Employee Benefit Plans and Other Postretirement Plans - Schedule of Effects of One-Percentage Point Change in Assumed Health Care Cost Trends on Postretirement Benefits (Details) (Postretirement Plans, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Postretirement Plans
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Effect on postretirement benefit obligation, 1-Percentage Point Increase	$ 1.3
Effect on net postretirement benefit cost, 1-Percentage Point Increase	0.1
Effect on postretirement benefit obligation, 1-Percentage Point Decrease	(1.1)
Effect on net postretirement benefit cost, 1-Percentage Point Decrease	$ (0.1)