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	242.0	[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	$ 54.0	[1]

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