Accumulated Other Comprehensive Income - Tax Effects on Each Component of Other Comprehensive Income Recognized in Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Foreign currency cumulative translation adjustments, Before Tax	$ 134.2	$ (149.9)
Unrealized cash flow hedge gains (losses), Before Tax	(56.5)	51.7
Reclassification adjustments on foreign currency hedges, Before Tax	(31.7)	(28.0)
Unrealized gains on securities, Before Tax	0.4	0.6
Adjustments to prior service cost and unrecognized actuarial assumptions, Before Tax	21.4	3.2
Total Other Comprehensive Gain (Loss), Before Tax	67.8	(122.4)
Foreign currency cumulative translation adjustments, Tax	0.0	0.0
Unrealized cash flow hedge gains (losses), Tax	(12.4)	(0.7)
Reclassification adjustments on foreign currency hedges, Tax	(7.3)	(6.4)
Unrealized gains on securities, Tax	0.0	0.0
Adjustments to prior service cost and unrecognized actuarial assumptions, Tax	1.4	(0.7)
Total Other Comprehensive Gain (Loss), Tax	(18.3)	(7.8)
Foreign currency cumulative translation adjustments, net of tax	134.2	(149.9)
Unrealized cash flow hedge gains (losses), net of tax	(44.1)	52.4
Reclassification adjustments on foreign currency hedges, net of tax	(24.4)	(21.6)
Unrealized gains on securities, net of tax	0.4	0.6
Adjustments to prior service cost and unrecognized actuarial assumptions, net of tax	20.0	3.9
Total Other Comprehensive Gain (Loss), net of tax	$ 86.1	$ (114.6)