Annual report pursuant to Section 13 and 15(d)

Income Taxes - Reconciliation between Provision for Income Taxes at Statutory Rate and Provision for Income Taxes at Effective Tax Rate (Detail)

v3.8.0.1
Income Taxes - Reconciliation between Provision for Income Taxes at Statutory Rate and Provision for Income Taxes at Effective Tax Rate (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Abstract]      
Tax expense at United States statutory rate $ 164.9 $ 127.7 $ 170.2
Increase (decrease) in tax resulting from:      
Differences between U.S. and foreign tax rates on foreign income, including withholding taxes (42.7) (16.6) 203.1
U.S. tax (benefit) on foreign income net of foreign tax credits (22.9) (10.2) (23.9)
(Decrease) increase in valuation allowances 183.7 (5.6) (205.6)
State taxes, net of federal benefit 1.9 0.3 1.7
Unrecognized tax benefits (4.0) 5.3 10.1
Excess tax benefits on equity awards (31.1)    
Other 7.5 3.8 (8.3)
Total $ 257.3 $ 104.7 $ 147.3