Components of Comprehensive Income (Loss), Net of Related Tax (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 481.3	$ 447.2	$ (113.3)	$ 825.6
Other comprehensive income (loss) (OCI):
Unrealized gains on derivative contracts, before tax	9.5	3.2	2.9	3.0
Unrealized gains on derivative contracts, tax	(2.6)	(1.0)	(0.5)	(0.6)
Net current period OCI, unrealized (losses) gain on derivative contracts	6.9	2.2	2.4	2.4
Unrealized gains (losses) on marketable debt securities before tax	2.6	(3.0)	5.8	(2.5)
Unrealized gains (losses) on marketable debt securities, tax	(0.8)	0.9	(1.8)	0.7
Net current period OCI, unrealized gains (losses) on marketable debt securities	1.8	(2.1)	4.0	(1.8)
Pension plans, before tax	15.4	2.0	22.4	23.7
Pension plans, tax	(4.8)	(1.3)	(7.2)	(8.1)
Net current period OCI, pension plans	10.6	0.7	15.2	15.6
Foreign currency translation (losses) gains	(57.2)	106.9	68.3	(246.0)
Net other comprehensive (loss) income	(37.9)	107.7	89.9	(229.8)
Comprehensive income (loss)	$ 443.4	$ 554.9	$ (23.4)	$ 595.8