Income Taxes - Components of Earnings Before Taxes and Income Taxes Paid (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
United States operations	$ (114.0)	$ (251.8)	$ (246.2)
Foreign operations	578.6	651.4	399.4
Total	464.6	399.6	153.2
Current:
Federal	438.5	134.2	55.8
State	2.4	12.4	18.9
Foreign	(13.7)	101.6	96.3
Current, Total	427.2	248.2	171.0
Deferred:
Federal	(1,728.5)	(108.5)	(120.6)
State	(95.5)	2.3	(20.0)
Foreign	48.0	(47.0)	(23.4)
Deferred, Total	(1,776.0)	(153.2)	(164.0)
(Benefit) provision for income taxes	(1,348.8)	95.0	7.0
Income taxes paid	$ 266.9	$ 269.6	$ 193.6