Long-term Debt (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Capital lease obligations	$ 20.0us-gaap_CapitalLeaseObligations	$ 22.2us-gaap_CapitalLeaseObligations
Other	1.0us-gaap_OtherLongTermDebt	1.2us-gaap_OtherLongTermDebt
2013 Term Loan Facility due September 2020 [Member]
Debt Instrument [Line Items]
Long-term debt	1,172.6	1,175.1
7.375% Senior Notes due November 2016 [Member]
Debt Instrument [Line Items]
Long-term debt	83.1	650.0
6.00% Senior Notes due November 2018 [Member]
Debt Instrument [Line Items]
Long-term debt	1,518.8	1,518.8
6.50% Senior Notes due September 2020 [Member]
Debt Instrument [Line Items]
Long-term debt	650.0	650.0
6.25% Senior Notes due November 2021 [Member]
Debt Instrument [Line Items]
Long-term debt	1,339.6	1,339.6
10.00% Senior Secured Second Lien Notes Due March 2022 [Member]
Debt Instrument [Line Items]
Long-term debt	975.8	0
7.875% Senior Notes due November 2026 [Member]
Debt Instrument [Line Items]
Long-term debt	247.7	247.6
Convertible Junior Subordinated Debentures due December 2066 [Member]
Debt Instrument [Line Items]
Long-term debt	383.0	382.3
Carrying value
Debt Instrument [Line Items]
Total long-term debt	$ 6,391.6	$ 5,986.8

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Including both current and noncurrent portions, carrying amount as of the balance sheet date of other forms of debt not elsewhere specified in the taxonomy with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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