Reclassifications Out of Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension and postretirement benefits
Amortization of prior service credit, net of tax	$ 0.2	$ 7.1	$ 3.9
Amortization of net actuarial gain, net of tax	11.8	30.0	6.1
Total reclassification, net of tax - pension and postretirement benefits	12.0	37.1	54.1
Cash flow hedges
Reclassification adjustment from AOCI on derivatives, net of tax	(0.2)	(0.8)	10.3
Total reclassification, net of tax	11.8	36.3	64.4
Commodity Contract [Member]
Cash flow hedges
Reclassification adjustment from AOCI on derivatives, net of tax	0.1	0.4	1.9
Foreign Currency Derivatives [Member]
Cash flow hedges
Reclassification adjustment from AOCI on derivatives, net of tax	(0.3)	(1.2)	8.4
Other Postretirement Benefit Plans, Defined Benefit [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Pension and postretirement benefits
Reclassification of prior service credit and net actuarial gain due to curtailment, net of tax	$ 0	$ 0	$ 44.1