Hess Midstream (HESM) 10-Q 5 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	HESM
Entity Registrant Name	Hess Midstream LP
Entity Central Index Key	0001789832
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity File Number	001-39163
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
Entity Common Stock, Shares Outstanding		18,028,308
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE
Title of 12(b) Security	Class A shares representing limited partner interests
Security Exchange Name	NYSE
Entity Interactive Data Current	Yes

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents	$ 3	$ 3.3
Accounts receivable—affiliate:
From contracts with customers	92.5	87.6
Other receivables	0.4	0.3
Other current assets	7.8	4.7
Total current assets	103.7	95.9
Equity investments	108.2	107.8
Property, plant and equipment, net	3,103.3	3,010.1
Long-term receivable—affiliate	1.1	1.2
Deferred tax asset	44.6	49.8
Other noncurrent assets	10.8	12.9
Total assets	3,371.7	3,277.7
Liabilities
Accounts payable—trade	40.1	30.6
Accounts payable—affiliate	19.8	47.9
Accrued liabilities	57.8	88.7
Current maturities of long-term debt	7.5
Other current liabilities	7.1	8.9
Total current liabilities	132.3	176.1
Long-term debt	1,895.5	1,753.5
Other noncurrent liabilities	24.7	16
Total liabilities	2,052.5	1,945.6
Partners' capital
Total partners' capital	126.2	131.1
Noncontrolling interest	1,193	1,200.6
Accumulated other comprehensive income		0.4
Total partners' capital	1,319.2	1,332.1
Total liabilities and partners' capital	3,371.7	3,277.7
Class A Shares
Partners' capital
Common unitholders	$ 126.2	$ 131.1

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Sep. 30, 2020	Dec. 31, 2019
Class A Shares
Common units issued	18,028,308	17,960,655
Common units outstanding	18,028,308	17,960,655
Class B Shares
Common units issued	266,416,928	266,416,928
Common units outstanding	266,416,928	266,416,928

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Millions, $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019		Sep. 30, 2020	Sep. 30, 2019
Revenues
Affiliate services		$ 264.7	$ 214.9	[1]	$ 825.1	$ 594.5	[1]
Type of Revenue [Extensible List]		hesm:AffiliateServicesMember	hesm:AffiliateServicesMember	[1]	hesm:AffiliateServicesMember	hesm:AffiliateServicesMember	[1]
Other income		$ 0.1			$ 0.3	$ 0.3	[1]
Total revenues		264.8	$ 214.9	[1]	825.4	594.8	[1]
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)		83.9	71.9	[1]	270.8	184.1	[1]
Depreciation expense		39.5	36	[1]	116.9	105	[1]
General and administrative expenses		4.2	7.7	[1]	15.9	19.4	[1]
Total costs and expenses		127.6	115.6	[1]	403.6	308.5	[1]
Income from operations		137.2	99.3	[1]	421.8	286.3	[1]
Income from equity investments		3.6	0.5	[1]	7.2	0.5	[1]
Interest expense, net		23.2	12.4	[1]	71.3	44.2	[1]
Gain on sale of property, plant and equipment					0.1
Income before income tax expense (benefit)		117.6	87.4	[1]	357.8	242.6	[1]
Income tax expense (benefit)		1.8			5.2
Net income		115.8	87.4	[1]	352.6	242.6	[1]
Less: Net income (loss) attributable to net parent investment	[1]		(13)			(44)
Less: Net income (loss) attributable to noncontrolling interest		110.2	81.3	[1]	335.2	232.6	[1]
Net income attributable to Hess Midstream LP		5.6	19.1	[1]	17.4	54	[1]
Less: General partner's interest in net income	[1]		1.3			3.1
Limited partners' interest in net income		$ 5.6	$ 17.8	[1]	$ 17.4	$ 50.9	[1]
Common Units
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]		$ 0.33			$ 0.93
Weighted average limited partner units outstanding prior to the Restructuring, Basic:
Units outstanding prior to the Restructuring, Basic	[1]		27.3			27.3
Weighted average limited partner units outstanding prior to the Restructuring, Diluted:
Units outstanding prior to the Restructuring, Diluted	[1]		27.5			27.5
Subordinated Units
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]		$ 0.33			$ 0.93
Weighted average limited partner units outstanding prior to the Restructuring, Basic:
Units outstanding prior to the Restructuring, Basic	[1]		27.3			27.3
Weighted average limited partner units outstanding prior to the Restructuring, Diluted:
Units outstanding prior to the Restructuring, Diluted	[1]		27.3			27.3
Class A Shares
Net income attributable to Hess Midstream LP per Class A share:
Net income attributable to Hess Midstream LP per Class A share, Basic		$ 0.31			$ 0.97
Net income attributable to Hess Midstream LP per Class A share, Diluted		$ 0.31			$ 0.95
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		18			18
Weighted average Class A shares outstanding subsequent to the restructuring, Diluted		18.1			18.1
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019		Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 115.8	$ 87.4	[1]	$ 352.6	$ 242.6	[1]
Effect of hedge (gains) losses reclassified to income			(0.2)	[1]	(0.4)	(0.6)	[1]
Total other comprehensive income			(0.2)	[1]	(0.4)	(0.6)	[1]
Comprehensive income		115.8	87.2	[1]	352.2	242	[1]
Less: Comprehensive income (loss) attributable to net parent investment	[1]		(13.2)			(44.6)
Less: Comprehensive income (loss) attributable to noncontrolling interest		110.2	81.3	[1]	334.8	232.6	[1]
Comprehensive income attributable to Hess Midstream LP		$ 5.6	$ 19.1	[1]	$ 17.4	$ 54	[1]
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL (UNAUDITED) - USD ($) $ in Millions		Total		Limited PartnerCommon Unitholders Public	Limited PartnerCommon Unitholders Affiliate	Limited PartnerSubordinated Unitholders Affiliate	Limited PartnerClass A Shares	General Partner	Noncontrolling Interest	Accumulated Other Comprehensive Income	Net Parent Investment
Balance, beginning of period at Dec. 31, 2018		$ 1,876.1	[1]	$ 357.1	$ 39.5	$ 105.3		$ 14.9	$ 2,194.1	$ 1.2	$ (836)
Net income		80.8	[1]	5.3	3.4	8.6		0.8	77.2		(14.5)
Equity-based compensation		0.3	[1]	0.3
Distributions to unitholders		(20.2)	[1]	(6.3)	(3.8)	(10.1)
Distributions to general partner								(0.6)			0.6
Distributions to noncontrolling interest									(57.1)		57.1
Contributions from noncontrolling interest									55.5		(55.5)
Other comprehensive income (loss)		(0.2)	[1]							(0.2)
Acquisition of HessWater Services		(225)	[1]								(225)
Balance, end of period at Mar. 31, 2019		1,711.8	[1]	356.4	39.1	103.8		15.1	2,269.7	1	(1,073.3)
Balance, beginning of period at Dec. 31, 2018		1,876.1	[1]	357.1	39.5	105.3		14.9	2,194.1	1.2	(836)
Net income	[1]	242.6
Other comprehensive income (loss)	[1]	(0.6)
Balance, end of period at Sep. 30, 2019		1,831.2	[1]	354.2	37.5	99.2		15.5	2,350.6	0.6	(1,026.4)
Balance, beginning of period at Mar. 31, 2019		1,711.8	[1]	356.4	39.1	103.8		15.1	2,269.7	1	(1,073.3)
Net income		74.4	[1]	4.9	3	7.9		1	74.1		(16.5)
Equity-based compensation		0.3	[1]	0.3
Distributions to unitholders		(21)	[1]	(6.5)	(4)	(10.5)
Distributions to general partner								(0.8)			0.8
Distributions to noncontrolling interest									(49)		49
Contributions from noncontrolling interest									12.8		(12.8)
Other comprehensive income (loss)		(0.2)	[1]							(0.2)
Balance, end of period at Jun. 30, 2019		1,765.3	[1]	355.1	38.1	101.2		15.3	2,307.6	0.8	(1,052.8)
Net income		87.4	[1]	5.5	3.4	8.9		1.3	81.3		(13)
Equity-based compensation		0.5	[1]	0.5
Distributions to unitholders		(21.8)	[1]	(6.9)	(4)	(10.9)
Distributions to general partner								(1.1)			1.1
Distributions to noncontrolling interest									(46.3)		46.3
Contributions from noncontrolling interest									8		(8)
Other comprehensive income (loss)		(0.2)	[1]							(0.2)
Balance, end of period at Sep. 30, 2019		1,831.2	[1]	$ 354.2	$ 37.5	$ 99.2		$ 15.5	2,350.6	0.6	$ (1,026.4)
Balance, beginning of period at Dec. 31, 2019		1,332.1					$ 131.1		1,200.6	0.4
Net income		129					6.5		122.5
Equity-based compensation		0.5					0.5
Distributions to unitholders		(121)					(7.6)		(113.4)
Other comprehensive income (loss)		(0.2)								(0.2)
Balance, end of period at Mar. 31, 2020		1,340.4					130.5		1,209.7	0.2
Balance, beginning of period at Dec. 31, 2019		1,332.1					131.1		1,200.6	0.4
Net income		352.6
Other comprehensive income (loss)		(0.4)
Balance, end of period at Sep. 30, 2020		1,319.2					126.2		1,193
Balance, beginning of period at Mar. 31, 2020		1,340.4					130.5		1,209.7	0.2
Net income		107.8					5.3		102.5
Equity-based compensation		0.3					0.3
Distributions to unitholders		(122.7)					(7.9)		(114.8)
Other comprehensive income (loss)		(0.2)								$ (0.2)
Acquisition of HessWater Services		1.6							1.6
Balance, end of period at Jun. 30, 2020		1,327.2					128.2		1,199
Net income		115.8					5.6		110.2
Equity-based compensation		0.4					0.4
Distributions to unitholders		(124.2)					(8)		(116.2)
Balance, end of period at Sep. 30, 2020		$ 1,319.2					$ 126.2		$ 1,193
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN PARTNERS' CAPITAL (UNAUDITED) (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Statement Of Partners Capital [Abstract]
Distributions to unitholders - per unit	$ 0.4363	$ 0.4310	$ 0.4258	$ 0.3970	$ 0.3833	$ 0.3701

