Other Income, Net - Schedule of Components of Other Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Securities earnings:
Dividends and interest			$ 20.0	$ 19.7
Securities transactions, net			0.3	0.2
Total	6.9	6.6	20.3	19.9
Equity in earnings of investees				(0.9)
Currency transactions, net			2.8	(1.5)
Insurance recoveries	8.8	2.2	10.0	3.8
Other, net			0.9	0.5
Total	$ 18.7	$ 8.7	$ 34.0	$ 21.8