Borrowings and Other Financing Instruments, Letters of Credit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Line of Credit Facility [Line Items]
Amount outstanding at period end	$ 294	$ 147
Letter of Credit
Line of Credit Facility [Line Items]
Amount outstanding at period end	$ 27	$ 8
Letter of Credit
Line of Credit Facility [Line Items]
Line of Credit Facility, Expiration Period	1 year