Segment Information (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2023		Sep. 30, 2022		Sep. 30, 2023		Sep. 30, 2022
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	$ 1,113		$ 1,137		$ 2,877		$ 2,849
Net income	229		247		536		555
Unregulated Operating Revenue	12		11		41		39
Regulated and Unregulated Operating Revenue	1,290		1,383		4,165		3,975	[1]
Affiliate Revenue	1		2		3		4
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue			1,290		4,165	[1]
Regulated Electric
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues	1,113		1,137		2,877		2,849
Net income	247		243		449		455
Regulated Natural Gas
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues	165		235		1,247		1,087
Net income	(16)		4		81		99
All Other
Segment Reporting Information [Line Items]
Net income	(2)		0		6		1
All Other | Total revenues
Segment Reporting Information [Line Items]
Unregulated Operating Revenue	$ 12	[2]	$ 11	[2]	$ 41	[1]	$ 39	[1]

[1] Total revenues include $3 million and $4 million of other affiliate revenue for the nine months ended Sept. 30, 2023 and 2022.

[2] Total revenues include $1 million and $2 million of other affiliate revenue for the three months ended Sept. 30, 2023 and 2022.