Acquisitions - Narrative (Details) $ in Millions				3 Months Ended	9 Months Ended
	Oct. 22, 2025 USD ($) facility MW	Sep. 18, 2024 USD ($)	Mar. 01, 2024 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2024 USD ($)
Business Combination [Line Items]
Fair value of noncontrolling interest in Energy Harbor			$ 749
Payments to acquire interest in subsidiaries and affiliates		$ 3,200
Vistra Vision
Business Combination [Line Items]
Subsidiary, ownership percentage, noncontrolling owner		15.00%
Lotus Infrastructure Partners | Subsequent Event
Business Combination [Line Items]
Number of natural gas generation facilities acquired | facility	7
Number of natural gas generation facilities capacity in megawatts | MW	2,600
Total purchase price	$ 1,900
Business combination, consideration transferred, liabilities incurred	800
Cash consideration	$ 1,100
Lotus Infrastructure Partners | Subsequent Event | Vistra Operations
Business Combination [Line Items]
Acquiring of membership interest	100.00%
Energy Harbor
Business Combination [Line Items]
Total purchase price			4,596
Cash consideration			3,100
Fair value of noncontrolling interest in Energy Harbor			$ 811
Business combination, acquisition related costs				$ 1	$ 25
Energy Harbor | Vistra Vision
Business Combination [Line Items]
Subsidiary, ownership percentage, noncontrolling owner			15.00%
Subsidiary, ownership percentage, parent			85.00%