1]

[1]	For more information, see Note 16, Subsequent Events.

Subsequent Events - Additional Information (Detail) - Subsequent Event	Jan. 27, 2020 $ / shares
Subsequent Event [Line Items]
Quarterly cash distribution declared date	Jan. 27, 2020
Quarterly cash distribution declared per Class A Share	$ 0.4258
Distribution made to limited partner, increase in percentage than prior year quarter declared	15.00%
Distribution paid date	Feb. 14, 2020
Record Date	Feb. 06, 2020

Segments - Total Assets for Reportable Segments (Parenthetical) (Detail) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

^[1]

Cash contributed to acquire equity method investments

$ 33.0

$ 67.3

Processing and Storage

Cash contributed to acquire equity method investments

$ 107.8

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Concentration of Credit Risk

12 Months Ended

Dec. 31, 2019

Risks And Uncertainties [Abstract]

Concentration of Credit Risk

Note 11. Concentration of Credit Risk

Hess represented approximately 100% of our total revenues and accounts receivable from contracts with customers for the years ended December 31, 2019, 2018 and 2017.

Equity-Based Compensation - Additional Information (Detail) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

^[1]

Dec. 31, 2017

^[1]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Equity-based compensation expense

$ 1.5

$ 0.9

$ 0.2

2017 Long-Term Incentive Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

$ 1.7

1 year 9 months 18 days

2017 Long-Term Incentive Plan | Officers and Employees

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Restricted shares vesting period

3 years

2017 Long-Term Incentive Plan | Directors

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Restricted shares vesting period

1 year

2017 Long-Term Incentive Plan | Common Class A

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares pursuant to vested awards

3,000,000

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2019

Revenue from Contracts with Customers on Disaggregated Basis

Revenue from contracts with customers on a disaggregated basis was as follows:

	Year Ended December 31,
	2019		2018		2017
(in millions)
Oil and gas gathering services	$	345.6	$	324.9	$	271.6
Water gathering and disposal services		77.3		50.3		13.9
Processing and storage services		294.7		251.4		227.3
Terminaling and export services		130.0		85.4		66.7
Total revenues from contracts with customers	$	847.6	$	712.0	$	579.5
Other income		0.7		0.7		-
Total revenues	$	848.3	$	712.7	$	579.5

Summary of Classification of Charges between Operating and Maintenance Expenses and General and Administrative Expenses

	Year Ended December 31,
	2019		2018		2017
(in millions)
Operating and maintenance expenses	$	53.1	$	50.2	$	57.3
General and administrative expenses		15.5		7.8		6.7
Total	$	68.6	$	58.0	$	64.0

Description of Business

12 Months Ended

Dec. 31, 2019

Description Of Business [Abstract]

Description of Business

Note 1. Description of Business

Description of Business. We are a fee-based, growth-oriented, Delaware limited partnership formed by Hess Infrastructure Partners GP LLC (“HIP GP LLC”) and our general partner in 2019 to own, operate, develop and acquire a diverse set of midstream assets and provide fee-based services to Hess and third-party customers. We are managed and controlled by Hess Midstream GP LLC, the general partner of our general partner. Our assets are primarily located in the Bakken and Three Forks shale plays in the Williston Basin area of North Dakota, which we collectively refer to as the Bakken.

Our assets and operations are organized into the following three segments: (i) gathering, (ii) processing and storage and (iii) terminaling and export (see Note 13, Segments).

The 2019 Restructuring. On December 16, 2019, the Company and the Partnership completed the transactions (the “Restructuring”) contemplated by the partnership restructuring agreement, dated October 3, 2019, by and among the Company, the Partnership and the other parties thereto. As a result of the Restructuring, the Company was delegated control of the Partnership and replaced the Partnership as its publicly traded successor.

Prior to the Restructuring, the Company and the Partnership were indirectly controlled by HIP GP LLC, the general partner of Hess Infrastructure Partners LP (“HIP”). HIP was originally formed as a joint venture between Hess and GIP II Blue Holding Partnership, L.P. (“GIP” and together with Hess, the “Sponsors”).

Prior to the Restructuring:

•

HIP owned an 80% noncontrolling economic interest in each of (i) Hess North Dakota Pipelines Operations LP (“Gathering Opco”), which owns crude oil and natural gas gathering pipelines and compressor stations in North Dakota; (ii) Hess TGP Operations LP (“HTGP Opco”), which owns the Tioga Gas Plant (“TGP”), a natural gas processing and fractionation plant, including a residue gas pipeline in North Dakota; and (iii) Hess North Dakota Export Logistics Operations LP (“Logistics Opco”), which owns a crude oil and natural gas liquids (“NGL”) rail loading facility, crude oil rail cars and crude oil pipeline and truck receipt terminal in North Dakota (the “Joint Interest Assets”), a 100% interest in a produced water gathering and disposal business owned by Hess Water Services Holdings LLC (“Hess Water Services”) and a 100% interest in Hess Midstream Partners GP LP (“MLP GP LP”), which held all of the Partnership’s outstanding incentive distribution rights (the “IDRs”) and the general partner interest in the Partnership (the “GP Interest”), and controlled the Partnership;

•

the Partnership, in connection with its initial public offering (“IPO”) on April 10, 2017, owned a 20% controlling interest in the Joint Interest Assets and a 100% interest in Hess Mentor Storage Holdings LLC (“Mentor Holdings”), which owns a propane storage cavern and related rail and truck loading and unloading and storage terminal in Minnesota; and

•

the Sponsors directly owned HIP and an aggregate of 10,282,654 common units representing limited partner interests in the Partnership and 27,279,654 subordinated units representing limited partner interests in the Partnership.

Pursuant to the Restructuring, which was consummated on December 16, 2019, the Partnership acquired HIP, including HIP’s 80% interest in the Joint Interest Assets, 100% interest in Hess Water Services and the outstanding economic general partner interest and IDRs. The Partnership’s organizational structure converted from a master limited partnership into an “Up-C” structure in which the Partnership’s public unitholders received newly issued Class A shares (“Class A Shares”) representing limited partner interest in Hess Midstream LP in a one-for-one exchange. The Partnership changed its name to “Hess Midstream Operations LP” and became a consolidated subsidiary of the Company.

After giving effect to the Restructuring:

•

the Partnership owns 100% of the Joint Interest Assets, Hess Water Services and MLP GP LP, which continues to hold all of the IDRs and the GP Interest;

•

the Sponsors (i) directly hold 266,416,928 Class B units (“Class B Units”) representing limited partner interests in the Partnership, (ii) indirectly own 100% of the ownership interests in our general partner, which holds 898,000 Class A Shares (economic and voting) and 266,416,928 Class B shares (non-economic, voting only) representing limited partner interests in the Company (“Class B Shares”) and (iii) received $601.8 million in cash;

•

Class B Units of the Partnership together with the same number of Class B Shares of the Company are convertible to Class A Shares of the Company on a one-for-one basis;

•

the Class A Shares commenced trading on the New York Stock Exchange under the symbol “HESM” on December 17, 2019;

•

the Company holds a 6.32% controlling interest in the Partnership and the Sponsors hold a 93.68% noncontrolling economic interest in the Partnership;

•

public limited partners hold a 6.0% voting interest and a 95.0% economic interest in the Company, which represents an indirect 6.0% economic interest in the Partnership;

•

the Sponsors and their respective affiliates hold a 94.0% voting interest and a 5.0% economic interest in the Company, which represents an indirect 94% economic interest in the Partnership; and

•

the Sponsors own 100% interest in the general partner of the Company and, through their ownership of the general partner, continue to have the right to elect the entire board of directors.

The acquisition of HIP by the Partnership, including its 80% economic interest in the Joint Interest Assets and 100% interest in Hess Water Services, was accounted for as an acquisition of a business under common control. Accordingly, our consolidated financial statements prior to the acquisition date of December 16, 2019 were retrospectively recast to include the financial results of HIP. See Note 3, Acquisitions.

LM4 Joint Venture. On January 25, 2018, we entered into a 50/50 joint venture with Targa Resources Corp. (“Targa”) to construct a new 200 MMcf/d gas processing plant called Little Missouri 4 (“LM4”). LM4 was placed in service in the third quarter of 2019. Targa is the operator of the plant. See Note 4, Related Party Transactions.

Acquisitions

12 Months Ended

Dec. 31, 2019

Business Combinations [Abstract]

Acquisitions

Note 3. Acquisitions

Hess Water Services Acquisition

On March 1, 2019, HIP acquired 100% of the membership interest in Hess Water Services that owns Hess’ existing Bakken water services business for $225.0 million in cash. HIP funded the purchase price through a combination of cash on hand and borrowings under its revolving credit facility. In connection with the Hess Water Services acquisition, HIP acquired the following:

(in millions)
Property, plant and equipment, net	$	70.8
Working capital		(1.2	)
Asset retirement obligations		(0.7	)
Net assets acquired	$	68.9

The transaction was accounted for as an acquisition of a business between entities under common control, and therefore, the related acquired assets and liabilities were transferred at Hess’ historical carrying value. We recognized $156.1 million of consideration in excess of the book value of net assets acquired as a capital distribution to Hess, which is reflected within Net parent investment in the accompanying consolidated statements of changes in partners’ capital.

Hess Water Services is included in our gathering segment (see Note 13, Segments).

Tioga System Acquisition

On March 22, 2019, we acquired 100% of the membership interest in Tioga Midstream Partners LLC from Summit Midstream Partners, LP that owns oil, gas, and water gathering assets (the “Tioga System Acquisition”). The transaction was accounted for as an asset acquisition. The Tioga System, located in Williams County in western North Dakota, is complementary to our infrastructure, and is currently delivering volumes into our gathering system.

We paid $89.2 million in cash at closing, net of cash acquired, and recognized a contingent liability for additional potential payments of $10 million in future periods subject to certain performance metrics. We funded the purchase price through a combination of cash on hand and borrowings under our revolving credit facility.

The acquired Tioga System is included in our gathering segment (see Note 13, Segments).

Hess Infrastructure Partners LP Acquisition

On December 16, 2019, the Company and the Partnership completed the Restructuring, pursuant to which the Partnership acquired all of the partnership interests in HIP from Hess and GIP, including HIP’s retained 80% economic interest in the Joint Interest Assets, 100% interest in Hess Water Services and the outstanding economic general partner and incentive distribution rights in the Partnership. The Partnership’s organizational structure converted from a master limited partnership into an “Up-C” structure in which the Partnership’s public unitholders received newly issued Class A Shares in Hess Midstream LP in a one-for-one exchange. The Partnership changed its name to “Hess Midstream Operations LP” and became a consolidated subsidiary of the Company. As a result of the Restructuring, the Sponsors held 898,000 Class A Shares in the Company, 266,416,928 Class B Units representing noncontrolling limited partner interests in the Partnership and received cash consideration of $601.8 million. Class B Units of the Partnership together with the same number of Class B Shares of the Company are convertible to Class A Shares of the Company on a one-for-one basis (see Note 8, Partners’ Capital and Distributions).

