Acquisitions - Consolidated Balance Sheet (Detail) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents		$ 3.3	$ 109.3	[1]
Accounts receivable—affiliate:
From contracts with customers		87.6	67.3	[1]
Other receivables		0.3	0.5	[1]
Other current assets		4.7	3.3	[1]
Total current assets		95.9	180.4	[1]
Equity investments		107.8	67.3	[1]
Property, plant and equipment, net		3,010.1	2,735.3	[1]
Long-term receivable—affiliate		1.2	1.3	[1]
Other noncurrent assets		12.9	6.9	[1]
Total assets		3,277.7	2,991.2	[1]
Liabilities
Accounts payable—trade		30.6	18.6	[1]
Accounts payable—affiliate		47.9	15.8	[1]
Accrued liabilities		88.7	85.6	[1]
Current maturities of long-term debt	[1]		11.3
Other current liabilities		8.9	6.8	[1]
Total current liabilities		176.1	138.1	[1]
Long-term debt		1,753.5	969.8	[1]
Other noncurrent liabilities		16.0	7.2	[1]
Total liabilities		1,945.6	1,115.1	[1]
General partner	[1]		14.9
Total Hess Midstream Partners LP partners' capital			516.8
Noncontrolling interest		1,200.6	2,194.1	[1]
Accumulated other comprehensive income		0.4	1.2	[1]
Net parent investment	[1]		(836.0)
Total partners' capital		1,332.1	1,876.1	[1]	$ 1,952.3	$ 1,809.9
Total liabilities and partners' capital		$ 3,277.7	2,991.2	[1]
Partnership as Previously Reported
Assets
Cash and cash equivalents			20.3
Accounts receivable—affiliate:
From contracts with customers			62.2
Other receivables			0.8
Other current assets			2.8
Total current assets			86.1
Equity investments			67.3
Property, plant and equipment, net			2,664.1
Other noncurrent assets			2.2
Total assets			2,819.7
Liabilities
Accounts payable—trade			15.3
Accounts payable—affiliate			15.8
Accrued liabilities			64.5
Other current liabilities			6.8
Total current liabilities			102.4
Other noncurrent liabilities			6.4
Total liabilities			108.8
General partner			14.9
Total Hess Midstream Partners LP partners' capital			516.8
Noncontrolling interest			2,194.1
Total partners' capital			2,710.9
Total liabilities and partners' capital			2,819.7
Restatement Adjustment | Acquisition of HIP
Assets
Cash and cash equivalents			89.0
Accounts receivable—affiliate:
From contracts with customers			5.1
Other receivables			(0.3)
Other current assets			0.5
Total current assets			94.3
Property, plant and equipment, net			71.2
Long-term receivable—affiliate			1.3
Other noncurrent assets			4.7
Total assets			171.5
Liabilities
Accounts payable—trade			3.3
Accrued liabilities			21.1
Current maturities of long-term debt			11.3
Total current liabilities			35.7
Long-term debt			969.8
Other noncurrent liabilities			0.8
Total liabilities			1,006.3
Accumulated other comprehensive income			1.2
Net parent investment			(836.0)
Total partners' capital			(834.8)
Total liabilities and partners' capital			171.5
Common Unitholders - Public
Liabilities
Common and subordinated unitholders	[1]		357.1
Common Unitholders - Public | Partnership as Previously Reported
Liabilities
Common and subordinated unitholders			357.1
Common Unitholders - Affiliate
Liabilities
Common and subordinated unitholders	[1]		39.5
Common Unitholders - Affiliate | Partnership as Previously Reported
Liabilities
Common and subordinated unitholders			39.5
Subordinated Unitholders - Affiliate
Liabilities
Common and subordinated unitholders	[1]		105.3
Subordinated Unitholders - Affiliate | Partnership as Previously Reported
Liabilities
Common and subordinated unitholders			$ 105.3

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