Fair Value Measurements and Other Financial Instruments - Carrying Amounts and Estimated Fair Values of Debt (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2015
6.50% Senior Notes Due December 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	6.50%
4.875% Senior Notes due December 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	4.875%
5.25% Senior Notes Due April 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	5.25%
4.50% Senior Notes due September 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	4.50%		4.50%
5.125% Senior Notes due December 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	5.125%
5.50% Senior Notes due September 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	5.50%		5.50%
6.875% Senior Notes Due July 2033
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Debt interest rate	6.875%
Carrying Amount
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other foreign loans	$ 30.2	$ 78.9
Other domestic loans	3.6	21.4
Total debt	3,258.0	4,359.0
Carrying Amount | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt	0.0	216.4
Carrying Amount | Continuing Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt	3,258.0	4,142.6
Carrying Amount | 6.50% Senior Notes Due December 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	423.6	423.1
Carrying Amount | 4.875% Senior Notes due December 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	420.4	419.6
Carrying Amount | 5.25% Senior Notes Due April 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	420.4	419.7
Carrying Amount | 4.50% Senior Notes due September 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	474.3	416.7
Carrying Amount | 5.125% Senior Notes due December 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	420.7	420.2
Carrying Amount | 5.50% Senior Notes due September 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	396.7	396.4
Carrying Amount | 6.875% Senior Notes Due July 2033
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	445.4	445.3
Carrying Amount | Term Loan A Due July 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Term Loan A Facility	0.0	249.9
Carrying Amount | Term Loan A Due July 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Term Loan A Facility	222.7	1,067.8
Fair Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other foreign loans	30.4	79.2
Other domestic loans	3.6	21.3
Total debt	3,596.2	4,546.4
Fair Value | Discontinued Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt	0.0	216.4
Fair Value | Continuing Operations
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total debt	3,596.2	4,330.0
Fair Value | 6.50% Senior Notes Due December 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	465.1	477.3
Fair Value | 4.875% Senior Notes due December 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	451.0	437.6
Fair Value | 5.25% Senior Notes Due April 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	455.6	441.1
Fair Value | 4.50% Senior Notes due September 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	544.4	453.4
Fair Value | 5.125% Senior Notes due December 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	456.2	437.3
Fair Value | 5.50% Senior Notes due September 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	439.9	418.8
Fair Value | 6.875% Senior Notes Due July 2033
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	527.3	462.7
Fair Value | Term Loan A Due July 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Term Loan A Facility	0.0	249.9
Fair Value | Term Loan A Due July 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Term Loan A Facility	$ 222.7	$ 1,067.8