Pension and Other Post-Retirement Benefit Plans - Schedule of Entity's Asset Allocation (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Components of net periodic benefit cost:
Percentage of Plan Assets	100.00%	100.00%
Domestic broadly diversified equity securities
Components of net periodic benefit cost:
Percentage of Plan Assets	0.00%	26.00%
Fixed income securities
Components of net periodic benefit cost:
Percentage of Plan Assets	99.00%	63.00%
International broadly diversified equity securities
Components of net periodic benefit cost:
Percentage of Plan Assets	0.00%	8.00%
Target Allocation 2016	0.00%
Cash and equivalent investments
Components of net periodic benefit cost:
Percentage of Plan Assets	1.00%	3.00%
Minimum | Domestic broadly diversified equity securities
Components of net periodic benefit cost:
Target Allocation 2016	0.00%
Minimum | Fixed income securities
Components of net periodic benefit cost:
Target Allocation 2016	80.00%
Minimum | Cash and equivalent investments
Components of net periodic benefit cost:
Target Allocation 2016	0.00%
Maximum | Domestic broadly diversified equity securities
Components of net periodic benefit cost:
Target Allocation 2016	10.00%
Maximum | Fixed income securities
Components of net periodic benefit cost:
Target Allocation 2016	100.00%
Maximum | Cash and equivalent investments
Components of net periodic benefit cost:
Target Allocation 2016	20.00%