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	$ 2,404,000	$ 2,130,000	$ 7,211,000	$ 6,390,000
Interest cost	4,477,000	4,900,000	13,431,000	14,700,000
Expected return on plan assets	(5,993,000)	(6,232,000)	(17,978,000)	(18,696,000)
Amortization of transition obligation	0	0	0	0
Amortization of prior service cost (credit)	218,000	360,000	653,000	1,079,000
Amortization of net loss (gain)	4,287,000	3,203,000	12,861,000	9,610,000
Net periodic benefit cost	5,393,000	4,361,000	16,178,000	13,083,000
Credits (costs) not recognized due to the effects of regulation	62,000	(1,076,000)	(1,330,000)	(3,226,000)
Net benefit cost recognized for financial reporting	5,455,000	3,285,000	14,848,000	9,857,000
Total contributions to Xcel Energy's pension plans during the period			22,000,000
Postretirement Health Care Benefits
Components of Net Periodic Benefit Cost [Abstract]
Service cost	342,000	314,000	1,026,000	944,000
Interest cost	588,000	707,000	1,764,000	2,123,000
Expected return on plan assets	(796,000)	(675,000)	(2,388,000)	(2,026,000)
Amortization of transition obligation	0	386,000	0	1,159,000
Amortization of prior service cost (credit)	(121,000)	(37,000)	(363,000)	(111,000)
Amortization of net loss (gain)	(2,000)	314,000	(5,000)	942,000
Net periodic benefit cost	11,000	1,009,000	34,000	3,031,000
Credits (costs) not recognized due to the effects of regulation	0	0	0	0
Net benefit cost recognized for financial reporting	11,000	1,009,000	34,000	3,031,000
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