CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	[1]	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income		$ 317.7	$ 325.5		$ 242.0	[1]
Other comprehensive income
Changes in fair value of cash flow hedges	[1]				3.3
Effect of hedge (gains) losses reclassified to income		(0.8)	(0.4)		(1.7)	[1]
Total other comprehensive income		(0.8)	(0.4)		1.6	[1]
Comprehensive income		316.9	325.1		243.6	[1]
Less: Comprehensive income (loss) attributable to net parent investment		(55.6)	(47.2)		27.0	[1]
Less: Comprehensive income (loss) attributable to noncontrolling interest		302.6	301.5		175.4	[1]
Comprehensive income attributable to Hess Midstream LP		$ 69.9	$ 70.8		$ 41.2	[1]

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