Earnings per Share/Limited Partner Unit - Partnership's Calculation of Earnings per Share Limited Partner Unit (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Diluted net income per share [Line Items]
Net income		$ 617.8	$ 484.9	$ 317.7
Less: Net income (loss) attributable to net parent investment				(55.0)
Less: Net income (loss) attributable to noncontrolling interest		571.4	460.9	302.6
Net income attributable to Hess Midstream LP		46.4	24.0	70.1
Less: General partners' interest in net income prior to the Restructuring				3.4
Limited partners' interest in net income		$ 46.4	$ 24.0	$ 66.7
Common Units
Weighted average limited partner units outstanding prior to the Restructuring, Basic:
Units outstanding prior to the Restructuring, Basic				27.3
Weighted average limited partner units outstanding prior to the Restructuring, Diluted:
Units outstanding prior to the Restructuring, Diluted				27.5
Subordinated Units
Weighted average limited partner units outstanding prior to the Restructuring, Basic:
Units outstanding prior to the Restructuring, Basic				27.3
Weighted average limited partner units outstanding prior to the Restructuring, Diluted:
Units outstanding prior to the Restructuring, Diluted				27.3
Class A Shares
Net income attributable to Hess Midstream LP per Class A share:
Net income attributable to Hess Midstream LP per Class A share, Basic	[1]	$ 1.81	$ 1.33	$ 1.21
Net income attributable to Hess Midstream LP per Class A share, Diluted	[1]	$ 1.76	$ 1.31	$ 1.20
Net income attributable to Hess Midstream LP per limited partner unit (basic and diluted):
Weighted average Class A shares outstanding, Basic		25.6	18.0	18.0
Weighted average Class A shares outstanding, Diluted		25.7	18.1	18.0

[1] *Net income attributable to Hess Midstream LP per Class A Share/limited partner unit for 2019 was calculated by combining net income per limited partner unit (common and subordinated) for the period prior to the Restructuring on December 16, 2019, and net income per Class A Share for the period subsequent to the Restructuring.