Segment Information (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information [Line Items]
Net income		$ 127	$ 128
Natural gas		434	204
Other		10	9
Regulated and Unregulated Operating Revenue		1,698	1,352
Affiliate Revenue		129	115
Total revenues
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue	[1],[2]	1,698	1,352
Regulated Electric
Segment Reporting Information [Line Items]
Net income		98	107
Revenues Including Intersegment Revenues	[1]	1,254	1,139
Regulated Natural Gas
Segment Reporting Information [Line Items]
Net income		29	20
Revenues Including Intersegment Revenues		434	204
All Other
Segment Reporting Information [Line Items]
Net income		0	1
All Other | Total revenues
Segment Reporting Information [Line Items]
Other		$ 10	$ 9

[1] Operating revenues include $129 million and $115 million of affiliate electric revenue for the three months ended March 31, 2022 and 2021.

[2] Operating revenues include an immaterial amount of affiliate gas revenue for the three months ended March 31, 2022 and 2021.