Debt Schedule of Debt Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Less unamortized discount	$ (25.7)	$ (30.3)
Long-term debt	2,019.3	2,191.5
Less: current portion of long-term debt	0.0	(176.8)
Total long-term debt outstanding	2,019.3	2,014.7
Revolving Credit Facility due 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	0.0	0.0
Senior Notes Due 2016 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	0.0	176.8
Senior Notes Due 2018 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	134.0	134.0
Senior Notes Due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	136.0	136.0
6.875% Senior Notes Due 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	625.0	625.0
Senior Notes Due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	500.0	500.0
5.25% Senior Notes Due 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 650.0	$ 650.0

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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