Accumulated Other Comprehensive Income - Tax Effects on Each Component of Accumulated Other Comprehensive Income Recognized in Statements of Comprehensive Income (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Foreign currency cumulative translation adjustments, Before Tax	$ 54.4	$ 134.2
Unrealized cash flow hedge (losses), Before Tax	(36.6)	(56.5)
Reclassification adjustments on cash flow hedges, Before Tax	(11.0)	(31.7)
Unrealized gains on securities, Before Tax		0.4
Adjustments to prior service cost and unrecognized actuarial assumptions, Before Tax	(3.7)	21.4
Total Other Comprehensive Income (Loss), Before Tax	3.1	67.8
Foreign currency cumulative translation adjustments, Tax	5.4
Unrealized cash flow hedge (losses), Tax	(10.3)	(12.4)
Reclassification adjustments on cash flow hedges, Tax	(2.0)	(7.3)
Unrealized gains on securities, Tax		0.0
Adjustments to prior service cost and unrecognized actuarial assumptions, Tax	(0.2)	1.4
Total Other Comprehensive Income (Loss), Tax	(7.1)	(18.3)
Foreign currency cumulative translation adjustments, net of tax	49.0	134.2
Unrealized cash flow hedge (losses), net Tax	(26.3)	(44.1)
Reclassification adjustments on cash flow hedges, net of tax	(9.0)	(24.4)
Unrealized gains on securities, net of tax		0.4
Adjustments to prior service cost and unrecognized actuarial assumptions, net of tax	(3.5)	20.0
Total Other Comprehensive Income (Loss), net of tax	$ 10.2	$ 86.1