Revenue from Contracts with Customers - PAC (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Total Customer Revenue	$ 4,719	$ 4,712
Operating revenue	6,030	6,081
Other revenue
Disaggregation of Revenue [Line Items]
Operating revenue	104	137
Regulated
Disaggregation of Revenue [Line Items]
Total Customer Revenue	4,115	4,094
Regulated | Retail electric
Disaggregation of Revenue [Line Items]
Total Customer Revenue	2,256	2,108
Regulated | Wholesale
Disaggregation of Revenue [Line Items]
Total Customer Revenue	236	193
Regulated | Transmission and distribution
Disaggregation of Revenue [Line Items]
Total Customer Revenue	509	496
Regulated | Other
Disaggregation of Revenue [Line Items]
Total Customer Revenue	22	25
PAC
Disaggregation of Revenue [Line Items]
Operating revenue	1,297	1,242
PAC | Other revenue
Disaggregation of Revenue [Line Items]
Operating revenue	5	13
PAC | Regulated
Disaggregation of Revenue [Line Items]
Total Customer Revenue	1,292	1,229
PAC | Regulated | Retail electric
Disaggregation of Revenue [Line Items]
Total Customer Revenue	1,185	1,145
PAC | Regulated | Wholesale
Disaggregation of Revenue [Line Items]
Total Customer Revenue	55	36
PAC | Regulated | Transmission and distribution
Disaggregation of Revenue [Line Items]
Total Customer Revenue	32	25
PAC | Regulated | Other
Disaggregation of Revenue [Line Items]
Total Customer Revenue	20	23
PAC | Regulated | Residential | Retail electric
Disaggregation of Revenue [Line Items]
Total Customer Revenue	505	483
PAC | Regulated | Commercial | Retail electric
Disaggregation of Revenue [Line Items]
Total Customer Revenue	370	359
PAC | Regulated | Industrial | Retail electric
Disaggregation of Revenue [Line Items]
Total Customer Revenue	273	271
PAC | Regulated | Other retail | Retail electric
Disaggregation of Revenue [Line Items]
Total Customer Revenue	$ 37	$ 32