Pension and Other Postretirement Employee Benefits (OPEB) Plans - Schedule of Defined Benefit Plans Disclosures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Assumptions Used to Determine Benefit Obligations at Period End:
Discount rate	6.00%
Change in Plan Assets:
Fair value of assets at beginning of period	$ 28
Fair value of assets at end of year	14	$ 28
Funded Status:
Fair value of assets	14	28
Retirement Plan
Change in Pension and Postretirement Benefit Obligations:
Projected benefit obligation at beginning of period	425	449
Acquisitions	23	0
Service cost	2	3
Interest cost	21	21
Participant contributions	0	0
Plan amendments	0	1
Actuarial (gain) loss	(24)	10
Benefits paid	(38)	(59)
Projected benefit obligation at end of year	409	425	$ 449
Accumulated benefit obligation at end of year	408	422
Change in Plan Assets:
Fair value of assets at beginning of period	285	320
Acquisitions	18	0
Employer contributions	19	0	0
Participant contributions	0	0
Actual gain on assets	1	24
Transfers	0	0
Benefits paid	(38)	(59)
Fair value of assets at end of year	285	285	320
Funded Status:
Projected benefit obligation	(409)	(425)	(449)
Fair value of assets	285	285	$ 320
Funded status at end of year	(124)	(140)
Amounts Recognized in the Balance Sheet Consist of:
Investments	1	0
Other current liabilities	0	0
Other noncurrent liabilities	(125)	(140)
Net liability recognized	(124)	(140)
Amounts Recognized in Accumulated Other Comprehensive Income Consist of:
Net actuarial (gain) loss	(5)	4
Prior services cost	0	3
Net actuarial (gain) loss and prior service cost	$ (5)	$ 7
Retirement Plan | Vistra Plan, Dynegy Plan And EEI Plan
Assumptions Used to Determine Benefit Obligations at Period End:
Discount rate	5.63%	4.97%	5.16%
Interest crediting rate for cash balance plans	3.75%	3.50%	3.00%
Retirement Plan | Expected return on plan assets (Vistra Plan)
Assumptions Used to Determine Benefit Obligations at Period End:
Expected rate of compensation increase	3.50%	3.64%	3.79%
Retirement Plan | Expected return on plan assets (Dynegy Plan)
Assumptions Used to Determine Benefit Obligations at Period End:
Expected rate of compensation increase	4.46%
OPEB Plans
Change in Pension and Postretirement Benefit Obligations:
Projected benefit obligation at beginning of period	$ 108	$ 110
Acquisitions	0	0
Service cost	1	1
Interest cost	5	5
Participant contributions	3	3
Plan amendments	0	0
Actuarial (gain) loss	(7)	1
Benefits paid	(11)	(12)
Projected benefit obligation at end of year	99	108	$ 110
Accumulated benefit obligation at end of year	0	0
Change in Plan Assets:
Fair value of assets at beginning of period	12	29
Acquisitions	0	0
Employer contributions	8	9	9
Participant contributions	2	3
Actual gain on assets	1	2
Transfers	(2)	(19)
Benefits paid	(11)	(12)
Fair value of assets at end of year	10	12	29
Funded Status:
Projected benefit obligation	(99)	(108)	(110)
Fair value of assets	10	12	$ 29
Funded status at end of year	(89)	(96)
Amounts Recognized in the Balance Sheet Consist of:
Investments	2	3
Other current liabilities	(8)	(9)
Other noncurrent liabilities	(83)	(90)
Net liability recognized	(89)	(96)
Amounts Recognized in Accumulated Other Comprehensive Income Consist of:
Net actuarial (gain) loss	(22)	(15)
Prior services cost	1	1
Net actuarial (gain) loss and prior service cost	$ (21)	$ (14)
OPEB Plans | Vistra Plan, Split-Participant Plan And Dynegy Plan
Assumptions Used to Determine Benefit Obligations at Period End:
Discount rate	5.62%	4.98%	5.18%