Long-Term Borrowings and Other Financing Instruments (Details) - USD ($) $ in Millions		Dec. 31, 2024	Dec. 31, 2023
Long-Term Borrowings and Other Financing Instruments
Unamortized discount		$ (4)	$ (3)
Unamortized debt expense		(15)	(11)
Long-term Debt		1,406	1,011
Long-term Debt, Current Maturities		$ 0	(200)
Series Due June 15, 2024 [Member] | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage		3.30%
Debt Instrument, Face Amount		$ 0	100
Series Due June 15, 2024 2 [Member] | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage		3.30%
Debt Instrument, Face Amount		$ 0	100
Series Due Sept. 1, 2038 [Member] | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage		6.375%
Debt Instrument, Face Amount		$ 200	200
Series Due Oct. 1, 2042 [Member] | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage		3.70%
Debt Instrument, Face Amount		$ 100	100
Series Due December 1, 2047 [Member] | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage		3.75%
Debt Instrument, Face Amount		$ 100	100
Series Due December 1, 2048 [Member] | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage		4.20%
Debt Instrument, Face Amount		$ 200	200
Series Due May 1, 2051 [Member] | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage		3.05%
Debt Instrument, Face Amount		$ 100	100
Series Due May 1, 2051 2 | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage		2.82%
Debt Instrument, Face Amount		$ 100	100
Series Due Sept. 15, 2052 | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage		4.86%
Debt Instrument, Face Amount		$ 100	100
Series Due June 15, 2053 | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage	[1]	5.30%
Debt Instrument, Face Amount	[1]	$ 125	125
Series Due June 15, 2054 | First Mortgage Bonds
Long-Term Borrowings and Other Financing Instruments
Debt Instrument, Interest Rate, Stated Percentage	[2]	5.65%
Debt Instrument, Face Amount	[2]	$ 400	$ 0

[1] 2023 financing.

[2] 2024 financing.