Our consolidated financial statements include $26.2 million of costs associated with the Restructuring. These costs were expensed as general and administrative expenses.

The acquisition of HIP was accounted for as an acquisition of a business under common control. Accordingly, consolidated financial statements prior to the acquisition date of December 16, 2019 were retrospectively recast to include the financial results of HIP. The Partnership previously consolidated 100% of the Joint Interest Assets and reflected a noncontrolling interest of 80% in such assets representing HIP’s historical ownership of the Joint Interest Assets; therefore, the recast of the previously reported financial information did not result in any changes in segment information, other than inclusion of Hess Water Services in the gathering segment.

Retrospective Adjusted Information Tables

The following tables present our financial position as of December 31, 2018 and the results of operations and cash flows for the years ended December 31, 2018 and 2017, giving effect to the acquisition of HIP. The results of HIP prior to the effective date of the acquisition are included in “Acquisition of HIP” and the consolidated results are included in “Consolidated Results” within the tables below. The Partnership, as previously reported, did not have any items of other comprehensive income during the periods presented.

Consolidated Balance Sheet

	December 31, 2018
	Partnership as Previously Reported		Acquisition of HIP			Consolidated Results
(in millions)
Assets
Cash and cash equivalents	$	20.3	$	89.0		$	109.3
Accounts receivable—affiliate:
From contracts with customers		62.2		5.1			67.3
Other receivables		0.8		(0.3	)		0.5
Other current assets		2.8		0.5			3.3
Total current assets		86.1		94.3			180.4
Equity Investments		67.3		-			67.3
Property, plant and equipment, net		2,664.1		71.2			2,735.3
Long-term receivable—affiliate		-		1.3			1.3
Other noncurrent assets		2.2		4.7			6.9
Total assets	$	2,819.7	$	171.5		$	2,991.2
Liabilities
Accounts payable—trade	$	15.3	$	3.3		$	18.6
Accounts payable—affiliate		15.8		-			15.8
Accrued liabilities		64.5		21.1			85.6
Current maturities of long-term debt		-		11.3			11.3
Other current liabilities		6.8		-			6.8
Total current liabilities		102.4		35.7			138.1
Long-term debt		-		969.8			969.8
Other noncurrent liabilities		6.4		0.8			7.2
Total liabilities		108.8		1,006.3			1,115.1
Common unitholders—public (17,014,377 units issued and outstanding)		357.1		-			357.1
Common unitholders—affiliate (10,282,654 units issued and outstanding)		39.5		-			39.5
Subordinated unitholders—affiliate (27,279,654 units issued and outstanding)		105.3		-			105.3
General partner		14.9		-			14.9
Total Hess Midstream Partners LP partners' capital		516.8		-			516.8
Noncontrolling interest		2,194.1		-			2,194.1
Accumulated other comprehensive income		-		1.2			1.2
Net parent investment		-		(836.0	)		(836.0	)
Total partners' capital		2,710.9		(834.8	)		1,876.1
Total liabilities and partners' capital	$	2,819.7	$	171.5		$	2,991.2

Consolidated Statements of Operations

	Year Ended December 31, 2018
	Partnership as Previously Reported		Acquisition of HIP			Consolidated Results
(in millions)
Revenues and other income
Affiliate services	$	661.7	$	50.3		$	712.0
Other income		0.7		-			0.7
Total revenues and other income		662.4		50.3			712.7
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)		154.3		39.2			193.5
Depreciation expense		123.0		3.9			126.9
General and administrative expenses		11.5		2.6			14.1
Total costs and expenses		288.8		45.7			334.5
Income from operations		373.6		4.6			378.2
Interest expense, net		1.3		52.0			53.3
Gain on sale of property, plant and equipment		-		0.6			0.6
Net income		372.3		(46.8	)		325.5
Less: Net income (loss) attributable to net parent investment		-		(46.8	)		(46.8	)
Less: Net income attributable to noncontrolling interest		301.5		-			301.5
Net income attributable to Hess Midstream Partners LP		70.8		-			70.8
Less: General partner's interest in net income attributable to Hess Midstream Partners LP		1.7		-			1.7
Limited partners' interest in net income attributable to Hess Midstream Partners LP	$	69.1		-		$	69.1
Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted):
Common	$	1.27				$	1.27
Subordinated	$	1.27				$	1.27
Weighted average limited partner units outstanding:
Basic:
Common		27.3					27.3
Subordinated		27.3					27.3
Diluted:
Common		27.4					27.4
Subordinated		27.3					27.3

	Year Ended December 31, 2017
	Partnership as Previously Reported		Acquisition of HIP			Consolidated Results
(in millions)
Revenues and other income
Affiliate services	$	565.6	$	13.9		$	579.5
Other income		0.2		(0.2	)		-
Total revenues and other income		565.8		13.7			579.5
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)		158.4		27.6			186.0
Depreciation expense		113.1		3.4			116.5
General and administrative expenses		8.1		5.8			13.9
Total costs and expenses		279.6		36.8			316.4
Income from operations		286.2		(23.1	)		263.1
Interest expense, net		1.4		24.4			25.8
Gain on sale of property, plant and equipment		-		4.7			4.7
Net income		284.8		(42.8	)		242.0
Less: Net income (loss) attributable to net parent investment		68.2		(42.8	)		25.4
Less: Net income attributable to noncontrolling interest		175.4		-			175.4
Net income attributable to Hess Midstream Partners LP		41.2		-			41.2
Less: General partner's interest in net income attributable to Hess Midstream Partners LP		0.8		-			0.8
Limited partners' interest in net income attributable to Hess Midstream Partners LP	$	40.4	$	-		$	40.4
Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted):
Common	$	0.75				$	0.75
Subordinated	$	0.75				$	0.75
Weighted average limited partner units outstanding (basic and diluted):
Common		26.9					26.9
Subordinated		26.9					26.9

Consolidated Statements of Cash Flows

	Year Ended December 31, 2018
	Partnership as Previously Reported			Acquisition of HIP			Consolidated Results
(in millions)
Cash flows from operating activities
Net income	$	372.3		$	(46.8	)	$	325.5
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense		123.0			3.9			126.9
(Gain) loss on sale of property, plant and equipment		-			(0.6	)		(0.6	)
(Gain) loss on interest rate swaps		-			(0.4	)		(0.4	)
Amortization of deferred financing costs		1.0			4.0			5.0
Unit-based compensation		0.9			-			0.9
Changes in assets and liabilities:
Accounts receivable—affiliate		(3.2	)		(3.1	)		(6.3	)
Other current and noncurrent assets		1.6			0.3			1.9
Accounts payable—trade		3.1			0.9			4.0
Accounts payable—affiliate		(6.7	)		0.3			(6.4	)
Accrued liabilities		2.7			14.6			17.3
Other current and noncurrent liabilities		(1.1	)		0.2			(0.9	)
Net cash provided by (used in) operating activities		493.6			(26.7	)		466.9
Cash flows from investing activities
Payments for equity investments		(67.3	)		-			(67.3	)
Proceeds from sale of property, plant and equipment		-			1.6			1.6
Additions to property, plant and equipment		(235.6	)		(6.3	)		(241.9	)
Net cash provided by (used in) investing activities		(302.9	)		(4.7	)		(307.6	)
Cash flows from financing activities
Repayments of bank borrowings - term loan		-			(2.5	)		(2.5	)
Financing costs		-			(1.0	)		(1.0	)
Distributions to Hess and GIP		-			(322.0	)		(322.0	)
Distributions to noncontrolling interest		(199.2	)		199.2			-
Contributions from noncontrolling interests		57.3			(57.3	)		-
Distributions to HESM limited partners		(74.1	)		-			(74.1	)
Distributions to HESM general partner		(1.6	)		1.6			-
Other contributions (distributions)		-			(6.1	)		(6.1	)
Net cash provided by (used in) financing activities		(217.6	)		(188.1	)		(405.7	)
Net increase (decrease) in cash and cash equivalents		(26.9	)		(219.5	)		(246.4	)
Cash and cash equivalents at beginning of period		47.2			308.5			355.7
Cash and cash equivalents at end of period	$	20.3		$	89.0		$	109.3

	Year Ended December 31, 2017
	Partnership as Previously Reported			Acquisition of HIP			Consolidated Results
(in millions)
Cash flows from operating activities
Net income	$	284.8		$	(42.8	)	$	242.0
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense		113.1			3.4			116.5
(Gain) loss on sale of property, plant and equipment		-			(4.7	)		(4.7	)
(Gain) loss on interest rate swaps		-			(1.7	)		(1.7	)
Amortization of deferred financing costs		0.6			3.2			3.8
Unit-based compensation		0.2			-			0.2
Changes in assets and liabilities:
Accounts receivable—affiliate		(15.2	)		(1.7	)		(16.9	)
Other current and noncurrent assets		(1.7	)		2.9			1.2
Accounts payable—trade		(16.6	)		(0.1	)		(16.7	)
Accounts payable—affiliate		34.4			(26.9	)		7.5
Accrued liabilities		(1.9	)		5.1			3.2
Other current and noncurrent liabilities		2.2			(0.1	)		2.1
Net cash provided by (used in) operating activities		399.9			(63.4	)		336.5
Cash flows from investing activities
Proceeds from sale of property, plant and equipment		-			12.8			12.8
Additions to property, plant and equipment		(136.4	)		(7.8	)		(144.2	)
Net cash provided by (used in) investing activities		(136.4	)		5.0			(131.4	)
Cash flows from financing activities
Cash distributions to parent prior to the IPO on April 10, 2017		(95.3	)		95.3			-
Cash contributions from parent prior to the IPO on April 10, 2017		67.1			(67.1	)		-
Proceeds from (repayments of) bank borrowings - revolver		-			(153.0	)		(153.0	)
Repayments of bank borrowings - term loan		-			(385.0	)		(385.0	)
Proceeds from issuance of fixed-rate senior notes		-			800.0			800.0
Financing costs		(3.9	)		(19.0	)		(22.9	)
IPO proceeds, net of underwriters' discounts		365.5			-			365.5
Distribution of IPO proceeds to Hess and GIP		(349.5	)		-			(349.5	)
Cash offering costs		(2.1	)		-			(2.1	)
Distributions to Hess and GIP		-			(100.0	)		(100.0	)
Distributions to HESM limited partners		(31.7	)		-			(31.7	)
Distributions to HESM general partner		(0.6	)		0.6			-
Distributions to noncontrolling interest		(244.6	)		244.6			-
Contributions from noncontrolling interest		78.5			(78.5	)		-
Other contributions (distributions)		-			27.6			27.6
Net cash provided by (used in) financing activities		(216.6	)		365.5			148.9
Net increase (decrease) in cash and cash equivalents		46.9			307.1			354.0
Cash and cash equivalents at beginning of period		0.3			1.4			1.7
Cash and cash equivalents at end of period	$	47.2		$	308.5		$	355.7

