Property, Plant and Equipment, Net - NPC (Details) - NPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Plant, net	$ 6,647	$ 6,559
Construction work- in-progress	244	142
Property, plant and equipment, net	$ 6,891	$ 6,701
Depreciation and amortization rate	3.20%	3.10%	3.30%
Regulated assets
Property, Plant and Equipment [Line Items]
Generation	$ 3,793	$ 3,690
Transmission	1,503	1,468
Distribution	3,920	3,771
General and intangible plant	836	791
Utility plant in-service	10,052	9,720
Accumulated depreciation and amortization	(3,406)	(3,162)
Plant, net	6,646	6,558
Nonregulated assets
Property, Plant and Equipment [Line Items]
Plant, net	$ 1	$ 1
Useful life, other	45 years
Minimum | Regulated assets
Property, Plant and Equipment [Line Items]
Useful life, generation	30 years
Useful life, transmission	45 years
Useful life, distribution	20 years
Useful life, other	5 years
Maximum | Regulated assets
Property, Plant and Equipment [Line Items]
Useful life, generation	55 years
Useful life, transmission	70 years
Useful life, distribution	65 years
Useful life, other	65 years