v3.26.3
Summary of Significant Accounting Policies - Schedule of Disaggregation of Revenue (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Disaggregation of Revenue [Line Items]        
Revenue $ 522 $ 429 $ 1,357 $ 1,119
Total operating revenues 522 429 1,357 1,119
Operating Segments        
Disaggregation of Revenue [Line Items]        
Revenue 522 429 1,357 1,119
Contract amortization (52) (50) (153) (139)
Mark-to-market for economic hedges 3 (4) 35 (28)
Total operating revenues 522 429 1,357 1,119
Less: Contract amortization 52 50 153 139
Less: Mark-to-market for economic hedges (3) 4 (35) 28
Less: Lease revenue $ (324) $ (282) $ (850) $ (765)
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 $ 247 $ 201 $ 625 $ 521
Total $ 324 $ 282 $ 850 $ 765
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 | Flexible Generation        
Disaggregation of Revenue [Line Items]        
Revenue $ 85 $ 106 $ 232 $ 224
Contract amortization (4) (5) (13) (14)
Mark-to-market for economic hedges (8) 26 1 8
Total operating revenues 85 106 232 224
Less: Contract amortization 4 5 13 14
Less: Mark-to-market for economic hedges 8 (26) (1) (8)
Less: Lease revenue (28) (29) (82) (87)
Total revenue from contracts with customers 69 56 162 143
Total 28 29 82 87
Operating Segments | Renewables & Storage        
Disaggregation of Revenue [Line Items]        
Revenue 437 323 1,125 895
Contract amortization (48) (45) (140) (125)
Mark-to-market for economic hedges 11 (30) 34 (36)
Total operating revenues 437 323 1,125 895
Less: Contract amortization 48 45 140 125
Less: Mark-to-market for economic hedges (11) 30 (34) 36
Less: Lease revenue (296) (253) (768) (678)
Total revenue from contracts with customers 178 145 463 378
Total 296 253 768 678
Operating Segments | Energy revenue        
Disaggregation of Revenue [Line Items]        
Revenue 424 363 1,082 949
Total operating revenues 424 363 1,082 949
Less: Lease revenue (257) (238) (671) (639)
Total 257 238 671 639
Operating Segments | Energy revenue | Flexible Generation        
Disaggregation of Revenue [Line Items]        
Revenue 20 13 35 24
Total operating revenues 20 13 35 24
Less: Lease revenue (1) (1) (2) (2)
Total 1 1 2 2
Operating Segments | Energy revenue | Renewables & Storage        
Disaggregation of Revenue [Line Items]        
Revenue 404 350 1,047 925
Total operating revenues 404 350 1,047 925
Less: Lease revenue (256) (237) (669) (637)
Total 256 237 669 637
Operating Segments | Capacity revenue        
Disaggregation of Revenue [Line Items]        
Revenue 128 94 333 269
Total operating revenues 128 94 333 269
Less: Lease revenue (67) (44) (179) (126)
Total 67 44 179 126
Operating Segments | Capacity revenue | Flexible Generation        
Disaggregation of Revenue [Line Items]        
Revenue 76 69 207 201
Total operating revenues 76 69 207 201
Less: Lease revenue (27) (28) (80) (85)
Total 27 28 80 85
Operating Segments | Capacity revenue | Renewables & Storage        
Disaggregation of Revenue [Line Items]        
Revenue 52 25 126 68
Total operating revenues 52 25 126 68
Less: Lease revenue (40) (16) (99) (41)
Total 40 16 99 41
Operating Segments | Other revenue        
Disaggregation of Revenue [Line Items]        
Revenue 19 26 60 68
Total operating revenues 19 26 60 68
Operating Segments | Other revenue | Flexible Generation        
Disaggregation of Revenue [Line Items]        
Revenue 1 3 2 5
Total operating revenues 1 3 2 5
Operating Segments | Other revenue | Renewables & Storage        
Disaggregation of Revenue [Line Items]        
Revenue 18 23 58 63
Total operating revenues $ 18 $ 23 $ 58 $ 63