Income Taxes - Component of Income Taxes Expenses (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Currently payable:
U.S. federal and state	$ 4.3	$ 34.1	$ 87.3
Non-U.S.	22.0	51.1	38.5
Total	26.3	85.2	125.8
Deferred income taxes (benefit):
U.S. federal and state	(4.1)	(145.5)	(96.9)
Non-U.S.	4.3	29.6	(148.9)
Total	0.2	(115.9)	(245.8)
Income tax expense (benefit)	$ 26.5	$ (30.7)	$ (120.0)