Pension and Other Postretirement Benefit Plans - Information for Pension Plans with an Accumulated Benefit Obligation in Excess of Plan Assets (Details) (Pension [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Projected Benefit Obligation	$ 714.5	$ 622.8
Accumulated Benefit Obligation	661.4	577.6
Fair Value of Plan Assets	$ 544.2	$ 501.6