Effects of Restatement on Condensed Consolidated Statements of Changes in Stockholders' Equity (Detail) $ in Millions	Mar. 31, 2017 USD ($)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	$ 5,111.9
Ending balance	13,382.2
Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	5,079.4
Ending balance	13,559.2
Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	32.5
Ending balance	(177.0)
Ordinary Shares
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	114.7
Ending balance	466.6
Ordinary Shares | Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	114.7
Ending balance	466.6
Ordinary Shares Held in Treasury and Employee Benefit Trust
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	(44.5)
Ending balance	(5.4)
Ordinary Shares Held in Treasury and Employee Benefit Trust | Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	(44.5)
Ending balance	(5.4)
Capital in Excess of Par Value of Ordinary Shares
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	2,694.7
Ending balance	10,507.6
Capital in Excess of Par Value of Ordinary Shares | Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	2,694.7
Ending balance	10,507.6
Retained Earnings
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	3,416.1
Ending balance	3,397.4
Retained Earnings | Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	2,801.4
Ending balance	2,992.2
Retained Earnings | Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	614.7
Ending balance	405.2
Accumulated Other Comprehensive Income (Loss)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	(1,057.4)
Ending balance	(990.4)
Accumulated Other Comprehensive Income (Loss) | Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	(475.2)
Ending balance	(408.2)
Accumulated Other Comprehensive Income (Loss) | Restatement Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	(582.2)
Ending balance	(582.2)
Noncontrolling Interest
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	(11.7)
Ending balance	6.4
Noncontrolling Interest | Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Beginning balance	(11.7)
Ending balance	$ 6.4