Partners' Capital and Distributions - Schedule of Distribution Paid by HIP to Hess and GIP Prior to Restructuring (Detail) - Hess Infrastructure Partners LP $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Second Quarter 2017
Distribution Made To Limited Partner [Line Items]
Total Distributions	$ 50.0
Second Quarter 2017 \| Hess Corporation
Distribution Made To Limited Partner [Line Items]
Total Distributions	27.1
Second Quarter 2017 \| GIP
Distribution Made To Limited Partner [Line Items]
Total Distributions	22.9
Third Quarter 2017
Distribution Made To Limited Partner [Line Items]
Total Distributions	50.0
Third Quarter 2017 \| Hess Corporation
Distribution Made To Limited Partner [Line Items]
Total Distributions	25.0
Third Quarter 2017 \| GIP
Distribution Made To Limited Partner [Line Items]
Total Distributions	25.0
Fourth Quarter 2018
Distribution Made To Limited Partner [Line Items]
Total Distributions	322.0
Fourth Quarter 2018 \| Hess Corporation
Distribution Made To Limited Partner [Line Items]
Total Distributions	160.0
Fourth Quarter 2018 \| GIP
Distribution Made To Limited Partner [Line Items]
Total Distributions	$ 162.0

Acquisitions - Consolidated Statements of Operations (Detail) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Revenues and other income

$ 847.6

$ 712.0

^[1]

$ 579.5

^[1]

hesm:AffiliateServicesMember

^[1]

hesm:AffiliateServicesMember

^[1]

$ 0.7

^[1]

$ 253.5

$ 214.9

$ 190.3

$ 189.6

$ 185.9

$ 183.8

$ 176.5

$ 166.5

848.3

712.7

^[1]

$ 579.5

^[1]

Operating and maintenance expenses (exclusive of depreciation shown separately below)

276.8

193.5

^[1]

186.0

^[1]

142.5

126.9

^[1]

116.5

^[1]

52.4

14.1

^[1]

13.9

^[1]

471.7

334.5

^[1]

316.4

^[1]

90.3

99.3

91.2

95.8

92.1

99.0

96.3

90.8

376.6

378.2

^[1]

263.1

^[1]

62.4

53.3

^[1]

25.8

^[1]

^[1]

0.6

4.7

Less: Net income (loss) attributable to net parent investment

75.1

87.4

74.4

80.8

78.9

86.1

82.8

77.7

317.7

325.5

^[1]

242.0

^[1]

(55.0)

(46.8)

^[1]

25.4

^[1]

Less: Net income (loss) attributable to noncontrolling interest

302.6

301.5

^[1]

175.4

^[1]

Less: General partner's interest in net income prior to the Restructuring

$ 16.1

$ 19.1

$ 16.8

$ 18.1

$ 17.2

$ 18.8

$ 17.8

$ 17.0

70.1

70.8

^[1]

41.2

^[1]

3.4

1.7

^[1]

0.8

^[1]

Partnership as Previously Reported

$ 66.7

69.1

^[1]

40.4

^[1]

Revenues and other income

$ 661.7

$ 565.6

hesm:AffiliateServicesMember

$ 0.7

$ 0.2

662.4

565.8

Operating and maintenance expenses (exclusive of depreciation shown separately below)

154.3

158.4

123.0

113.1

11.5

8.1

288.8

279.6

373.6

286.2

1.3

1.4

Less: Net income (loss) attributable to net parent investment

372.3

284.8

68.2

Less: Net income (loss) attributable to noncontrolling interest

301.5

175.4

Less: General partner's interest in net income prior to the Restructuring

70.8

41.2

1.7

0.8

Restatement Adjustment | Acquisition of HIP

69.1

40.4

Revenues and other income

$ 50.3

$ 13.9

hesm:AffiliateServicesMember

$ (0.2)

$ 50.3

13.7

Operating and maintenance expenses (exclusive of depreciation shown separately below)

39.2

27.6

3.9

3.4

2.6

5.8

45.7

36.8

4.6

(23.1)

52.0

24.4

0.6

4.7

Less: Net income (loss) attributable to net parent investment

(46.8)

(42.8)

$ (46.8)

$ (42.8)

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

$ 0.33

$ 0.29

$ 0.32

$ 0.31

$ 0.34

$ 0.32

$ 0.30

$ 1.27

^[1]

$ 0.75

^[1]

Weighted average limited partner units outstanding, Basic:

Units outstanding prior to the Restructuring, Basic

27.3

^[1]

26.9

^[1]

Weighted average limited partner units outstanding, Diluted:

Units outstanding prior to the Restructuring, Diluted

27.5

27.4

^[1]

26.9

^[1]

Weighted average limited partner units outstanding (basic and diluted):

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

26.9

Common Units | Partnership as Previously Reported

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

$ 1.27

$ 0.75

Weighted average limited partner units outstanding, Basic:

Units outstanding prior to the Restructuring, Basic

27.3

Weighted average limited partner units outstanding, Diluted:

Units outstanding prior to the Restructuring, Diluted

27.4

Weighted average limited partner units outstanding (basic and diluted):

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

26.9

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

$ 0.33

$ 0.29

$ 0.32

$ 0.31

$ 0.34

$ 0.32

$ 0.30

$ 1.27

^[1]

$ 0.75

^[1]

Weighted average limited partner units outstanding, Basic:

Units outstanding prior to the Restructuring, Basic

27.3

^[1]

26.9

^[1]

Weighted average limited partner units outstanding, Diluted:

Units outstanding prior to the Restructuring, Diluted

27.3

^[1]

26.9

^[1]

Weighted average limited partner units outstanding (basic and diluted):

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

26.9

Subordinated Units | Partnership as Previously Reported

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Net income attributable to Hess Midstream Partners per limited partner unit

$ 1.27

$ 0.75

Weighted average limited partner units outstanding, Basic:

Units outstanding prior to the Restructuring, Basic

27.3

Weighted average limited partner units outstanding, Diluted:

Units outstanding prior to the Restructuring, Diluted

27.3

Weighted average limited partner units outstanding (basic and diluted):

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

26.9

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2019

Property Plant And Equipment [Abstract]

Components of Property, Plant and Equipment

Property, plant and equipment, at cost, is as follows:

	Estimated useful lives	December 31, 2019			December 31, 2018
(in millions, except for number of years)
Gathering assets
Pipelines	22 years	$	1,352.7		$	1,098.1
Compressors, pumping stations and terminals	22 to 25 years		725.9			558.9
Gas plant assets
Pipelines, pipes and valves	22 to 25 years		460.0			460.0
Equipment	12 to 30 years		428.2			428.2
Buildings	35 years		182.3			182.3
Processing and fractionation facilities	25 years		188.6			185.5
Logistics facilities and railcars	20 to 25 years		385.5			385.8
Storage facilities	20 to 25 years		19.5			19.5
Other	20 to 25 years		13.0			11.4
Construction-in-progress	N/A		149.3			158.5
Total property, plant and equipment, at cost			3,905.0			3,488.2
Accumulated depreciation			(894.9	)		(752.9	)
Property, plant and equipment, net		$	3,010.1		$	2,735.3

Partners' Capital and Distributions - Additional Information (Detail) $ / shares in Units, $ in Millions		3 Months Ended	12 Months Ended
	Dec. 16, 2019 USD ($) $ / shares shares	Jun. 30, 2017 USD ($)	Dec. 31, 2019
Distribution Made To Limited Partner [Line Items]
Period of cash distribution to unitholders			45 days
Hess and GIP
Distribution Made To Limited Partner [Line Items]
Cash consideration \| $	$ 601.8
Payments of special distribution \| $		$ 349.5
Hess
Distribution Made To Limited Partner [Line Items]
Percentage of distribution		50.00%
GIP
Distribution Made To Limited Partner [Line Items]
Percentage of distribution		50.00%
Hess Infrastructure Partners LP Acquisition
Distribution Made To Limited Partner [Line Items]
Stock split conversion ratio	1
Common units of the partnership converted into class A shares \| shares	17,062,655
Hess Infrastructure Partners LP Acquisition \| Common Class A
Distribution Made To Limited Partner [Line Items]
Units representing noncontrolling limited partner interests \| shares	898,000
Hess Infrastructure Partners LP Acquisition \| Class B Shares
Distribution Made To Limited Partner [Line Items]
Units representing noncontrolling limited partner interests \| shares	266,416,928
Cash consideration \| $	$ 601.8
Business acquisition, share price \| $ / shares	$ 0.0001

Acquisitions (Tables)

12 Months Ended

Dec. 31, 2019

Business Combinations [Abstract]

Summary of Hess Water Services Acquisition

In connection with the Hess Water Services acquisition, HIP acquired the following:

(in millions)
Property, plant and equipment, net	$	70.8
Working capital		(1.2	)
Asset retirement obligations		(0.7	)
Net assets acquired	$	68.9

Consolidated Balance Sheet

	December 31, 2018
	Partnership as Previously Reported		Acquisition of HIP			Consolidated Results
(in millions)
Assets
Cash and cash equivalents	$	20.3	$	89.0		$	109.3
Accounts receivable—affiliate:
From contracts with customers		62.2		5.1			67.3
Other receivables		0.8		(0.3	)		0.5
Other current assets		2.8		0.5			3.3
Total current assets		86.1		94.3			180.4
Equity Investments		67.3		-			67.3
Property, plant and equipment, net		2,664.1		71.2			2,735.3
Long-term receivable—affiliate		-		1.3			1.3
Other noncurrent assets		2.2		4.7			6.9
Total assets	$	2,819.7	$	171.5		$	2,991.2
Liabilities
Accounts payable—trade	$	15.3	$	3.3		$	18.6
Accounts payable—affiliate		15.8		-			15.8
Accrued liabilities		64.5		21.1			85.6
Current maturities of long-term debt		-		11.3			11.3
Other current liabilities		6.8		-			6.8
Total current liabilities		102.4		35.7			138.1
Long-term debt		-		969.8			969.8
Other noncurrent liabilities		6.4		0.8			7.2
Total liabilities		108.8		1,006.3			1,115.1
Common unitholders—public (17,014,377 units issued and outstanding)		357.1		-			357.1
Common unitholders—affiliate (10,282,654 units issued and outstanding)		39.5		-			39.5
Subordinated unitholders—affiliate (27,279,654 units issued and outstanding)		105.3		-			105.3
General partner		14.9		-			14.9
Total Hess Midstream Partners LP partners' capital		516.8		-			516.8
Noncontrolling interest		2,194.1		-			2,194.1
Accumulated other comprehensive income		-		1.2			1.2
Net parent investment		-		(836.0	)		(836.0	)
Total partners' capital		2,710.9		(834.8	)		1,876.1
Total liabilities and partners' capital	$	2,819.7	$	171.5		$	2,991.2

