Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Debt securities
Liabilities:
Debt, weighted average interest rate	4.24%	3.99%
Decommissioning fund investments, debt securities average maturities	8 years	7 years
Decommissioning fund investments, debt maturities, one through five years, fair value	$ 825
Decommissioning fund investments, debt maturities, five through ten years, fair value	972
Decommissioning fund investments, debt maturities, after ten years, fair value	355
Fair Value, Recurring
Assets:
Sub-total	41	$ 5
Liabilities:
Total liabilities	41	5
Fair Value, Recurring | Equity securities
Assets:
Assets measured at net asset value	783	821
Fair Value, Recurring | Debt securities
Assets:
Assets measured at net asset value	300	0
Fair Value, Recurring | Commodity Contracts
Assets:
Assets	41	5
Liabilities:
Derivative liabilities	41	5
Fair Value, Recurring | Interest Rate Swaps
Assets:
Assets	0	0
Liabilities:
Derivative liabilities	0	0
Fair Value, Recurring | Total
Assets:
Sub-total	7,425	6,946
Total assets	8,508	7,767
Liabilities:
Total liabilities	6,105	4,718
Fair Value, Recurring | Total | Equity securities
Assets:
Nuclear decommissioning trust, fair value	1,469	1,560
Fair Value, Recurring | Total | Debt securities
Assets:
Nuclear decommissioning trust, fair value	1,852	2,059
Fair Value, Recurring | Total | Commodity Contracts
Assets:
Assets	4,055	3,231
Liabilities:
Derivative liabilities	6,076	4,691
Fair Value, Recurring | Total | Interest Rate Swaps
Assets:
Assets	49	96
Liabilities:
Derivative liabilities	29	27
Level 1 | Fair Value, Recurring
Assets:
Sub-total	4,251	3,566
Liabilities:
Total liabilities	3,002	2,118
Level 1 | Fair Value, Recurring | Equity securities
Assets:
Nuclear decommissioning trust, fair value	1,469	1,560
Level 1 | Fair Value, Recurring | Debt securities
Assets:
Nuclear decommissioning trust, fair value	99	83
Level 1 | Fair Value, Recurring | Commodity Contracts
Assets:
Assets	2,683	1,923
Liabilities:
Derivative liabilities	3,002	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	2,227	2,534
Liabilities:
Total liabilities	1,212	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	1,753	1,976
Level 2 | Fair Value, Recurring | Commodity Contracts
Assets:
Assets	425	462
Liabilities:
Derivative liabilities	1,183	975
Level 2 | Fair Value, Recurring | Interest Rate Swaps
Assets:
Assets	49	96
Liabilities:
Derivative liabilities	29	27
Level 3
Assets:
Assets	906	841
Liabilities:
Derivative liabilities	1,850	1,593
Level 3 | Fair Value, Recurring
Assets:
Sub-total	906	841
Liabilities:
Total liabilities	1,850	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	906	841
Liabilities:
Derivative liabilities	1,850	1,593
Level 3 | Fair Value, Recurring | Interest Rate Swaps
Assets:
Assets	0	0
Liabilities:
Derivative liabilities	$ 0	$ 0