Compensation Expense for Share-Based Payment Arrangements and Associated Tax Impacts (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	$ 18.0	$ 17.9	$ 61.3	$ 56.7
Tax Benefits Recognized	6.8	6.8	23.0	21.3
Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	12.7	12.1	41.7	36.4
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	2.2	3.7	10.7	14.9
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-Based Compensation Expense	$ 3.1	$ 2.1	$ 8.9	$ 5.4