Accumulated Other Comprehensive Income (Loss) (Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			$ (319.7)	$ (244.3)
Net Change	$ 0.0	$ (13.2)	46.0	25.9
Ending balance	(273.7)	(218.4)	(273.7)	(218.4)
Net Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			27.6	6.0
Net Change			24.7	32.3
Ending balance	52.3	38.3	52.3	38.3
Net Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			(4.7)	2.9
Net Change			5.3	(6.4)
Ending balance	0.6	(3.5)	0.6	(3.5)
Net Foreign Currency Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			(1.7)	7.1
Net Change			(2.4)	(10.5)
Ending balance	(4.1)	(3.4)	(4.1)	(3.4)
Net Pension and Other Postretirement Benefit Adjustments
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			(340.9)	(260.3)
Net Change			18.4	10.5
Ending balance	$ (322.5)	$ (249.8)	$ (322.5)	$ (249.8)