CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 162.0	$ 107.8	$ 321.6	$ 236.8
Other comprehensive income
Effect of hedge (gains) losses reclassified to income		(0.2)		(0.4)
Total other comprehensive income		(0.2)		(0.4)
Comprehensive income	162.0	107.6	321.6	236.4
Less: Comprehensive income (loss) attributable to noncontrolling interest	151.0	102.3	302.0	224.6
Comprehensive income attributable to Hess Midstream LP	$ 11.0	$ 5.3	$ 19.6	$ 11.8