Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2025	Dec. 31, 2024
Debt securities
Liabilities:
Debt, weighted average interest rate	4.17%	3.99%
Decommissioning fund investments, debt securities average maturities	8 years	7 years
Decommissioning fund investments, debt maturities, one through five years, fair value	$ 768
Decommissioning fund investments, debt maturities, five through ten years, fair value	1,025
Decommissioning fund investments, debt maturities, after ten years, fair value	374
Fair Value, Recurring
Assets:
Sub-total	26	$ 5
Liabilities:
Total liabilities	26	5
Fair Value, Recurring | Equity securities
Assets:
Assets measured at net asset value	867	821
Fair Value, Recurring | Debt securities
Assets:
Assets measured at net asset value	303	0
Fair Value, Recurring | Commodity Contracts
Assets:
Assets	26	5
Liabilities:
Derivative liabilities	26	5
Fair Value, Recurring | Interest Rate Swaps
Assets:
Assets	0	0
Liabilities:
Derivative liabilities	0	0
Fair Value, Recurring | Total
Assets:
Sub-total	7,051	6,946
Total assets	8,221	7,767
Liabilities:
Total liabilities	5,516	4,718
Fair Value, Recurring | Total | Equity securities
Assets:
Nuclear decommissioning trust, fair value	1,644	1,560
Fair Value, Recurring | Total | Debt securities
Assets:
Nuclear decommissioning trust, fair value	1,864	2,059
Fair Value, Recurring | Total | Commodity Contracts
Assets:
Assets	3,515	3,231
Liabilities:
Derivative liabilities	5,482	4,691
Fair Value, Recurring | Total | Interest Rate Swaps
Assets:
Assets	28	96
Liabilities:
Derivative liabilities	34	27
Level 1 | Fair Value, Recurring
Assets:
Sub-total	4,043	3,566
Liabilities:
Total liabilities	2,841	2,118
Level 1 | Fair Value, Recurring | Equity securities
Assets:
Nuclear decommissioning trust, fair value	1,644	1,560
Level 1 | Fair Value, Recurring | Debt securities
Assets:
Nuclear decommissioning trust, fair value	80	83
Level 1 | Fair Value, Recurring | Commodity Contracts
Assets:
Assets	2,319	1,923
Liabilities:
Derivative liabilities	2,841	2,118
Level 1 | Fair Value, Recurring | Interest Rate Swaps
Assets:
Assets	0	0
Liabilities:
Derivative liabilities	0	0
Level 2 | Fair Value, Recurring
Assets:
Sub-total	2,200	2,534
Liabilities:
Total liabilities	983	1,002
Level 2 | Fair Value, Recurring | Equity securities
Assets:
Nuclear decommissioning trust, fair value	0	0
Level 2 | Fair Value, Recurring | Debt securities
Assets:
Nuclear decommissioning trust, fair value	1,784	1,976
Level 2 | Fair Value, Recurring | Commodity Contracts
Assets:
Assets	388	462
Liabilities:
Derivative liabilities	949	975
Level 2 | Fair Value, Recurring | Interest Rate Swaps
Assets:
Assets	28	96
Liabilities:
Derivative liabilities	34	27
Level 3
Assets:
Assets	782	841
Liabilities:
Derivative liabilities	1,666	1,593
Level 3 | Fair Value, Recurring
Assets:
Sub-total	782	841
Liabilities:
Total liabilities	1,666	1,593
Level 3 | Fair Value, Recurring | Equity securities
Assets:
Nuclear decommissioning trust, fair value	0	0
Level 3 | Fair Value, Recurring | Debt securities
Assets:
Nuclear decommissioning trust, fair value	0	0
Level 3 | Fair Value, Recurring | Commodity Contracts
Assets:
Assets	782	841
Liabilities:
Derivative liabilities	1,666	1,593
Level 3 | Fair Value, Recurring | Interest Rate Swaps
Assets:
Assets	0	0
Liabilities:
Derivative liabilities	$ 0	$ 0