Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 1,162	$ 1,185	$ 1,091
Retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	950	975	898
Retail | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	383	396	363
Retail | C&I
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	559	572	526
Retail | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	8	7	9
Interchange
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	204	202	189
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	8	8	4
Alternative and Other [Member]
Disaggregation of Revenue [Line Items]
Alternative revenue and other	15	16	14
Regulated Electric | Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,007	991	910
Regulated Electric | Retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	800	785	721
Regulated Electric | Retail | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	299	293	272
Regulated Electric | Retail | C&I
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	494	485	441
Regulated Electric | Retail | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	7	7	8
Regulated Electric | Interchange
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	204	202	189
Regulated Electric | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3	4	0
Regulated Electric | Alternative and Other [Member]
Disaggregation of Revenue [Line Items]
Alternative revenue and other	12	11	12
Regulated Natural Gas | Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	154	194	180
Regulated Natural Gas | Retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	149	190	176
Regulated Natural Gas | Retail | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	84	103	91
Regulated Natural Gas | Retail | C&I
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	65	87	85
Regulated Natural Gas | Retail | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0
Regulated Natural Gas | Interchange
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0
Regulated Natural Gas | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	5	4	4
Regulated Natural Gas | Alternative and Other [Member]
Disaggregation of Revenue [Line Items]
Alternative revenue and other	3	4	2
All Other | Total revenue from contracts with customers
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1	0	1
All Other | Retail
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1	0	1
All Other | Retail | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0
All Other | Retail | C&I
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0
All Other | Retail | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1	0	1
All Other | Interchange
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0
All Other | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0	0
All Other | Alternative and Other [Member]
Disaggregation of Revenue [Line Items]
Alternative revenue and other	0	1	0
Total revenues
Disaggregation of Revenue [Line Items]
Total revenues	1,177	1,201	1,105
Total revenues | Regulated Electric
Disaggregation of Revenue [Line Items]
Total revenues	1,019	1,002	922
Total revenues | Regulated Natural Gas
Disaggregation of Revenue [Line Items]
Total revenues	157	198	182
Total revenues | All Other
Disaggregation of Revenue [Line Items]
Total revenues	$ 1	$ 1	$ 1