Accumulated Other Comprehensive (Loss) Income - Tax Effects on Each Component of Other Comprehensive Income Recognized in Statements of Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Foreign currency cumulative translation adjustments, Before Tax	$ (128.2)	$ (305.2)	$ (223.1)
Unrealized cash flow hedge gains, Before Tax	29.7	59.1	60.5
Reclassification adjustments on foreign currency hedges, Before Tax	(19.6)	(121.0)	(33.3)
Reclassification adjustments on securities, Before tax			(0.4)
Unrealized gains/(losses) on securities, Before Tax	0.5	(0.2)	(0.5)
Adjustments to prior service cost and unrecognized actuarial assumptions, Before Tax	27.3	(25.0)	(104.8)
Total Other Comprehensive (Loss) Income, Before Tax	(90.3)	(392.3)	(301.6)
Foreign currency cumulative translation adjustments, Tax	1.8
Unrealized cash flow hedge gains, Tax	1.4	6.4	4.6
Reclassification adjustments on foreign currency hedges, Tax	6.2	(28.0)	(14.4)
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	5.3	(3.6)	(29.0)
Total Other Comprehensive (Loss) Income, Tax	14.7	(25.2)	(38.8)
Foreign currency cumulative translation adjustments, net of tax	(130.0)	(305.2)	(223.1)
Unrealized cash flow hedge gains, net of tax	28.3	52.7	55.9
Reclassification adjustments on foreign currency hedges, net of tax	(25.8)	(93.0)	(18.9)
Reclassification adjustments on securities, net of tax			(0.4)
Unrealized gains/(losses) on securities, net of tax	0.5	(0.2)	(0.5)
Adjustments to prior service cost and unrecognized actuarial assumptions, net of tax	22.0	(21.4)	(75.8)
Total Other Comprehensive (Loss) Income, net of tax	$ (105.0)	$ (367.1)	$ (262.8)