Other Comprehensive Income Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Other Comprehensive Income (Loss), before Tax
Other Comprehensive Income (Loss), before Tax	$ 1.4	$ 107.8
Unrealized gain on foreign currency cash flow hedges	0.2	0.0
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract]
Other Comprehensive Income (Loss), Tax	(0.5)	(40.9)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Other Comprehensive Income (Loss), Net of Tax	0.9	66.9
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Other Comprehensive Income (Loss), before Tax
Other Comprehensive Income (Loss), before Tax	1.1	107.6
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract]
Other Comprehensive Income (Loss), Tax	(0.4)	(40.8)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Other Comprehensive Income (Loss), Net of Tax	0.7	66.8
Amortization of net actuarial loss1
Other Comprehensive Income (Loss), before Tax
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0.1	0.3
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract]
Reclassification from AOCI, Current Period, Tax	0.0	(0.1)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.1	0.2
Amortization of prior service cost1
Other Comprehensive Income (Loss), before Tax
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	1.0	0.7
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract]
Reclassification from AOCI, Current Period, Tax	(0.4)	(0.3)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0.6	0.4
Removal of obligation relating to Union VEBA
Other Comprehensive Income (Loss), before Tax
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		106.6
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract]
Reclassification from AOCI, Current Period, Tax		(40.4)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		66.2
Reclassification of unrealized loss upon sale of available for sale securities2
Other Comprehensive Income (Loss), before Tax
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax		0.1
Other Comprehensive Income (Loss), before Tax		0.1
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract]
Reclassification from AOCI, Current Period, Tax		(0.1)
Other Comprehensive Income (Loss), Tax		(0.1)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0.0
Other Comprehensive Income (Loss), Net of Tax		0.0
Foreign currency translation gain
Other Comprehensive Income (Loss), before Tax
Other Comprehensive Income (Loss), before Tax		0.1
Unrealized gain on foreign currency cash flow hedges	0.2
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract]
Other Comprehensive Income (Loss), Tax		0.0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax	(0.1)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Other Comprehensive Income (Loss), Net of Tax		$ 0.1
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	0.1
Foreign currency translation gain | Canadian Pension Plan
Other Comprehensive Income (Loss), before Tax
Canadian Pension foreign currency translation changes (before tax)	0.1
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent, Parenthetical Disclosures [Abstract]
Canadian Pension foreign currency translation changes (tax)	0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Canadian Pension foreign currency translation changes (net of tax)	$ 0.1