Borrowings and Other Financing Instruments, Long-Term Borrowings and Other Financing Instruments (Details) (USD $)	1 Months Ended
	Mar. 31, 2013 PSCo First Mortgage Bonds Series Due March 15, 2023	Mar. 31, 2013 PSCo First Mortgage Bonds Series Due March 15, 2043	May 31, 2013 NSP-Minnesota First Mortgage Bonds Series Due May 15, 2023	May 31, 2013 Xcel Energy Inc. Unsecured Senior Notes Series Due May 9, 2016
Long-Term Borrowings and Other Financing Instruments [Abstract]
Face amount	$ 250,000,000	$ 250,000,000	$ 400,000,000	$ 450,000,000
Interest rate, stated percentage (in hundredths)	2.50%	3.95%	2.60%	0.75%
Maturity date	Mar. 15, 2023	Mar. 15, 2043	May 15, 2023	May 09, 2016