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]
Net income	$ 15		$ 14		$ 62		$ 46
Regulated and Unregulated Operating Revenue	278		255		606		536
Affiliate Revenue	52		46		99		92
Natural gas	35		31		113		88
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	278	[1]	255	[1]	606	[2]	536	[2]
Regulated Electric
Segment Reporting Information [Line Items]
Net income	15		16		47		40
Regulated Electric | Total revenues
Segment Reporting Information [Line Items]
Regulated Operating Revenue, Electric	243	[1]	224	[1]	493	[2]	448	[2]
Regulated Natural Gas
Segment Reporting Information [Line Items]
Net income	(1)		(2)		14		6
Revenues Including Intersegment Revenues	35		31		113		88
All Other
Segment Reporting Information [Line Items]
Net income	$ 1		$ 0		$ 1		$ 0

[1] Total revenues include $52 million and $46 million of affiliate electric revenue for the three months ended June 30, 2022 and 2021, respectively.

[2] Total revenues include $99 million and $92 million of affiliate electric revenue for the six months ended June 30, 2022 and 2021, respectively