Future year net unrealized gain/loss recorded at balance sheet date expected to become realized (Details) $ in Millions	Dec. 31, 2023 USD ($)
Electricity [Member]
Commodity contracts:
Other Commitment, Due in Next Twelve Months	$ 39
Other Commitment, Due in Second Year	18
Other Commitment, Due in Third Year	2
Other Commitment, Due in Fourth Year	(2)
Other Commitment, Due in Fifth Year	(1)
Other Commitment, Due after Fifth Year	(1)
Total	51
Natural Gas [Member]
Commodity contracts:
Other Commitment, Due in Next Twelve Months	104
Other Commitment, Due in Second Year	36
Other Commitment, Due in Third Year	14
Other Commitment, Due in Fourth Year	(1)
Other Commitment, Due in Fifth Year	0
Other Commitment, Due after Fifth Year	0
Total	155
Unrealized Gain Loss On Derivatives [Member]
Commodity contracts:
Other Commitment, Due in Next Twelve Months	143
Other Commitment, Due in Second Year	54
Other Commitment, Due in Third Year	12
Other Commitment, Due in Fourth Year	(1)
Other Commitment, Due in Fifth Year	(1)
Other Commitment, Due after Fifth Year	(1)
Total	$ 206