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities
Net income		$ 352.6	$ 242.6	[1]
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense		116.9	105	[1]
(Gain) loss on sale of property, plant and equipment		(0.1)
(Gain) loss on interest rate swaps		(0.4)	(0.6)	[1]
(Income) loss from equity investments		(7.2)	(0.5)	[1]
(Increase) decrease in capitalized interest	[1]		(4.1)
Distributions from equity investments		6.8
Amortization of deferred financing costs		5.1	3.8	[1]
Equity-based compensation expense		1.2	1.1	[1]
Deferred income tax expense (benefit)		5.2
Changes in assets and liabilities:
Accounts receivable – affiliate		(4.9)	(7.6)	[1]
Other current and noncurrent assets		(3.4)	(4.7)	[1]
Accounts payable – trade		9.5	3.7	[1]
Accounts payable – affiliate		(0.5)	(1.5)	[1]
Accrued liabilities		(12.6)
Other current and noncurrent liabilities		(1)	(2.8)	[1]
Net cash provided by (used in) operating activities		467.2	334.4	[1]
Cash flows from investing activities
Proceeds from sale of property, plant and equipment		0.1
Additions to property, plant and equipment		(246)	(194.9)	[1]
Acquisitions	[1]		(89.2)
Payments for equity investments	[1]		(33)
Net cash provided by (used in) investing activities		(245.9)	(386)	[1]
Cash flows from financing activities
Net proceeds from (repayments of) bank borrowings with maturities of 90 days or less		146	176	[1]
Repayments of bank borrowings with maturities of greater than 90 days	[1]		(7.5)
Financing costs		(1.3)
Distributions to shareholders/unitholders		(23.5)	(63)	[1]
Distributions to noncontrolling interest		(344.4)
Hess Water Services acquisition final settlement		1.6
Capital distribution to Hess associated with acquisitions	[1]		(156.1)
Net cash provided by (used in) financing activities		(221.6)	(50.6)	[1]
Increase (decrease) in cash and cash equivalents		(0.3)	(102.2)	[1]
Cash and cash equivalents, beginning of period		3.3	109.3	[1]
Cash and cash equivalents, end of period		3	7.1	[1]
Supplemental disclosure of non-cash investing and financing activities:
(Increase) decrease in accrued capital expenditures and related liabilities		$ 43.8	(13.9)	[1]
Hess
Cash flows from investing activities
Acquisitions	[1]		$ (68.9)
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Description of Business

Description of Business	9 Months Ended
	Sep. 30, 2020
Description Of Business [Abstract]
Description of Business	Note 1. D escription of Business Hess Midstream LP (“the Company”) is a fee-based, growth-oriented, Delaware limited partnership formed by Hess Infrastructure Partners GP LLC (“HIP GP LLC”) and our general partner to own, operate, develop and acquire a diverse set of midstream assets and provide fee-based services to Hess Corporation (“Hess”) and third-party customers. We are managed and controlled by Hess Midstream GP LLC, the general partner of our general partner. On December 16, 2019, we completed the acquisition of Hess Infrastructure Partners LP (“HIP”), incentive distribution rights simplification and conversion from a master limited partnership into an “Up-C” structure (collectively, the “Restructuring”) contemplated by the partnership restructuring agreement, dated October 3, 2019, by and among the Company, Hess Midstream Operations LP (the “Partnership”) and the other parties thereto. Prior to the Restructuring, the Company and the Partnership were indirectly controlled by HIP GP LLC, the general partner of 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”). All references to “Hess Midstream Operations LP,” “the Partnership,” “us,” “we” or similar terms, when referring to periods between April 10, 2017 (the initial public offering date) and December 16, 2019, refer to Hess Midstream Operations LP (formerly known as Hess Midstream Partners LP, the predecessor registrant to Hess Midstream LP), including its consolidated subsidiaries. All references to “Hess Midstream LP,” “the Company,” “us,” “our,” “we” or similar terms, when referring to periods subsequent to December 16, 2019, refer to Hess Midstream LP, including its consolidated subsidiaries. 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 reportable segments: (1) gathering, (2) processing and storage and (3) terminaling and export (see Note 13, Segments).

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	Note 2. Basis of Presentation The consolidated financial statements included in this report reflect all normal and recurring adjustments which, in the opinion of management, are necessary for a fair presentation of our consolidated financial position at September 30, 2020 and December 31, 2019, the consolidated results of operations for the three and nine months ended September 30, 2020 and 2019, and consolidated cash flows for the nine months ended September 30, 2020 and 2019. The unaudited results of operations for the interim periods reported are not necessarily indicative of results to be expected for the full year. The consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted from these interim consolidated financial statements. These financial statements, therefore, should be read in conjunction with the financial statements and related notes included in the Company’s annual report on Form 10‑K for the year ended December 31, 2019. On December 16, 2019, we completed the acquisition of HIP, which was accounted for as a business combination of entities under common control. Accordingly, our consolidated financial statements prior to the acquisition date were retrospectively recast to include the financial results of HIP. See Note 3, Acquisitions. We consolidate the activities of the Partnership, and prior to the Restructuring the activities of Hess North Dakota Pipelines Operations LP, Hess TGP Operations LP and Hess North Dakota Export Logistics Operations LP (collectively, the “Joint Interest Assets”), as variable interest entities (“VIE”) under U.S. 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 13, Segments). We currently do not have any independent assets or operations other than our interest in the Partnership. Our noncontrolling interest represents the approximate 93.7% 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. New Accounting Pronouncements. On January 1, 2020, we adopted 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 “incurred loss” model. The adoption of this ASU did not have a material impact on our consolidated financial statements. In March 2020, the Financial Accounting Standards Board (“FASB”) issued ASU 2020-04, Reference Rate Reform, as a new Accounting Standards Codification (“ASC”) Topic, ASC 848. The purpose of ASC 848 is to provide optional guidance to ease the potential effects on financial reporting of the market-wide migration away from Interbank Offered Rates, such as LIBOR, which is expected to be phased out at the end of calendar year 2021, to alternative reference rates. ASC 848 applies only to contracts, hedging relationships, debt arrangements and other transactions that reference a benchmark reference rate expected to be discontinued because of reference rate reform. ASC 848 contains optional expedients and exceptions for applying U.S. GAAP to transactions affected by this reform. The amendments in the ASU are effective for all entities as of March 12, 2020 through December 31, 2022. We are currently assessing the impact of adopting this new guidance as well as when to adopt this guidance.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2020
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 LLC (“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. 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. In May 2020, we received $1.6 million from Hess as part of the final purchase price settlement, which is reflected within Noncontrolling interest 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 interests of 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 each of the Joint Interest Assets, 100% interest in Hess Water Services and the outstanding economic general partner and incentive distribution rights in the Partnership. T he Partnership’s 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 the results of operations for the three and nine months ended September 30, 2019 and cash flows for the nine months ended September 30, 2019 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 Statement of Operations Three Months Ended September 30, 2019 Partnership as Previously Reported Acquisition of HIP Consolidated Results (in millions) Revenues and other income Affiliate services $ 195.4 $ 19.5 $ 214.9 Total revenues and other income 195.4 19.5 214.9 Costs and expenses Operating and maintenance expenses (exclusive of depreciation shown separately below) 56.5 15.4 71.9 Depreciation expense 34.5 1.5 36.0 General and administrative expenses 3.9 3.8 7.7 Total costs and expenses 94.9 20.7 115.6 Income from operations 100.5 (1.2 ) 99.3 Earnings from equity investments 0.5 - 0.5 Interest expense, net 0.6 11.8 12.4 Net income 100.4 (13.0 ) 87.4 Less: Net income (loss) attributable to net parent investment - (13.0 ) (13.0 ) Less: Net income attributable to noncontrolling interest 81.3 - 81.3 Net income attributable to Hess Midstream Partners LP 19.1 - 19.1 Less: General partner's interest in net income attributable to Hess Midstream Partners LP 1.3 - 1.3 Limited partners' interest in net income attributable to Hess Midstream Partners LP $ 17.8 $ - $ 17.8 Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted): Common $ 0.33 $ - $ 0.33 Subordinated $ 0.33 $ - $ 0.33 Weighted average limited partner units outstanding: Basic: Common 27.3 - 27.3 Subordinated 27.3 - 27.3 Diluted: Common 27.5 - 27.5 Subordinated 27.3 - 27.3 Nine Months Ended September 30, 2019 Partnership as Previously Reported Acquisition of HIP Consolidated Results (in millions) Revenues and other income Affiliate services $ 542.1 $ 52.4 $ 594.5 Other income 0.3 - 0.3 Total revenues and other income 542.4 52.4 594.8 Costs and expenses Operating and maintenance expenses (exclusive of depreciation shown separately below) 142.0 42.1 184.1 Depreciation expense 101.1 3.9 105.0 General and administrative expenses 11.6 7.8 19.4 Total costs and expenses 254.7 53.8 308.5 Income from operations 287.7 (1.4 ) 286.3 Earnings from equity investments 0.5 - 0.5 Interest expense, net 1.6 42.6 44.2 Net income 286.6 (44.0 ) 242.6 Less: Net income (loss) attributable to net parent investment - (44.0 ) (44.0 ) Less: Net income attributable to noncontrolling interest 232.6 - 232.6 Net income attributable to Hess Midstream Partners LP 54.0 - 54.0 Less: General partner's interest in net income attributable to Hess Midstream Partners LP 3.1 - 3.1 Limited partners' interest in net income attributable to Hess Midstream Partners LP $ 50.9 $ - $ 50.9 Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted): Common $ 0.93 $ - $ 0.93 Subordinated $ 0.93 $ - $ 0.93 Weighted average limited partner units outstanding: Basic: Common 27.3 - 27.3 Subordinated 27.3 - 27.3 Diluted: Common 27.5 - 27.5 Subordinated 27.3 - 27.3 Consolidated Statement of Cash Flows Nine Months Ended September 30, 2019 Partnership as Previously Reported Acquisition of HIP Consolidated Results (in millions) Cash flows from operating activities Net income $ 286.6 $ (44.0 ) $ 242.6 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Depreciation expense 101.1 3.9 105.0 (Gain) loss on interest rate swaps - (0.6 ) (0.6 ) Earnings from equity investments (0.5 ) - (0.5 ) (Increase) decrease in capitalized interest - (4.1 ) (4.1 ) Amortization of deferred financing costs 0.9 2.9 3.8 Equity-based compensation 1.1 - 1.1 Changes in assets and liabilities: Accounts receivable—affiliate (5.2 ) (2.4 ) (7.6 ) Other current and noncurrent assets (5.0 ) 0.3 (4.7 ) Accounts payable—trade 2.2 1.5 3.7 Accounts payable—affiliate 4.3 (5.8 ) (1.5 ) Accrued liabilities 9.2 (9.2 ) - Other current and noncurrent liabilities (2.5 ) (0.3 ) (2.8 ) Net cash provided by (used in) operating activities 392.2 (57.8 ) 334.4 Cash flows from investing activities Payments for equity investments (33.0 ) - (33.0 ) Acquisitions from Hess - (68.9 ) (68.9 ) Acquisitions from third parties, net of cash acquired (61.0 ) (28.2 ) (89.2 ) Additions to property, plant and equipment (184.4 ) (10.5 ) (194.9 ) Net cash provided by (used in) investing activities (278.4 ) (107.6 ) (386.0 ) Cash flows from financing activities Net proceeds from (repayments of) bank borrowings with maturities of 90 days or less 11.0 165.0 176.0 Repayments of bank borrowings with maturities of greater than 90 days - (7.5 ) (7.5 ) Capital distribution to Hess associated with acquisitions - (156.1 ) (156.1 ) Distributions to unitholders (63.0 ) - (63.0 ) Distributions to general partner (2.5 ) 2.5 - Distributions to noncontrolling interest (152.4 ) 152.4 - Contributions from noncontrolling interest 76.3 (76.3 ) - Net cash provided by (used in) financing activities (130.6 ) 80.0 (50.6 ) Net increase (decrease) in cash and cash equivalents (16.8 ) (85.4 ) (102.2 ) Cash and cash equivalents at beginning of period 20.3 89.0 109.3 Cash and cash equivalents at end of period $ 3.5 $ 3.6 $ 7.1

