Income Taxes (Details) (USD $)			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 State Jurisdiction [Member]	Sep. 30, 2012 Xcel Energy Inc. [Member] Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Year(s) no longer subject to audit as statute of limitations has expired				2008
Earliest year subject to examination			2008	2009
Year(s) under examination			None	2010 and 2011
Unrecognized Tax Benefits [Abstract]
Unrecognized tax benefit - Permanent tax positions	$ 100,000	$ 0
Unrecognized tax benefit - Temporary tax positions	1,200,000	1,500,000
Total unrecognized tax benefit	1,300,000	1,500,000
NOL carryforwards	(900,000)	(1,100,000)
Amounts accrued for penalties related to unrecognized tax benefits	$ 0	$ 0