Exit Activities and Discontinued Operations - Schedule of Retention Benefit Liability Roll Forward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Restructuring Reserve [Roll Forward]
Other current liabilities	$ 144		$ 156
Retention Benefits | D.E. Karn Generating Complex
Restructuring Reserve [Roll Forward]
Retention benefit liability at beginning of period	14	$ 11
Costs deferred as a regulatory asset	1	2
Retention benefit liability at the end of the period	15	13
Other current liabilities	$ 5	$ 4