v3.26.1
Summary of Significant Accounting Policies - 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]        
Revenues $ 481 $ 392 $ 835 $ 690
Total operating revenues 481 392 835 690
Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenues 481 392 835 690
Contract amortization (51) (45) (101) (89)
Mark-to-market for economic hedges 2 (13) 32 (24)
Total operating revenues 481 392 835 690
Less: Contract amortization 51 45 101 89
Less: Mark-to-market for economic hedges (2) 13 (32) 24
Less: Lease revenue $ (318) $ (273) $ (526) $ (483)
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration] Total operating revenues Total operating revenues Total operating revenues Total operating revenues
Total revenue from contracts with customers $ 212 $ 177 $ 378 $ 320
Total $ 318 $ 273 $ 526 $ 483
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration] Total operating revenues Total operating revenues Total operating revenues Total operating revenues
Operating Segments | Energy revenue        
Disaggregation of Revenue [Line Items]        
Revenues $ 397 $ 338 $ 658 $ 586
Total operating revenues 397 338 658 586
Less: Lease revenue (258) (232) (414) (401)
Total 258 232 414 401
Operating Segments | Capacity revenue        
Disaggregation of Revenue [Line Items]        
Revenues 108 90 205 175
Total operating revenues 108 90 205 175
Less: Lease revenue (60) (41) (112) (82)
Total 60 41 112 82
Operating Segments | Other revenues        
Disaggregation of Revenue [Line Items]        
Revenues 25 22 41 42
Total operating revenues 25 22 41 42
Operating Segments | Flexible Generation        
Disaggregation of Revenue [Line Items]        
Revenues 86 50 147 118
Contract amortization (4) (4) (9) (9)
Mark-to-market for economic hedges 16 (20) 9 (18)
Total operating revenues 86 50 147 118
Less: Contract amortization 4 4 9 9
Less: Mark-to-market for economic hedges (16) 20 (9) 18
Less: Lease revenue (25) (29) (54) (58)
Total revenue from contracts with customers 49 45 93 87
Total 25 29 54 58
Operating Segments | Flexible Generation | Energy revenue        
Disaggregation of Revenue [Line Items]        
Revenues 8 5 15 11
Total operating revenues 8 5 15 11
Less: Lease revenue 0 0 (1) (1)
Total 0 0 1 1
Operating Segments | Flexible Generation | Capacity revenue        
Disaggregation of Revenue [Line Items]        
Revenues 66 68 131 132
Total operating revenues 66 68 131 132
Less: Lease revenue (25) (29) (53) (57)
Total 25 29 53 57
Operating Segments | Flexible Generation | Other revenues        
Disaggregation of Revenue [Line Items]        
Revenues 0 1 1 2
Total operating revenues 0 1 1 2
Operating Segments | Renewables & Storage        
Disaggregation of Revenue [Line Items]        
Revenues 395 342 688 572
Contract amortization (47) (41) (92) (80)
Mark-to-market for economic hedges (14) 7 23 (6)
Total operating revenues 395 342 688 572
Less: Contract amortization 47 41 92 80
Less: Mark-to-market for economic hedges 14 (7) (23) 6
Less: Lease revenue (293) (244) (472) (425)
Total revenue from contracts with customers 163 132 285 233
Total 293 244 472 425
Operating Segments | Renewables & Storage | Energy revenue        
Disaggregation of Revenue [Line Items]        
Revenues 389 333 643 575
Total operating revenues 389 333 643 575
Less: Lease revenue (258) (232) (413) (400)
Total 258 232 413 400
Operating Segments | Renewables & Storage | Capacity revenue        
Disaggregation of Revenue [Line Items]        
Revenues 42 22 74 43
Total operating revenues 42 22 74 43
Less: Lease revenue (35) (12) (59) (25)
Total 35 12 59 25
Operating Segments | Renewables & Storage | Other revenues        
Disaggregation of Revenue [Line Items]        
Revenues 25 21 40 40
Total operating revenues $ 25 $ 21 $ 40 $ 40