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Note 4. Related Party Transactions Commercial Agreements Effective January 1, 2014, we entered into long-term fee-based (i) gas gathering, (ii) crude oil gathering, (iii) gas processing and fractionation, (iv) storage services, and (v) terminal and export services 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. 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. For the three and nine months ended September 30, 2020 and 2019, 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. We retain control of our assets and the flow of volumes based on available capacity within our integrated gathering, processing and terminaling systems. 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. Revenues from contracts with customers on a disaggregated basis are as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (in millions) Oil and gas gathering services $ 118.7 $ 86.4 $ 349.2 $ 245.6 Water gathering and disposal services 24.2 19.5 71.7 52.4 Processing and storage services 90.1 74.0 273.7 207.8 Terminaling and export services 31.7 35.0 130.5 88.7 Total revenues from contracts with customers $ 264.7 $ 214.9 $ 825.1 $ 594.5 Other income 0.1 - 0.3 0.3 Total revenues $ 264.8 $ 214.9 $ 825.4 $ 594.8 During the three and nine months ended September 30, 2020, we earned $7.8 million and $11.9 million, respectively, of minimum volume shortfall fee payments, compared with $3.0 million and $6.5 million for the three and nine months ended September 30, 2019, respectively. The following table presents third-party pass-through costs for which we recognize revenues in an amount equal to the costs. These third-party costs are included in Operating and maintenance expenses in the accompanying unaudited consolidated statements of operations. Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (in millions) Rail transportation costs $ 5.0 $ 12.0 $ 49.3 $ 24.1 Produced water trucking and disposal costs 14.0 14.5 45.6 40.2 Electricity fees 10.3 8.3 29.7 23.2 Total $ 29.3 $ 34.8 $ 124.6 $ 87.5 Omnibus and Employee Secondment Agreements Under our omnibus and employee secondment agreements, Hess provides substantial operational and administrative services to us in support of our assets and operations. For the three and nine months ended September 30, 2020 and 2019, 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. Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (in millions) Operating and maintenance expenses $ 16.7 $ 13.4 $ 47.5 $ 36.3 General and administrative expenses 3.9 $ 3.7 11.2 10.5 Total $ 20.6 $ 17.1 $ 58.7 $ 46.8 LM4 Agreements Separately from our commercial agreements with Hess, we entered into a gas processing agreement with Little Missouri 4 (“LM4”), a 50/50 joint venture with Targa Resources Corp., under which we pay a processing fee per Mcf of natural gas and reimburse LM4 for our proportionate share of electricity costs. These processing fees are included in Operating and maintenance expenses in the accompanying consolidated statements of operations. In addition, we share profits and losses and receive distributions from LM4 under the LM4 amended and restated limited liability company agreement based on our ownership interest. For the three and nine months ended September 30, 2020 and 2019, we had the following activity related to our agreements with LM4: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (in millions) Processing fee incurred $ 6.8 $ 0.9 $ 18.2 $ 0.9 Earnings from equity investments 3.6 0.5 7.2 0.5 Distributions received from equity investments 3.0 - 6.8 -

Property, Plant and Equipment

Property, Plant and Equipment	9 Months Ended
	Sep. 30, 2020
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 September 30, 2020 December 31, 2019 (in millions, except for number of years) Gathering assets Pipelines 22 years $ 1,449.7 $ 1,352.7 Compressors, pumping stations and terminals 22 to 25 years 770.8 725.9 Gas plant assets Pipelines, pipes and valves 22 to 25 years 460.0 460.0 Equipment 12 to 30 years 428.3 428.2 Buildings 35 years 182.3 182.3 Processing and fractionation facilities 25 years 188.7 188.6 Logistics facilities and railcars 20 to 25 years 385.9 385.5 Storage facilities 20 to 25 years 19.5 19.5 Other 20 to 25 years 20.9 13.0 Construction-in-progress N/A 208.7 149.3 Total property, plant and equipment, at cost 4,114.8 3,905.0 Accumulated depreciation (1,011.5 ) (894.9 ) Property, plant and equipment, net $ 3,103.3 $ 3,010.1

Accrued Liabilities

Accrued Liabilities	9 Months Ended
	Sep. 30, 2020
Accrued Liabilities Current [Abstract]
Accrued Liabilities	Note 6. Accrued Liabilities Accrued liabilities are as follows: September 30, 2020 December 31, 2019 (in millions) Accrued capital expenditures $ 18.5 $ 34.7 Accrued interest 13.9 18.7 Other accruals 25.4 35.3 Total $ 57.8 $ 88.7

Debt and Interest Expense

Debt and Interest Expense	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt and Interest Expense	Note 7. Debt and Interest Expense Fixed‑Rate Senior Notes As of September 30, 2020, the Partnership had $800.0 million of 5.625% fixed‑rate senior notes due 2026 that were issued to qualified institutional investors. The notes are guaranteed by certain subsidiaries of the Partnership. Interest is payable semi‑annually on February 15 and August 15. In addition, as of September 30, 2020, the Partnership had $550.0 million of 5.125% fixed‑rate senior notes due 2028 that were issued 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. 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 September 30, 2020, 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 As of September 30, 2020, the Partnership had 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. Facility fees accrue on the total capacity of the revolving credit facility. Borrowings under the 5-year Term Loan A facility will generally bear interest at LIBOR plus the applicable margin ranging from 1.55% to 2.50%, 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 September 30, 2020, borrowings of $178.0 million were drawn under the Partnership’s revolving credit facility, and borrowings of $400.0 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 September 30, 2020, the Partnership was in compliance with these financial covenants. Fair Value Measurement At September 30, 2020, our total debt had a carrying value of $1,903.0 million and had a fair value of approximately $1,938.6 million, based on Level 2 inputs in the fair value measurement hierarchy. 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

Partners' Capital and Distribut

Partners' Capital and Distributions	9 Months Ended
	Sep. 30, 2020
Partners Capital Notes [Abstract]
Partners' Capital and Distributions	Note 8. Partners’ Capital and Distributions Our partnership agreement requires that, within 45 days after the end of each quarter, we distribute all of our available cash, as defined in the partnership agreement, to shareholders of record on the applicable record date. The following table details the distributions declared and/or paid for the periods presented: z Period Record Date Distribution Date Distribution per Common and Subordinated Unit/Class A share 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 February 6, 2020 February 14, 2020 $ 0.4258 First Quarter 2020 May 4, 2020 May 14, 2020 $ 0.4310 Second Quarter 2020 August 6, 2020 August 14, 2020 $ 0.4363 Third Quarter 2020 (1) November 5, 2020 November 13, 2020 $ 0.4417 (1)

Equity-Based Compensation

Equity-Based Compensation	9 Months Ended
	Sep. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Equity-Based Compensation	Note 9. Equity‑Based Compensation Equity‑based award activity for the nine months ended September 30, 2020 is as follows: Weighted Average Award Date Number of Shares Fair Value Outstanding and unvested shares at December 31, 2019 136,060 $ 21.95 Granted 175,888 10.71 Forfeited (15,951 ) 14.84 Vested (67,653 ) 21.96 Outstanding and unvested shares at September 30, 2020 228,344 $ 13.78 As of September 30, 2020, $2.1 million of compensation cost related to unvested restricted shares awarded under our long-term incentive plan remains to be recognized over an expected weighted‑average period of 1.9 years.

Earnings per Share_Limited Part

Earnings per Share/Limited Partner Unit	9 Months Ended
	Sep. 30, 2020
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. Approximately 100% of income tax expense is attributed to earnings of Class A 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. 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. Three Months Ended September 30, Nine Months Ended September 30, (in millions, except per share amounts) 2020 2019 2020 2019 Net income $ 115.8 $ 87.4 $ 352.6 $ 242.6 Less: Net income attributable to net parent investment - (13.0 ) - (44.0 ) Less: Net income attributable to noncontrolling interest 110.2 81.3 335.2 232.6 Net income attributable to Hess Midstream LP 5.6 19.1 17.4 54.0 Less: General partner's interest in net income prior to the Restructuring - 1.3 - 3.1 Limited partners' interest in net income $ 5.6 $ 17.8 $ 17.4 $ 50.9 Common unitholders' interest in net income attributable to Hess Midstream LP $ 8.9 $ 25.5 Subordinated unitholders' interest in net income attributable to Hess Midstream LP $ 8.9 $ 25.4 Net income attributable to Hess Midstream LP per Class A share: Basic: $ 0.31 $ 0.97 Diluted: $ 0.31 $ 0.95 Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted): Common $ 0.33 $ 0.93 Subordinated $ 0.33 $ 0.93 Weighted average Class A shares outstanding subsequent to the Restructuring: Basic: 18.0 18.0 Diluted: 18.1 18.1 Weighted average limited partner units outstanding prior to the Restructuring Basic: Common 27.3 27.3 Subordinated 27.3 27.3 Diluted: Common 27.5 27.5 Subordinated 27.3 27.3 For the three and nine months ended September 30, 2020, the weighted average number of Class A shares outstanding included 98,306 and 76,198 dilutive restricted shares, respectively. For the three and nine months ended September 30, 2019, the weighted average number of common units outstanding included 140,197 and 135,060 dilutive restricted units, respectively.

