Accumulated Other Comprehensive Income (Loss) (Details 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) [Line Items]
Other Comprehensive Income (Loss)	$ 0.0	$ (13.2)	$ 46.0	$ 25.9
Net Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(11.0)	(9.0)	39.7	51.9
Tax Effect	4.0	3.3	(15.0)	(19.6)
Other Comprehensive Income (Loss)	(7.0)	(5.7)	24.7	32.3
Net Unrealized Gains (Losses) on Securities Available for Sale | Noncredit-Related Unrealized Losses on Securities OTTI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	0.0	5.5	0.0	3.7
Tax Effect	0.0	(2.1)	0.0	(1.4)
Other Comprehensive Income (Loss)	0.0	3.4	0.0	2.3
Net Unrealized Gains (Losses) on Securities Available for Sale | Other Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(11.0)	(14.2)	39.4	48.8
Tax Effect	4.0	5.4	(14.9)	(18.2)
Other Comprehensive Income (Loss)	(7.0)	(8.8)	24.5	30.6
Net Unrealized Gains (Losses) on Securities Available for Sale | Reclassification Adjustment for (Gains) Losses Included in Net Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	0.0	(0.3)	0.3	(0.6)
Tax Effect	0.0	0.0	(0.1)	0.0
Other Comprehensive Income (Loss)	0.0	(0.3)	0.2	(0.6)
Net Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	6.5	(11.3)	8.9	(9.8)
Tax Effect	(3.3)	3.9	(3.6)	3.4
Other Comprehensive Income (Loss)	3.2	(7.4)	5.3	(6.4)
Net Unrealized Gains (Losses) on Cash Flow Hedges | Reclassification Adjustment for (Gains) Losses Included in Net Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	0.1	(3.7)	2.4	(3.3)
Tax Effect	0.0	1.4	(0.9)	1.2
Other Comprehensive Income (Loss)	0.1	(2.3)	1.5	(2.1)
Net Unrealized Gains (Losses) on Cash Flow Hedges | Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	6.4	(7.6)	6.5	(6.5)
Tax Effect	(3.3)	2.5	(2.7)	2.2
Other Comprehensive Income (Loss)	3.1	(5.1)	3.8	(4.3)
Net Foreign Currency Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	16.2	35.4	15.1	13.5
Tax Effect	(18.5)	(39.0)	(17.5)	(24.0)
Other Comprehensive Income (Loss)	(2.3)	(3.6)	(2.4)	(10.5)
Net Foreign Currency Adjustments | Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(32.6)	(77.1)	(69.7)	(57.2)
Tax Effect	0.0	3.6	14.6	3.0
Other Comprehensive Income (Loss)	(32.6)	(73.5)	(55.1)	(54.2)
Net Foreign Currency Adjustments | Long-Term Intra-Entity Foreign Currency Transaction Gains (Losses)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	(0.3)	(7.4)	0.2	(9.0)
Tax Effect	0.1	3.0	(0.1)	3.0
Other Comprehensive Income (Loss)	(0.2)	(4.4)	0.1	(6.0)
Net Foreign Currency Adjustments | Net Investment Hedge Gains (Losses)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	49.1	119.9	84.6	79.7
Tax Effect	(18.6)	(45.6)	(32.0)	(30.0)
Other Comprehensive Income (Loss)	30.5	74.3	52.6	49.7
Net Pension and Other Postretirement Benefit Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	9.6	6.5	28.8	19.0
Tax Effect	(3.5)	(3.0)	(10.4)	(8.5)
Other Comprehensive Income (Loss)	6.1	3.5	18.4	10.5
Net Pension and Other Postretirement Benefit Adjustments | Reclassification Adjustment for (Gains) Losses Included in Net Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Before Tax	9.6	6.5	28.8	19.0
Tax Effect	(3.5)	(3.0)	(10.4)	(8.5)
Other Comprehensive Income (Loss)	$ 6.1	$ 3.5	$ 18.4	$ 10.5