Consolidated Statements of Operations

	Year Ended December 31, 2018
	Partnership as Previously Reported		Acquisition of HIP			Consolidated Results
(in millions)
Revenues and other income
Affiliate services	$	661.7	$	50.3		$	712.0
Other income		0.7		-			0.7
Total revenues and other income		662.4		50.3			712.7
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)		154.3		39.2			193.5
Depreciation expense		123.0		3.9			126.9
General and administrative expenses		11.5		2.6			14.1
Total costs and expenses		288.8		45.7			334.5
Income from operations		373.6		4.6			378.2
Interest expense, net		1.3		52.0			53.3
Gain on sale of property, plant and equipment		-		0.6			0.6
Net income		372.3		(46.8	)		325.5
Less: Net income (loss) attributable to net parent investment		-		(46.8	)		(46.8	)
Less: Net income attributable to noncontrolling interest		301.5		-			301.5
Net income attributable to Hess Midstream Partners LP		70.8		-			70.8
Less: General partner's interest in net income attributable to Hess Midstream Partners LP		1.7		-			1.7
Limited partners' interest in net income attributable to Hess Midstream Partners LP	$	69.1		-		$	69.1
Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted):
Common	$	1.27				$	1.27
Subordinated	$	1.27				$	1.27
Weighted average limited partner units outstanding:
Basic:
Common		27.3					27.3
Subordinated		27.3					27.3
Diluted:
Common		27.4					27.4
Subordinated		27.3					27.3

	Year Ended December 31, 2017
	Partnership as Previously Reported		Acquisition of HIP			Consolidated Results
(in millions)
Revenues and other income
Affiliate services	$	565.6	$	13.9		$	579.5
Other income		0.2		(0.2	)		-
Total revenues and other income		565.8		13.7			579.5
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)		158.4		27.6			186.0
Depreciation expense		113.1		3.4			116.5
General and administrative expenses		8.1		5.8			13.9
Total costs and expenses		279.6		36.8			316.4
Income from operations		286.2		(23.1	)		263.1
Interest expense, net		1.4		24.4			25.8
Gain on sale of property, plant and equipment		-		4.7			4.7
Net income		284.8		(42.8	)		242.0
Less: Net income (loss) attributable to net parent investment		68.2		(42.8	)		25.4
Less: Net income attributable to noncontrolling interest		175.4		-			175.4
Net income attributable to Hess Midstream Partners LP		41.2		-			41.2
Less: General partner's interest in net income attributable to Hess Midstream Partners LP		0.8		-			0.8
Limited partners' interest in net income attributable to Hess Midstream Partners LP	$	40.4	$	-		$	40.4
Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted):
Common	$	0.75				$	0.75
Subordinated	$	0.75				$	0.75
Weighted average limited partner units outstanding (basic and diluted):
Common		26.9					26.9
Subordinated		26.9					26.9

Consolidated Statements of Cash Flows

	Year Ended December 31, 2018
	Partnership as Previously Reported			Acquisition of HIP			Consolidated Results
(in millions)
Cash flows from operating activities
Net income	$	372.3		$	(46.8	)	$	325.5
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense		123.0			3.9			126.9
(Gain) loss on sale of property, plant and equipment		-			(0.6	)		(0.6	)
(Gain) loss on interest rate swaps		-			(0.4	)		(0.4	)
Amortization of deferred financing costs		1.0			4.0			5.0
Unit-based compensation		0.9			-			0.9
Changes in assets and liabilities:
Accounts receivable—affiliate		(3.2	)		(3.1	)		(6.3	)
Other current and noncurrent assets		1.6			0.3			1.9
Accounts payable—trade		3.1			0.9			4.0
Accounts payable—affiliate		(6.7	)		0.3			(6.4	)
Accrued liabilities		2.7			14.6			17.3
Other current and noncurrent liabilities		(1.1	)		0.2			(0.9	)
Net cash provided by (used in) operating activities		493.6			(26.7	)		466.9
Cash flows from investing activities
Payments for equity investments		(67.3	)		-			(67.3	)
Proceeds from sale of property, plant and equipment		-			1.6			1.6
Additions to property, plant and equipment		(235.6	)		(6.3	)		(241.9	)
Net cash provided by (used in) investing activities		(302.9	)		(4.7	)		(307.6	)
Cash flows from financing activities
Repayments of bank borrowings - term loan		-			(2.5	)		(2.5	)
Financing costs		-			(1.0	)		(1.0	)
Distributions to Hess and GIP		-			(322.0	)		(322.0	)
Distributions to noncontrolling interest		(199.2	)		199.2			-
Contributions from noncontrolling interests		57.3			(57.3	)		-
Distributions to HESM limited partners		(74.1	)		-			(74.1	)
Distributions to HESM general partner		(1.6	)		1.6			-
Other contributions (distributions)		-			(6.1	)		(6.1	)
Net cash provided by (used in) financing activities		(217.6	)		(188.1	)		(405.7	)
Net increase (decrease) in cash and cash equivalents		(26.9	)		(219.5	)		(246.4	)
Cash and cash equivalents at beginning of period		47.2			308.5			355.7
Cash and cash equivalents at end of period	$	20.3		$	89.0		$	109.3

	Year Ended December 31, 2017
	Partnership as Previously Reported			Acquisition of HIP			Consolidated Results
(in millions)
Cash flows from operating activities
Net income	$	284.8		$	(42.8	)	$	242.0
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense		113.1			3.4			116.5
(Gain) loss on sale of property, plant and equipment		-			(4.7	)		(4.7	)
(Gain) loss on interest rate swaps		-			(1.7	)		(1.7	)
Amortization of deferred financing costs		0.6			3.2			3.8
Unit-based compensation		0.2			-			0.2
Changes in assets and liabilities:
Accounts receivable—affiliate		(15.2	)		(1.7	)		(16.9	)
Other current and noncurrent assets		(1.7	)		2.9			1.2
Accounts payable—trade		(16.6	)		(0.1	)		(16.7	)
Accounts payable—affiliate		34.4			(26.9	)		7.5
Accrued liabilities		(1.9	)		5.1			3.2
Other current and noncurrent liabilities		2.2			(0.1	)		2.1
Net cash provided by (used in) operating activities		399.9			(63.4	)		336.5
Cash flows from investing activities
Proceeds from sale of property, plant and equipment		-			12.8			12.8
Additions to property, plant and equipment		(136.4	)		(7.8	)		(144.2	)
Net cash provided by (used in) investing activities		(136.4	)		5.0			(131.4	)
Cash flows from financing activities
Cash distributions to parent prior to the IPO on April 10, 2017		(95.3	)		95.3			-
Cash contributions from parent prior to the IPO on April 10, 2017		67.1			(67.1	)		-
Proceeds from (repayments of) bank borrowings - revolver		-			(153.0	)		(153.0	)
Repayments of bank borrowings - term loan		-			(385.0	)		(385.0	)
Proceeds from issuance of fixed-rate senior notes		-			800.0			800.0
Financing costs		(3.9	)		(19.0	)		(22.9	)
IPO proceeds, net of underwriters' discounts		365.5			-			365.5
Distribution of IPO proceeds to Hess and GIP		(349.5	)		-			(349.5	)
Cash offering costs		(2.1	)		-			(2.1	)
Distributions to Hess and GIP		-			(100.0	)		(100.0	)
Distributions to HESM limited partners		(31.7	)		-			(31.7	)
Distributions to HESM general partner		(0.6	)		0.6			-
Distributions to noncontrolling interest		(244.6	)		244.6			-
Contributions from noncontrolling interest		78.5			(78.5	)		-
Other contributions (distributions)		-			27.6			27.6
Net cash provided by (used in) financing activities		(216.6	)		365.5			148.9
Net increase (decrease) in cash and cash equivalents		46.9			307.1			354.0
Cash and cash equivalents at beginning of period		0.3			1.4			1.7
Cash and cash equivalents at end of period	$	47.2		$	308.5		$	355.7

CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL - USD ($)
$ in Millions

Total

Prior To Restructuring

After Restructuring

Limited Partners

Class A Shares

Limited Partners

After Restructuring

Class A Shares

Limited Partners

Common Unitholders - Public

Limited Partners

Common Unitholders - Public

Prior To Restructuring

Limited Partners

Common Unitholders - Affiliate

Limited Partners

Common Unitholders - Affiliate

Prior To Restructuring

Limited Partners

Subordinated Unitholders - Affiliate

Limited Partners

Subordinated Unitholders - Affiliate

Prior To Restructuring

General Partner

Prior To Restructuring

Noncontrolling Interest

Prior To Restructuring

Noncontrolling Interest

After Restructuring

Accumulated Other Comprehensive Income

Net Parent Investment

Prior To Restructuring

Balance, beginning of period at Dec. 31, 2016

$ 1,809.9

Contribution of net assets to Hess Midstream Partners LP

$ 134.6

$ 357.2

$ 14.6

$ 2,025.2

(2,531.6)

Distributions of IPO proceeds

365.5

$ 365.5

(349.5)

(95.7)

(253.8)

Offering costs

(10.7)

Other comprehensive income (loss)

242.0

^[1]

12.6

7.6

20.2

0.8

175.4

25.4

1.6

^[1]

$ 1.6

Equity-based compensation

0.2

Distributions to unitholders

(31.7)

(9.9)

(6.0)

(15.8)

Distributions to general partner

(0.6)

0.6

Contributions from noncontrolling interest

(244.6)

244.6

78.5

(78.5)

Balance, end of period at Dec. 31, 2017

(75.0)

1,952.3

357.7

40.5

107.8

14.8

2,034.5

1.6

(604.6)

Other comprehensive income (loss)

325.5

^[1]

21.6

13.0

34.5

1.7

301.5

(46.8)

(0.4)

^[1]

(0.4)

Equity-based compensation

0.9

Distributions to unitholders

(74.1)

(23.1)

(14.0)

(37.0)

Distributions to general partner

(1.6)

1.6

Contributions from noncontrolling interest

(199.2)

199.2

57.3

(57.3)

Balance, end of period at Dec. 31, 2018

(328.1)

1,876.1

^[1]

357.1

39.5

105.3

14.9

2,194.1

1.2

(836.0)

Other comprehensive income (loss)

317.7

$ 325.0

$ (7.3)

$ (0.5)

$ 20.8

$ 12.9

$ 33.5

$ 3.4

$ 309.4

$ (6.8)

$ (55.0)

(0.8)

Equity-based compensation

1.3

$ 0.2

1.3

Distributions to unitholders

$ (85.4)

$ (26.8)

$ (16.0)

$ (42.6)

Distributions to general partner

$ (3.8)

3.8

Contributions from noncontrolling interest

(200.6)

200.6

$ 76.3

$ (76.3)

Acquisition of Hess Water Services

(225.0)

Equity exchange related to Restructuring

$ 81.4

$ (352.4)

