Risk Management - Net Investment Hedging Effect on the Income Statements (Details) - Net Investment Hedging - Designated as Hedging Instrument - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Gain/(loss) recognized in OCI on derivative	$ (8)	$ 91	$ 0
Gain/(loss) reclassified from Accumulated OCI into income	83	26	0
Foreign Exchange Contract [Member]
Derivative [Line Items]
Gain/(loss) recognized in OCI on derivative	(8)	91	0
(Gain) loss on divestitures and impairments, net | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gain/(loss) reclassified from Accumulated OCI into income	83	26	$ 0
KML and U.S. Portion of Cochin Pipeline | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gain/(loss) reclassified from Accumulated OCI into income	$ 83
Trans Mountain and Trans Mountain Expansion Project | Foreign Exchange Contract [Member]
Derivative [Line Items]
Gain/(loss) reclassified from Accumulated OCI into income		$ 26