Employee Benefit Plans - Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates (Details) (Other Post-retirement Benefits [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Other Post-retirement Benefits [Member]
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Effect of one percentage point increase on total of service and interest cost components of net periodic post-retirement health care benefit cost	$ 0
Effect of one percentage point decrease on total of service and interest cost components of net periodic post-retirement health care benefit cost	0
Effect of one percentage point increase on the health care component of the accumulated post-retirement benefit obligation	0.4
Effect of one percentage point decrease on the health care component of the accumulated post-retirement benefit obligation	$ (0.3)