Fair Value of Financial Assets and Liabilities, Impact of Derivative Activity (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Financial Impact of Qualifying Fair Value Hedges on Earnings [Abstract]
Derivative instruments designated as fair value hedges	$ 0	$ 0
Gain (Loss) on Fair Value Hedges Recognized in Earnings	0	0
Other Derivative Instruments [Member] | Natural Gas Commodity Contract [Member]
Impact of Derivative Activity on Accumulated Other Comprehensive Income (Loss) Regulatory Assets and Liabilities and Income [Abstract]
Pre-tax fair value gains recognized during the period in regulatory assets and liabilities	800,000
Pre-tax gains reclassified into income during the period from regulatory assets and liabilities	$ 500,000