$ (36.4)

$ (96.2)

$ (14.5)

(569.8)

$ 987.9

Cash consideration related to Restructuring

(601.8)

Recognition of Deferred Tax Asset

49.8

50.0

(0.2)

Balance, end of period at Dec. 31, 2019

$ 1,332.1

$ 131.1

$ 1,200.6

$ 0.4

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Summary of Significant Accounting Policies and Basis of Presentation - Additional Information (Detail) - USD ($)

12 Months Ended

Dec. 16, 2019

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Doubtful accounts written off

$ 0

Allowance for doubtful accounts

Impairment of long-lived assets

$ 0

Operating lease right-of-use assets included within other noncurrent assets

$ 800,000

Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]

us-gaap:OtherAssetsNoncurrent

Operating lease liabilities included within other current liabilities

$ 200,000

Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]

us-gaap:OtherLiabilitiesCurrent

Operating lease liabilities included within other noncurrent liabilities

$ 600,000

Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]

us-gaap:OtherLiabilitiesNoncurrent

Finance lease

$ 0

Cash contributed to acquire equity method investments

$ 33,000,000

67,300,000

^[1]

Minimum

Depreciation lives of assets

12 years

Maximum

Depreciation lives of assets

35 years

Revolving Credit Facility | Other Noncurrent Assets

Unamortized deferred financing costs

$ 12,200,000

6,900,000

Fixed-Rate Senior Notes and Term Loan | Long-term Debt

Unamortized deferred financing costs

28,500,000

$ 16,500,000

LM4

Cash contributed to acquire equity method investments

100,300,000

Capitalized interests expenses

$ 4,100,000

Hess and GIP

Noncontrolling interest percentage

93.68%

Hess Infrastructure Partners Limited Partnership Joint Interest Assets

Noncontrolling interest percentage prior to restructuring

80.00%

Percentage of ownership interest

80.00%

General Partner Interest and IDRs

Percentage of ownership interest

2.00%

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Partners' Capital and Distributions (Tables)

12 Months Ended

Dec. 31, 2019

Partners Capital Notes [Abstract]

Schedule of Distributions Declared and Paid

The following table details the distributions declared and/or paid for the periods presented:

Period	Record Date	Distribution Date	Distribution per Common and Subordinated Unit/Class A Share
First Quarter 2018	May 4, 2018	May 14, 2018	$0.3333
Second Quarter 2018	August 2, 2018	August 13, 2018	$0.3452
Third Quarter 2018	November 5, 2018	November 13, 2018	$0.3575
Fourth Quarter 2018	February 4, 2019	February 13, 2019	$0.3701
First Quarter 2019	May 3, 2019	May 14, 2019	$0.3833
Second Quarter 2019	August 5, 2019	August 13, 2019	$0.3970
Third Quarter 2019	November 4, 2019	November 13, 2019	$0.4112
Fourth Quarter 2019⁽¹⁾	February 6, 2020	February 14, 2020	$0.4258

(1)

For more information, see Note 16, Subsequent Events.

Schedule of Distribution Paid by HIP to Hess and GIP Prior to Restructuring

The following table details distributions paid by HIP to Hess and GIP prior to the Restructuring (in millions):

Type of Distributions	Period	Distribution to Hess Corporation		Distribution to GIP		Total Distributions
HIP LP Distributions	Second Quarter 2017		27.1		22.9	$	50.0
HIP LP Distributions	Third Quarter 2017		25.0		25.0	$	50.0
HIP LP Distributions	Fourth Quarter 2018		160.0		162.0	$	322.0

Acquisitions - Summary of Hess Water Services Acquisition (Detail) - Hess Infrastructure Partners LP $ in Millions	Mar. 01, 2019 USD ($)
Business Acquisition [Line Items]
Property, plant and equipment, net	$ 70.8
Working capital	(1.2)
Asset retirement obligations	(0.7)
Net assets acquired	$ 68.9

Concentration of Credit Risk - Additional Information (Detail) - Credit Concentration Risk	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%
Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%

Segments (Tables)

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

Financial Data for Each Reportable Segment

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated
(in millions)
For the Year Ended December 31, 2019
Revenues and other income	$	422.9	$	295.3	$	130.1	$	-		$	848.3
Net income (loss)		186.0		176.1		54.8		(99.2	)		317.7
Net income (loss) attributable to Hess Midstream LP		34.6		34.6		10.5		(9.6	)		70.1
Depreciation expense		81.6		44.7		16.2		-			142.5
Proportional share of equity affiliates' depreciation		-		2.0		-		-			2.0
Income from equity investments		-		3.4		-		-			3.4
Interest expense, net		-		-		-		62.4			62.4
Income tax expense (benefit)		-		-		-		(0.1	)		(0.1	)
Transaction costs		-		-		-		26.2			26.2
Adjusted EBITDA		267.6		222.8		71.0		(10.7	)		550.7
Capital expenditures*		373.6		42.5		0.2		-			416.3
	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated
(in millions)
For the Year Ended December 31, 2018
Revenues and other income	$	375.2	$	251.4	$	86.1	$	-		$	712.7
Net income (loss)		199.6		148.8		36.1		(59.0	)		325.5
Net income (loss) attributable to Hess Midstream LP		38.4		30.7		7.3		(5.6	)		70.8
Depreciation expense		67.2		43.9		15.8		-			126.9
Interest expense, net		-		-		-		53.3			53.3
Gain on sale of property, plant and equipment		-		-		-		0.6			0.6
Adjusted EBITDA		266.8		192.7		51.9		(6.3	)		505.1
Capital expenditures		257.0		10.0		4.3		-			271.3

	Gathering		Processing and Storage		Terminaling and Export		Interest and Other			Consolidated
(in millions)
For the Year Ended December 31, 2017
Revenues and other income	$	285.5	$	227.3	$	66.7	$	-		$	579.5
Net income (loss)		132.1		123.8		14.4		(28.3	)		242.0
Net income (loss) attributable to Hess Midstream LP		23.3		18.8		2.4		(3.3	)		41.2
Depreciation expense		57.8		43.6		15.1		-			116.5
Interest expense, net		-		-		-		25.8			25.8
Gain on sale of property, plant and equipment		-		-		-		4.7			4.7
Adjusted EBITDA		189.9		167.4		29.5		(7.2	)		379.6
Capital expenditures		77.8		15.9		24.6		-			118.3
*Includes acquisition, expansion and maintenance capital expenditures.

Total Assets for Reportable Segments

Total assets for reportable segments are as follows:


	December 31, 2019		December 31, 2018
(in millions)
Gathering	$	1,844.9	$	1,544.0
Processing and Storage⁽¹⁾		1,055.1		1,008.6
Terminaling and Export		310.7		320.2
Interest and Other		67.0		118.4
Total assets	$	3,277.7	$	2,991.2

⁽¹⁾	Includes $107.8 million of investment in equity investees.

Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

$ 3,905.0

$ 3,488.2

Accumulated depreciation

(894.9)

(752.9)

Logistics Facilities and Railcars

3,010.1

2,735.3

^[1]

385.5

385.8

Storage Facilities

19.5

Other

13.0

11.4

Construction-In-Progress

$ 149.3

158.5

Minimum

Property, plant and equipment, Estimated useful life

12 years

Minimum | Logistics Facilities and Railcars

Property, plant and equipment, Estimated useful life

20 years

Minimum | Storage Facilities

Property, plant and equipment, Estimated useful life

20 years

Minimum | Other

Property, plant and equipment, Estimated useful life

20 years

Maximum

Property, plant and equipment, Estimated useful life

35 years

Maximum | Logistics Facilities and Railcars

Property, plant and equipment, Estimated useful life

25 years

Maximum | Storage Facilities

Property, plant and equipment, Estimated useful life

25 years

Maximum | Other

Property, plant and equipment, Estimated useful life

25 years

Gathering Assets | Pipelines

Property, plant and equipment, Estimated useful life

22 years

Gathering Assets | Compressors, Pumping Stations and Terminals

$ 1,352.7

1,098.1

Gathering Assets | Minimum | Compressors, Pumping Stations and Terminals

$ 725.9

558.9

Property, plant and equipment, Estimated useful life

22 years

Gathering Assets | Maximum | Compressors, Pumping Stations and Terminals

Property, plant and equipment, Estimated useful life

25 years

Gas Plant Assets | Pipelines, Pipes and Valves

Gas Plant Assets | Equipment

$ 460.0

460.0

Gas Plant Assets | Buildings

$ 428.2

428.2

Property, plant and equipment, Estimated useful life

35 years

Gas Plant Assets | Processing and Fractionation Facilities

$ 182.3

182.3

Property, plant and equipment, Estimated useful life

25 years

Gas Plant Assets | Minimum | Pipelines, Pipes and Valves

$ 188.6

$ 185.5

Property, plant and equipment, Estimated useful life

22 years

Gas Plant Assets | Minimum | Equipment

Property, plant and equipment, Estimated useful life

12 years

Gas Plant Assets | Maximum | Pipelines, Pipes and Valves

Property, plant and equipment, Estimated useful life

25 years

Gas Plant Assets | Maximum | Equipment

Property, plant and equipment, Estimated useful life

30 years

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Equity-Based Compensation - Schedule of Equity-based Award Activity (Detail) - Restricted Share - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding and unvested shares/units at December 31, 2018, Number of Shares	114,237
Granted, Number of Shares	74,528
Forfeited, Number of Shares	(4,427)
Vested, Number of Shares	(48,278)
Outstanding and unvested shares at December 31, 2019, Number of Shares	136,060	114,237
Outstanding and unvested shares/units at December 31, 2018, Weighted Average Award Date Fair Value	$ 21.06
Granted, Weighted Average Award Date Fair Value	22.76
Forfeited, Weighted Average Award Date Fair Value	21.36
Vested, Weighted Average Award Date Fair Value	21.15
Outstanding and unvested shares at December 31, 2019, Weighted Average Award Date Fair Value	$ 21.95	$ 21.06
Fair value of shares granted	$ 1.7	$ 1.9	$ 1.0
Fair value of shares vested	$ 1.0	$ 0.4

Summary of Significant Accounting Policies and Basis of Presentation

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies and Basis of Presentation

Note 2. Summary of Significant Accounting Policies and Basis of Presentation

Consolidation. The consolidated financial statements include our accounts and the accounts of entities over which we have a controlling financial interest through our ownership or the majority voting interests of the entity. We consolidate the activities of the Partnership, and prior to the Restructuring the activities of Gathering Opco, HTGP Opco and Logistics Opco, each as a variable interest entity (“VIE”) under U.S. Generally Accepted Accounting Principles (“GAAP”). We have concluded that we are the primary beneficiary of the VIE, as defined in the accounting standards, since we have the power, through our ownership, to direct those activities that most significantly impact the economic performance of the Partnership. This conclusion was based on a qualitative analysis that considered the Partnership’s governance structure and the delegation of control provisions, which provide us the ability to control the operations of the Partnership. All financial statement activities associated with the VIE are captured within gathering, processing and storage, and terminaling and export segments (see Note 14, Segments). Our noncontrolling interest represents the 93.68% interest in the Partnership retained by Hess and GIP. Prior to the Restructuring, our noncontrolling interest represented the 80% interest in the Joint Interest Assets retained by HIP. All intercompany transactions and balances have been eliminated.

