Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 6,480	$ 6,216	$ 13,860	$ 13,731
Mark-to-market for economic hedging activities	875	64	1,347	(1,880)
Revenue	6,659	6,348	14,088	14,070
Less: Revenues accounted for under topics other than ASC 606 and ASC 815	31	13	47	21
Derivative revenue	884	77	1,352	(1,855)
Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(13)	(5)	(16)	(6)
Revenue	(13)	(6)	(19)	(16)
Less: Revenues accounted for under topics other than ASC 606 and ASC 815	0	0	0	0
Retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,344	6,027	13,573	13,390
Derivative revenue	9	16	19	43
Retail revenue | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(8)	0	(8)	0
Derivative revenue	0	0	0	0
Energy revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	110	83	262	211
Derivative revenue	29	5	91	71
Energy revenue | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(3)	(1)	(6)	1
Derivative revenue	(2)	(1)	(5)	1
Capacity revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	44	49	86	91
Derivative revenue	19	17	41	23
Capacity revenue | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(1)	0	(2)	0
Derivative revenue	0	0	0	0
Derivative revenue
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	84	75	24	166
Less: Realized and unrealized ASC 815 revenue	148	119	181	318
Derivative revenue | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	2	0	2	(11)
Less: Realized and unrealized ASC 815 revenue	0	(1)	(3)	(10)
Other revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	84	122	160	231
Contract amortization	(7)	(8)	(17)	(19)
Other revenue | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(3)	(5)	(5)	(6)
Contract amortization	0	0	0	0
Total operating revenue
Disaggregation of Revenue [Line Items]
Revenue	6,659	6,348	14,088	14,070
Total operating revenue | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue	(13)	(6)	(19)	(16)
Other revenue, derivative
Disaggregation of Revenue [Line Items]
Derivative revenue	7	6	6	15
Other revenue, derivative | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Derivative revenue	0	0	0	0
Home | Retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,176	2,859	6,305	5,519
Home | Retail revenue | Corporate/Eliminations
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	(8)	0	(8)	0
Business | Retail revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,168	3,168	7,268	7,871
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	2,755	2,501	4,986	4,537
Revenue	2,763	2,515	4,996	4,549
Less: Revenues accounted for under topics other than ASC 606 and ASC 815	0	0	0	0
Texas | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,692	2,395	4,870	4,353
Derivative revenue	0	0	0	0
Texas | Energy revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16	16	23	20
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	0	0	0	0
Less: Realized and unrealized ASC 815 revenue	8	14	10	12
Texas | Other revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	55	104	103	176
Contract amortization	0	0	0	0
Texas | Total operating revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	2,763	2,515	4,996	4,549
Texas | Other revenue, derivative | Operating Segments
Disaggregation of Revenue [Line Items]
Derivative revenue	8	14	10	12
Texas | Home | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,766	1,563	3,126	2,799
Texas | Business | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	926	832	1,744	1,554
East | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,412	2,398	5,893	6,462
Revenue	2,532	2,503	6,047	6,679
Less: Revenues accounted for under topics other than ASC 606 and ASC 815	12	6	22	5
East | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,361	2,358	5,789	6,374
Derivative revenue	9	16	19	43
East | Energy revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	46	28	127	102
Derivative revenue	15	13	58	60
East | Capacity revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	39	49	80	90
Derivative revenue	19	17	41	23
East | Derivative revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	65	52	14	87
Less: Realized and unrealized ASC 815 revenue	108	99	132	212
East | Other revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	27	23	53	44
Contract amortization	(6)	(7)	(16)	(18)
East | Total operating revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	2,532	2,503	6,047	6,679
East | Other revenue, derivative | Operating Segments
Disaggregation of Revenue [Line Items]
Derivative revenue	0	1	0	(1)
East | Home | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	537	446	1,239	1,097
East | Business | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,824	1,912	4,550	5,277
West/Services/Other | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	859	878	2,062	2,146
Revenue	910	892	2,129	2,266
Less: Revenues accounted for under topics other than ASC 606 and ASC 815	19	7	25	16
West/Services/Other | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	832	830	1,987	2,071
Derivative revenue	0	0	0	0
West/Services/Other | Energy revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	51	40	118	88
Derivative revenue	16	(7)	38	10
West/Services/Other | Capacity revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6	0	8	1
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	17	23	8	90
Less: Realized and unrealized ASC 815 revenue	32	7	42	104
West/Services/Other | Other revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5	0	9	17
Contract amortization	(1)	(1)	(1)	(1)
West/Services/Other | Total operating revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	910	892	2,129	2,266
West/Services/Other | Other revenue, derivative | Operating Segments
Disaggregation of Revenue [Line Items]
Derivative revenue	(1)	(9)	(4)	4
West/Services/Other | Home | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	414	406	1,013	1,031
West/Services/Other | Business | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	418	424	974	1,040
Vivint Smart Home | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	467	444	935	592
Revenue	467	444	935	592
Less: Revenues accounted for under topics other than ASC 606 and ASC 815	0	0	0	0
Vivint Smart Home | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	467	444	935	592
Derivative revenue	0	0	0	0
Vivint Smart Home | Energy revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Derivative revenue	0	0	0	0
Vivint Smart Home | Capacity revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Derivative revenue	0	0	0	0
Vivint Smart Home | Derivative revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Mark-to-market for economic hedging activities	0	0	0	0
Less: Realized and unrealized ASC 815 revenue	0	0	0	0
Vivint Smart Home | Other revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0	0
Contract amortization	0	0	0	0
Vivint Smart Home | Total operating revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue	467	444	935	592
Vivint Smart Home | Other revenue, derivative | Operating Segments
Disaggregation of Revenue [Line Items]
Derivative revenue	0	0	0	0
Vivint Smart Home | Home | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	467	444	935	592
Vivint Smart Home | Business | Retail revenue | Operating Segments
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 0	$ 0	$ 0	$ 0