Components of Income Before Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Domestic	$ 1,190.7	$ 1,581.6	$ 1,267.3
Foreign	(60.3)	755.5	750.3
Income before income taxes	$ 1,130.4	$ 2,337.1	$ 2,017.6