Segment Information (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2022		Sep. 30, 2021		Sep. 30, 2022		Sep. 30, 2021
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	$ 1,137		$ 1,048		$ 2,849		$ 2,608
Revenues Including Intersegment Revenues					2,849		2,609
Net income	247		215		555		516
Unregulated Operating Revenue	11		12		39		34
Regulated and Unregulated Operating Revenue	1,383		1,237		3,975		3,572
Affiliate Revenue	2		2		4		4
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	1,383	[1]	1,237	[1]	3,975	[2]	3,573	[2]
Intersegment Eliminations
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	0						(1)
Regulated Electric
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues	1,137		1,048				2,608
Net income	243		212		455		400
Regulated Electric | Intersegment Eliminations
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	0						1
Regulated Natural Gas
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues	235		177		1,087		930
Net income	4		8		99		121
All Other
Segment Reporting Information [Line Items]
Net income	0		(5)		1		(5)
All Other | Total revenues
Segment Reporting Information [Line Items]
Unregulated Operating Revenue	$ 11	[1]	$ 12	[1]	$ 39	[2]	$ 34	[2]

[1] Total revenues include $2 million and $1 million of other affiliate revenue for the three months ended Sept. 30, 2022 and 2021.

[2] Total revenues include $4 million and $3 million of other affiliate revenue for the nine months ended Sept. 30, 2022 and 2021.