CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Millions, $ in Millions		3 Months Ended			6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019		Jun. 30, 2020	Jun. 30, 2019
Revenues
Affiliate services		$ 269.8	$ 190.2	[1]	$ 560.4	$ 379.6	[1]
Type of Revenue [Extensible List]		hesm:AffiliateServicesMember	hesm:AffiliateServicesMember	[1]	hesm:AffiliateServicesMember	hesm:AffiliateServicesMember	[1]
Other income			$ 0.1	[1]	$ 0.2	$ 0.3	[1]
Total revenues		$ 269.8	190.3	[1]	560.6	379.9	[1]
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)		95.0	57.9	[1]	186.9	112.2	[1]
Depreciation expense		38.9	35.4	[1]	77.4	69.0	[1]
General and administrative expenses		4.1	5.8	[1]	11.7	11.7	[1]
Total costs and expenses		138.0	99.1	[1]	276.0	192.9	[1]
Income from operations		131.8	91.2	[1]	284.6	187.0	[1]
Income from equity investments		0.9			3.6
Interest expense, net		23.3	16.8	[1]	48.1	31.8	[1]
Gain on sale of property, plant and equipment		0.1			0.1
Income before income tax expense (benefit)		109.5	74.4	[1]	240.2	155.2	[1]
Income tax expense (benefit)		1.7			3.4
Net income		107.8	74.4	[1]	236.8	155.2	[1]
Less: Net income (loss) attributable to net parent investment	[1]		(16.5)			(31.0)
Less: Net income (loss) attributable to noncontrolling interest		102.5	74.1	[1]	225.0	151.3	[1]
Net income attributable to Hess Midstream LP		5.3	16.8	[1]	11.8	34.9	[1]
Less: General partner's interest in net income	[1]		1.0			1.8
Limited partners' interest in net income		$ 5.3	$ 15.8	[1]	$ 11.8	$ 33.1	[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]		$ 0.29			$ 0.61
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]		$ 0.29			$ 0.61
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		$ 0.29			$ 0.66
Net income attributable to Hess Midstream LP per Class A share, Diluted		$ 0.29			$ 0.64
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		18.0			18.0
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.