Concentration of Credit Risk

Concentration of Credit Risk	9 Months Ended
	Sep. 30, 2020
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 for the three and nine months ended September 30, 2020 and 2019.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
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 September 30, 2020, our reserves for estimated remediation liabilities included in Accrued liabilities and Other noncurrent liabilities were $1.3 million and $3.0 million, respectively, compared with $0.7 million and $2.1 million, respectively, as of December 31, 2019. Legal Proceedings 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. As of September 30, 2020 and December 31, 2019, we did not have material accrued liabilities for 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.

Segments

Segments	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Segments	Note 13. Segments Our operations are located in the United States and are organized into three reportable segments: (1) gathering, (2) processing and storage and (3) 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. Our CODM evaluates the segments’ operating performance based on multiple measures including Adjusted EBITDA, defined as net income (loss) before net interest expense, income tax expense (benefit), depreciation and amortization and our proportional share of depreciation of equity affiliates, as further adjusted to eliminate the impact of certain items that we do not consider indicative of our ongoing operating performance, such as transaction costs, other income and other non-cash, non‑recurring items, if applicable. The following tables reflect certain financial data for each reportable segment: Gathering Processing and Storage Terminaling and Export Interest and Other Consolidated (in millions) For the Three Months Ended September 30, 2020 Revenues and other income $ 142.9 $ 90.2 $ 31.7 $ - $ 264.8 Net income (loss) 72.4 50.7 18.0 (25.3 ) 115.8 Net income (loss) attributable to Hess Midstream LP 4.5 3.2 1.1 (3.2 ) 5.6 Depreciation expense 24.2 11.2 4.1 - 39.5 Proportional share of equity affiliates' depreciation - 1.3 - - 1.3 Income from equity investments - 3.6 - - 3.6 Interest expense, net - - - 23.2 23.2 Income tax expense (benefit) - - - 1.8 1.8 Adjusted EBITDA 96.6 63.2 22.1 (0.3 ) 181.6 Capital expenditures* 30.2 36.1 0.1 - 66.4 Gathering Processing and Storage Terminaling and Export Interest and Other Consolidated (in millions) For the Three Months Ended September 30, 2019 Revenues and other income $ 105.9 $ 74.0 $ 35.0 $ - $ 214.9 Net income (loss) 46.5 42.8 14.3 (16.2 ) 87.4 Net income (loss) attributable to Hess Midstream LP 9.1 8.8 2.8 (1.6 ) 19.1 Depreciation expense 20.8 11.2 4.0 - 36.0 Proportional share of equity affiliates' depreciation - 0.5 - - 0.5 Interest expense, net - - - 12.4 12.4 Adjusted EBITDA 67.3 54.5 18.3 (3.8 ) 136.3 Capital expenditures* 96.7 15.0 0.4 - 112.1 Gathering Processing and Storage Terminaling and Export Interest and Other Consolidated (in millions) For the Nine Months Ended September 30, 2020 Revenues and other income $ 420.9 $ 274.0 $ 130.5 $ - $ 825.4 Net income (loss) 220.0 159.2 54.6 (81.2 ) 352.6 Net income (loss) attributable to Hess Midstream LP 13.9 10.0 3.4 (9.9 ) 17.4 Depreciation expense 71.2 33.6 12.1 - 116.9 Proportional share of equity affiliates' depreciation - 3.8 - - 3.8 Income from equity investments - 7.2 - - 7.2 Interest expense, net - - - 71.3 71.3 Income tax expense (benefit) - - - 5.2 5.2 Gain on sale of property, plant and equipment 0.1 - - - 0.1 Adjusted EBITDA 291.1 196.6 66.7 (4.7 ) 549.7 Capital expenditures* 71.9 129.9 0.4 - 202.2 Gathering Processing and Storage Terminaling and Export Interest and Other Consolidated (in millions) For the Nine Months Ended September 30, 2019 Revenues and other income $ 298.0 $ 208.0 $ 88.8 $ - $ 594.8 Net income (loss) 132.5 124.2 38.8 (52.9 ) 242.6 Net income (loss) attributable to Hess Midstream LP 25.8 25.4 7.8 (5.0 ) 54.0 Depreciation expense 59.5 33.5 12.0 - 105.0 Proportional share of equity affiliates' depreciation - 0.5 - - 0.5 Interest expense, net - - - 44.2 44.2 Adjusted EBITDA 192.0 158.2 50.8 (8.7 ) 392.3 Capital expenditures* 284.2 23.7 0.1 - 308.0 *Includes acquisition, expansion and maintenance capital expenditures. Total assets for the reportable segments are as follows: September 30, 2020 December 31, 2019 (in millions) Gathering $ 1,862.6 $ 1,844.9 Processing and Storage (1) 1,153.7 1,055.1 Terminaling and Export 296.1 310.7 Interest and Other 59.3 67.0 Total assets $ 3,371.7 $ 3,277.7 (1) Includes investment in equity investees of $108.2 million as of September 30, 2020 and $107.8 as of December 31, 2019.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Note 14. Subsequent Events On October 26, 2020, the board of directors of our general partner declared a quarterly cash distribution of $0.4417 per Class A share for the quarter ended September 30, 2020, a 1.2% increase compared to the distribution on the Class A shares for the quarter ended June 30, 2020, which equals a 5% increase on an annualized basis. The distribution will be payable on November 13, 2020, to shareholders of record as of the close of business on November 5, 2020.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Presentation	The consolidated financial statements included in this report reflect all normal and recurring adjustments which, in the opinion of management, are necessary for a fair presentation of our consolidated financial position at September 30, 2020 and December 31, 2019, the consolidated results of operations for the three and nine months ended September 30, 2020 and 2019, and consolidated cash flows for the nine months ended September 30, 2020 and 2019. The unaudited results of operations for the interim periods reported are not necessarily indicative of results to be expected for the full year. The consolidated financial statements were prepared in accordance with the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain notes or other financial information that are normally required by U.S. generally accepted accounting principles (“GAAP”) have been condensed or omitted from these interim consolidated financial statements. These financial statements, therefore, should be read in conjunction with the financial statements and related notes included in the Company’s annual report on Form 10‑K for the year ended December 31, 2019. On December 16, 2019, we completed the acquisition of HIP, which was accounted for as a business combination of entities under common control. Accordingly, our consolidated financial statements prior to the acquisition date were retrospectively recast to include the financial results of HIP. See Note 3, Acquisitions. We consolidate the activities of the Partnership, and prior to the Restructuring the activities of Hess North Dakota Pipelines Operations LP, Hess TGP Operations LP and Hess North Dakota Export Logistics Operations LP (collectively, the “Joint Interest Assets”), as variable interest entities (“VIE”) under U.S. 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 13, Segments). We currently do not have any independent assets or operations other than our interest in the Partnership. Our noncontrolling interest represents the approximate 93.7% 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.
New Accounting Pronouncements	New Accounting Pronouncements. On January 1, 2020, we adopted 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 “incurred loss” model. The adoption of this ASU did not have a material impact on our consolidated financial statements. In March 2020, the Financial Accounting Standards Board (“FASB”) issued ASU 2020-04, Reference Rate Reform, as a new Accounting Standards Codification (“ASC”) Topic, ASC 848. The purpose of ASC 848 is to provide optional guidance to ease the potential effects on financial reporting of the market-wide migration away from Interbank Offered Rates, such as LIBOR, which is expected to be phased out at the end of calendar year 2021, to alternative reference rates. ASC 848 applies only to contracts, hedging relationships, debt arrangements and other transactions that reference a benchmark reference rate expected to be discontinued because of reference rate reform. ASC 848 contains optional expedients and exceptions for applying U.S. GAAP to transactions affected by this reform. The amendments in the ASU are effective for all entities as of March 12, 2020 through December 31, 2022. We are currently assessing the impact of adopting this new guidance as well as when to adopt this guidance.

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Consolidated Statements of Operations	Consolidated Statement of Operations Three Months Ended September 30, 2019 Partnership as Previously Reported Acquisition of HIP Consolidated Results (in millions) Revenues and other income Affiliate services $ 195.4 $ 19.5 $ 214.9 Total revenues and other income 195.4 19.5 214.9 Costs and expenses Operating and maintenance expenses (exclusive of depreciation shown separately below) 56.5 15.4 71.9 Depreciation expense 34.5 1.5 36.0 General and administrative expenses 3.9 3.8 7.7 Total costs and expenses 94.9 20.7 115.6 Income from operations 100.5 (1.2 ) 99.3 Earnings from equity investments 0.5 - 0.5 Interest expense, net 0.6 11.8 12.4 Net income 100.4 (13.0 ) 87.4 Less: Net income (loss) attributable to net parent investment - (13.0 ) (13.0 ) Less: Net income attributable to noncontrolling interest 81.3 - 81.3 Net income attributable to Hess Midstream Partners LP 19.1 - 19.1 Less: General partner's interest in net income attributable to Hess Midstream Partners LP 1.3 - 1.3 Limited partners' interest in net income attributable to Hess Midstream Partners LP $ 17.8 $ - $ 17.8 Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted): Common $ 0.33 $ - $ 0.33 Subordinated $ 0.33 $ - $ 0.33 Weighted average limited partner units outstanding: Basic: Common 27.3 - 27.3 Subordinated 27.3 - 27.3 Diluted: Common 27.5 - 27.5 Subordinated 27.3 - 27.3 Nine Months Ended September 30, 2019 Partnership as Previously Reported Acquisition of HIP Consolidated Results (in millions) Revenues and other income Affiliate services $ 542.1 $ 52.4 $ 594.5 Other income 0.3 - 0.3 Total revenues and other income 542.4 52.4 594.8 Costs and expenses Operating and maintenance expenses (exclusive of depreciation shown separately below) 142.0 42.1 184.1 Depreciation expense 101.1 3.9 105.0 General and administrative expenses 11.6 7.8 19.4 Total costs and expenses 254.7 53.8 308.5 Income from operations 287.7 (1.4 ) 286.3 Earnings from equity investments 0.5 - 0.5 Interest expense, net 1.6 42.6 44.2 Net income 286.6 (44.0 ) 242.6 Less: Net income (loss) attributable to net parent investment - (44.0 ) (44.0 ) Less: Net income attributable to noncontrolling interest 232.6 - 232.6 Net income attributable to Hess Midstream Partners LP 54.0 - 54.0 Less: General partner's interest in net income attributable to Hess Midstream Partners LP 3.1 - 3.1 Limited partners' interest in net income attributable to Hess Midstream Partners LP $ 50.9 $ - $ 50.9 Net income attributable to Hess Midstream Partners LP per limited partner unit (basic and diluted): Common $ 0.93 $ - $ 0.93 Subordinated $ 0.93 $ - $ 0.93 Weighted average limited partner units outstanding: Basic: Common 27.3 - 27.3 Subordinated 27.3 - 27.3 Diluted: Common 27.5 - 27.5 Subordinated 27.3 - 27.3
Consolidated Statements of Cash Flows	Consolidated Statement of Cash Flows Nine Months Ended September 30, 2019 Partnership as Previously Reported Acquisition of HIP Consolidated Results (in millions) Cash flows from operating activities Net income $ 286.6 $ (44.0 ) $ 242.6 Adjustments to reconcile net income to net cash provided by (used in) operating activities: Depreciation expense 101.1 3.9 105.0 (Gain) loss on interest rate swaps - (0.6 ) (0.6 ) Earnings from equity investments (0.5 ) - (0.5 ) (Increase) decrease in capitalized interest - (4.1 ) (4.1 ) Amortization of deferred financing costs 0.9 2.9 3.8 Equity-based compensation 1.1 - 1.1 Changes in assets and liabilities: Accounts receivable—affiliate (5.2 ) (2.4 ) (7.6 ) Other current and noncurrent assets (5.0 ) 0.3 (4.7 ) Accounts payable—trade 2.2 1.5 3.7 Accounts payable—affiliate 4.3 (5.8 ) (1.5 ) Accrued liabilities 9.2 (9.2 ) - Other current and noncurrent liabilities (2.5 ) (0.3 ) (2.8 ) Net cash provided by (used in) operating activities 392.2 (57.8 ) 334.4 Cash flows from investing activities Payments for equity investments (33.0 ) - (33.0 ) Acquisitions from Hess - (68.9 ) (68.9 ) Acquisitions from third parties, net of cash acquired (61.0 ) (28.2 ) (89.2 ) Additions to property, plant and equipment (184.4 ) (10.5 ) (194.9 ) Net cash provided by (used in) investing activities (278.4 ) (107.6 ) (386.0 ) Cash flows from financing activities Net proceeds from (repayments of) bank borrowings with maturities of 90 days or less 11.0 165.0 176.0 Repayments of bank borrowings with maturities of greater than 90 days - (7.5 ) (7.5 ) Capital distribution to Hess associated with acquisitions - (156.1 ) (156.1 ) Distributions to unitholders (63.0 ) - (63.0 ) Distributions to general partner (2.5 ) 2.5 - Distributions to noncontrolling interest (152.4 ) 152.4 - Contributions from noncontrolling interest 76.3 (76.3 ) - Net cash provided by (used in) financing activities (130.6 ) 80.0 (50.6 ) Net increase (decrease) in cash and cash equivalents (16.8 ) (85.4 ) (102.2 ) Cash and cash equivalents at beginning of period 20.3 89.0 109.3 Cash and cash equivalents at end of period $ 3.5 $ 3.6 $ 7.1

