Accumulated Other Comprehensive Loss - Schedule of Changes in Accumulated Other Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Accumulated Comprehensive Income Loss [Line Items]
Marketable securities, Balance at beginning of year	$ 1.9	$ 1.2	$ 2.1	$ 6.4
Marketable securities, Unrealized gain (loss) arising during the year		(6.8)	(0.2)	(12.0)
Marketable securities, Balance at end of year	1.9	(5.6)	1.9	(5.6)
Currency translation adjustment, Balance at beginning of year	31.8	51.6	53.3	37.5
Other comprehensive income (loss)	4.5	(32.1)	(17.0)	(18.0)
Currency translation adjustment, Balance at end of year	36.3	19.5	36.3	19.5
Balance at beginning of period	(61.9)	(13.2)	(42.0)	(23.3)
Other comprehensive income (loss)	3.9	(57.8)	(15.3)	(48.9)
Balance at end of period	(55.5)	(50.8)	(55.5)	(50.8)
Defined Benefit Pension Plans
Accumulated Comprehensive Income Loss [Line Items]
Balance at beginning of year	(99.4)	(71.1)	(101.5)	(72.6)
Amortization of prior service cost and net losses included in net periodic pension cost	2.1	1.5	4.2	3.0
Balance at end of year	(97.3)	(69.6)	(97.3)	(69.6)
OPEB
Accumulated Comprehensive Income Loss [Line Items]
Balance at beginning of year	3.8	5.1	4.1	5.4
Balance at end of year	3.6	4.9	3.6	4.9
Amortization of prior service credit	$ (0.2)	$ (0.2)	$ (0.5)	$ (0.5)