Schedule I, Condensed Financial Statements of Xcel Energy Inc, Notes to Condensed Financial Statements (Details) - Xcel Energy Inc. - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts Receivable	$ 363,617,000	$ 363,617,000	$ 315,866,000
Accounts Payable	0	0	0
Dividends [Abstract]
Cash dividends paid to Xcel Energy by subsidiaries		923,000,000	784,000,000	$ 857,000,000
Money Pool [Abstract]
Lending limit	250,000,000	250,000,000	250,000,000	250,000,000
Loan outstanding at period end	0	0	0	16,000,000
Average loan outstanding	77,000,000	66,000,000	27,000,000	25,000,000
Maximum loan outstanding	$ 211,000,000	$ 211,000,000	$ 141,000,000	$ 250,000,000
Weighted average interest rate, computed on a daily basis (percentage)	0.80%	0.69%	0.42%	0.22%
Weighted average interest rate at period end (percentage)				0.45%
Money pool interest income	$ 200,000	$ 500,000	$ 100,000	$ 100,000
NSP-Minnesota
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts Receivable	58,642,000	58,642,000	58,952,000
Accounts Payable	0	0	0
NSP-Wisconsin
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts Receivable	13,969,000	13,969,000	17,391,000
Accounts Payable	0	0	0
PSCo
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts Receivable	131,680,000	131,680,000	114,524,000
Accounts Payable	0	0	0
SPS
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts Receivable	30,897,000	30,897,000	21,357,000
Accounts Payable	0	0	0
Xcel Energy Services Inc.
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts Receivable	92,809,000	92,809,000	73,054,000
Accounts Payable	0	0	0
Xcel Energy Ventures Inc.
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts Receivable	17,060,000	17,060,000	20,003,000
Accounts Payable	0	0	0
Other Subsidiaries
Accounts Receivable and Payable with Affiliates [Abstract]
Accounts Receivable	18,560,000	18,560,000	10,585,000
Accounts Payable	$ 0	$ 0	$ 0