Commitments and Contingencies (Details) $ in Millions	1 Months Ended									9 Months Ended
	Aug. 31, 2024 state	May 31, 2024 petition unit category	Aug. 31, 2023 application	May 31, 2023 facility	Mar. 31, 2023 state	Oct. 31, 2022	Jul. 31, 2022 application	Jan. 31, 2022 application	Oct. 31, 2021 application	Sep. 30, 2025 USD ($) application lawsuit	Apr. 30, 2025 USD ($)	Mar. 31, 2025 USD ($)	Feb. 28, 2025	Jul. 31, 2019 plant
Loss Contingencies [Line Items]
Legal claim, duration						5 years
Number of nuclear power plants | plant														2
Greenhouse gas emissions, final rule, number of states filing petitions challenging final rule | petition		17
Environmental protection agency, number of categories of unit | category		2
Environmental protection agency, number of potential unit | unit		10
United States Environmental Protection Agency
Loss Contingencies [Line Items]
Cross-state air pollution rule, 2015 ozone national ambient air quality standards, federal implementation plan, beginning 2023 ozone season, number of states subject to rule | state					22
Clean air act, regional haze program, best available retrofit technology alternative, sulfur dioxide emissions, number of electricity generation units in texas subject to program | facility				6
Federal coal combustion residual rule, proposed groundwater monitoring and closure requirement, number of states challenging rule | state	17
Illinois Environmental Protection Agency
Loss Contingencies [Line Items]
Coal combustion residuals, rules for closure of coal ash ponds in Illinois, number of operating permit applications filed | application									18	11
Coal combustion residuals, rules for closure of coal ash ponds in Illinois, number of construction permit application filed | application			1				5	3
ASAOC
Loss Contingencies [Line Items]
Total costs										$ 110.0
Moss Landing Power Plant (Battery Storage Project) | ASAOC
Loss Contingencies [Line Items]
Total costs										110.0
Martin Lake Steam Electric Station | Maximum
Loss Contingencies [Line Items]
Clean air act, regional haze program, best available retrofit technology alternative, sulfur dioxide emissions, number of years remaining before generation unit is subject to program period				3 years
Coleto Creek | Maximum
Loss Contingencies [Line Items]
Clean air act, regional haze program, best available retrofit technology alternative, sulfur dioxide emissions, number of years remaining before generation unit is subject to program period				5 years
Beaver Valley, Davis-Besse And Perry Facilities
Loss Contingencies [Line Items]
Nuclear decontamination and property insurance, maximum coverage											$ 2,250.0
Non-nuclear property damage insurance, maximum coverage											1,000.0	$ 1,500.0
Non-nuclear property damage insurance, deductible per accident, general											10.0
Non-nuclear property damage insurance, deductible per incident, natural hazard											20.0
Accidental outage insurance, coverage for obtaining replacement energy after 12 week waiting period, maximum weekly coverage first 52 weeks										2.5	4.5
Accidental outage insurance, coverage for obtaining replacement										1.5	2.7
Accidental outage insurance, coverage for obtaining replacement energy after 12 week waiting period, maximum weekly payments, remaining 26 weeks non-nuclear and 71 weeks nuclear property										2.0	3.6
Accidental outage insurance, coverage for obtaining replacement energy, coverage limit for non-nuclear accidents										208.0	291.0
Accidental outage insurance, coverage for obtaining replacement energy, coverage limit for nuclear accidents										$ 350.0	$ 490.0
Gas Index Pricing Litigation | Wisconsin
Loss Contingencies [Line Items]
Loss contingency, pending claims, number | lawsuit										1
Greenhouse Gas Emissions (GHG)
Loss Contingencies [Line Items]
Litigation, period		90 days
Legacy CCR Rulemaking
Loss Contingencies [Line Items]
Litigation, period													120 days
Letters of Credit | Vistra Operations Company LLC
Loss Contingencies [Line Items]
Letters of credit outstanding										$ 2,782.0
Letters of Credit | Vistra Operations Company LLC | Support Risk Management and Trading Margin Requirements Including Over the Counter Hedging Transactions and Collateral Postings with Electric Reliability Council of Texas
Loss Contingencies [Line Items]
Letters of credit outstanding										2,400.0
Letters of Credit | Vistra Operations Company LLC | Support Battery and Solar Development Projects
Loss Contingencies [Line Items]
Letters of credit outstanding										257.0
Letters of Credit | Vistra Operations Company LLC | Support Executory Contracts and Insurance Agreements
Loss Contingencies [Line Items]
Letters of credit outstanding										25.0
Letters of Credit | Vistra Operations Company LLC | Support Retail Electric Provider's financial requirements with the Public Utility Commission of Texas
Loss Contingencies [Line Items]
Letters of credit outstanding										86.0
Letters of Credit | Vistra Operations Company LLC | Miscellaneous Credit Support Requirements
Loss Contingencies [Line Items]
Letters of credit outstanding										14.0
Surety Bonds | Vistra Operations Company LLC
Loss Contingencies [Line Items]
Surety bonds outstanding										$ 995.0