Accumulated Other Comprehensive Loss - Changes In Accumulated Other Comprehensive Loss (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Defined Benefit Pension Plans	Sep. 30, 2013 Defined Benefit Pension Plans	Sep. 30, 2014 Defined Benefit Pension Plans	Sep. 30, 2013 Defined Benefit Pension Plans	Sep. 30, 2014 OPEB Plans	Sep. 30, 2014 OPEB Plans	Sep. 30, 2013 OPEB Plans	Jun. 30, 2013 OPEB Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Marketable securities, Balance at beginning of period	$ (2.4)	$ 5.4	$ 10.8	$ 4.2
Other comprehensive income (loss) - unrealized gains (losses) arising during the year		8.2	(13.2)	9.4
Marketable securities, Balance at end of period	(2.4)	13.6	(2.4)	13.6
Currency translation, Balance at beginning of period	(63.7)	(85.1)	(56.8)	(63.5)
Other comprehensive income (loss)	(46.7)	21.0	(53.6)	(0.6)
Currency translation, Balance at end of period	(110.4)	(64.1)	(110.4)	(64.1)
Balance at beginning of period					(105.6)	(132.3)	(109.4)	(137.3)	3.2	3.4	(0.5)	(0.6)
Other comprehensive income - amortization of prior service cost and net losses included in net periodic pension cost					1.9	2.4	5.7	7.4	(0.2)	(0.4)	(0.1)
Balance at end of period					(103.7)	(129.9)	(103.7)	(129.9)	3.0	3.0	(0.6)	(0.6)
Balance at beginning of period	(168.5)	(212.6)	(152.0)	(197.1)
Other comprehensive income (loss)	(45.0)	31.6	(61.5)	16.1
Balance at end of period	$ (213.5)	$ (181.0)	$ (213.5)	$ (181.0)