Other Income, Net - Schedule of Components of Other Income (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Securities earnings:
Dividends and interest			$ 19.8	$ 20.0
Securities transactions, net			0.1	0.3
Total	$ 6.5	$ 6.9	19.9	20.3
Currency transactions, net			0.6	2.8
Insurance recoveries	0.1	8.8	3.5	10.0
Other, net			1.4	0.9
Total other income	$ 5.9	$ 18.7	$ 25.4	$ 34.0