Benefit Plans and Other Postretirement Benefits (Details) (USD $)	1 Months Ended	3 Months Ended
	Jan. 31, 2013	Mar. 31, 2013	Mar. 31, 2012
Pension Benefits [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost		$ 1,421,000	$ 1,134,000
Interest cost		1,731,000	1,910,000
Expected return on plan assets		(2,499,000)	(2,611,000)
Amortization of transition obligation		0	0
Amortization of prior service cost (credit)		104,000	443,000
Amortization of net loss		1,981,000	1,435,000
Net benefit cost recognized for financial reporting		2,738,000	2,311,000
Total contributions to Xcel Energy's pension plans during the period	11,300,000
Postretirement Health Care Benefits [Member]
Components of Net Periodic Benefit Cost [Abstract]
Service cost		6,000	5,000
Interest cost		190,000	264,000
Expected return on plan assets		(11,000)	(13,000)
Amortization of transition obligation		0	43,000
Amortization of prior service cost (credit)		(88,000)	(4,000)
Amortization of net loss		241,000	114,000
Net benefit cost recognized for financial reporting		338,000	409,000
Xcel Energy Inc. [Member] | Pension Benefits [Member]
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