v3.26.1
Derivatives - Schedule of Pretax Effect on Net Income of Derivatives Not Under Hedge Accounting, Including Realized and Unrealized Effects (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Derivative Instruments, Gain (Loss) [Line Items]        
Unrealized net gain (loss) from changes in fair value on derivative instruments: $ 49 $ (60) $ 379 $ 124
Total unrealized net gain (loss) from change in fair value on derivative instruments (530) 50 (121) (749)
Net unrealized gain (loss) on derivative instruments (481) (10) 258 (625)
Interest Rate Swaps        
Derivative Instruments, Gain (Loss) [Line Items]        
Unrealized net gain (loss) from changes in fair value on derivative instruments: (13) (6) (14) (11)
Total unrealized net gain (loss) from change in fair value on derivative instruments 4 (20) 21 (63)
Income Statement Location [Axis]: us-gaap:Revenues | Commodity Contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Unrealized net gain (loss) from changes in fair value on derivative instruments: 81 (69) 367 143
Total unrealized net gain (loss) from change in fair value on derivative instruments (643) 119 (293) (606)
Income Statement Location [Axis]: vistra:CostOfFuelPurchasedPowerAndDelivery | Commodity Contracts        
Derivative Instruments, Gain (Loss) [Line Items]        
Unrealized net gain (loss) from changes in fair value on derivative instruments: (19) 15 26 (8)
Total unrealized net gain (loss) from change in fair value on derivative instruments $ 109 $ (49) $ 151 $ (80)