Long Term Debt (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Long-term debt	$ 1,960.5	$ 1,245.5
Less current portion of long-term debt	(0.3)	(0.5)
Long-term debt, net of current maturities	1,960.2	1,245.0
Senior Unsecured Notes 5.25 Percent Due 2022
Debt Instrument [Line Items]
Senior notes	1,315.0
Senior Unsecured Notes 6.875 Percent Due 2020
Debt Instrument [Line Items]
Senior notes	645.2	644.7
Senior Unsecured Notes 8.5 Percent Due 2018
Debt Instrument [Line Items]
Senior notes		600.0
Other Long Term Debt
Debt Instrument [Line Items]
Senior notes	$ 0.3	$ 0.8

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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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Carrying amount of long-term debt, net of unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

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