Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	$ (32.4)	$ (75.9)
Other comprehensive (loss) income before reclassifications	(89.9)	34.5
Amounts reclassified from AOCI	3.1	9.0
Other comprehensive (loss) income, net of tax	(86.8)	43.5	(4.4)
Balance, ending	(119.2)	(32.4)	(75.9)
Losses on Cash Flow Hedges [Member]
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	(6.0)	(9.0)
Other comprehensive (loss) income before reclassifications	(0.1)	(1.8)
Amounts reclassified from AOCI	1.8	4.8
Other comprehensive (loss) income, net of tax	1.7	3.0
Balance, ending	(4.3)	(6.0)
Unrealized Gains on Investment Securities [Member]
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	4.3	0.8
Other comprehensive (loss) income before reclassifications	0.4	3.5
Amounts reclassified from AOCI	0	0
Other comprehensive (loss) income, net of tax	0.4	3.5
Balance, ending	4.7	4.3
Defined Benefit Pension and Other Postretirement Plans [Member]
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	(47.0)	(84.9)
Other comprehensive (loss) income before reclassifications	(18.9)	33.7
Amounts reclassified from AOCI	1.3	4.2
Other comprehensive (loss) income, net of tax	(17.6)	37.9
Balance, ending	(64.6)	(47.0)
Foreign Currency Translation [Member]
Changes in the Components of Accumulated Other Comprehensive Loss, Net of Tax [Roll Forward]
Balance, beginning	16.3	17.2
Other comprehensive (loss) income before reclassifications	(71.3)	(0.9)
Amounts reclassified from AOCI	0	0
Other comprehensive (loss) income, net of tax	(71.3)	(0.9)
Balance, ending	$ (55.0)	$ 16.3