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Summary of Revenues From Contracts With Customers on Disaggregated Basis	Revenues from contracts with customers on a disaggregated basis are as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (in millions) Oil and gas gathering services $ 118.7 $ 86.4 $ 349.2 $ 245.6 Water gathering and disposal services 24.2 19.5 71.7 52.4 Processing and storage services 90.1 74.0 273.7 207.8 Terminaling and export services 31.7 35.0 130.5 88.7 Total revenues from contracts with customers $ 264.7 $ 214.9 $ 825.1 $ 594.5 Other income 0.1 - 0.3 0.3 Total revenues $ 264.8 $ 214.9 $ 825.4 $ 594.8
Summary of Third-party Pass-through Costs for Which Revenues in Amount Equal to Costs are Recognized and Classification of Charges between Operating and Maintenance Expenses and General and Administrative Expenses	The following table presents third-party pass-through costs for which we recognize revenues in an amount equal to the costs. These third-party costs are included in Operating and maintenance expenses in the accompanying unaudited consolidated statements of operations. Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (in millions) Rail transportation costs $ 5.0 $ 12.0 $ 49.3 $ 24.1 Produced water trucking and disposal costs 14.0 14.5 45.6 40.2 Electricity fees 10.3 8.3 29.7 23.2 Total $ 29.3 $ 34.8 $ 124.6 $ 87.5 Under our omnibus and employee secondment agreements, Hess provides substantial operational and administrative services to us in support of our assets and operations. For the three and nine months ended September 30, 2020 and 2019, 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. Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (in millions) Operating and maintenance expenses $ 16.7 $ 13.4 $ 47.5 $ 36.3 General and administrative expenses 3.9 $ 3.7 11.2 10.5 Total $ 20.6 $ 17.1 $ 58.7 $ 46.8
Summary of Activity Related to Agreements with Related Party	For the three and nine months ended September 30, 2020 and 2019, we had the following activity related to our agreements with LM4: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (in millions) Processing fee incurred $ 6.8 $ 0.9 $ 18.2 $ 0.9 Earnings from equity investments 3.6 0.5 7.2 0.5 Distributions received from equity investments 3.0 - 6.8 -

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	9 Months Ended
	Sep. 30, 2020
Property Plant And Equipment [Abstract]
Components of Property, Plant and Equipment	Property, plant and equipment, at cost, is as follows: Estimated useful lives September 30, 2020 December 31, 2019 (in millions, except for number of years) Gathering assets Pipelines 22 years $ 1,449.7 $ 1,352.7 Compressors, pumping stations and terminals 22 to 25 years 770.8 725.9 Gas plant assets Pipelines, pipes and valves 22 to 25 years 460.0 460.0 Equipment 12 to 30 years 428.3 428.2 Buildings 35 years 182.3 182.3 Processing and fractionation facilities 25 years 188.7 188.6 Logistics facilities and railcars 20 to 25 years 385.9 385.5 Storage facilities 20 to 25 years 19.5 19.5 Other 20 to 25 years 20.9 13.0 Construction-in-progress N/A 208.7 149.3 Total property, plant and equipment, at cost 4,114.8 3,905.0 Accumulated depreciation (1,011.5 ) (894.9 ) Property, plant and equipment, net $ 3,103.3 $ 3,010.1

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2020
Accrued Liabilities Current [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities are as follows: September 30, 2020 December 31, 2019 (in millions) Accrued capital expenditures $ 18.5 $ 34.7 Accrued interest 13.9 18.7 Other accruals 25.4 35.3 Total $ 57.8 $ 88.7

Partners' Capital and Distrib_2

Partners' Capital and Distributions (Tables)	9 Months Ended
	Sep. 30, 2020
Partners Capital Notes [Abstract]
Schedule of Distributions Declared and Paid	The following table details the distributions declared and/or paid for the periods presented: z Period Record Date Distribution Date Distribution per Common and Subordinated Unit/Class A share 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 February 6, 2020 February 14, 2020 $ 0.4258 First Quarter 2020 May 4, 2020 May 14, 2020 $ 0.4310 Second Quarter 2020 August 6, 2020 August 14, 2020 $ 0.4363 Third Quarter 2020 (1) November 5, 2020 November 13, 2020 $ 0.4417 (1)

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Equity-based Award Activity	Equity‑based award activity for the nine months ended September 30, 2020 is as follows: Weighted Average Award Date Number of Shares Fair Value Outstanding and unvested shares at December 31, 2019 136,060 $ 21.95 Granted 175,888 10.71 Forfeited (15,951 ) 14.84 Vested (67,653 ) 21.96 Outstanding and unvested shares at September 30, 2020 228,344 $ 13.78

Earnings per Share_Limited Pa_2

Earnings per Share/Limited Partner Unit (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Schedule of Earnings per Share Limited Partner Unit	Subsequent to the Restructuring, we calculate earnings per Class A Share and we do not have any other participating securities. Approximately 100% of income tax expense is attributed to earnings of Class A 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. 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. Three Months Ended September 30, Nine Months Ended September 30, (in millions, except per share amounts) 2020 2019 2020 2019 Net income $ 115.8 $ 87.4 $ 352.6 $ 242.6 Less: Net income attributable to net parent investment - (13.0 ) - (44.0 ) Less: Net income attributable to noncontrolling interest 110.2 81.3 335.2 232.6 Net income attributable to Hess Midstream LP 5.6 19.1 17.4 54.0 Less: General partner's interest in net income prior to the Restructuring - 1.3 - 3.1 Limited partners' interest in net income $ 5.6 $ 17.8 $ 17.4 $ 50.9 Common unitholders' interest in net income attributable to Hess Midstream LP $ 8.9 $ 25.5 Subordinated unitholders' interest in net income attributable to Hess Midstream LP $ 8.9 $ 25.4 Net income attributable to Hess Midstream LP per Class A share: Basic: $ 0.31 $ 0.97 Diluted: $ 0.31 $ 0.95 Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted): Common $ 0.33 $ 0.93 Subordinated $ 0.33 $ 0.93 Weighted average Class A shares outstanding subsequent to the Restructuring: Basic: 18.0 18.0 Diluted: 18.1 18.1 Weighted average limited partner units outstanding prior to the Restructuring Basic: Common 27.3 27.3 Subordinated 27.3 27.3 Diluted: Common 27.5 27.5 Subordinated 27.3 27.3

Segments (Tables)

