Property, Plant and Equipment, Net - PAC (Details) - PAC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Utility plant in-service	$ 32,262	$ 30,717
Accumulated depreciation and amortization	(10,507)	(9,838)
Utility plant in-service, net	21,755	20,879
Plant, net	21,773	20,888
Construction work- in-progress	1,141	1,542
Property, plant and equipment, net	$ 22,914	$ 22,430
Depreciation and amortization rate	3.50%	4.10%	3.30%
Accelerated depreciation		$ 376	$ 125
Amount of acquisition adjustments	$ 156
Acquisition adjustments, accumulated depreciation	143	140
Revised depreciation rates, 2021 depreciation increase
Property, Plant and Equipment [Line Items]
Depreciation	$ 158
Minimum
Property, Plant and Equipment [Line Items]
Useful life, generation	15 years
Useful life, transmission	60 years
Useful life, distribution	20 years
Useful life, intangible asset	5 years
Useful life, other	5 years
Maximum
Property, Plant and Equipment [Line Items]
Useful life, generation	59 years
Useful life, transmission	90 years
Useful life, distribution	75 years
Useful life, intangible asset	75 years
Useful life, other	60 years
Generation
Property, Plant and Equipment [Line Items]
Utility plant in-service	$ 13,679	12,861
Transmission
Property, Plant and Equipment [Line Items]
Utility plant in-service	7,894	7,632
Distribution
Property, Plant and Equipment [Line Items]
Utility plant in-service	8,044	7,660
Intangible plant
Property, Plant and Equipment [Line Items]
Utility plant in-service	1,106	1,054
Other
Property, Plant and Equipment [Line Items]
Utility plant in-service	$ 1,539	1,510
Computer software | Minimum
Property, Plant and Equipment [Line Items]
Useful life, intangible asset	5 years
Computer software | Maximum
Property, Plant and Equipment [Line Items]
Useful life, intangible asset	10 years
Nonregulated assets
Property, Plant and Equipment [Line Items]
Plant, net	$ 18	$ 9
Nonregulated assets | Minimum
Property, Plant and Equipment [Line Items]
Useful life, other	14 years
Nonregulated assets | Maximum
Property, Plant and Equipment [Line Items]
Useful life, other	95 years