Revenues (Details) - Regulated Electric - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024		Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 419		$ 499
Total revenues
Disaggregation of Revenue [Line Items]
Total revenues	428		508
Retail
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	312		380
Retail | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	86		101
Retail | C&I
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	217	[1]	267
Retail | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9		12
Wholesale
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	36		45
Transmission
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	71		74
Alternative and Other
Disaggregation of Revenue [Line Items]
Alternative revenue and other	$ 9		$ 9

[1] In 2024, revenues from one C&I customer represented approximately 10.7% of total revenues.