Debt, Credit Facilities and Financings - Schedule of Long-Term Debt Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2025	May 31, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 15,770		$ 16,298
Total other long-term debt	55		55
Unamortized debt premiums, discounts, and issuance costs	(151)		(171)
Less amounts due currently	(230)		(880)
Total long-term debt, less amounts due currently	$ 15,540		15,418
Bridge Loan
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	1.625%
Construction Loans
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	1.875%
Term Loan
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	2.00%
Vistra Operations Senior Secured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 4,400		5,144
Energy Harbor Revenue Bonds
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	431		431
Vistra Operations Senior Unsecured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	7,300		7,300
Vistra Operations Credit Facilities, Term Loan B-3 Facility due December 20, 2030 | Line of Credit
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	2,462		2,475
BCOP Credit Facility, Bridge Loans due November 1, 2025 / December 3, 2026 | Bridge Loan
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	367		367
BCOP Credit Facility, Bridge Loans due November 1, 2025 / December 3, 2026 | Construction Loans
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	88		0
BCOP Credit Facility, Bridge Loans due November 1, 2025 / December 3, 2026 | Term Loan
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	121		0
Vistra Zero Credit Facility, Term Loan B Facility due April 30, 2031 | Line of Credit
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	697		697
5.125% Senior Secured Notes, due May 13, 2025 | Vistra Operations Senior Secured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 0		744
Debt instrument, interest rate, stated percentage	5.125%	5.125%
5.050% Senior Secured Notes, due December 30, 2026 | Vistra Operations Senior Secured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 500		500
Debt instrument, interest rate, stated percentage	5.05%
3.700% Senior Secured Notes, due January 30, 2027 | Vistra Operations Senior Secured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 800		800
Debt instrument, interest rate, stated percentage	3.70%
4.300% Senior Secured Notes, due July 15, 2029 | Vistra Operations Senior Secured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 800		800
Debt instrument, interest rate, stated percentage	4.30%
6.950% Senior Secured Notes, due October 15, 2033 | Vistra Operations Senior Secured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 1,050		1,050
Debt instrument, interest rate, stated percentage	6.95%
6.000% Senior Secured Notes, due April 15, 2034 | Vistra Operations Senior Secured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 500		500
Debt instrument, interest rate, stated percentage	6.00%
5.700% Senior Secured Notes, due December 30, 2034 | Vistra Operations Senior Secured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 750		750
Debt instrument, interest rate, stated percentage	5.70%
3.375% Revenue Bond, due August 1, 2029 | Energy Harbor Revenue Bonds
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 100		100
Debt instrument, interest rate, stated percentage	3.375%
4.750% Revenue Bonds, due June 1, 2033 and July 1, 2033 | Energy Harbor Revenue Bonds
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 285		285
Debt instrument, interest rate, stated percentage	4.75%
3.750% Revenue Bond, due October 1, 2047 | Energy Harbor Revenue Bonds
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 46		46
Debt instrument, interest rate, stated percentage	3.75%
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%
5.625% Senior Unsecured Notes, due February 15, 2027 | Vistra Operations Senior Unsecured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 1,300		1,300
Debt instrument, interest rate, stated percentage	5.625%
5.000% Senior Unsecured Notes, due July 31, 2027 | Vistra Operations Senior Unsecured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 1,300		1,300
Debt instrument, interest rate, stated percentage	5.00%
4.375% Senior Unsecured Notes, due May 1, 2029 | Vistra Operations Senior Unsecured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 1,250		1,250
Debt instrument, interest rate, stated percentage	4.375%
7.750% Senior Unsecured Notes, due October 15, 2031 | Vistra Operations Senior Unsecured Notes
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 1,450		1,450
Debt instrument, interest rate, stated percentage	7.75%
6.875% Senior Unsecured Notes, due April 15, 2032 | 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	6.875%
Equipment Financing Agreements | Other Debt
Debt Instrument [Line Items]
Total long-term debt, including amounts due currently	$ 55		$ 55