Commitments and Contingencies - Schedule of Long-term Commitments (Detail) $ in Millions	Dec. 31, 2024 USD ($)
Other Commitments [Line Items]
2025	$ 621
2026	358
2027	240
2028	171
2029	153
Thereafter	1,340
Total future minimum payments	2,883
Transportation [Member]
Other Commitments [Line Items]
2025	146
2026	145
2027	176
2028	138
2029	120
Thereafter	1,200
Total future minimum payments	1,925
Capital Projects [Member]
Other Commitments [Line Items]
2025	279	[1]
2026	161	[1]
2027	17	[1]
2028	0	[1]
2029	0	[1]
Thereafter	0	[1]
Total future minimum payments	457	[1]
Fuel and Gas Supply [Member]
Other Commitments [Line Items]
2025	156
2026	27
2027	4
2028	1
2029	0
Thereafter	0
Total future minimum payments	188
Long-term Service Agreements [Member]
Other Commitments [Line Items]
2025	21
2026	22
2027	40
2028	30
2029	31
Thereafter	33
Total future minimum payments	177
Leases [Member]
Other Commitments [Line Items]
2025	4
2026	2
2027	2
2028	2
2029	2
Thereafter	107
Total future minimum payments	119
Other [Member]
Other Commitments [Line Items]
2025	15	[2]
2026	1	[2]
2027	1	[2]
2028	0	[2]
2029	0	[2]
Thereafter	0	[2]
Total future minimum payments	$ 17	[2]

[1] These estimates are subject to continuing review and adjustment and actual capital expenditures may vary significantly from these estimates.

[2] Other includes contractual obligations under demand side management and purchased power agreements.