Employees, Retirement and Incentive Plans Performance Units (Details) (Performance Shares [Member], USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 Certain Officers [Member]	Sep. 30, 2014 Executive Officer [Member]	Sep. 30, 2014 Long-term Incentive Plan [Member]	Sep. 30, 2014 Long-term Incentive Plan [Member] Certain Officers [Member]	Sep. 30, 2014 Long-term Incentive Plan [Member] Executive Officer [Member]	Sep. 30, 2014 Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years	3 years				3 years
Estimated Share Payouts, Outstanding Nonvested Performance Unit Awards Minimum			100.00%
Range of performance units earned, based on performance units granted, minimum (percent)					0.00%	50.00%
Range of Performance Units Earned, Based on Performance Units Granted, Maximum					200.00%	150.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding at January 1, 2014 (nonvested)	75,216
Vesting and transfer of full ownership to recipients	(17,938)
Outstanding at September 30, 2014 (nonvested)	57,278
Fair value of vested units transferred to recipients				$ 0.5
Total unrecognized compensation related to nonvested units				$ 0.9
Weighted average remaining contractual term (years)				1 year 3 months 20 days