Segment Information (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2022		Jun. 30, 2021		Jun. 30, 2022		Jun. 30, 2021
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	$ 884		$ 827		$ 1,712		$ 1,560
Net income	132		134		308		301
Unregulated Operating Revenue	11		9		28		22
Regulated and Unregulated Operating Revenue	1,169		1,174		2,592		2,335
Affiliate Revenue	1		1		2		2
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	1,169	[1]	1,174	[1]	2,592	[2]	2,335	[2]
Regulated Electric
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues	884		827		1,712		1,560
Net income	116		107		212		188
Regulated Natural Gas
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues	274		338		852		753
Net income	14		30		95		114
All Other
Segment Reporting Information [Line Items]
Net income	2		(3)		1		(1)
All Other | Total revenues
Segment Reporting Information [Line Items]
Unregulated Operating Revenue	$ 11	[1]	$ 9	[1]	$ 28	[2]	$ 22	[2]

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

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