Revenue from Contract with Customer - NPC (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total operating revenue	$ 26,337	$ 25,150	$ 20,952
Regulated assets | Retail Electric
Disaggregation of Revenue [Line Items]
Customer revenue	10,884	9,801	9,421
NPC
Disaggregation of Revenue [Line Items]
Other revenue	21	22	26
Total operating revenue	2,630	2,139	1,998
NPC | Regulated assets
Disaggregation of Revenue [Line Items]
Customer revenue	2,609	2,117	1,972
NPC | Regulated assets | Wholesale, transmission and other
Disaggregation of Revenue [Line Items]
Customer revenue	82	74	62
NPC | Regulated assets | Fully bundled | Retail Electric
Disaggregation of Revenue [Line Items]
Customer revenue	2,507	2,021	1,886
NPC | Regulated assets | Fully bundled | Residential | Retail Electric
Disaggregation of Revenue [Line Items]
Customer revenue	1,440	1,207	1,145
NPC | Regulated assets | Fully bundled | Commercial | Retail Electric
Disaggregation of Revenue [Line Items]
Customer revenue	525	414	384
NPC | Regulated assets | Fully bundled | Industrial | Retail Electric
Disaggregation of Revenue [Line Items]
Customer revenue	528	386	345
NPC | Regulated assets | Fully bundled | Other retail | Retail Electric
Disaggregation of Revenue [Line Items]
Customer revenue	14	14	12
NPC | Regulated assets | Distribution-only service | Retail Electric
Disaggregation of Revenue [Line Items]
Customer revenue	20	22	24
NPC | Regulated assets | Fully bundled and distribution services only customer | Retail Electric
Disaggregation of Revenue [Line Items]
Customer revenue	$ 2,527	$ 2,043	$ 1,910