Share-Based Compensation Plans (Compensation Expense for Share-Based Arrangements and Tax Impacts) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 20.0	$ 19.2	$ 45.8	$ 42.1
Tax Benefits Recognized	7.6	7.2	17.3	15.8
Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	14.7	13.4	30.0	26.9
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	0.8	1.7	7.2	7.7
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 4.5	$ 4.1	$ 8.6	$ 7.5