Acquisitions and Divestiture - 2017 Divestiture (Details) - USD ($) $ in Millions		12 Months Ended
	Apr. 28, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Divestiture cash consideration		$ 0	$ 0	$ 1
Excess proceeds from divestiture from Parent				$ 20
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Zydeco
Business Acquisition [Line Items]
Divestiture cash consideration	$ 21
Book value of net assets divested	1
Excess proceeds from divestiture from Parent	20
Shell Pipeline Company L P | Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Zydeco
Business Acquisition [Line Items]
Divestiture cash consideration	$ 19