Borrowings and Other Financing Instruments, Debt Redemption (Details) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended
	May 31, 2013	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Long-Term Borrowings and Other Financing Instruments [Abstract]
Interest charges	$ 6,300,000	$ 146,828,000	$ 151,921,000	$ 286,441,000	$ 303,751,000
Xcel Energy Inc. | Junior Subordinated Notes | Series Due Jan. 1, 2068
Long-Term Borrowings and Other Financing Instruments [Abstract]
Repurchased debt	$ 400,000,000
Interest rate, stated percentage (in hundredths)	7.60%