Borrowings and Other Financing Instruments Long-Term Borrowings (Details) - Bonds [Member] - USD ($)	Jun. 15, 2020	May 26, 2020	May 18, 2020	May 15, 2020	Apr. 01, 2020
XCEL ENERGY INC [Member] | Series due June 1, 2030 [Domain]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 600,000,000
Debt Instrument, Interest Rate, Stated Percentage					3.40%
XCEL ENERGY INC [Member] | Series Due October 15, 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 500,000,000
Debt Instrument, Interest Rate, Stated Percentage	0.50%
PSCo [Member] | Series Due June 1, 2030
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 375,000,000
Debt Instrument, Interest Rate, Stated Percentage				2.70%
PSCo [Member] | Series due Jan. 15, 2031 [Domain]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 375,000,000
Debt Instrument, Interest Rate, Stated Percentage				1.90%
SPS | Series Due 2050 [Domain]
Debt Instrument [Line Items]
Debt Instrument, Face Amount			$ 350,000,000
Debt Instrument, Interest Rate, Stated Percentage			3.15%
NSP-Wisconsin | Series Due May 1, 2051 [Domain]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 100,000,000
Debt Instrument, Interest Rate, Stated Percentage		3.05%
NSP Minnesota [Member] | Series Due June 1, 2051 [Domain]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 700,000,000
Debt Instrument, Interest Rate, Stated Percentage	2.60%