Segment Information (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Net income		$ 47	$ 32
Regulated and Unregulated Operating Revenue		328	281
Affiliate Revenue		47	46
Natural gas		78	57
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	[1]	328	281
Regulated Electric
Segment Reporting Information [Line Items]
Net income		32	24
Regulated Electric | Total revenues
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	[1]	250	224
Regulated Natural Gas
Segment Reporting Information [Line Items]
Net income		15	8
Revenues Including Intersegment Revenues		$ 78	$ 57

[1] Total revenues include $47 million and $46 million of affiliate electric revenue for the three months ended March 31, 2022 and 2021, respectively