Revenue from Contract with Customer - PAC (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue from External Customer [Line Items]
Total operating revenue	$ 25,150	$ 20,952	$ 19,844
PAC
Revenue from External Customer [Line Items]
Other revenue	41	98	82
Total operating revenue	5,296	5,341	5,068
Regulated assets | Retail Electric
Revenue from External Customer [Line Items]
Customer revenue	9,801	9,421	9,465
Regulated assets | Wholesale
Revenue from External Customer [Line Items]
Customer revenue	727	366	457
Regulated assets | Transmission and distribution
Revenue from External Customer [Line Items]
Customer revenue	2,000	1,779	1,819
Regulated assets | Other
Revenue from External Customer [Line Items]
Customer revenue	109	110	2
Regulated assets | PAC
Revenue from External Customer [Line Items]
Customer revenue	5,255	5,243	4,986
Regulated assets | PAC | Retail Electric
Revenue from External Customer [Line Items]
Customer revenue	4,847	4,932	4,711
Regulated assets | PAC | Wholesale
Revenue from External Customer [Line Items]
Customer revenue	157	107	99
Regulated assets | PAC | Transmission and distribution
Revenue from External Customer [Line Items]
Customer revenue	143	96	98
Regulated assets | PAC | Other
Revenue from External Customer [Line Items]
Customer revenue	108	108	78
Regulated assets | PAC | Residential | Retail Electric
Revenue from External Customer [Line Items]
Customer revenue	1,914	1,910	1,783
Regulated assets | PAC | Commercial | Retail Electric
Revenue from External Customer [Line Items]
Customer revenue	1,559	1,578	1,522
Regulated assets | PAC | Industrial | Retail Electric
Revenue from External Customer [Line Items]
Customer revenue	1,125	1,185	1,176
Regulated assets | PAC | Other retail | Retail Electric
Revenue from External Customer [Line Items]
Customer revenue	$ 249	$ 259	$ 230