CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 129.0	$ 80.8	[1]
Effect of hedge (gains) losses reclassified to income		(0.2)	(0.2)	[1]
Total other comprehensive income		(0.2)	(0.2)	[1]
Comprehensive income		128.8	80.6	[1]
Less: Comprehensive income (loss) attributable to net parent investment	[1]		(14.7)
Less: Comprehensive income (loss) attributable to noncontrolling interest		122.3	77.2	[1]
Comprehensive income attributable to Hess Midstream LP		$ 6.5	$ 18.1	[1]

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