Debt Schedule of Debt Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 1,864.3	$ 2,015.6
Less unamortized discount	(12.9)	(16.8)
Debt, Long-term and Short-term, Combined Amount	1,864.3	2,015.6
Long-term debt	1,589.4	2,015.6
Total long-term debt outstanding	1,589.4	2,015.6
Less: current portion of long-term debt	(274.9)	0.0
Revolving Credit Facility due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	0.0	0.0
6.875% Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	275.3	382.4
5.375% Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	465.1	500.0
5.25% Senior Notes Due 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	636.8	650.0
Senior Notes Due 2026 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500.0	$ 500.0

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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