Property, Plant and Equipment, Net - MEC (Details) - MEC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant in-service, net, excluding construction work-in-process	$ 20,301	$ 19,201
Property, plant and equipment, net	21,091	20,301
Revenue Sharing Arrangement, Anticipated Equity Returns Exceeding Threshold
Public Utility, Property, Plant and Equipment [Line Items]
Regulatory liability, additions	$ 296	$ 115	$ 0
Electric
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation and amortization rate	3.20%	3.30%	3.20%
Natural gas
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation and amortization rate	2.90%	2.80%	2.80%
Regulated assets
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant in-service	$ 28,319	$ 26,571
Accumulated depreciation and amortization	(8,024)	(7,376)
Utility plant in-service, net, excluding construction work-in-process	20,295	19,195
Construction work- in-progress	790	1,100
Regulated assets | Electric
Public Utility, Property, Plant and Equipment [Line Items]
Generation	18,582	17,397
Transmission	2,662	2,474
Distribution	4,931	4,661
Regulated assets | Natural gas
Public Utility, Property, Plant and Equipment [Line Items]
Distribution	2,144	2,039
Nonregulated assets
Public Utility, Property, Plant and Equipment [Line Items]
Utility plant in-service, net, excluding construction work-in-process	$ 6	$ 6
Minimum | Regulated assets | Electric
Public Utility, Property, Plant and Equipment [Line Items]
Useful life, generation	20 years
Useful life, transmission	55 years
Useful life, distribution	15 years
Minimum | Regulated assets | Natural gas
Public Utility, Property, Plant and Equipment [Line Items]
Useful life, distribution	30 years
Minimum | Nonregulated assets
Public Utility, Property, Plant and Equipment [Line Items]
Useful life, other	20 years
Maximum | Regulated assets | Electric
Public Utility, Property, Plant and Equipment [Line Items]
Useful life, generation	62 years
Useful life, transmission	80 years
Useful life, distribution	80 years
Maximum | Regulated assets | Natural gas
Public Utility, Property, Plant and Equipment [Line Items]
Useful life, distribution	75 years
Maximum | Nonregulated assets
Public Utility, Property, Plant and Equipment [Line Items]
Useful life, other	50 years