Accumulated Other Comprehensive (Loss) Income - Tax Effects on Each Component of Other Comprehensive Income Recognized in Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Foreign currency cumulative translation adjustments, Before Tax	$ (305.2)	$ (223.1)	$ (35.0)
Unrealized cash flow hedge gains, Before Tax	59.1	60.5	63.6
Reclassification adjustments on foreign currency hedges, Before Tax	(121.0)	(33.3)	(7.8)
Reclassification adjustments on securities, Before Tax		(0.4)
Unrealized gains/(losses) on securities, Before Tax	(0.2)	(0.5)	0.1
Adjustments to prior service cost and unrecognized actuarial assumptions, Before Tax	(25.0)	(104.8)	50.3
Total Other Comprehensive (Loss) Income, Before Tax	(392.3)	(301.6)	71.2
Foreign currency cumulative translation adjustments, Tax	0.0	0.0	0.0
Unrealized cash flow hedge gains, Tax	6.4	4.6	30.2
Reclassification adjustments on foreign currency hedges, Tax	(28.0)	(14.4)	(3.4)
Reclassification adjustments on securities, Tax	0.0	0.0	0.0
Unrealized gains/(losses) on securities, Tax	0.0	0.0	0.0
Adjustments to prior service cost and unrecognized actuarial assumptions, Tax	(3.6)	(29.0)	11.8
Total Other Comprehensive (Loss) Income, Tax	(25.2)	(38.8)	38.6
Foreign currency cumulative translation adjustments, net of tax	(305.2)	(223.1)	(35.0)
Unrealized cash flow hedge gains, net of tax	52.7	55.9	33.4
Reclassification adjustments on foreign currency hedges, net of tax	(93.0)	(18.9)	(4.4)
Reclassification adjustments on securities, net of tax		(0.4)	0.0
Unrealized gains/(losses) on securities, net of tax	(0.2)	(0.5)	0.1
Adjustments to prior service cost and unrecognized actuarial assumptions, net of tax	(21.4)	(75.8)	38.5
Total Other Comprehensive (Loss) Income, net of tax	$ (367.1)	$ (262.8)	$ 32.6