Benefit Plans and Other Postretirement Benefits (Details) (USD $)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2013	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Pension Benefits
Components of Net Periodic Benefit Cost [Abstract]
Service cost		$ 1,420,000	$ 1,150,000	$ 2,841,000	$ 2,284,000
Interest cost		1,731,000	1,925,000	3,462,000	3,835,000
Expected return on plan assets		(2,498,000)	(2,634,000)	(4,997,000)	(5,245,000)
Amortization of transition obligation		0	0	0	0
Amortization of prior service cost (credit)		104,000	443,000	208,000	886,000
Amortization of net loss		1,981,000	1,487,000	3,962,000	2,922,000
Net benefit cost recognized for financial reporting		2,738,000	2,371,000	5,476,000	4,682,000
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	12,000	10,000
Interest cost		190,000	274,000	380,000	538,000
Expected return on plan assets		(10,000)	(12,000)	(21,000)	(25,000)
Amortization of transition obligation		0	43,000	0	86,000
Amortization of prior service cost (credit)		(88,000)	(3,000)	(176,000)	(7,000)
Amortization of net loss		241,000	128,000	482,000	242,000
Net benefit cost recognized for financial reporting		339,000	435,000	677,000	844,000
Xcel Energy Inc. | Pension Benefits
Components of Net Periodic Benefit Cost [Abstract]
Total contributions to Xcel Energy's pension plans during the period	$ 191,500,000
Number of Xcel Energy's pension plans to which contributions were made	4