Reconciliation of Total Provision for Income Taxes with Amount Computed at Statutory Federal Tax Rate (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Tax at Statutory Rate	$ 531.0	$ 512.7	$ 416.6
Tax Exempt Income	(7.2)	(4.8)	(4.9)
Leveraged Lease Adjustments	0.2	0.1	(3.4)
Foreign Tax Rate Differential	(50.9)	(44.2)	(44.1)
State Taxes, net	30.0	33.0	29.6
Other	(18.5)	(5.6)	(15.4)
Provision for Income Taxes	$ 484.6	$ 491.2	$ 378.4