Commitments and Contingencies, Legal Contingencies (Details) (USD $)	Jun. 30, 2013 Native Village of Kivalina vs. Xcel Energy Inc. et al. [Member]	Feb. 29, 2008 Native Village of Kivalina vs. Xcel Energy Inc. et al. [Member] Counterparty	Jun. 30, 2013 Comer vs. Xcel Energy Inc. et al. [Member]	May 31, 2011 Comer vs. Xcel Energy Inc. et al. [Member] Counterparty
Legal Contingencies [Abstract]
Number of other entities against which the native village of Kivalina has filed a lawsuit		23
Accrual for legal contingency	$ 0		$ 0
Minimum number of utility, oil, chemical and coal companies against which a lawsuit was filed in U.S. District Court in Mississippi				85