Borrowings and Other Financing Instruments Long-Term Borrowings (Details) - Bonds [Member] $ in Millions	Jun. 30, 2024 USD ($)
PSCo | Series Due May 15, 2034
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 450
Debt Instrument, Interest Rate, Stated Percentage	5.35%
PSCo | Series Due May 15, 2054
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 750
Debt Instrument, Interest Rate, Stated Percentage	5.75%
SPS | Series Due June 1, 2054
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 600
Debt Instrument, Interest Rate, Stated Percentage	6.00%
NSP-Wisconsin | Series Due June 15, 2054
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 400
Debt Instrument, Interest Rate, Stated Percentage	5.65%
NSP-Minnesota | Series Due March 15, 2054
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 700
Debt Instrument, Interest Rate, Stated Percentage	5.40%
XCEL ENERGY INC [Member] | Series Due March 15, 2034
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 800
Debt Instrument, Interest Rate, Stated Percentage	5.50%