Components of Comprehensive Income, Net of Related Tax (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Comprehensive Income (Loss) [Line Items]
Net income	$ 273.9	$ 236.1
Other comprehensive income (loss)
Unrealized gains on derivative contracts, before tax	1.7	3.2
Unrealized gains on derivative contracts, tax	(0.6)	(1.1)
Unrealized gains on derivative contracts	1.1	2.1
Unrealized gains (losses) on marketable debt securities, before tax	1.2	(0.3)
Unrealized gains (losses)on marketable debt securities, tax	(0.2)	0.1
Unrealized gains (losses) on marketable debt securities, net of tax	1.0	(0.2)
Pension plans, before tax	6.4	21.3
Pension plans, tax	(2.1)	(6.7)
Pension plans, net of tax	4.3	14.6
Foreign currency translation losses	(1.1)	(96.0)
Net other comprehensive income (loss)	5.3	(79.5)
Comprehensive income	$ 279.2	$ 156.6