Segments (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Financial Data for Each Reportable Segment	The following tables reflect certain financial data for each reportable segment: Gathering Processing and Storage Terminaling and Export Interest and Other Consolidated (in millions) For the Three Months Ended September 30, 2020 Revenues and other income $ 142.9 $ 90.2 $ 31.7 $ - $ 264.8 Net income (loss) 72.4 50.7 18.0 (25.3 ) 115.8 Net income (loss) attributable to Hess Midstream LP 4.5 3.2 1.1 (3.2 ) 5.6 Depreciation expense 24.2 11.2 4.1 - 39.5 Proportional share of equity affiliates' depreciation - 1.3 - - 1.3 Income from equity investments - 3.6 - - 3.6 Interest expense, net - - - 23.2 23.2 Income tax expense (benefit) - - - 1.8 1.8 Adjusted EBITDA 96.6 63.2 22.1 (0.3 ) 181.6 Capital expenditures* 30.2 36.1 0.1 - 66.4 Gathering Processing and Storage Terminaling and Export Interest and Other Consolidated (in millions) For the Three Months Ended September 30, 2019 Revenues and other income $ 105.9 $ 74.0 $ 35.0 $ - $ 214.9 Net income (loss) 46.5 42.8 14.3 (16.2 ) 87.4 Net income (loss) attributable to Hess Midstream LP 9.1 8.8 2.8 (1.6 ) 19.1 Depreciation expense 20.8 11.2 4.0 - 36.0 Proportional share of equity affiliates' depreciation - 0.5 - - 0.5 Interest expense, net - - - 12.4 12.4 Adjusted EBITDA 67.3 54.5 18.3 (3.8 ) 136.3 Capital expenditures* 96.7 15.0 0.4 - 112.1 Gathering Processing and Storage Terminaling and Export Interest and Other Consolidated (in millions) For the Nine Months Ended September 30, 2020 Revenues and other income $ 420.9 $ 274.0 $ 130.5 $ - $ 825.4 Net income (loss) 220.0 159.2 54.6 (81.2 ) 352.6 Net income (loss) attributable to Hess Midstream LP 13.9 10.0 3.4 (9.9 ) 17.4 Depreciation expense 71.2 33.6 12.1 - 116.9 Proportional share of equity affiliates' depreciation - 3.8 - - 3.8 Income from equity investments - 7.2 - - 7.2 Interest expense, net - - - 71.3 71.3 Income tax expense (benefit) - - - 5.2 5.2 Gain on sale of property, plant and equipment 0.1 - - - 0.1 Adjusted EBITDA 291.1 196.6 66.7 (4.7 ) 549.7 Capital expenditures* 71.9 129.9 0.4 - 202.2 Gathering Processing and Storage Terminaling and Export Interest and Other Consolidated (in millions) For the Nine Months Ended September 30, 2019 Revenues and other income $ 298.0 $ 208.0 $ 88.8 $ - $ 594.8 Net income (loss) 132.5 124.2 38.8 (52.9 ) 242.6 Net income (loss) attributable to Hess Midstream LP 25.8 25.4 7.8 (5.0 ) 54.0 Depreciation expense 59.5 33.5 12.0 - 105.0 Proportional share of equity affiliates' depreciation - 0.5 - - 0.5 Interest expense, net - - - 44.2 44.2 Adjusted EBITDA 192.0 158.2 50.8 (8.7 ) 392.3 Capital expenditures* 284.2 23.7 0.1 - 308.0 *Includes acquisition, expansion and maintenance capital expenditures.
Total Assets for Reportable Segments	Total assets for the reportable segments are as follows: September 30, 2020 December 31, 2019 (in millions) Gathering $ 1,862.6 $ 1,844.9 Processing and Storage (1) 1,153.7 1,055.1 Terminaling and Export 296.1 310.7 Interest and Other 59.3 67.0 Total assets $ 3,371.7 $ 3,277.7 (1) Includes investment in equity investees of $108.2 million as of September 30, 2020 and $107.8 as of December 31, 2019.

Description of Business - Addit

Description of Business - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2020Segment
Description Of Business [Abstract]
Number of reportable segments	3

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2020
Hess Infrastructure Partners Limited Partnership Joint Interest Assets
Accounting Policies [Line Items]
Noncontrolling interest percentage prior to restructuring	80.00%
Hess and GIP
Accounting Policies [Line Items]
Noncontrolling interest percentage	93.70%

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - USD ($) $ in Millions		Dec. 16, 2019	Dec. 15, 2019	Mar. 22, 2019	Mar. 01, 2019	May 31, 2020	Sep. 30, 2019
Business Acquisition [Line Items]
Cash paid for business acquisition, net of cash acquired	[1]						$ 89.2
Hess Infrastructure Partners LP Acquisition
Business Acquisition [Line Items]
Percentage of ownership interest		80.00%	80.00%
Cash consideration		$ 601.8
Stock split conversion ratio		1
Hess Infrastructure Partners LP Acquisition | Class A Shares
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%
Hess Water Services and Hess Midstream Partners GP Limited Partner
Business Acquisition [Line Items]
Percentage of ownership interest			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
Hess
Business Acquisition [Line Items]
Business combination consideration transferred in excess of book value of net assets acquired as capital distribution					$ 156.1
Hess | Final Purchase Settlement
Business Acquisition [Line Items]
Business combination consideration transferred in excess of book value of net assets acquired as capital distribution						$ 1.6
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
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Acquisitions - Consolidated Sta

Acquisitions - Consolidated Statements of Operations (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended									9 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019		Jun. 30, 2019	[1]	Mar. 31, 2019	[1]	Sep. 30, 2020	Sep. 30, 2019
Revenues and other income
Affiliate services		$ 264.7			$ 214.9	[1]					$ 825.1	$ 594.5	[1]
Type of Revenue [Extensible List]		hesm:AffiliateServicesMember			hesm:AffiliateServicesMember	[1]					hesm:AffiliateServicesMember	hesm:AffiliateServicesMember	[1]
Total revenues		$ 264.8			$ 214.9	[1]					$ 825.4	$ 594.8	[1]
Other income		0.1									0.3	0.3	[1]
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)		83.9			71.9	[1]					270.8	184.1	[1]
Depreciation expense		39.5			36	[1]					116.9	105	[1]
General and administrative expenses		4.2			7.7	[1]					15.9	19.4	[1]
Total costs and expenses		127.6			115.6	[1]					403.6	308.5	[1]
Income from operations		137.2			99.3	[1]					421.8	286.3	[1]
Earnings from equity investments		3.6			0.5	[1]					7.2	0.5	[1]
Interest expense, net		23.2			12.4	[1]					71.3	44.2	[1]
Net income		115.8	$ 107.8	$ 129	87.4	[1]	$ 74.4		$ 80.8		352.6	242.6	[1]
Less: Net income (loss) attributable to net parent investment	[1]				(13)							(44)
Less: Net income (loss) attributable to noncontrolling interest		110.2			81.3	[1]					335.2	232.6	[1]
Net income attributable to Hess Midstream LP		5.6			19.1	[1]					17.4	54	[1]
Less: General partner's interest in net income	[1]				1.3							3.1
Limited partners' interest in net income		$ 5.6			$ 17.8	[1]					$ 17.4	$ 50.9	[1]
Common Units
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]				$ 0.33							$ 0.93
Weighted average limited partner units outstanding, Basic:
Units outstanding prior to the Restructuring, Basic	[1]				27.3							27.3
Weighted average limited partner units outstanding, Diluted:
Units outstanding prior to the Restructuring, Diluted	[1]				27.5							27.5
Subordinated Units
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]				$ 0.33							$ 0.93
Weighted average limited partner units outstanding, Basic:
Units outstanding prior to the Restructuring, Basic	[1]				27.3							27.3
Weighted average limited partner units outstanding, Diluted:
Units outstanding prior to the Restructuring, Diluted	[1]				27.3							27.3
Partnership as Previously Reported
Revenues and other income
Affiliate services					$ 195.4							$ 542.1
Type of Revenue [Extensible List]					hesm:AffiliateServicesMember							hesm:AffiliateServicesMember
Total revenues					$ 195.4							$ 542.4
Other income												0.3
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)					56.5							142
Depreciation expense					34.5							101.1
General and administrative expenses					3.9							11.6
Total costs and expenses					94.9							254.7
Income from operations					100.5							287.7
Earnings from equity investments					0.5							0.5
Interest expense, net					0.6							1.6
Net income					100.4							286.6
Less: Net income (loss) attributable to noncontrolling interest					81.3							232.6
Net income attributable to Hess Midstream LP					19.1							54
Less: General partner's interest in net income					1.3							3.1
Limited partners' interest in net income					$ 17.8							$ 50.9
Partnership as Previously Reported | Common Units
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							$ 0.93
Weighted average limited partner units outstanding, Basic:
Units outstanding prior to the Restructuring, Basic					27.3							27.3
Weighted average limited partner units outstanding, Diluted:
Units outstanding prior to the Restructuring, Diluted					27.5							27.5
Partnership as Previously Reported | Subordinated Units
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							$ 0.93
Weighted average limited partner units outstanding, Basic:
Units outstanding prior to the Restructuring, Basic					27.3							27.3
Weighted average limited partner units outstanding, Diluted:
Units outstanding prior to the Restructuring, Diluted					27.3							27.3
Restatement Adjustment | Acquisition of HIP
Revenues and other income
Affiliate services					$ 19.5							$ 52.4
Type of Revenue [Extensible List]					hesm:AffiliateServicesMember							hesm:AffiliateServicesMember
Total revenues					$ 19.5							$ 52.4
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)					15.4							42.1
Depreciation expense					1.5							3.9
General and administrative expenses					3.8							7.8
Total costs and expenses					20.7							53.8
Income from operations					(1.2)							(1.4)
Interest expense, net					11.8							42.6
Net income					(13)							(44)
Less: Net income (loss) attributable to net parent investment					$ (13)							$ (44)
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Acquisitions - Consolidated S_2

