Employee Benefit Plans - Schedule of Weighted-Average Assumptions Used in Calculating Net Periodic Benefit Costs (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Pension Benefits
Assumptions for benefit obligations at measurement date:
Discount rate	4.20%	3.90%
Assumptions for periodic benefit cost for the year ended:
Discount rate	3.90%	4.60%
Expected long-term rate of return on plan assets	6.50%	6.50%
Other Postretirement Benefits
Assumptions for benefit obligations at measurement date:
Discount rate	4.20%	3.90%
Assumptions for periodic benefit cost for the year ended:
Discount rate	3.90%	4.60%
Expected long-term rate of return on plan assets	6.50%	6.50%
Assumptions for year-end valuations:
Health care cost trend rate assumed for next year, pre-age 65	7.00%	7.30%
Health care cost trend rate assumed for next year, post-age 65	7.10%	7.40%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50%	4.50%
Year the rate reaches the ultimate trend rate	2037	2028