Business, Significant Accounting Policies, Significant Events, and Recent Developments - Narrative (Details) $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2025 USD ($) MW	Mar. 31, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) segment MW	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)	Jul. 31, 2025 USD ($)	Jul. 02, 2025 USD ($)	Jan. 16, 2025 facility MW	Nov. 27, 2024 MW
Line of Credit Facility [Line Items]
Number of reportable segments | segment				5
Property, plant and equipment — net	$ 17,736			$ 17,736		$ 18,173
Other current liabilities	694			694		645
Other noncurrent liabilities	1,326			1,326		1,270
Insurance settlements receivable	324	$ 439		324		0
Insurance recoveries	80			80
Interest costs incurred	6			20
Other income, net	191		$ 59	186	$ 146
Pulaski | Term Loan | Subsequent Event
Line of Credit Facility [Line Items]
Debt instrument, face amount							$ 168	$ 168
Accounts Receivable Securitization Program | Maximum
Line of Credit Facility [Line Items]
Account receivable securitization program, total borrowing capacity	1,000			1,000
Accounts Receivable Securitization Program | Maximum | Subsequent Event
Line of Credit Facility [Line Items]
Account receivable securitization program, total borrowing capacity							$ 1,100
ASAOC
Line of Credit Facility [Line Items]
Total cost				110
Interest costs incurred	25			102
Moss Landing Power Plant (Battery Storage Project)
Line of Credit Facility [Line Items]
Other current liabilities		8
Insurance settlements receivable	304	425		304		0
Insurance recoveries	0			0
Interest costs incurred	0			0
Moss Landing Power Plant (Battery Storage Project) | Moss Landing Battery Energy Storage System Phase I
Line of Credit Facility [Line Items]
Battery energy storage system capacity | MW									300
Depreciation expense		400
Insurance settlements, limit amount	$ 500			$ 500
Insurance settlements receivable		425
Moss Landing Power Plant (Battery Storage Project) | Moss Landing Battery Energy Storage System Phases II and III
Line of Credit Facility [Line Items]
Number of battery facilities | facility									2
Moss Landing Power Plant (Battery Storage Project) | Moss Landing Battery Energy Storage System Phase III
Line of Credit Facility [Line Items]
Battery energy storage system capacity | MW	350			350
Moss Landing Power Plant (Battery Storage Project) | Moss Landing Battery Energy Storage System Phase II
Line of Credit Facility [Line Items]
Battery energy storage system capacity | MW	100			100
Property, plant and equipment — net	$ 170			$ 170
Moss Landing Power Plant (Battery Storage Project) | ASAOC
Line of Credit Facility [Line Items]
Total cost				110
Estimated liability costs incurred	18			18
Environmental remediation obligation	92			92
Other current liabilities	74			74
Other noncurrent liabilities	18			18
Interest costs incurred	25			102
Martin Lake Incident
Line of Credit Facility [Line Items]
Insurance settlements receivable	20	$ 14		20		0
Insurance recoveries	80			80
Interest costs incurred	6			20
Martin Lake Incident | ASAOC
Line of Credit Facility [Line Items]
Interest costs incurred	0			0
Martin Lake Incident | ERCOT
Line of Credit Facility [Line Items]
Battery energy storage system capacity | MW										815
Depreciation expense						$ 1
Total cash capital expenditures				280
Capital expenditures incurred				100
Insurance recoveries				100
Interest costs incurred				$ 20
Other income, net	$ 80