Borrowings and Other Financing Instruments - Borrowings and Other Financing Instruments, Long-Term Borrowings and Other Financing Instruments (Details) $ in Millions	9 Months Ended
	Sep. 30, 2023 USD ($)
Debt Instrument [Line Items]
Term of letters of credit (in years)	1 year
Bonds [Member] | Series Due April 1, 2053
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 850
Debt Instrument, Interest Rate, Stated Percentage	5.25%