Revenues (Details) - Regulated Electric - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Retail
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	$ 1,598	$ 1,255	$ 1,137
Retail | Residential
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	445	375	359
Retail | C&I
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	1,102	842	739
Retail | Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	51	38	39
Wholesale
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	407	873	345
Transmission
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	296	287	279
Other
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	10	6	4
Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Revenue from Contracts with Customers	2,311	2,421	1,765
Alternative revenue and other
Disaggregation of Revenue [Line Items]
Alternative revenue and other	115	44	105
Total revenues
Disaggregation of Revenue [Line Items]
Total revenues	$ 2,426	$ 2,465	$ 1,870