Description of Business and Basis of Presentation (Details)	6 Months Ended
	Jun. 30, 2020 segment shares	Apr. 01, 2020 shares	Mar. 31, 2020	Dec. 31, 2019 shares
Description Of Business And Basis Of Presentation [Line Items]
Common units (in units)		393,289,537
Number of reportable segments | segment	1
Shell Pipeline Company L P
Description Of Business And Basis Of Presentation [Line Items]
Preferred units (in units)	50,782,904			0
Limited Partner | Shell Pipeline Company L P
Description Of Business And Basis Of Presentation [Line Items]
Ownership interest percentage	68.50%
Common units (in units)	269,457,304
Limited Partner | Partnership Interests Restructuring Agreement | Series A Perpetual Convertible Preferred Units
Description Of Business And Basis Of Presentation [Line Items]
Preferred units (in units)	50,782,904
Economic Interest | General Partner
Description Of Business And Basis Of Presentation [Line Items]
Noncontrolling interest		2.00%	2.00%
Pecten Midstream LLC (“Pecten”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	100.00%
Sand Dollar Pipeline LLC (“Sand Dollar”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	100.00%
Triton West LLC (“Triton”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	100.00%
Zydeco Pipeline Company LLC (“Zydeco”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	92.50%
Zydeco Pipeline Company LLC (“Zydeco”) | Zydeco Pipeline Company LLC (“Zydeco”) | Shell Pipeline Company L P
Description Of Business And Basis Of Presentation [Line Items]
Retained Ownership	7.50%
Mattox Pipeline Company LLC ("Mattox")
Description Of Business And Basis Of Presentation [Line Items]
Ownership	79.00%
Amberjack Pipeline Company LLC (“Amberjack”) - Series A
Description Of Business And Basis Of Presentation [Line Items]
Ownership	75.00%			75.00%
Amberjack Pipeline Company LLC (“Amberjack”) - Series B
Description Of Business And Basis Of Presentation [Line Items]
Ownership	50.00%			50.00%
Mars Oil Pipeline Company LLC (“Mars”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	71.50%			71.50%
Odyssey Pipeline L.L.C. (“Odyssey”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	71.00%
Bengal Pipeline Company LLC (“Bengal”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	50.00%			50.00%
Crestwood Permian Basin LLC (“Permian Basin”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	50.00%			50.00%
LOCAP LLC (“LOCAP”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	41.48%			41.48%
Explorer Pipeline Company ("Explorer")
Description Of Business And Basis Of Presentation [Line Items]
Ownership	38.59%			38.59%
Poseidon Oil Pipeline Company LLC (“Poseidon”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	36.00%			36.00%
Colonial Pipeline Company (“Colonial”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	16.125%			16.125%
Proteus Oil Pipeline Company, LLC (“Proteus”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	10.00%			10.00%
Endymion Oil Pipeline Company, LLC (“Endymion”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	10.00%			10.00%
Cleopatra Gas Gathering Company, LLC (“Cleopatra”)
Description Of Business And Basis Of Presentation [Line Items]
Ownership	1.00%