Use of Estimates. We prepare our consolidated financial statements in conformity with the U.S. GAAP, which require management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the years presented. Changes in facts and circumstances may result in revised estimates and actual results could differ from those estimates.

Common Control Transactions. Assets and businesses acquired from Hess and its subsidiaries are accounted for as common control transactions whereby the net assets acquired are combined with net assets of the Company at Hess’ historical carrying value. If any recognized consideration transferred in such a transaction exceeds the carrying value of the net assets acquired, the excess is treated as a capital distribution to Hess, similar to a dividend. To the extent that such transactions require prior periods to be retrospectively adjusted, historical net equity amounts prior to the transaction date are reflected in “Net Parent Investment.” Cash consideration up to the carrying value of net assets acquired is presented as an investing activity in our consolidated statement of cash flows. Cash consideration in excess of the carrying value of net assets acquired is presented as a financing activity in our consolidated statement of cash flows.

Cash and Cash Equivalents. Cash equivalents consist of highly liquid investments, which are readily convertible into cash and have maturities of three months or less when acquired.

Accounts Receivable. We record affiliate accounts receivable upon performance of services to affiliated companies. Generally, we receive payments from affiliated companies on a monthly basis, shortly after performance of services. There were no doubtful accounts written off, nor have we provided an allowance for doubtful accounts, as of December 31, 2019 and 2018.

Property, Plant and Equipment. Property, plant and equipment are stated at the lower of historical cost less accumulated depreciation subject to the results of impairment testing. We capitalize all construction-related direct labor and material costs, as well as indirect construction costs. Indirect construction costs include general engineering, taxes and the cost of funds used during construction. Costs, including complete asset replacements and enhancements or upgrades that increase the original efficiency, productivity or capacity of property, plant and equipment, are also capitalized. The costs of repairs, minor replacements and other projects, which do not increase the original efficiency, productivity or capacity of property, plant and equipment, are expensed as incurred.

Capitalization of Interest. Interest charges from borrowings are capitalized on material projects using the weighted average cost of outstanding borrowings until the project is substantially complete and ready for its intended use. Capitalized interest is depreciated over the useful lives of the assets in the same manner as the depreciation of the underlying assets.

Impairment of Long‑Lived Assets. We review long-lived assets for impairment whenever events or changes in business circumstances indicate the net book values of the assets may not be recoverable. Impairment is indicated when the undiscounted cash flows estimated to be generated by those assets are less than the assets’ net book value. Undiscounted cash flows are based on identifiable cash flows that are largely independent of the cash flows of other assets and liabilities. If impairment occurs, a loss is recognized for the difference between the fair value and net book value. Such fair value is generally determined by discounting anticipated future net cash flows, an income valuation approach, or by a market-based valuation approach, which are Level 3 fair value measurements. Factors that indicate potential impairment include a significant decrease in the market value of the asset, operating or cash flow losses associated with the use of the asset, and a significant change in the asset’s physical condition or use. No impairments of long‑lived assets were recorded during the years ended December 31, 2019, 2018 and 2017.

Leases. We determine if an arrangement is a lease at inception. Operating lease right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease right-of-use assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The operating lease right-of-use asset includes any initial direct costs and excludes lease incentives received. The lease term used in measurement of our lease obligations may include periods covered by an option to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected not to recognize lease assets and lease liabilities for leases with a term of 12 months or less for all classes of underlying assets. Our lease agreements may include lease and non-lease components, which are generally accounted for separately.

As of December 31, 2019, we had $0.8 million of operating lease right-of-use assets included within other noncurrent assets on our consolidated balance sheet. Operating lease liabilities were $0.2 million and $0.6 million included within other current liabilities and other noncurrent liabilities, respectively, on our consolidated balance sheet. As of December 31, 2019, we did not have any finance leases.

Equity Investments. We account for our investment in LM4 under the equity method of accounting, as we do not control, but have a significant influence over, its operations. As of December 31, 2019, we contributed $100.3 million of cash for our gross interest in LM4 and capitalized $4.1 million of interest expense associated with our investment in LM4. Difference in the basis of the investment and the underlying net asset value of the equity investee is amortized into net income over the remaining useful lives of the underlying assets. Earnings from equity investments represent our proportionate share of net income generated by the equity investee. We classify distributions received from equity method investees on the basis of the nature of the activity of the investee that generated the distribution as either a return on investment classified as cash inflows from operating activities or a return of investment classified as cash inflows from investing activities when such information is available to us.

Deferred Financing Costs. We capitalize debt issuance costs and fees incurred related to the procurement of our credit facilities. We amortize such costs as additional interest expense over the life of the credit agreement using the straight-line method, which approximates the effective interest method. Unamortized deferred financing costs related to our revolving credit facility are presented in Other noncurrent assets (2019: $12.2 million, 2018: $6.9 million) and unamortized deferred financing costs related to our fixed-rate senior notes and our term loan are presented as a direct reduction to the Long-term debt (2019: $28.5 million, 2018: $16.5 million) in the accompanying consolidated balance sheets.

Asset Retirement Obligations. We record legal obligations to remove and dismantle long-lived assets. We recognize a liability for the fair value of legally required asset retirement obligations associated with long-lived assets in the period in which the retirement obligations are incurred if the liability can be reasonably estimated. The associated asset retirement costs are capitalized as part of the carrying amount of the long-lived assets. Accretion expense is included in Depreciation expense in the consolidated statement of operations. We have not incurred significant asset retirement obligations.

Net Parent Investment. Net parent investment represents HIP’s historical activity as well as Hess’ historical investment in Hess Water Services prior to its acquisition by HIP, the accumulated net operating results through the date when we obtained control of HIP, and the net effect of transactions between HIP and the Sponsors, and between Hess and Hess Water Services. Retrospectively adjusted financial information from prior to the acquisition of HIP is included in Net parent investment.

Revenue Recognition—Contracts with Customers. We earn substantially all of our revenues by charging fees for gathering, compressing and processing natural gas and fractionating NGLs; gathering, terminaling, loading and transporting crude oil and NGLs, gathering and disposing produced water, and storing and terminaling propane. We do not own or take title to the volumes that we handle. Effective January 1, 2014, we entered into i) gas gathering, ii) crude oil gathering, iii) gas processing and fractionation, iv) storage services, and v) terminal and export services fee‑based commercial agreements with certain subsidiaries of Hess, and effective January 1, 2019, we entered into water gathering and disposal services fee-based agreements with certain subsidiaries of Hess. In 2018 and partial year 2017, Hess Water Services had documented intercompany arrangements with certain subsidiaries of Hess pursuant to which it provided produced water gathering and disposal services and charged agreed-upon fees per barrel for the services performed.

Our responsibilities to provide each of the above services for each year under each of the commercial agreements are considered separate, distinct performance obligations. We recognize revenues for each performance obligation under our commercial agreements over‑time as services are rendered using the output method, measured using the amount of volumes serviced during the period. The minimum volume commitments are subject to fluctuation based on nominations covering substantially all of Hess’ production and projected third-party volumes that will be purchased in the Bakken. As the minimum volume commitments are subject to fluctuation, and these commercial agreements contain fee inflation escalators and fee recalculation mechanisms, substantially all of the transaction price, as this term is defined in ASC 606, is variable at inception of each of the commercial agreements. As the variability is resolved prior to the recognition of revenue, we do not apply a constraint to the transaction price at the inception of the commercial agreements. We elected the practical expedient to recognize revenue in the amount to which we have a right to invoice as permitted under ASC 606. Due to this election and as the transaction price allocated to our unsatisfied performance obligations is entirely variable, we have elected the exemption provided by ASC 606 from the disclosure of revenue recognizable in future periods as our unsatisfied performance obligations are fulfilled. There are no significant financing components in any of our commercial agreements.

The minimum volumes that Hess provides to our assets under our commercial agreements include dedicated production covering substantially all of Hess’ existing and future owned or controlled production in the Bakken and projected third-party volumes owned or controlled by Hess through dedicated third-party contracts. If Hess delivers volumes less than the applicable minimum volume commitments under our commercial agreements during any quarter, Hess is obligated to pay us a shortfall fee equal to the volume deficiency multiplied by the related gathering, processing and/or terminaling fee, as applicable. Our responsibility to stand-ready to service a minimum volume over each quarterly commitment period represents a separate, distinct performance obligation. Currently, and for the remainder of the Initial Term of each commercial agreement as described in Note 4, volume deficiencies are measured quarterly and recognized as revenue in the same period, as any associated shortfall payments are not subject to future reduction or offset. During the Secondary Term of each commercial agreement as described in Note 4, Hess will be entitled to receive a credit, calculated in barrels or Mcf, as applicable, with respect to the amount of any shortfall fee paid by Hess, which will initially be reported in deferred revenue. Hess may apply such credit against the fees payable for any volumes delivered to us under the applicable agreement in excess of Hess’ nominated volumes up to four quarters after such credit is earned. Unused credits by Hess will be recognized as revenue when they expire after four quarters. However, Hess will not be entitled to receive any such credit with respect to crude oil terminaling services under our terminal and export services agreement

Our revenues also included pass‑through third‑party rail transportation costs, third-party produced water trucking and disposal costs, and electricity fees for which we recognize revenues in an amount equal to the costs.

Depreciation Expense. We calculate depreciation using the straight-line method based on the estimated useful lives after considering salvage values of our assets. Depreciation lives range from 12 to 35 years. However, factors such as maintenance levels, economic conditions impacting the demand for these assets, and regulatory or environmental requirements could cause us to change our estimates, thus impacting the future calculation of depreciation.

Equity‑Based Compensation. Equity‑based compensation issued to the officers, directors and employees of our general partner is recorded at grant‑date fair value. Expense is recognized on a straight‑line basis over the vesting period of the award and is included in General and administrative expenses in the accompanying consolidated statements of operations. Forfeitures are recognized as they occur.

Income Taxes. Deferred income taxes are determined using the liability method and reflect temporary differences between the financial statement carrying amount and income tax basis of assets and liabilities recorded using the statutory income tax rate. Regular assessments are made of the likelihood of those deferred tax assets being realized. If it is more likely than not that some or all of the deferred tax assets will not be realized, a valuation allowance is recorded to reduce the deferred tax assets to the amount expected to be realized.

Prior to the Restructuring on December 16, 2019, we were not a separate taxable entity for U.S. federal and state income tax purposes; therefore, we did not provide for income tax benefit or expense. Each partner was subject to income taxes on its share of the Partnership’s earnings.

