Commitments and Contingencies, Fuel Contracts (Details) $ in Millions	Dec. 31, 2022 USD ($)
Coal
Unrecorded Unconditional Purchase Obligation, to be Paid, Year One	$ 196
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Two	99
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Three	54
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Four	33
2027	35
Thereafter	0
Total	417
Natural Gas Supply
Unrecorded Unconditional Purchase Obligation, to be Paid, Year One	504
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Two	6
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Three	0
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Four	0
2027	0
Thereafter	0
Total	510
Natural Gas Storage and Transportation
Unrecorded Unconditional Purchase Obligation, to be Paid, Year One	107
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Two	106
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Three	108
Unrecorded Unconditional Purchase Obligation, to be Paid, Year Four	110
2027	110
Thereafter	475
Total	$ 1,016