Reportable Segments - Financial Data (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Operating revenues	$ 8,352	$ 7,418	$ 7,564
Depreciation and Amortization	1,316	1,189	1,225
Interest Expense	(508)	(501)	(528)
Income Tax Expense (Benefit)	110	80	30
Net income (loss)	1,486	(773)	791
Total Assets	37,679	33,471
Expenditures for Long-Lived Assets	3,399	2,536	2,587
Total Regulatory Assets	3,716	2,112
Interest income from securitization bonds	1	1	5
Continuing Operations
Segment Reporting Information [Line Items]
Operating revenues	8,352	7,418	7,564
Depreciation and Amortization	1,316	1,189	1,225
Interest income	3	4	22
Interest Expense	(529)	(529)	(567)
Income Tax Expense (Benefit)	110	80	30
Income (loss) from continuing operations	668	483	515
Total Assets	35,341	32,689
Expenditures for Long-Lived Assets	3,228	2,515	2,508
Discontinued Operations
Segment Reporting Information [Line Items]
Income Tax Expense (Benefit)	201	(333)	108
Income (loss) from discontinued operations, net	818	(1,256)	276
Total Assets	2,338	782
Expenditures for Long-Lived Assets	171	21	79
Electric
Segment Reporting Information [Line Items]
Operating revenues	3,763	3,470	3,519
Natural Gas
Segment Reporting Information [Line Items]
Operating revenues	4,336	3,631	3,750
Corporate and Other
Segment Reporting Information [Line Items]
Operating revenues	253	317	295
Operating Segments | Electric
Segment Reporting Information [Line Items]
Operating revenues	3,763	3,470	3,519
Depreciation and Amortization	756	670	746
Interest income	0	3	27
Interest Expense	(226)	(220)	(225)
Income Tax Expense (Benefit)	95	72	96
Net income (loss)	475	230	419
Total Assets	16,439	14,516
Expenditures for Long-Lived Assets	2,008	1,281	1,216
Operating Segments | Natural Gas
Segment Reporting Information [Line Items]
Operating revenues	4,336	3,631	3,750
Depreciation and Amortization	502	473	439
Interest income	1	8	6
Interest Expense	(141)	(153)	(144)
Income Tax Expense (Benefit)	80	125	2
Net income (loss)	403	278	251
Total Assets	16,153	15,041
Expenditures for Long-Lived Assets	1,178	1,139	1,098
Operating Segments | Corporate and Other
Segment Reporting Information [Line Items]
Operating revenues	253	317	295
Depreciation and Amortization	58	46	40
Interest income	118	104	134
Interest Expense	(278)	(267)	(343)
Income Tax Expense (Benefit)	(65)	(117)	(68)
Net income (loss)	(210)	(25)	(155)
Total Assets	2,749	3,132
Expenditures for Long-Lived Assets	42	95	194
Intersegment Eliminations
Segment Reporting Information [Line Items]
Operating revenues	0	0	0
Depreciation and Amortization	0	0	0
Interest income	(116)	(111)	(145)
Interest Expense	116	111	145
Income Tax Expense (Benefit)	0	0	0
Net income (loss)	0	0	$ 0
Benefit obligations | Corporate and Other
Segment Reporting Information [Line Items]
Total Regulatory Assets	$ 427	$ 540