Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 7,477	$ 5,268	$ 15,466	$ 13,197
Mark-to-market for economic hedging activities	719	1,517	2,996	2,238
Revenue	7,282	5,243	15,178	13,334
Less: Revenues accounted for under topics other than 606 and 815	4	(14)	6	(12)
Derivative revenue	717	1,507	2,980	2,232
Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(7)	(2)	(10)	(5)
Revenue	0	2	17	1
Less: Revenues accounted for under topics other than 606 and 815	0	0	0	0
Retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,951	4,816	14,521	10,978
Retail revenue \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(1)	(2)	(1)	(2)
Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	306	171	584	653
Derivative revenue	(30)	21	(1)	79
Energy revenue \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9	1	14	2
Derivative revenue	9	(1)	13	1
Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	90	271	206	426
Derivative revenue	9	40	22	77
Capacity revenue \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Derivative revenue	0	0	0	0
Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	(148)	(70)	(281)	(102)
Less: Realized and unrealized ASC 815 revenue	(199)	(11)	(294)	149
Derivative revenue \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	(3)	5	14	6
Less: Realized and unrealized ASC 815 revenue	7	4	27	6
Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	96	71	170	1,395
Contract amortization	(13)	(16)	(22)	(16)
Other revenue \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(5)	(2)	(10)	(5)
Contract amortization	0	0	0	0
Total operating revenue
Disaggregation of Revenue [Line Items]
Revenue	7,282	5,243	15,178	13,334
Total operating revenue \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue	0	2	17	1
Other revenue, derivative
Disaggregation of Revenue [Line Items]
Derivative revenue	(30)	(2)	(34)	95
Other revenue, derivative \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Derivative revenue	1	0	0	(1)
Home \| Retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,650	2,275	5,311	4,746
Home \| Retail revenue \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(1)	(2)	(1)	(2)
Business \| Retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,301	2,541	9,210	6,232
Business \| Retail revenue \| Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Texas \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,709	2,027	4,739	5,636
Revenue	2,696	2,025	4,719	5,727
Less: Revenues accounted for under topics other than 606 and 815	0	0	0	0
Texas \| Retail revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,571	1,958	4,523	4,072
Texas \| Energy revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	38	14	53	299
Derivative revenue	0	0	0	0
Texas \| Capacity revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Derivative revenue	0	0	0	0
Texas \| Derivative revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	(1)	(3)	(3)	(4)
Less: Realized and unrealized ASC 815 revenue	(13)	(2)	(20)	91
Texas \| Other revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	88	56	146	1,360
Contract amortization	0	0	0	0
Texas \| Total operating revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	2,696	2,025	4,719	5,727
Texas \| Other revenue, derivative \| Operating Segments
Disaggregation of Revenue [Line Items]
Derivative revenue	(12)	1	(17)	95
Texas \| Other revenue, ancillary \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		1,200
Texas \| Home \| Retail revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,661	1,376	2,950	2,709
Texas \| Business \| Retail revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	910	582	1,573	1,363
East \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,643	2,419	8,436	5,815
Revenue	3,516	2,430	8,234	5,925
Less: Revenues accounted for under topics other than 606 and 815	(4)	(7)	(13)	(7)
East \| Retail revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,400	2,118	7,921	5,331
East \| Energy revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	128	101	332	227
Derivative revenue	(19)	24	26	84
East \| Capacity revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	89	255	204	396
Derivative revenue	9	40	22	77
East \| Derivative revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	(106)	(46)	(236)	(50)
Less: Realized and unrealized ASC 815 revenue	(123)	18	(189)	117
East \| Other revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16	10	33	29
Contract amortization	(11)	(8)	(20)	(8)
East \| Total operating revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	3,516	2,430	8,234	5,925
East \| Other revenue, derivative \| Operating Segments
Disaggregation of Revenue [Line Items]
Derivative revenue	(7)	0	(1)	6
East \| Home \| Retail revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	453	416	1,128	1,000
East \| Business \| Retail revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,947	1,702	6,793	4,331
West/Services/Other \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,132	824	2,301	1,751
Revenue	1,070	786	2,208	1,681
Less: Revenues accounted for under topics other than 606 and 815	8	(7)	19	(5)
West/Services/Other \| Retail revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	981	742	2,078	1,577
West/Services/Other \| Energy revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	131	55	185	125
Derivative revenue	(20)	(2)	(40)	(6)
West/Services/Other \| Capacity revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1	16	2	30
Derivative revenue	0	0	0	0
West/Services/Other \| Derivative revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	(38)	(26)	(56)	(54)
Less: Realized and unrealized ASC 815 revenue	(70)	(31)	(112)	(65)
West/Services/Other \| Other revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(3)	7	1	11
Contract amortization	(2)	(8)	(2)	(8)
West/Services/Other \| Total operating revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	1,070	786	2,208	1,681
West/Services/Other \| Other revenue, derivative \| Operating Segments
Disaggregation of Revenue [Line Items]
Derivative revenue	(12)	(3)	(16)	(5)
West/Services/Other \| Home \| Retail revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	537	485	1,234	1,039
West/Services/Other \| Business \| Retail revenue \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 444	$ 257	$ 844	$ 538

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Amount of amortization expense for asset recognized from cost incurred to obtain or fulfill contract with customer.

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