Schedule I, Condensed Financial Statements of Xcel Energy Inc, Condensed Statements of Income (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income
Equity earnings of subsidiaries									$ 34,390	$ 30,151	$ 30,020
Expenses and other deductions
Other income									(5,400)	(5,296)	(2,972)
Interest charges and financing costs									595,282	566,608	575,199
Income before income taxes									1,527,204	1,545,121	1,432,210
Income tax benefit									542,719	523,815	483,976
Net income	$ 209,025	$ 426,463	$ 196,931	$ 152,066	$ 196,339	$ 368,582	$ 195,164	$ 261,221	984,485	1,021,306	948,234
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Pension and retiree medical benefits, net of tax of $(2,777), $(2,528) and $5,897, respectively									(7,906)	(7,517)	1,408
Other Comprehensive Income (Loss), Net of Tax									(1,614)	(1,864)
Comprehensive Income, Net of Tax									$ 982,871	$ 1,019,442	$ 954,612
Weighted average common shares outstanding:
Basic (in shares)									507,768	503,847	496,073
Diluted (in shares)									508,168	504,117	496,532
Earnings per average common share:
Basic (in dollars per share)	$ 0.41	$ 0.84	$ 0.39	$ 0.30	$ 0.39	$ 0.73	$ 0.39	$ 0.52	$ 1.94	$ 2.03	$ 1.91
Diluted (in dollars per share)	0.41	0.84	0.39	0.30	0.39	0.73	0.39	0.52	1.94	2.03	1.91
Cash dividends declared per common share (in dollars per share)	$ 0.32	$ 0.32	$ 0.32	$ 0.32	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 1.28	$ 1.20	$ 1.11
Xcel Energy Inc.
Income
Equity earnings of subsidiaries									$ 1,045,788	$ 1,077,714	$ 1,018,783
Total income									1,045,788	1,077,714	1,018,783
Expenses and other deductions
Operating expenses									19,865	19,756	18,513
Other income									(1,242)	(537)	(206)
Interest charges and financing costs									91,801	84,830	102,914
Total expenses and other deductions									110,424	104,049	121,221
Income before income taxes									935,364	973,665	897,562
Income tax benefit									(49,121)	(47,641)	(50,672)
Net income									984,485	1,021,306	948,234
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Pension and retiree medical benefits, net of tax of $(2,777), $(2,528) and $5,897, respectively									(4,380)	(4,022)	4,714
Derivative instruments, net of tax of $1,764, $1,390 and $2,558, respectively									2,766	2,125	1,488
Other, net of tax of $0, $21 and $117, respectively									0	33	176
Other Comprehensive Income (Loss), Net of Tax									(1,614)	(1,864)	6,378
Comprehensive Income, Net of Tax									$ 982,871	$ 1,019,442	$ 954,612