CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenues
Affiliate services	$ 294.8	$ 269.8	$ 583.6	$ 560.4
Type of Revenue [Extensible List]	hesm:AffiliateServicesMember	hesm:AffiliateServicesMember	hesm:AffiliateServicesMember	hesm:AffiliateServicesMember
Other income				$ 0.2
Total revenues	$ 294.8	$ 269.8	$ 583.6	560.6
Costs and expenses
Operating and maintenance expenses (exclusive of depreciation shown separately below)	63.6	95.0	123.4	186.9
Depreciation expense	40.4	38.9	80.6	77.4
General and administrative expenses	5.2	4.1	11.5	11.7
Total costs and expenses	109.2	138.0	215.5	276.0
Income from operations	185.6	131.8	368.1	284.6
Income from equity investments	2.9	0.9	5.6	3.6
Interest expense, net	22.9	23.3	46.0	48.1
Gain on sale of property, plant and equipment		0.1		0.1
Income before income tax expense	165.6	109.5	327.7	240.2
Income tax expense	3.6	1.7	6.1	3.4
Net income	162.0	107.8	321.6	236.8
Less: Net income attributable to noncontrolling interest	151.0	102.5	302.0	225.0
Net income attributable to Hess Midstream LP	11.0	5.3	$ 19.6	$ 11.8
Class A Shares
Costs and expenses
Net income	$ 11.0	$ 5.3
Net income attributable to Hess Midstream LP per Class A share:
Net income attributable to Hess Midstream LP per Class A share, Basic	$ 0.44	$ 0.29	$ 0.89	$ 0.66
Net income attributable to Hess Midstream LP per Class A share, Diluted	$ 0.44	$ 0.29	$ 0.87	$ 0.64
Weighted average Class A shares outstanding
Weighted average Class A shares outstanding subsequent to the restructuring, Basic	25.0	18.0	22.2	18.0
Weighted average Class A shares outstanding subsequent to the restructuring, Diluted	25.1	18.1	22.3	18.1