Acquisitions - Consolidated Statements of Cash Flows (Detail) - USD ($) $ in Millions		3 Months Ended									9 Months Ended			12 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019		Jun. 30, 2019	[1]	Mar. 31, 2019		Sep. 30, 2020	Sep. 30, 2019		Dec. 31, 2019
Cash flows from operating activities
Net income		$ 115.8	$ 107.8	$ 129	$ 87.4	[1]	$ 74.4		$ 80.8	[1]	$ 352.6	$ 242.6	[1]
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense		39.5			36	[1]					116.9	105	[1]
(Gain) loss on interest rate swaps											(0.4)	(0.6)	[1]
Amortization of deferred financing costs											5.1	3.8	[1]
Equity-based compensation expense											1.2	1.1	[1]
Changes in assets and liabilities:
Accounts receivable – affiliate											(4.9)	(7.6)	[1]
Other current and noncurrent assets											(3.4)	(4.7)	[1]
Accounts payable – trade											9.5	3.7	[1]
Accounts payable – affiliate											(0.5)	(1.5)	[1]
Accrued liabilities											(12.6)
Other current and noncurrent liabilities											(1)	(2.8)	[1]
Net cash provided by (used in) operating activities											467.2	334.4	[1]
(Income) loss from equity investments		(3.6)			(0.5)	[1]					(7.2)	(0.5)	[1]
(Increase) decrease in capitalized interest	[1]											4.1
Cash flows from investing activities
Payments for equity investments	[1]											(33)
Acquisitions from Hess												(68.9)
Acquisitions	[1]											(89.2)
Additions to property, plant and equipment											(246)	(194.9)	[1]
Net cash provided by (used in) investing activities											(245.9)	(386)	[1]
Cash flows from financing activities
Net proceeds from (repayments of) bank borrowings with maturities of 90 days or less											146	176	[1]
Repayments of bank borrowings with maturities of greater than 90 days	[1]											(7.5)
Capital distribution to Hess associated with acquisitions	[1]											(156.1)
Distributions to shareholders/unitholders											(23.5)	(63)	[1]
Distributions to noncontrolling interest											(344.4)
Net cash provided by (used in) financing activities											(221.6)	(50.6)	[1]
Increase (decrease) in cash and cash equivalents											(0.3)	(102.2)	[1]
Cash and cash equivalents, beginning of period				$ 3.3					109.3	[1]	3.3	109.3	[1]	$ 109.3	[1]
Cash and cash equivalents, end of period		$ 3			7.1	[1]					$ 3	7.1	[1]	3.3
Partnership as Previously Reported
Cash flows from operating activities
Net income					100.4							286.6
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense					34.5							101.1
Amortization of deferred financing costs												0.9
Equity-based compensation expense												1.1
Changes in assets and liabilities:
Accounts receivable – affiliate												(5.2)
Other current and noncurrent assets												(5)
Accounts payable – trade												2.2
Accounts payable – affiliate												4.3
Accrued liabilities												9.2
Other current and noncurrent liabilities												(2.5)
Net cash provided by (used in) operating activities												392.2
(Income) loss from equity investments					(0.5)							(0.5)
Cash flows from investing activities
Payments for equity investments												(33)
Acquisitions												(61)
Additions to property, plant and equipment												(184.4)
Net cash provided by (used in) investing activities												(278.4)
Cash flows from financing activities
Net proceeds from (repayments of) bank borrowings with maturities of 90 days or less												11
Distributions to shareholders/unitholders												(63)
Distributions to general partner												(2.5)
Distributions to noncontrolling interest												(152.4)
Contributions from noncontrolling interest												76.3
Net cash provided by (used in) financing activities												(130.6)
Increase (decrease) in cash and cash equivalents												(16.8)
Cash and cash equivalents, beginning of period									20.3			20.3		20.3
Cash and cash equivalents, end of period					3.5							3.5
Restatement Adjustment | Acquisition of HIP
Cash flows from operating activities
Net income					(13)							(44)
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation expense					1.5							3.9
(Gain) loss on interest rate swaps												(0.6)
Amortization of deferred financing costs												2.9
Changes in assets and liabilities:
Accounts receivable – affiliate												(2.4)
Other current and noncurrent assets												0.3
Accounts payable – trade												1.5
Accounts payable – affiliate												(5.8)
Accrued liabilities												(9.2)
Other current and noncurrent liabilities												(0.3)
Net cash provided by (used in) operating activities												(57.8)
(Increase) decrease in capitalized interest												4.1
Cash flows from investing activities
Acquisitions from Hess												(68.9)
Acquisitions												(28.2)
Additions to property, plant and equipment												(10.5)
Net cash provided by (used in) investing activities												(107.6)
Cash flows from financing activities
Net proceeds from (repayments of) bank borrowings with maturities of 90 days or less												165
Repayments of bank borrowings with maturities of greater than 90 days												(7.5)
Capital distribution to Hess associated with acquisitions												(156.1)
Distributions to general partner												2.5
Distributions to noncontrolling interest												152.4
Contributions from noncontrolling interest												(76.3)
Net cash provided by (used in) financing activities												80
Increase (decrease) in cash and cash equivalents												(85.4)
Cash and cash equivalents, beginning of period									$ 89			89		$ 89
Cash and cash equivalents, end of period					$ 3.6							$ 3.6
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
LM4
Related Party Transaction [Line Items]
Percentage of ownership in joint venture	50.00%		50.00%
Credit Concentration Risk | Revenue
Related Party Transaction [Line Items]
Revenues attributable to fee based commercial agreements	100.00%	100.00%	100.00%	100.00%
Hess
Related Party Transaction [Line Items]
Minimum volume shortfall fee payments	$ 7.8	$ 3	$ 11.9	$ 6.5
Hess | Credit Concentration Risk | Revenue
Related Party Transaction [Line Items]
Revenues attributable to fee based commercial agreements	100.00%	100.00%	100.00%	100.00%
Targa Resources Corp. | LM4
Related Party Transaction [Line Items]
Percentage of ownership in joint venture	50.00%		50.00%

Related Party Transactions - Su

Related Party Transactions - Summary of Revenues From Contracts With Customers on Disaggregated Basis (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019		Sep. 30, 2020	Sep. 30, 2019
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	$ 264.7	$ 214.9	[1]	$ 825.1	$ 594.5	[1]
Other income	0.1			0.3	0.3	[1]
Total revenues	264.8	214.9	[1]	825.4	594.8	[1]
Oil and Gas Gathering Services
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	118.7	86.4		349.2	245.6
Water Gathering and Disposal Services
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	24.2	19.5		71.7	52.4
Processing and Storage Services
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	90.1	74		273.7	207.8
Terminaling and Export Services
Disaggregation Of Revenue [Line Items]
Total revenues from contracts with customers	$ 31.7	$ 35		$ 130.5	$ 88.7
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Related Party Transactions - _2

Related Party Transactions - Summary of Third-party Pass-through Costs for Which Revenues in Amount Equal to Costs are Recognized (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019		Sep. 30, 2020	Sep. 30, 2019
Related Party Transaction [Line Items]
Reimbursement revenue	$ 264.7	$ 214.9	[1]	$ 825.1	$ 594.5	[1]
Hess
Related Party Transaction [Line Items]
Total	29.3	34.8		124.6	87.5
Hess | Rail Transportation Costs
Related Party Transaction [Line Items]
Reimbursement revenue	5	12		49.3	24.1
Hess | Produced Water Trucking and Disposal Costs
Related Party Transaction [Line Items]
Reimbursement revenue	14	14.5		45.6	40.2
Hess | Electricity Fees
Related Party Transaction [Line Items]
Reimbursement revenue	$ 10.3	$ 8.3		$ 29.7	$ 23.2
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Related Party Transactions - _3

Related Party Transactions - Summary of Classification of Charges between Operating and Maintenance Expenses and General and Administrative Expenses (Detail) - Hess - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Related Party Transaction [Line Items]
Operating and maintenance expenses	$ 16.7	$ 13.4	$ 47.5	$ 36.3
General and administrative expenses	3.9	3.7	11.2	10.5
Total	$ 20.6	$ 17.1	$ 58.7	$ 46.8

Related Party Transactions - _4

Related Party Transactions - Summary of Activity Related to Agreements with Related Party (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019		Sep. 30, 2020	Sep. 30, 2019
Related Party Transaction [Line Items]
Earnings from equity investments	$ 3.6	$ 0.5	[1]	$ 7.2	$ 0.5	[1]
Distributions received from equity investments				6.8
LM4
Related Party Transaction [Line Items]
Processing fee incurred	6.8	0.9		18.2	0.9
Earnings from equity investments	3.6	$ 0.5		7.2	$ 0.5
Distributions received from equity investments	$ 3			$ 6.8
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Property, Plant and Equipment -

Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 4,114.8	$ 3,905
Accumulated depreciation	(1,011.5)	(894.9)
Property, plant and equipment, net	3,103.3	3,010.1
Logistics Facilities and Railcars
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 385.9	385.5
Logistics Facilities and Railcars | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	20 years
Logistics Facilities and Railcars | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Storage Facilities
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 19.5	19.5
Storage Facilities | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	20 years
Storage Facilities | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Other
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 20.9	13
Other | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	20 years
Other | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Construction-In-Progress
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 208.7	149.3
Gathering Assets | Pipelines
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	22 years
Total property, plant and equipment, at cost	$ 1,449.7	1,352.7
Gathering Assets | Compressors, Pumping Stations and Terminals
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 770.8	725.9
Gathering Assets | Compressors, Pumping Stations and Terminals | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	22 years
Gathering Assets | Compressors, Pumping Stations and Terminals | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Gas Plant Assets | Pipelines, Pipes and Valves
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 460	460
Gas Plant Assets | Pipelines, Pipes and Valves | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	22 years
Gas Plant Assets | Pipelines, Pipes and Valves | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Gas Plant Assets | Equipment
Property Plant And Equipment [Line Items]
Total property, plant and equipment, at cost	$ 428.3	428.2
Gas Plant Assets | Equipment | Minimum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	12 years
Gas Plant Assets | Equipment | Maximum
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	30 years
Gas Plant Assets | Buildings
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	35 years
Total property, plant and equipment, at cost	$ 182.3	182.3
Gas Plant Assets | Processing and Fractionation Facilities
Property Plant And Equipment [Line Items]
Property, plant and equipment, Estimated useful life	25 years
Total property, plant and equipment, at cost	$ 188.7	$ 188.6

Accrued Liabilities - Schedule

Accrued Liabilities - Schedule of Accrued Liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Accrued Liabilities Current [Abstract]
Accrued capital expenditures	$ 18.5	$ 34.7
Accrued interest	13.9	18.7
Other accruals	25.4	35.3
Total	$ 57.8	$ 88.7

Debt and Interest Expense - Add

Debt and Interest Expense - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2020USD ($)
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.
Carrying Value
Debt Instrument [Line Items]
Total debt	$ 1,903,000,000
Level 2
Debt Instrument [Line Items]
Total debt fair value	$ 1,938,600,000
Revolving Credit Facility
Debt Instrument [Line Items]
Credit facility - Term	5 years
Maximum borrowing capacity	$ 1,000,000,000
Borrowings	$ 178,000,000
Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Interest rate applicable margin	1.55%
Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Interest rate applicable margin	2.50%
Term Loan A Facility
Debt Instrument [Line Items]
Credit facility - Term	5 years
Maximum borrowing capacity	$ 400,000,000
Borrowings	$ 400,000,000
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%
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]
Fixed-rate senior notes	$ 800,000,000
5.625% Fixed Rate Senior Notes due 2026 | Fixed-Rate Senior Notes
Debt Instrument [Line Items]
Debt instrument interest rate	5.625%
Debt instrument due year	2026
Frequency of periodic interest payment	semi‑annually
Interest payment terms	Interest is payable semi‑annually 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
5.125% Fixed Rate Senior Notes due 2028 | Fixed-Rate Senior Notes
Debt Instrument [Line Items]
Debt instrument interest rate	5.125%
Debt instrument due year	2028
Frequency of periodic interest payment	semi‑annually
Interest payment terms	Interest is payable semi‑annually on June 15 and December 15.

