Accumulated Other Comprehensive Loss Changes in Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (71.0)	$ (119.1)	$ (150.4)
Other comprehensive income (loss) before Reclassifications	(94.7)	40.1	20.6
Amounts reclassified from accumulated other comprehensive loss	1.4	8.0	10.7
Other comprehensive (loss) income	(93.3)	48.1	31.3
Ending balance	(164.3)	(71.0)	(119.1)
Cash flow hedges gain (loss):
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(0.2)	(0.5)	(0.2)
Other comprehensive income (loss) before Reclassifications	0.9	0.6	(0.4)
Amounts reclassified from accumulated other comprehensive loss	(0.7)	(0.3)	0.1
Other comprehensive (loss) income	0.2	0.3	(0.3)
Ending balance	0	(0.2)	(0.5)
Unrealized Gain (Loss) on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	0.4	0.7	1.0
Other comprehensive income (loss) before Reclassifications	(0.1)	(0.3)	(0.3)
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Other comprehensive (loss) income	(0.1)	(0.3)	(0.3)
Ending balance	0.3	0.4	0.7
Amortization of defined benefit pension and post retirement benefit items:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(67.0)	(130.1)	(153.7)
Other comprehensive income (loss) before Reclassifications	(59.8)	54.8	13.0
Amounts reclassified from accumulated other comprehensive loss	2.1	8.3	10.6
Other comprehensive (loss) income	(57.7)	63.1	23.6
Ending balance	(124.7)	(67.0)	(130.1)
Cumulative Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(4.2)	10.8	2.5
Other comprehensive income (loss) before Reclassifications	(35.7)	(15.0)	8.3
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Other comprehensive (loss) income	(35.7)	(15.0)	8.3
Ending balance	$ (39.9)	$ (4.2)	$ 10.8