Segments and Related Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023		Dec. 31, 2022
Segment Reporting Information [Line Items]
Investment in subsidiaries	$ 246	$ 244
Natural Gas	2,230	2,645		$ 3,080
Other	64	115		107
Revenues Including Intersegment Revenues	13,401	14,096		15,207
Regulated and Unregulated Operating Revenue	13,441	14,206		15,310
Depreciation and amortization	2,744	2,448		2,413
Interest charges and financing costs	1,182	1,004		925
Total income tax benefit	(402)	(146)		(135)
Net income (loss)	1,936	1,771		1,736
Electric fuel and purchased power	3,788	4,278		5,005
Cost of natural gas sold and transported	951	1,456		1,910
Operating and maintenance expenses	2,540	2,444		2,491
Other income (expense), net	143	22		(13)
Electric	11,147	11,446		12,123
Regulated Electric
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues	11,149	11,448		12,125
Regulated Natural Gas
Segment Reporting Information [Line Items]
Revenues Including Intersegment Revenues	2,252	2,648		3,082
All Other
Segment Reporting Information [Line Items]
Net income (loss)	(147)	(134)		(159)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	2,730	2,434		2,398
Interest charges and financing costs	880	766		722
Total income tax benefit	(358)	(85)		(94)
Net income (loss)	2,083	1,905		1,895
Regulated Operating Revenue	(13,377)	(14,091)		(15,203)
Electric fuel and purchased power	3,788	4,278		5,005
Cost of natural gas sold and transported	951	1,456		1,910
Operating and maintenance expenses	2,511	2,397		2,439
Other income (expense), net	816	945	[1]	932
Operating Segments [Member] | Regulated Electric
Segment Reporting Information [Line Items]
Depreciation and amortization	2,373	2,111		2,122
Interest charges and financing costs	767	670		636
Total income tax benefit	(420)	(135)		(162)
Net income (loss)	1,846	1,686		1,631
Electric fuel and purchased power	3,788	4,278		5,005
Cost of natural gas sold and transported	0	0		0
Operating and maintenance expenses	2,102	2,011		2,069
Other income (expense), net	693	827	[1]	824
Electric	11,147	11,446		12,123
Operating Segments [Member] | Regulated Natural Gas
Segment Reporting Information [Line Items]
Natural Gas	2,230	2,645		3,080
Depreciation and amortization	357	323		276
Interest charges and financing costs	113	96		86
Total income tax benefit	62	50		68
Net income (loss)	237	219		264
Electric fuel and purchased power	0	0		0
Cost of natural gas sold and transported	951	1,456		1,910
Operating and maintenance expenses	409	386		370
Other income (expense), net	123	118	[1]	108
Operating Segments [Member] | All Other
Segment Reporting Information [Line Items]
Other	64	115		107
Intersegment Eliminations
Segment Reporting Information [Line Items]
Regulated Operating Revenue	(24)	(5)		(4)
Intersegment Eliminations | Regulated Electric
Segment Reporting Information [Line Items]
Electric	2	2		2
Intersegment Eliminations | Regulated Natural Gas
Segment Reporting Information [Line Items]
Natural Gas	$ 22	$ 3		$ 2

[1] Other segment expenses, net, for 2023 additionally includes loss on Comanche Unit 3 litigation and workforce reduction expenses.