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	$ 6,302,000	$ 5,679,000	$ 18,905,000	$ 17,039,000
Interest cost	11,540,000	12,776,000	34,620,000	38,329,000
Expected return on plan assets	(15,955,000)	(16,326,000)	(47,865,000)	(48,977,000)
Amortization of transition obligation	0	0	0	0
Amortization of prior service (credit) cost	(266,000)	57,000	(798,000)	171,000
Amortization of net loss	10,855,000	8,552,000	32,563,000	25,652,000
Net periodic benefit cost	12,476,000	10,738,000	37,425,000	32,214,000
Additional cost recognized due to the effects of regulation	0	0	0	0
Net benefit cost recognized for financial reporting	12,476,000	10,738,000	37,425,000	32,214,000
Total contributions to Xcel Energy's pension plans during the period			44,400,000
Postretirement Health Care Benefits
Components of Net Periodic Benefit Cost [Abstract]
Service cost	803,000	706,000	2,409,000	2,119,000
Interest cost	5,934,000	6,131,000	17,802,000	18,395,000
Expected return on plan assets	(7,307,000)	(6,264,000)	(21,921,000)	(18,792,000)
Amortization of transition obligation	196,000	2,751,000	588,000	8,253,000
Amortization of prior service (credit) cost	(1,229,000)	(1,288,000)	(3,687,000)	(3,863,000)
Amortization of net loss	3,490,000	2,734,000	10,469,000	8,198,000
Net periodic benefit cost	1,887,000	4,770,000	5,660,000	14,310,000
Additional cost recognized due to the effects of regulation	0	972,000	0	2,918,000
Net benefit cost recognized for financial reporting	1,887,000	5,742,000	5,660,000	17,228,000
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