Regulatory Matters (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended						3 Months Ended
	Nov. 19, 2013	Oct. 23, 2013	Dec. 21, 2012	Jan. 02, 2014 Retail Customers [Member]	Jan. 02, 2014 Matanuska Electric Association, Inc. [Member]	Jan. 02, 2014 Seward [Member]	Mar. 31, 2014 Forecast [Member]
Regulatory Matters [Line Items]
Proposed increase (decrease) in base rate revenue	$ 16.0	$ (0.2)	$ 30.0
Proposed percentage increase decrease in base rate revenue	12.50%	(0.10%)	26.00%
Base rate revenue for proposed rate increase (decrease)	127.4	143.0	115.0
Increase (decrease) in system demand and energy rate				6.00%	8.00%	5.00%
Interruptible storage service agreement costs							$ 0.4