Schedule I, Condensed Financial Statements of Xcel Energy Inc, Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net cash provided by (used in) operating activities	$ 3,025,839	$ 2,648,192	$ 2,584,036
Investing activities
Payments for (Proceeds from) Other Investing Activities	(145)	(3,695)	(4,766)
Net cash provided by (used in) investing activities	(3,622,774)	(3,117,251)	(3,213,384)
Financing activities
Proceeds from (repayment of) short-term borrowings, net	(173,500)	260,500	157,000
Proceeds from issuance of long-term debt	1,626,212	837,584	1,431,895
Repayment of long-term debt	(250,882)	(275,948)	(652,451)
Proceeds from issuance of common stock	7,011	180,798	231,767
Dividends paid	(606,574)	(561,411)	(514,042)
Net cash provided by (used in) financing activities	602,267	441,523	654,169
Net change in cash and cash equivalents	5,332	(27,536)	24,821
Cash and cash equivalents at beginning of period	79,608	107,144	82,323
Cash and cash equivalents at end of period	84,940	79,608	107,144
Xcel Energy Inc.
Operating activities
Net cash provided by (used in) operating activities	704,823	842,832	545,177
Investing activities
Capital contributions to subsidiaries	(820,382)	(422,459)	(535,653)
Investments in the utility money pool	(971,200)	(1,148,000)	(1,778,000)
Return of investments in the utility money pool	987,200	1,204,000	1,706,000
Payments for (Proceeds from) Other Investing Activities	(16)	0	0
Net cash provided by (used in) investing activities	(804,398)	(366,459)	(607,653)
Financing activities
Proceeds from (repayment of) short-term borrowings, net	203,500	(95,500)	297,000
Proceeds from issuance of long-term debt	495,449	0	447,595
Repayment of long-term debt	0	0	(400,000)
Proceeds from issuance of common stock	7,011	180,798	231,767
Dividends paid	(606,574)	(561,411)	(514,042)
Net cash provided by (used in) financing activities	99,386	(476,113)	62,320
Net change in cash and cash equivalents	(189)	260	(156)
Cash and cash equivalents at beginning of period	706	446	602
Cash and cash equivalents at end of period	$ 517	$ 706	$ 446