Segment Information (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended
		Jun. 30, 2023		Jun. 30, 2022		Jun. 30, 2023		Jun. 30, 2022
Segment Reporting Information [Line Items]
Net income		$ 26		$ 15		$ 71		$ 62
Regulated and Unregulated Operating Revenue		260		278		591		606
Affiliate Revenue		51		52
Natural gas		24		35		101		113
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	[1]					592		606
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net income						(1)		0
Regulated Electric
Segment Reporting Information [Line Items]
Net income		30		15		63		47
Regulated Electric | Total revenues
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric		236	[2]	243	[2]	490	[1]	493	[1]
Regulated Natural Gas
Segment Reporting Information [Line Items]
Net income		(3)		(1)		8		14
Revenues Including Intersegment Revenues		24		35		102		113
Regulated Natural Gas | Total revenues
Segment Reporting Information [Line Items]
Natural gas						101		113
Regulated Natural Gas | Intersegment Eliminations
Segment Reporting Information [Line Items]
Natural gas						1		0
All Other
Segment Reporting Information [Line Items]
Net income		$ (1)		$ 1		$ 0		$ 1

[1] Total revenues include $101 million and $99 million of affiliate electric revenue for the six months ended June 30, 2023 and 2022, respectively.

[2] Total revenues include $51 million and $52 million of affiliate electric revenue for the three months ended June 30, 2023 and 2022, respectively.