Employee Benefit Plans - Assumptions Used in Calculations (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assumptions used to determine benefit obligations at December 31:
Discount rate	4.00%	4.60%
Pension [Member]
Assumptions used to determine benefit obligations at December 31:
Discount rate	3.80%	4.60%	3.70%
Rate of compensation increase	4.50%	4.60%	4.60%
Assumptions used to determine net periodic benefit cost for years ended December 31:
Discount rate (pre-spin off)	4.60%	3.70%	4.20%
Discount rate (post-spin off)	4.04%	0.00%	0.00%
Expected long-term return on plan assets	8.50%	8.50%	8.50%
Rate of compensation increase	4.50%	4.60%	4.50%
Postretirement [Member]
Assumptions used to determine benefit obligations at December 31:
Discount rate	3.96%	4.60%	3.60%
Rate of compensation increase	4.50%	4.50%	4.50%
Assumptions used to determine net periodic benefit cost for years ended December 31:
Discount rate (pre-spin off)	4.60%	3.60%	4.10%
Discount rate (post-spin off)	4.00%	0.00%	0.00%
Expected long-term return on plan assets	0.00%	0.00%	0.00%
Rate of compensation increase	4.50%	4.50%	4.50%