Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Renewable Energy Sales [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 184	$ 213	$ 533	$ 513
Revenues over the remaining terms of the related contacts	205		205
Natural Gas Transportation Services [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	53	$ 52	157	$ 155
Revenues over the remaining terms of the related contacts	$ 2,000		$ 2,000