Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenues	$ 1,905	$ 1,875	$ 4,525	$ 4,654
Net Income (Loss)	228	118	578	443
Total Assets	40,976		40,976		$ 39,715
Natural Gas
Segment Reporting Information [Line Items]
Revenues	695	764	2,265	2,539
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	3	74	4	126
Corporate and Other | Pension and Other Postretirement Plans Costs
Segment Reporting Information [Line Items]
Regulatory assets	374		374		385
Operating Segments | Electric
Segment Reporting Information [Line Items]
Revenues	1,207	1,037	2,256	1,989
Net Income (Loss)	215	180	336	303
Total Assets	22,176		22,176		21,089
Operating Segments | Natural Gas
Segment Reporting Information [Line Items]
Revenues	695	764	2,265	2,539
Net Income (Loss)	47	35	330	269
Total Assets	17,669		17,669		17,429
Operating Segments | Corporate and Other
Segment Reporting Information [Line Items]
Revenues	3	74	4	126
Net Income (Loss)	(34)	$ (97)	(88)	$ (129)
Total Assets	$ 1,131		$ 1,131		$ 1,197