Borrowings and Other Financing Instruments, Long-Term Borrowings (Details) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount (Premium), Net		$ (41)	$ (37)
Unamortized Debt Issuance Expense		(59)	(53)
Long-term Debt, Current Maturities		0	(250)
Long-term Debt		7,450	6,610
Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months		0
Long-term Debt, Maturities, Repayments of Principal in Year Two		250
Long-term Debt, Maturities, Repayments of Principal in Year Three		0
Long-term Debt, Maturities, Repayments of Principal in Year Four		0
Long-term Debt, Maturities, Repayments of Principal in Year Five		350
Deferred Finance Costs, Noncurrent, Net		59	53
Long-term Debt		7,450	6,610
First Mortgage Bonds | Series Due March 15, 2023 [Member]
Debt Instrument [Line Items]
Face amount		$ 0	250
Interest rate, stated percentage (in hundredths)		2.50%
First Mortgage Bonds | Series Due May 15, 2025 [Member]
Debt Instrument [Line Items]
Face amount		$ 250	250
Interest rate, stated percentage (in hundredths)		2.90%
First Mortgage Bonds | Series Due June 15, 2028 [Member]
Debt Instrument [Line Items]
Face amount		$ 350	350
Interest rate, stated percentage (in hundredths)		3.70%
First Mortgage Bonds | Series Due Jan. 15, 2031 [Member]
Debt Instrument [Line Items]
Face amount		$ 375	375
Interest rate, stated percentage (in hundredths)		1.90%
First Mortgage Bonds | Series Due Sept. 1, 2037 [Member]
Debt Instrument [Line Items]
Face amount		$ 350	350
Interest rate, stated percentage (in hundredths)		6.25%
First Mortgage Bonds | Series Due Aug. 1, 2038 [Member]
Debt Instrument [Line Items]
Face amount		$ 300	300
Interest rate, stated percentage (in hundredths)		6.50%
First Mortgage Bonds | Series Due Aug. 15, 2041 [Member]
Debt Instrument [Line Items]
Face amount		$ 250	250
Interest rate, stated percentage (in hundredths)		4.75%
First Mortgage Bonds | Series Due Sept. 15, 2042 [Member]
Debt Instrument [Line Items]
Face amount		$ 500	500
Interest rate, stated percentage (in hundredths)		3.60%
First Mortgage Bonds | Series Due March 15, 2043 [Member]
Debt Instrument [Line Items]
Face amount		$ 250	250
Interest rate, stated percentage (in hundredths)		3.95%
First Mortgage Bonds | Series Due March 15, 2044 [Member]
Debt Instrument [Line Items]
Face amount		$ 300	300
Interest rate, stated percentage (in hundredths)		4.30%
First Mortgage Bonds | Series Due June 15, 2046 [Member]
Debt Instrument [Line Items]
Face amount		$ 250	250
Interest rate, stated percentage (in hundredths)		3.55%
First Mortgage Bonds | Series Due June 15, 2047 [Member]
Debt Instrument [Line Items]
Face amount		$ 400	400
Interest rate, stated percentage (in hundredths)		3.80%
First Mortgage Bonds | Series Due June 15, 2048 [Member]
Debt Instrument [Line Items]
Face amount		$ 350	350
Interest rate, stated percentage (in hundredths)		4.10%
First Mortgage Bonds | Series Due September 15, 2049 [Domain]
Debt Instrument [Line Items]
Face amount		$ 400	400
Interest rate, stated percentage (in hundredths)		4.05%
First Mortgage Bonds | Series Due March 1, 2050 [Domain]
Debt Instrument [Line Items]
Face amount		$ 550	550
Interest rate, stated percentage (in hundredths)		3.20%
First Mortgage Bonds | Series Due Jan. 15, 2051 [Member]
Debt Instrument [Line Items]
Face amount		$ 375	375
Interest rate, stated percentage (in hundredths)		2.70%
First Mortgage Bonds | Series Due June 15, 2031
Debt Instrument [Line Items]
Face amount		$ 750	750
Interest rate, stated percentage (in hundredths)		1.875%
First Mortgage Bonds | Series Due June 1, 2032 2
Debt Instrument [Line Items]
Face amount	[1]	$ 300	300
Interest rate, stated percentage (in hundredths)	[1]	4.10%
First Mortgage Bonds | Series Due June 1, 2052
Debt Instrument [Line Items]
Face amount	[1]	$ 400	400
Interest rate, stated percentage (in hundredths)	[1]	4.50%
First Mortgage Bonds | Series Due April 1, 2053
Debt Instrument [Line Items]
Face amount	[2]	$ 850	$ 0
Interest rate, stated percentage (in hundredths)	[2]	5.25%

[1] 2022 financing

[2] 2023 financing.