Fair Value Measurements and Other Financial Instruments - Carrying Amounts and Estimated Fair Values of Debt (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
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%
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%
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 borrowings	$ 122.9	$ 30.2
Other domestic borrowings	1.8	3.6
Total debt	3,335.7	3,258.0
Carrying Amount | 6.50% Senior Notes due December 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	423.8	423.6
Carrying Amount | 4.875% Senior Notes due December 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	420.7	420.4
Carrying Amount | 5.25% Senior Notes due April 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	420.8	420.4
Carrying Amount | 4.50% Senior Notes due September 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	459.6	474.3
Carrying Amount | 5.125% Senior Notes due December 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	421.0	420.7
Carrying Amount | 5.50% Senior Notes due September 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	396.9	396.7
Carrying Amount | 6.875% Senior Notes due July 2033
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	445.5	445.4
Carrying Amount | Term Loan A Facility due July 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Term Loan A Facility	222.7	222.7
Fair Value
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other foreign borrowings	121.7	30.4
Other domestic borrowings	2.1	3.6
Total debt	3,520.0	3,596.2
Fair Value | 6.50% Senior Notes due December 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	449.8	465.1
Fair Value | 4.875% Senior Notes due December 2022
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	432.4	451.0
Fair Value | 5.25% Senior Notes due April 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	434.7	455.6
Fair Value | 4.50% Senior Notes due September 2023
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	518.5	544.4
Fair Value | 5.125% Senior Notes due December 2024
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	428.9	456.2
Fair Value | 5.50% Senior Notes due September 2025
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	412.9	439.9
Fair Value | 6.875% Senior Notes due July 2033
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Senior Notes	496.3	527.3
Fair Value | Term Loan A Facility due July 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Term Loan A Facility	$ 222.7	$ 222.7