v3.26.1
Revenue - Schedule of Disaggregation of Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers $ 4,401 $ 3,753 $ 9,402 $ 8,003
Total revenues 4,017 4,250 9,657 8,183
Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers       5
Total revenues       24
Retail energy charge in ERCOT        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 2,253 2,206 4,147 4,192
Retail energy charge in Northeast/Midwest        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1,091 793 2,350 1,832
Wholesale generation revenue from ISO/RTO        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 620 474 1,996 1,348
Capacity revenue from ISO/RTO        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 134 30 256 50
Revenue from other wholesale contracts        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 303 250 653 581
Transferable PTC revenues        
Disaggregation of Revenue [Line Items]        
Total revenues 3 4 5 6
Hedging revenues — realized        
Disaggregation of Revenue [Line Items]        
Total revenues 154 427 151 622
Hedging revenues — unrealized        
Disaggregation of Revenue [Line Items]        
Total revenues (562) 50 74 (463)
Business interruption insurance proceeds        
Disaggregation of Revenue [Line Items]        
Total revenues 22 21 28 21
Intangible amortization and other revenues        
Disaggregation of Revenue [Line Items]        
Total revenues (1) (5) (3) (6)
Intersegment sales        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Intersegment sales — unrealized        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Total other revenues        
Disaggregation of Revenue [Line Items]        
Total revenues (384) 497 255 180
Total other revenues | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenues       19
Operating Segments        
Disaggregation of Revenue [Line Items]        
Total revenues 6,053 6,845 15,084 11,764
Operating Segments | Retail        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 3,344 2,999 6,497 6,024
Total revenues 3,610 3,532 7,299 6,700
Operating Segments | Texas        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 203 150 544 357
Total revenues 1,418 1,788 4,405 1,998
Operating Segments | East        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 774 534 2,209 1,454
Total revenues 954 1,480 3,214 2,860
Operating Segments | West        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 79 68 150 162
Total revenues 71 25 160 182
Operating Segments | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 1 0  
Total revenues 0 20 6 24
Operating Segments | Retail energy charge in ERCOT | Retail        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 2,253 2,206 4,147 4,192
Operating Segments | Retail energy charge in ERCOT | Texas        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Retail energy charge in ERCOT | East        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Retail energy charge in ERCOT | West        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Retail energy charge in ERCOT | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Retail energy charge in Northeast/Midwest | Retail        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1,091 793 2,350 1,832
Operating Segments | Retail energy charge in Northeast/Midwest | Texas        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Retail energy charge in Northeast/Midwest | East        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Retail energy charge in Northeast/Midwest | West        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Retail energy charge in Northeast/Midwest | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Wholesale generation revenue from ISO/RTO | Retail        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Wholesale generation revenue from ISO/RTO | Texas        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 106 41 329 119
Operating Segments | Wholesale generation revenue from ISO/RTO | East        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 496 412 1,632 1,182
Operating Segments | Wholesale generation revenue from ISO/RTO | West        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 18 21 35 47
Operating Segments | Wholesale generation revenue from ISO/RTO | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Capacity revenue from ISO/RTO | Retail        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Capacity revenue from ISO/RTO | Texas        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Capacity revenue from ISO/RTO | East        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 134 30 256 50
Operating Segments | Capacity revenue from ISO/RTO | East | Income Statement Location [Axis]: us-gaap:Revenues        
Disaggregation of Revenue [Line Items]        
Net capacity sold (346) (134) (667) (207)
Net capacity purchased 212 104 411 157
Operating Segments | Capacity revenue from ISO/RTO | West        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Capacity revenue from ISO/RTO | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Revenue from other wholesale contracts | Retail        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Operating Segments | Revenue from other wholesale contracts | Texas        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 97 109 215 238
Operating Segments | Revenue from other wholesale contracts | East        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 144 92 321 222
Operating Segments | Revenue from other wholesale contracts | West        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 61 47 115 115
Operating Segments | Revenue from other wholesale contracts | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 1 0 5
Operating Segments | Transferable PTC revenues | Retail        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Transferable PTC revenues | Texas        
Disaggregation of Revenue [Line Items]        
Total revenues 3 4 5 6
Operating Segments | Transferable PTC revenues | East        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Transferable PTC revenues | West        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Transferable PTC revenues | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Hedging revenues — realized | Retail        