Partners' Capital and Distrib_3

Partners' Capital and Distributions - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2020
Partners Capital Notes [Abstract]
Period of cash distribution to shareholders	45 days

Partners' Capital and Distrib_4

Partners' Capital and Distributions - Schedule of Distributions Declared and Paid (Detail)	9 Months Ended
	Sep. 30, 2020$ / shares
First Quarter 2019
Distribution Made To Limited Partner [Line Items]
Record Date	May 3, 2019
Distribution Date	May 14, 2019
Distribution per Common and Subordinated Unit/Class A share	$ 0.3833
Second Quarter 2019
Distribution Made To Limited Partner [Line Items]
Record Date	Aug. 5, 2019
Distribution Date	Aug. 13, 2019
Distribution per Common and Subordinated Unit/Class A share	$ 0.3970
Third Quarter 2019
Distribution Made To Limited Partner [Line Items]
Record Date	Nov. 4, 2019
Distribution Date	Nov. 13, 2019
Distribution per Common and Subordinated Unit/Class A share	$ 0.4112
Fourth Quarter 2019
Distribution Made To Limited Partner [Line Items]
Record Date	Feb. 6, 2020
Distribution Date	Feb. 14, 2020
Distribution per Common and Subordinated Unit/Class A share	$ 0.4258
First Quarter 2020
Distribution Made To Limited Partner [Line Items]
Record Date	May 4, 2020
Distribution Date	May 14, 2020
Distribution per Common and Subordinated Unit/Class A share	$ 0.4310
Second Quarter 2020
Distribution Made To Limited Partner [Line Items]
Record Date	Aug. 6, 2020
Distribution Date	Aug. 14, 2020
Distribution per Common and Subordinated Unit/Class A share	$ 0.4363
Third Quarter 2020
Distribution Made To Limited Partner [Line Items]
Record Date	Nov. 5, 2020	[1]
Distribution Date	Nov. 13, 2020	[1]
Distribution per Common and Subordinated Unit/Class A share	$ 0.4417	[1]
[1]	For more information, see Note 14, Subsequent Events.

Equity-Based Compensation - Sch

Equity-Based Compensation - Schedule of Equity-based Award Activity (Detail) - Restricted Share	9 Months Ended
	Sep. 30, 2020$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding and unvested shares at December 31, 2019, Number of Shares | shares	136,060
Granted, Number of Shares | shares	175,888
Forfeited, Number of Shares | shares	(15,951)
Vested, Number of Shares | shares	(67,653)
Outstanding and unvested shares at September 30, 2020, Number of Shares | shares	228,344
Outstanding and unvested shares at December 31, 2019, Weighted Average Award Date Fair Value | $ / shares	$ 21.95
Granted, Weighted Average Award Date Fair Value | $ / shares	10.71
Forfeited, Weighted Average Award Date Fair Value | $ / shares	14.84
Vested, Weighted Average Award Date Fair Value | $ / shares	21.96
Outstanding and unvested shares at September 30, 2020, Weighted Average Award Date Fair Value | $ / shares	$ 13.78

Equity-Based Compensation - Add

Equity-Based Compensation - Additional Information (Detail) - 2017 Long-Term Incentive Plan $ in Millions	9 Months Ended
	Sep. 30, 2020USD ($)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Cost related to restricted shares to be recognized	$ 2.1
Cost related to unvested restricted shares to be recognized, over an expected weighted-average period	1 year 10 months 24 days

Earnings per Share_Limited Pa_3

Earnings per Share/Limited Partner Unit - Additional Information (Detail) - shares	Dec. 16, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Dilutive Restricted Shares
Limited Partners Capital Account [Line Items]
Weighted average number shares		98,306		76,198
Dilutive Restricted Units
Limited Partners Capital Account [Line Items]
Weighted average number shares			140,197		135,060
Hess and GIP | Class A Shares
Limited Partners Capital Account [Line Items]
Percentage of income tax expense attributed to earnings of Class A Shares	100.00%
Conversion of Class B units and Class B shares into Class A shares	100.00%

Earnings per Share_Limited Pa_4

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									9 Months Ended
		Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019		Jun. 30, 2019	[1]	Mar. 31, 2019	[1]	Sep. 30, 2020	Sep. 30, 2019
Limited Partners Capital Account [Line Items]
Net income		$ 115.8	$ 107.8	$ 129	$ 87.4	[1]	$ 74.4		$ 80.8		$ 352.6	$ 242.6	[1]
Less: Net income (loss) attributable to net parent investment	[1]				(13)							(44)
Less: Net income (loss) attributable to noncontrolling interest		110.2			81.3	[1]					335.2	232.6	[1]
Net income attributable to Hess Midstream LP		5.6			19.1	[1]					17.4	54	[1]
Less: General partner's interest in net income	[1]				1.3							3.1
Limited partners' interest in net income		$ 5.6			17.8	[1]					$ 17.4	50.9	[1]
Common Units
Limited Partners Capital Account [Line Items]
Common unitholders' interest in net income attributable to Hess Midstream LP					$ 8.9							$ 25.5
Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):
Basic and diluted	[1]				$ 0.33							$ 0.93
Weighted average limited partner units outstanding prior to the Restructuring, Basic:
Units outstanding prior to the Restructuring, Basic	[1]				27.3							27.3
Weighted average limited partner units outstanding prior to the Restructuring, Diluted:
Units outstanding prior to the Restructuring, Diluted	[1]				27.5							27.5
Subordinated Units
Limited Partners Capital Account [Line Items]
Common unitholders' interest in net income attributable to Hess Midstream LP					$ 8.9							$ 25.4
Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):
Basic and diluted	[1]				$ 0.33							$ 0.93
Weighted average limited partner units outstanding prior to the Restructuring, Basic:
Units outstanding prior to the Restructuring, Basic	[1]				27.3							27.3
Weighted average limited partner units outstanding prior to the Restructuring, Diluted:
Units outstanding prior to the Restructuring, Diluted	[1]				27.3							27.3
Class A Shares
Net income attributable to Hess Midstream LP per Class A share:
Net income attributable to Hess Midstream LP per Class A share, Basic		$ 0.31									$ 0.97
Net income attributable to Hess Midstream LP per Class A share, Diluted		$ 0.31									$ 0.95
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		18									18
Weighted average Class A shares outstanding subsequent to the restructuring, Diluted		18.1									18.1
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Concentration of Credit Risk -

Concentration of Credit Risk - Additional Information (Detail) - Credit Concentration Risk	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%
Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	100.00%	100.00%	100.00%	100.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Estimated remediation liabilities included in accrued liabilities	$ 1,300,000	$ 700,000
Estimated remediation liabilities included in other noncurrent liabilities	3,000,000	2,100,000
Accrued liabilities for legal contingencies	$ 0	$ 0

Segments - Additional Informati

Segments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2020Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Segments - Financial Data for E

Segments - Financial Data for Each Reportable Segment (Detail) - USD ($) $ in Millions	3 Months Ended									9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019		Jun. 30, 2019	[1]	Mar. 31, 2019	[1]	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues and other income	$ 264.8			$ 214.9	[1]					$ 825.4	$ 594.8	[1]
Net income (loss)	115.8	$ 107.8	$ 129	87.4	[1]	$ 74.4		$ 80.8		352.6	242.6	[1]
Net income (loss) attributable to Hess Midstream LP	5.6			19.1	[1]					17.4	54	[1]
Depreciation expense	39.5			36	[1]					116.9	105	[1]
Proportional share of equity affiliates' depreciation	1.3			0.5						3.8	0.5
Income from equity investments	3.6			0.5	[1]					7.2	0.5	[1]
Interest expense, net	23.2			12.4	[1]					71.3	44.2	[1]
Income tax expense (benefit)	1.8									5.2
Gain on sale of property, plant and equipment										0.1
Adjusted EBITDA	181.6			136.3						549.7	392.3
Capital expenditures	66.4			112.1						202.2	308
Interest and Other
Segment Reporting Information [Line Items]
Net income (loss)	(25.3)			(16.2)						(81.2)	(52.9)
Net income (loss) attributable to Hess Midstream LP	(3.2)			(1.6)						(9.9)	(5)
Interest expense, net	23.2			12.4						71.3	44.2
Income tax expense (benefit)	1.8									5.2
Adjusted EBITDA	(0.3)			(3.8)						(4.7)	(8.7)
Gathering Opco | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	142.9			105.9						420.9	298
Net income (loss)	72.4			46.5						220	132.5
Net income (loss) attributable to Hess Midstream LP	4.5			9.1						13.9	25.8
Depreciation expense	24.2			20.8						71.2	59.5
Gain on sale of property, plant and equipment										0.1
Adjusted EBITDA	96.6			67.3						291.1	192
Capital expenditures	30.2			96.7						71.9	284.2
Processing and Storage | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	90.2			74						274	208
Net income (loss)	50.7			42.8						159.2	124.2
Net income (loss) attributable to Hess Midstream LP	3.2			8.8						10	25.4
Depreciation expense	11.2			11.2						33.6	33.5
Proportional share of equity affiliates' depreciation	1.3			0.5						3.8	0.5
Income from equity investments	3.6									7.2
Adjusted EBITDA	63.2			54.5						196.6	158.2
Capital expenditures	36.1			15						129.9	23.7
Terminaling and Export | Operating Segments
Segment Reporting Information [Line Items]
Revenues and other income	31.7			35						130.5	88.8
Net income (loss)	18			14.3						54.6	38.8
Net income (loss) attributable to Hess Midstream LP	1.1			2.8						3.4	7.8
Depreciation expense	4.1			4						12.1	12
Adjusted EBITDA	22.1			18.3						66.7	50.8
Capital expenditures	$ 0.1			$ 0.4						$ 0.4	$ 0.1
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Segments - Total Assets for Rep

Segments - Total Assets for Reportable Segments (Detail) - USD ($) $ in Millions		Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets		$ 3,371.7	$ 3,277.7
Interest and Other
Segment Reporting Information [Line Items]
Total assets		59.3	67
Gathering Opco | Operating Segments
Segment Reporting Information [Line Items]
Total assets		1,862.6	1,844.9
Processing and Storage | Operating Segments
Segment Reporting Information [Line Items]
Total assets	[1]	1,153.7	1,055.1
Terminaling and Export | Operating Segments
Segment Reporting Information [Line Items]
Total assets		$ 296.1	$ 310.7
[1]	Includes investment in equity investees of $108.2 million as of September 30, 2020 and $107.8 as of December 31, 2019.

Segments - Total Assets for R_2

Segments - Total Assets for Reportable Segments (Parenthetical) (Detail) - USD ($) $ in Millions		9 Months Ended		12 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Cash contributed to acquire equity investments	[1]		$ 33
Processing and Storage
Segment Reporting Information [Line Items]
Cash contributed to acquire equity investments		$ 108.2		$ 107.8
[1]	The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - Subsequent Event	Oct. 26, 2020$ / shares
Subsequent Event [Line Items]
Quarterly cash distribution declared date	Oct. 26, 2020
Distribution made to limited partner, increase in percentage than prior year quarter declared	1.20%
Distribution made to limited partner, increase in percentage on an annualized basis	5.00%
Distribution Date	Nov. 13, 2020
Record Date	Nov. 5, 2020
Class A Shares
Subsequent Event [Line Items]
Quarterly cash distribution declared per class A share	$ 0.4417