CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019		Jun. 30, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 107.8	$ 74.4	[1]	$ 236.8	$ 155.2	[1]
Effect of hedge (gains) losses reclassified to income	(0.2)	(0.2)		(0.4)	(0.4)
Total other comprehensive income	(0.2)	(0.2)	[1]	(0.4)	(0.4)
Comprehensive income	107.6	74.2		236.4	154.8
Less: Comprehensive income (loss) attributable to net parent investment		(16.7)			(31.4)
Less: Comprehensive income (loss) attributable to noncontrolling interest	102.3	74.1		224.6	151.3
Comprehensive income attributable to Hess Midstream LP	$ 5.3	$ 16.8		$ 11.8	$ 34.9

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