Borrowings and Other Financing Instruments Long-Term Borrowings (Details) - Bonds [Member] $ in Millions	Sep. 30, 2023 USD ($)
PSCo | Series Due April 1, 2053
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 850
Debt Instrument, Interest Rate, Stated Percentage	5.25%
SPS | Series Due September 15, 2053
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 100
Debt Instrument, Interest Rate, Stated Percentage	6.00%
NSP-Wisconsin | Series Due June 15, 2053
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 125
Debt Instrument, Interest Rate, Stated Percentage	5.30%
NSP-Minnesota | Series Due May 15, 2053
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 800
Debt Instrument, Interest Rate, Stated Percentage	5.10%
XCEL ENERGY INC [Member] | Series Due August 15, 2033
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 800
Debt Instrument, Interest Rate, Stated Percentage	5.45%