Property, Plant and Equipment, Net - NPC (Details) - NPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Plant, net	$ 6,651	$ 6,647
Construction work-in-progress	341	244
Property, plant and equipment, net	6,992	6,891
Regulated
Property, Plant and Equipment [Line Items]
Generation	3,810	3,793
Distribution	1,508	1,503
Transmission	3,979	3,920
General and intangible	831	836
Utility plant in-service	10,128	10,052
Accumulated depreciation and amortization	(3,478)	(3,406)
Plant, net	$ 6,650	6,646
Regulated | Minimum
Property, Plant and Equipment [Line Items]
Useful life, generation	30 years
Useful life, distribution	45 years
Useful life, transmission	20 years
Useful life, other	5 years
Regulated | Maximum
Property, Plant and Equipment [Line Items]
Useful life, generation	55 years
Useful life, distribution	70 years
Useful life, transmission	65 years
Useful life, other	65 years
Nonregulated
Property, Plant and Equipment [Line Items]
Plant, net	$ 1	$ 1
Useful life, other	45 years