Letters of Credit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Line of Credit Facility [Line Items]
Amount outstanding at period end	$ 60	$ 47
Long-term Debt, Current Maturities	$ (200)	0
Series Due May 1, 2051 [Member] | First Mortgage Bonds
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	3.05%
Debt Instrument, Face Amount	$ 100	100
Series Due May 1, 2051 2 | First Mortgage Bonds
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.82%
Debt Instrument, Face Amount	$ 100	100
Letter of Credit
Line of Credit Facility [Line Items]
Amount outstanding at period end	$ 0	0
Letter of Credit
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Period	1 year
Credit Facilities
Line of Credit Facility [Line Items]
Long-term Line of Credit	$ 0	$ 0