Share-Based Compensation Plans - Total Compensation Expense for Share-Based Payment Arrangements to Employees (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share-Based Compensation Expense	$ 118.2	$ 125.2	$ 95.5
Tax Benefits Recognized	29.9	31.4	24.0
Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share-Based Compensation Expense	95.7	96.4	78.2
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share-Based Compensation Expense	$ 22.5	$ 28.8	$ 17.3