Long-term Debt (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended	9 Months Ended
	Aug. 31, 2011	Sep. 30, 2011		Dec. 31, 2010
Debt Instrument
Total long-term debt		$ 1,574.7		$ 1,622.2
Less: current portion		408.5	[1]	38.9	[1]
Long-term debt, excluding current portion		1,166.2		1,583.3
7.25% Senior Unsecured Notes due 2011
Debt Instrument
Effective Interest Rate		7.25%	[2]
Stated Interest Rate		7.25%
Debt Maturity Date		Aug. 15, 2011
Book Value		0		36.3
Fair Value		0	[3]	37.0	[3]
Aggregate principal amount matured	36.3
Amount paid, including accrued and unpaid interest for debt maturity	37.6
6.25% Senior Unsecured Notes due 2014
Debt Instrument
Effective Interest Rate		6.29%	[2]
Stated Interest Rate		6.25%
Debt Maturity Date		Nov. 15, 2014
Book Value		354.6		353.3
Fair Value		370.1	[3]	378.0	[3]
Unamortized Discount		0.3
Face Value		350.0
10.00% Senior Unsecured Notes due 2017
Debt Instrument
Effective Interest Rate		10.38%
Stated Interest Rate		10.00%
Debt Maturity Date		Jul. 15, 2017
Book Value		590.3		589.4
Fair Value		681.0	[3]	705.0	[3]
Unamortized Discount		9.7
4.75% Convertible Senior Notes due 2023
Debt Instrument
Effective Interest Rate		3.50%
Stated Interest Rate		4.75%
Debt Maturity Date		Mar. 15, 2023
Book Value		203.3		205.0
Fair Value		213.8	[3]	235.0	[3]
Unamortized Premium		3.3
Capped call, shares that may be purchased		16.3
Capped call, strike price before adjustment		$ 12.42
Capped call, strike price		$ 12.30
Capped call, cap price before adjustment		$ 18.26
Capped call, cap price		$ 18.08
4.25% Convertible Senior Notes due 2023
Debt Instrument
Effective Interest Rate		0.58%
Stated Interest Rate		4.25%
Debt Maturity Date		Mar. 15, 2023
Book Value		406.6		417.4
Fair Value		404.5	[3]	444.4	[3]
Unamortized Premium		6.6
Call Date of Convertible Senior Notes		Mar. 15, 2012
Other notes payable and capitalized leases
Debt Instrument
Book Value		$ 19.9		$ 20.8

[1] On March 15, 2012, holders of our 4.25% Convertible Senior Notes due 2023 (the “4.25% Notes”) may require us to repurchase their notes for cash at par and as such, we included these notes in the current portion of long-term debt on our September 30, 2011 unaudited Consolidated Balance Sheet. Any 4.25% Notes not repurchased on March 15, 2012 will be reclassified to long-term debt.

[2] Excludes the effect of related interest rate swaps.

[3] Fair values are derived from trading quotes by institutions making a market in the securities and estimations of value by those institutions using proprietary models.