Benefit Plans and Other Postretirement Benefits (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Pension Benefits
Components of Net Periodic Benefit Cost [Abstract]
Service cost	$ 1,421,000	$ 1,142,000	$ 4,262,000	$ 3,426,000
Interest cost	1,731,000	1,918,000	5,193,000	5,753,000
Expected return on plan assets	(2,499,000)	(2,622,000)	(7,496,000)	(7,867,000)
Amortization of transition obligation	0	0	0	0
Amortization of prior service cost (credit)	104,000	442,000	312,000	1,328,000
Amortization of net loss	1,981,000	1,460,000	5,943,000	4,382,000
Net benefit cost recognized for financial reporting	2,738,000	2,340,000	8,214,000	7,022,000
Total contributions to Xcel Energy's pension plans during the period			11,300,000
Postretirement Health Care Benefits
Components of Net Periodic Benefit Cost [Abstract]
Service cost	6,000	5,000	18,000	15,000
Interest cost	190,000	268,000	570,000	806,000
Expected return on plan assets	(11,000)	(13,000)	(32,000)	(38,000)
Amortization of transition obligation	0	42,000	0	128,000
Amortization of prior service cost (credit)	(88,000)	(4,000)	(264,000)	(11,000)
Amortization of net loss	241,000	123,000	723,000	365,000
Net benefit cost recognized for financial reporting	338,000	421,000	1,015,000	1,265,000
Xcel Energy Inc. | Pension Benefits
Components of Net Periodic Benefit Cost [Abstract]
Total contributions to Xcel Energy's pension plans during the period			$ 192,200,000
Number of Xcel Energy's pension plans to which contributions were made	4		4