On March 1, 2019, HIP acquired Hess Water Services (see Note 3, Acquisitions). For the periods prior to March 1, 2019, Hess Water Services was included in the consolidated income tax returns of Hess. The provision for Hess Water Services’ income taxes and income tax assets and liabilities were determined as if it were a standalone taxpayer for all periods presented. For the period from March 1, 2019 through the Restructuring date of December 16, 2019, Hess Water Services was not taxable itself and was not part of a separate taxable entity; therefore, no income tax provision was recognized.

Net Income Per Limited Partner Unit. Prior to the Restructuring, we identified the general partner interest and IDRs as participating securities and computed income per unit using the two‑class method under which net income per unit was calculated for common units and participating securities considering both distributions declared and participation rights in undistributed earnings as if all such earnings had been distributed during that period. Net income per unit applicable to limited partners, including subordinated unitholders, was computed by dividing limited partners' interest in net income, after deducting the general partner's 2% interest and IDRs, by the weighted‑average number of outstanding common and subordinated units.

Environmental and Legal Contingencies. We accrue and expense environmental costs on an undiscounted basis to remediate existing conditions related to past operations when the future costs are probable and reasonably estimable.

In the ordinary course of business, the Company is from time to time party to various judicial and administrative proceedings. We regularly assess the need for accounting recognition or disclosure of these contingencies. In the case of a known contingency, we accrue a liability when the loss is probable and the amount is reasonably estimable. If a range of amounts can be reasonably estimated and no amount within the range is a better estimate than any other amount, then the minimum of the range is accrued.

Fair Value Measurements. We measure assets and liabilities requiring fair value presentation using an exit price (i.e., the price that would be received to sell an asset or paid to transfer a liability) and disclose such amounts according to the level of valuation inputs under the following hierarchy:

Level 1: Quoted prices in an active market for identical assets or liabilities.

Level 2: Inputs other than quoted prices that are directly or indirectly observable.

Level 3: Unobservable inputs that are significant to the fair value of assets or liabilities.

The classification of an asset or liability within the fair value measurement hierarchy is based on the lowest level of input significant to its fair value.

There were no nonrecurring fair value measurements during the years ended December 31, 2019 and 2018. We had other short‑term financial instruments, primarily cash and cash equivalents, accounts receivable and accounts payable, for which the carrying value approximated their fair value as of December 31, 2019 and 2018.

Derivatives. We may utilize derivative instruments for financial risk management activities. In these activities, we may use futures, forwards, options and swaps, individually or in combination, to mitigate our exposure to fluctuations in interest rates.

All derivative instruments are recorded at fair value in our consolidated balance sheet. Our policy for recognizing the changes in fair value of derivatives varies based on the designation of the derivative. The changes in fair value of derivatives that are not designated as hedges are recognized in earnings. Derivatives may be designated as hedges of expected future cash flows or forecasted transactions (cash flow hedges). Changes in fair value of derivatives that are designated as cash flow hedges are recorded as a component of other comprehensive income (loss). Amounts included in Accumulated other comprehensive income (loss) for cash flow hedges are reclassified into earnings in the same period that the hedged item is recognized in earnings.

New Accounting Pronouncements

In June 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, Financial Instruments – Credit Losses. This ASU makes changes to the impairment model for trade receivables, net investments in leases, debt securities, loans and certain other instruments. The standard requires the use of a forward-looking "expected loss" model compared with the current "incurred loss" model. We will adopt this ASU in the first quarter of 2020 when the standard becomes effective and it is not expected to have a material impact on our consolidated financial statements.

In February 2016, the FASB issued ASU 2016-02, Leases, as a new Accounting Standards Codification (“ASC”) Topic, ASC 842. We adopted ASC 842 on January 1, 2019 using the modified retrospective method. Accordingly, comparative financial statements for periods prior to the adoption date of ASC 842 were not affected. In addition, we have elected to apply the ‘package’ of practical expedients allowing us to avoid reassessing whether existing contracts are (or contain) leases, whether the lease classification for existing leases would differ under ASC 842, and whether initial direct costs incurred for existing leases are capitalizable under ASC 842. Finally, we have elected to apply the practical expedient allowing us to avoid reassessing land easements that were not previously accounted for as leases under ASC 840. We have not elected the ‘hindsight’ practical expedient when determining lease term. As a result, no cumulative effect adjustment to Partners’ capital was recognized. The adoption of ASC 842 did not have a material impact on our consolidated financial statements.

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Summary of Difference between the Effective Income Tax Rate and U.S. Statutory Rate

The difference between the effective income tax rate and the U.S. statutory rate is reconciled below:

	Year Ended December 31,
	2019 ⁽¹⁾				2018 ⁽²⁾				2017 ⁽²⁾
U.S. statutory rate		21.0		%		21.0		%		35.0		%
Non-taxable income from pre-Restructuring period		(21.4	)			(20.6	)			(37.6	)
Change in enacted tax laws		-				-				(1.7	)
Noncontrolling interest in partnership		0.4				-				-
Valuation allowance		-				(0.4	)			4.3
Effective rate		-		%		-		%		-		%
(1) Represents effective income tax rate reconciliation for Hess Midstream LP.
(2) Represents effective income tax rate reconciliation for the pre-Restructuring period, inclusive of stand-alone income tax provision for Hess Water Services.

Components of Deferred Tax Assets and Liabilities

The components of deferred tax assets and liabilities are as follows:

	December 31,
	2019⁽¹⁾		2018⁽²⁾
(in millions)
Deferred tax liabilities
Investments	$	0.2	$	-
Property, plant and equipment		-		10.7
Total deferred tax liabilities		0.2		10.7
Deferred tax assets
Investments		49.8		-
Net operating loss carryforwards		0.2		16.9
Asset retirement obligations		-		0.2
Total deferred tax assets		50.0		17.1
Valuation allowance		-		(6.4	)
Total deferred tax assets, net of valuation allowance		50.0		10.7
Net deferred tax assets (liabilities)	$	49.8	$	-
(1) Represents components of deferred tax assets and liabilities for Hess Midstream LP.
(2) Represents components of deferred tax assets and liabilities for Hess Water Services.

Segments - Financial Data for Each Reportable Segment (Detail) - USD ($)
$ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

$ 253.5

$ 214.9

$ 190.3

$ 189.6

$ 185.9

$ 183.8

$ 176.5

$ 166.5

$ 848.3

$ 712.7

^[1]

$ 579.5

^[1]

Net income (loss) attributable to Hess Midstream LP

75.1

87.4

74.4

80.8

78.9

86.1

82.8

77.7

317.7

325.5

^[1]

242.0

^[1]

$ 16.1

$ 19.1

$ 16.8

$ 18.1

$ 17.2

$ 18.8

$ 17.8

$ 17.0

70.1

70.8

^[1]

41.2

^[1]

Proportional share of equity affiliates' depreciation

142.5

126.9

^[1]

116.5

^[1]

2.0

Income from equity investments

3.4

62.4

53.3

^[1]

25.8

^[1]

Income tax expense (benefit)

^[1]

0.6

4.7

(0.1)

Transaction costs

26.2

550.7

505.1

379.6

416.3

^[2]

271.3

118.3

Interest and Other

Net income (loss) attributable to Hess Midstream LP

(99.2)

(59.0)

(28.3)

(9.6)

(5.6)

(3.3)

62.4

53.3

25.8

Income tax expense (benefit)

0.6

4.7

(0.1)

Transaction costs

26.2

Gathering Opco | Operating Segments

(10.7)

(6.3)

(7.2)

422.9

375.2

285.5

Net income (loss) attributable to Hess Midstream LP

186.0

199.6

132.1

34.6

38.4

23.3

81.6

67.2

57.8

267.6

266.8

189.9

Processing and Storage | Operating Segments

373.6

^[2]

257.0

77.8

295.3

251.4

227.3

Net income (loss) attributable to Hess Midstream LP

176.1

148.8

123.8

34.6

30.7

18.8

Proportional share of equity affiliates' depreciation

44.7

43.9

43.6

2.0

Income from equity investments

3.4

222.8

192.7

167.4

Terminaling and Export | Operating Segments

42.5

^[2]

10.0

15.9

130.1

86.1

66.7

Net income (loss) attributable to Hess Midstream LP

54.8

36.1

14.4

10.5

7.3

2.4

16.2

15.8

15.1

71.0

51.9

29.5

Limited Partners Capital Account [Line Items]

$ 0.2

^[2]

$ 4.3

$ 24.6

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.
[2]	Includes acquisition, expansion and maintenance capital expenditures.

Earnings per Share/Limited Partner Unit - Partnership's Calculation of Earnings per Share Limited Partner Unit (Detail) - USD ($)
$ / shares in Units, shares in Millions, $ in Millions

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Less: Net income (loss) attributable to net parent investment

$ 75.1

$ 87.4

$ 74.4

$ 80.8

$ 78.9

$ 86.1

$ 82.8

$ 77.7

$ 317.7

$ 325.5

^[1]

$ 242.0

^[1]

(55.0)

(46.8)

^[1]

25.4

^[1]

Less: Net income (loss) attributable to noncontrolling interest

302.6

301.5

^[1]

175.4

^[1]

Less: General partner's interest in net income prior to the Restructuring

$ 16.1

$ 19.1

$ 16.8

$ 18.1

$ 17.2

$ 18.8

$ 17.8

$ 17.0

70.1

70.8

^[1]

41.2

^[1]

3.4

1.7

^[1]

0.8

^[1]

$ 66.7

69.1

^[1]

40.4

^[1]

Limited Partners Capital Account [Line Items]

Common unitholders' interest in net income attributable to Hess Midstream LP

$ 34.6

$ 20.2

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Basic and diluted

$ 0.33

$ 0.29

$ 0.32

$ 0.31

$ 0.34

$ 0.32

$ 0.30

$ 1.27

^[1]

$ 0.75

^[1]

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

26.9

Weighted average limited partner units outstanding prior to the Restructuring, Basic:

Units outstanding prior to the Restructuring, Basic

27.3

^[1]

26.9

^[1]

Weighted average limited partner units outstanding prior to the Restructuring, Diluted:

Units outstanding prior to the Restructuring, Diluted

27.5

27.4

^[1]

26.9

^[1]

Limited Partners Capital Account [Line Items]

Common unitholders' interest in net income attributable to Hess Midstream LP

$ 34.5

$ 20.2

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Basic and diluted

$ 0.33

$ 0.29

$ 0.32

$ 0.31

$ 0.34

$ 0.32

$ 0.30

$ 1.27

^[1]

$ 0.75

^[1]

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

26.9

Weighted average limited partner units outstanding prior to the Restructuring, Basic:

Units outstanding prior to the Restructuring, Basic

27.3

^[1]

26.9

^[1]

Weighted average limited partner units outstanding prior to the Restructuring, Diluted:

Units outstanding prior to the Restructuring, Diluted

27.3

^[1]

26.9

^[1]

Common Class A

Net income attributable to Hess Midstream LP per Class A share/limited partner unit:

Net income attributable to Hess Midstream LP per Class A share/limited partner unit, Basic

$ 1.21

Net income attributable to Hess Midstream LP per Class A share/limited partner unit, Diluted

$ 1.20

Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):

Basic and diluted

$ 0.28

Weighted average Class A shares outstanding subsequent to the Restructuring (basic and diluted):

18.0

[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Accrued Liabilities (Tables)

12 Months Ended

Dec. 31, 2019

Accrued Liabilities Current [Abstract]

Schedule of Accrued Liabilities

Accrued liabilities are as follows:

	December 31, 2019		December 31, 2018
(in millions)
Accrued capital expenditures	$	34.7	$	52.4
Accrued interest		18.7		16.9
Other accruals		35.3		16.3
Total	$	88.7	$	85.6

Related Party Transactions

12 Months Ended

Dec. 31, 2019

Related Party Transactions

Note 4. Related Party Transactions

We are part of the consolidated operations of Hess, and substantially all of our revenues as shown on the accompanying consolidated statements of operations for the years ended December 31, 2019, 2018 and 2017 were derived from transactions with Hess and its affiliates, although we plan to provide our services to third parties in the future. Hess also provides substantial operational and administrative services to us in support of our assets and operations.

