Debt, Credit Facilities and Financings - Schedule of Maturities of Long-Term Debt (Details) - USD ($) $ in Millions	Oct. 31, 2025	Sep. 30, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Remainder of 2025		$ 208
2026		2,014
2027		3,432
2028		32
2029		2,283
Thereafter		8,161
Unamortized premiums, discounts and debt issuance costs		(142)
Total long-term debt, including amounts due currently		15,988	$ 16,298
Vistra Operations Senior Unsecured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently		7,300	7,300
Vistra Operations Senior Secured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently		4,400	5,144
5.500% Senior Unsecured Notes, due September 1, 2026 | Vistra Operations Senior Unsecured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently		$ 1,000	$ 1,000
Debt instrument, interest rate, stated percentage		5.50%
Senior Secured Notes Due | Vistra Operations Senior Secured Notes | Subsequent Event
Debt Instrument [Line Items]
Debt instrument, face amount	$ 2,000