Components of Comprehensive Income, Net of Related Tax (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 431.2	$ 371.4	$ 1,256.8	$ 964.5
Other comprehensive income (OCI):
Unrealized gains on derivative contracts, before tax	3.7	7.5	6.7	7.9
Unrealized gains on derivative contracts, tax	(0.9)	(2.6)	(1.5)	(2.4)
Unrealized gains on derivative contracts, net of tax	2.8	4.9	5.2	5.5
Unrealized gains (losses) on marketable debt securities, before tax		1.0	(2.5)	4.7
Unrealized gains (losses) on marketable debt securities, tax		(0.1)	0.7	(1.1)
Unrealized gains (losses) on marketable debt securities, net of tax		0.9	(1.8)	3.6
Pension plans, before tax	17.8	14.5	41.5	22.0
Pension plans, tax	(5.8)	(4.4)	(13.9)	(7.0)
Pension plans, net of tax	12.0	10.1	27.6	15.0
Foreign currency translation losses	(163.4)	(278.0)	(409.4)	(231.4)
Net other comprehensive income (loss)	(148.6)	(262.1)	(378.4)	(207.3)
Comprehensive income	$ 282.6	$ 109.3	$ 878.4	$ 757.2