Other Income, Net - Schedule of Components of Other Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Securities earnings:
Dividends and interest	$ 26.5	$ 26.6	$ 26.4
Securities transactions, net		0.3	0.2
Total	26.5	26.9	26.6
Equity in earnings of investees			0.5
Insurance recoveries	3.7	10.4	9.4
Currency transactions, net	(0.1)	4.0	(3.8)
Disposal of property and equipment, net	(0.8)	(0.9)	(0.5)
Gain on bargain purchase and remeasurement of our existing investment in acquiree			54.6
Other, net	2.7	1.6	1.2
Total other income	$ 32.0	$ 42.0	$ 88.0