Other Income, Net - Schedule of Components of Other Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Securities earnings:
Dividends and interest			$ 13.2	$ 13.3
Securities transactions, net			0.2	0.1
Total	$ 6.7	$ 6.6	13.4	13.4
Currency transactions, net			1.3	(0.1)
Insurance recoveries	0.3	0.4	3.4	1.2
Other, net			1.4	0.8
Total	$ 7.4	$ 10.2	$ 19.5	$ 15.3