Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Balance as of January 1	$ 2,293	$ 2,293
Goodwill attributable to Gas Storage and Pipelines 2019 acquisition of Blue Union and LEAP	171	0
Balance at December 31	$ 2,464	$ 2,293