Segment Information (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Net income		$ 45	$ 47
Regulated and Unregulated Operating Revenue		331	328
Affiliate Revenue		50	47
Natural gas		77	78
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	[1]	331	328
Regulated Electric
Segment Reporting Information [Line Items]
Net income		33	32
Regulated Electric | Total revenues
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	[1]	254	250
Regulated Natural Gas
Segment Reporting Information [Line Items]
Net income		11	15
Revenues Including Intersegment Revenues		77	78
All Other
Segment Reporting Information [Line Items]
Net income		$ 1	$ 0

[1] Total revenues include $50 million and $47 million of affiliate electric revenue for the three months ended March 31, 2023 and 2022, respectively.