Commercial Agreements

Effective January 1, 2014, we entered into i) gas gathering, ii) crude oil gathering, iii) gas processing and fractionation, iv) storage services, and v) terminal and export services fee‑based commercial agreements with certain subsidiaries of Hess. Effective January 1, 2019, in connection with the Hess Water Services Acquisition, we entered into long-term fee-based water services agreements with certain subsidiaries of Hess. In addition, in 2018 and a portion of 2017, Hess Water Services had documented intercompany arrangements with certain subsidiaries of Hess pursuant to which it provided produced water gathering and disposal services and charged agreed-upon fees per barrel for the services performed.

Under our commercial agreements, we provide gathering, compression, processing, fractionation, storage, terminaling, loading, transportation and produced water disposal services to Hess, for which we receive a fee per barrel of crude oil, barrel of water, Mcf of natural gas, or Mcf equivalent of NGLs, as applicable, delivered during each month, and Hess is obligated to provide us with minimum volumes of crude oil, water, natural gas and NGLs. These agreements also include inflation escalators and fee recalculation mechanisms that allow fees to be adjusted annually.

In September 2018, we amended and restated our gas gathering and gas processing and fractionation agreements with Hess to enable us to provide certain services to Hess in respect of volumes to be delivered to and processed at the LM4 plant. Effective January 1, 2019, Hess pays us a combined processing fee per Mcf of natural gas, or Mcf equivalent of NGLs, as applicable, for aggregate volumes processed at LM4 and TGP. In addition, the fee recalculation mechanism continues to apply to the amended and restated agreements and, effective January 1, 2019, incorporates the revenues received and expected to be received by Hess from sourcing third-party dedicated production in order to further align the interests of us and Hess in promoting the growth of third-party volumes on our Bakken assets.

Except for the water services agreements and except for a certain gathering sub-system as described below, each of our commercial agreements with Hess retains its initial 10‑year term (“Initial Term”) and we have the unilateral right to extend each commercial agreement for one additional 10‑year term (“Secondary Term”). Initial Term for the water services agreements is 14 years and the Secondary Term is 10 years. The amended and restated gas gathering agreement also extends the Initial Term of the gathering agreement with respect to a certain gathering sub-system by 5 years to provide for a 15-year Initial Term and decreases the Secondary Term for that gathering sub-system by 5 years to provide for a 5-year Secondary Term. During the Secondary Term of the agreements, the fee recalculation model will be replaced by an inflation-based fee structure.

For the years ended December 31, 2019, 2018 and 2017, approximately 100% of our revenues were attributable to our fee‑based commercial agreements with Hess, including revenues from third‑party volumes contracted with Hess and delivered to us under these agreements. Together with Hess, we are pursuing strategic relationships with third-party producers and other midstream companies with operations in the Bakken in order to maximize our utilization rates.

During the year ended December 31, 2019, we earned $8.3 million of minimum volume shortfall fee payments (2018: $47.5 million, 2017: $61.6 million). In addition, during the year ended December 31, 2019, we recognized, as part of the affiliate revenues, $40.2 million of reimbursements from Hess related to third‑party rail transportation costs (2018: $16.8 million, 2017: $17.0 million). Furthermore, during the year ended December 31, 2019, we recognized, as part of affiliate revenues, $57.7 million of reimbursements from Hess related third-party produced water trucking and disposal costs (2018: $36.5 million, 2017: $5.1 million). Finally, during the year ended December 31, 2019, we recognized, as part of affiliate revenues, $32.2 million of reimbursements from Hess related to electricity fees (2018: $27.2 million, 2017: $24.9 million). The related third-party rail transportation costs, produced water trucking and disposal costs and electricity fees were included in Operating and maintenance expenses in the accompanying consolidated statements of operations.

Revenue from contracts with customers on a disaggregated basis was as follows:

	Year Ended December 31,
	2019		2018		2017
(in millions)
Oil and gas gathering services	$	345.6	$	324.9	$	271.6
Water gathering and disposal services		77.3		50.3		13.9
Processing and storage services		294.7		251.4		227.3
Terminaling and export services		130.0		85.4		66.7
Total revenues from contracts with customers	$	847.6	$	712.0	$	579.5
Other income		0.7		0.7		-
Total revenues	$	848.3	$	712.7	$	579.5

Omnibus and Employee Secondment Agreements

We entered into an omnibus agreement with Hess under which we pay Hess on a monthly basis an amount equal to the total allocable costs of Hess’ employees and contractors, subcontractors or other outside personnel engaged by Hess and its subsidiaries to the extent such employees and outside personnel perform operational and administrative services for us in support of our assets, plus a specified percentage markup of such amount depending on the type of service provided, as well as an allocable share of direct costs of providing these services.

We also entered into an employee secondment agreement with Hess under which certain employees of Hess are seconded to our general partner to provide services with respect to our assets and operations, including executive oversight, business and corporate development, unitholder and investor relations, communications and public relations, routine and emergency maintenance and repair services, routine operational services, routine administrative services, construction services, and such other operational, commercial and business services that are necessary to develop and execute the Company’s business strategy. On a monthly basis, we pay a secondment fee to Hess that is intended to cover and reimburse Hess for the total costs actually incurred by Hess and its affiliates in connection with employing the seconded employees to the extent such total costs are attributable to the provision of services with respect to the Company’s assets and operations.

For the years ended December 31, 2019, 2018 and 2017, we had the following charges from Hess. The classification of these charges between operating and maintenance expenses and general and administrative expenses is based on the fundamental nature of the services being performed for our operations.

	Year Ended December 31,
	2019		2018		2017
(in millions)
Operating and maintenance expenses	$	53.1	$	50.2	$	57.3
General and administrative expenses		15.5		7.8		6.7
Total	$	68.6	$	58.0	$	64.0

LM4 Agreements

Separately from our commercial agreements with Hess, effective January 24, 2018, we entered into a gas processing agreement with LM4 under which we deliver natural gas to LM4, and LM4 processes and redelivers certain volumes of residue gas and NGLs resulting from such processing services. The agreement has a 16-year initial term, after which it is automatically renewed for subsequent one-year terms unless terminated by either party. Under this agreement, we pay a processing fee per Mcf of natural gas and reimburse LM4 for our proportionate share of electricity costs. We are entitled to 50% of the available processing capacity of the LM4 gas processing plant. Should Targa not use all of the remaining processing capacity at the plant on any day, such unutilized portion of the available capacity will be available for our use. Regardless of the actual portion of the plant available capacity utilized by each joint venture member during a given period, under the LM4 amended and restated limited liability company agreement, profits and losses of the LM4 joint venture are allocated 50/50 between Targa and us. LM4 was placed in service in the third quarter of 2019.

During the year ended December 31, 2019, we incurred $6.3 million of expenses under the LM4 gas processing agreement, which are included in Operating and maintenance expenses in the accompanying consolidated statements of operations. In addition, during the year ended December 31, 2019, we recognized $3.4 million of earnings from equity investments, as presented in our accompanying consolidated statements of operations.

Acquisitions - Consolidated Balance Sheet (Detail) - USD ($)
$ in Millions

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Assets

$ 3.3

$ 109.3

^[1]

87.6

67.3

^[1]

Other receivables

0.3

0.5

^[1]

Other current assets

4.7

3.3

^[1]

Total current assets

95.9

180.4

^[1]

Equity investments

107.8

67.3

^[1]

Long-term receivable—affiliate

3,010.1

2,735.3

^[1]

1.2

1.3

^[1]

12.9

6.9

^[1]

3,277.7

2,991.2

^[1]

Accounts payable—affiliate

30.6

18.6

^[1]

47.9

15.8

^[1]

Current maturities of long-term debt

88.7

85.6

^[1]

^[1]

11.3

Other current liabilities

8.9

6.8

^[1]

176.1

138.1

^[1]

Long-term debt

1,753.5

969.8

^[1]

16.0

7.2

^[1]

Total Hess Midstream Partners LP partners' capital

1,945.6

1,115.1

^[1]

General partner

^[1]

14.9

516.8

Noncontrolling interest

1,200.6

2,194.1

^[1]

Accumulated other comprehensive income

0.4

1.2

^[1]

Net parent investment

^[1]

(836.0)

1,332.1

1,876.1

^[1]

$ 1,952.3

$ 1,809.9

Partnership as Previously Reported

$ 3,277.7

2,991.2

^[1]

Assets

20.3

62.2

0.8

2.8

86.1

67.3

2,664.1

2.2

2,819.7

Accounts payable—affiliate

15.3

15.8

Other current liabilities

64.5

6.8

102.4

6.4

Total Hess Midstream Partners LP partners' capital

108.8

General partner

14.9

516.8

Noncontrolling interest

2,194.1

2,710.9

Restatement Adjustment | Acquisition of HIP

2,819.7

Assets

89.0

5.1

Other receivables

(0.3)

Other current assets

0.5

Total current assets

94.3

Long-term receivable—affiliate

71.2

1.3

4.7

171.5

3.3

Current maturities of long-term debt

21.1

11.3

35.7

Long-term debt

969.8

0.8

Accumulated other comprehensive income

1,006.3

1.2

Net parent investment

(836.0)

(834.8)

Common Unitholders - Public

171.5

Common Unitholders - Public | Partnership as Previously Reported

^[1]

357.1

Common Unitholders - Affiliate

357.1

Common Unitholders - Affiliate | Partnership as Previously Reported

^[1]

39.5

Subordinated Unitholders - Affiliate

39.5

Subordinated Unitholders - Affiliate | Partnership as Previously Reported

^[1]

105.3