Disaggregation of Revenue [Line Items]        
Total revenues 188 370 389 644
Operating Segments | Hedging revenues — realized | Texas        
Disaggregation of Revenue [Line Items]        
Total revenues (36) (9) (69) (36)
Operating Segments | Hedging revenues — realized | East        
Disaggregation of Revenue [Line Items]        
Total revenues (22) 28 (220) (50)
Operating Segments | Hedging revenues — realized | West        
Disaggregation of Revenue [Line Items]        
Total revenues 24 38 51 64
Operating Segments | Hedging revenues — realized | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Hedging revenues — unrealized | Retail        
Disaggregation of Revenue [Line Items]        
Total revenues 57 141 363 (16)
Operating Segments | Hedging revenues — unrealized | Texas        
Disaggregation of Revenue [Line Items]        
Total revenues 63 90 573 (53)
Operating Segments | Hedging revenues — unrealized | East        
Disaggregation of Revenue [Line Items]        
Total revenues (650) (99) (820) (349)
Operating Segments | Hedging revenues — unrealized | West        
Disaggregation of Revenue [Line Items]        
Total revenues (32) (82) (42) (46)
Operating Segments | Hedging revenues — unrealized | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 1
Operating Segments | Business interruption insurance proceeds | Retail        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Business interruption insurance proceeds | Texas        
Disaggregation of Revenue [Line Items]        
Total revenues 22 0 22 0
Operating Segments | Business interruption insurance proceeds | East        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Business interruption insurance proceeds | West        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Business interruption insurance proceeds | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenues 0 21 6 21
Operating Segments | Intangible amortization and other revenues | Retail        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Intangible amortization and other revenues | Texas        
Disaggregation of Revenue [Line Items]        
Total revenues 0 (2) 0 (2)
Operating Segments | Intangible amortization and other revenues | East        
Disaggregation of Revenue [Line Items]        
Total revenues (1) (3) (3) (4)
Operating Segments | Intangible amortization and other revenues | West        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Intangible amortization and other revenues | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Intersegment sales | Retail        
Disaggregation of Revenue [Line Items]        
Total revenues 21 22 50 48
Operating Segments | Intersegment sales | Texas        
Disaggregation of Revenue [Line Items]        
Total revenues 755 738 1,735 1,791
Operating Segments | Intersegment sales | East        
Disaggregation of Revenue [Line Items]        
Total revenues 942 856 2,253 1,916
Operating Segments | Intersegment sales | West        
Disaggregation of Revenue [Line Items]        
Total revenues 0 1 1 2
Operating Segments | Intersegment sales | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenues 0 (2) 0 (3)
Operating Segments | Intersegment sales — unrealized | Retail        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Intersegment sales — unrealized | Texas        
Disaggregation of Revenue [Line Items]        
Total revenues 408 817 1,595 (65)
Operating Segments | Intersegment sales — unrealized | East        
Disaggregation of Revenue [Line Items]        
Total revenues (89) 164 (205) (107)
Operating Segments | Intersegment sales — unrealized | West        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Intersegment sales — unrealized | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Operating Segments | Total other revenues | Retail        
Disaggregation of Revenue [Line Items]        
Total revenues 266 533 802 676
Operating Segments | Total other revenues | Texas        
Disaggregation of Revenue [Line Items]        
Total revenues 1,215 1,638 3,861 1,641
Operating Segments | Total other revenues | East        
Disaggregation of Revenue [Line Items]        
Total revenues 180 946 1,005 1,406
Operating Segments | Total other revenues | West        
Disaggregation of Revenue [Line Items]        
Total revenues (8) (43) 10 20
Operating Segments | Total other revenues | Asset Closure        
Disaggregation of Revenue [Line Items]        
Total revenues 0 19 6  
Eliminations        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1 1 2 1
Total revenues (2,036) (2,595) (5,427) (3,581)
Eliminations | Retail energy charge in ERCOT        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Eliminations | Retail energy charge in Northeast/Midwest        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Eliminations | Wholesale generation revenue from ISO/RTO        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Eliminations | Capacity revenue from ISO/RTO        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 0 0 0 0
Eliminations | Revenue from other wholesale contracts        
Disaggregation of Revenue [Line Items]        
Total revenue from contracts with customers 1 1 2 1
Eliminations | Transferable PTC revenues        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Eliminations | Hedging revenues — realized        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Eliminations | Hedging revenues — unrealized        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Eliminations | Business interruption insurance proceeds        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Eliminations | Intangible amortization and other revenues        
Disaggregation of Revenue [Line Items]        
Total revenues 0 0 0 0
Eliminations | Intersegment sales        
Disaggregation of Revenue [Line Items]        
Total revenues (1,718) (1,615) (4,039) (3,754)
Eliminations | Intersegment sales — unrealized        
Disaggregation of Revenue [Line Items]        
Total revenues (319) (981) (1,390) 172
Eliminations | Total other revenues        
Disaggregation of Revenue [Line Items]        
Total revenues $ (2,037) $ (2,596) $ (5,429) $ (3,582)