Long-term Debt (Details) (USD $) In Millions, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2012		Mar. 02, 2012	Dec. 31, 2011
Debt Instrument
Total long-term debt	$ 1,456.4			$ 1,615.7
Less: current portion	217.7	[1]		404.8	[1]
Long-term debt, excluding current portion	1,238.7			1,210.9
6.25% Senior Unsecured Notes due 2014
Debt Instrument
Effective Interest Rate	6.29%
Book Value	353.5			354.3
Long-term Debt, Fair Value	378.0	[2]		374.5
Stated Interest Rate	6.25%
Debt Maturity Date	Nov. 15, 2014
Unamortized Discount	0.2
10.00% Senior Unsecured Notes due 2017
Debt Instrument
Effective Interest Rate	10.38%
Book Value	591.2			590.6
Long-term Debt, Fair Value	679.5	[2]		690.0
Stated Interest Rate	10.00%
Debt Maturity Date	Jul. 15, 2017
Unamortized Discount	8.8
4.00% Senior Notes due 2022
Debt Instrument
Effective Interest Rate	4.13%
Book Value	246.9			0
Long-term Debt, Fair Value	254.4	[2]	246.8	0
Stated Interest Rate	4.00%
Debt Maturity Date	Mar. 15, 2022
Unamortized Discount	3.1		3.2
4.00% Notes, Face Value	250.0
4.00% Notes, Frequency of Periodic Payment	semi-annually
4.00% Notes, Date of First Required Payment	Sep. 15, 2012
4.00% Notes, Capitalized Direct Fees	2.5
4.00% Notes, Repurchase price percentage due to change of control	101.00%
4.75% Convertible Senior Notes due 2023
Debt Instrument
Effective Interest Rate	3.50%
Book Value	201.6			202.7
Long-term Debt, Fair Value	215.0	[2]		220.5
Stated Interest Rate	4.75%
Debt Maturity Date	Mar. 15, 2023
Unamortized Premium	1.6
Repurchase of convertible notes for cash, date	Mar. 15, 2013
Conversion ratio before adjustment for dividends	82.4612
Current conversion ratio	83.3669
Conversion price before adjustment for dividends	$ 12.13
Current conversion price	$ 12.00
Capped call, shares that may be purchased	16,700,000
Capped call, strike price	$ 12.00
Capped call, strike price before adjustment	$ 12.13
Capped call, cap price	$ 17.64
Capped call, cap price before adjustment	$ 17.83
4.25% Convertible Senior Notes due 2023
Debt Instrument
Book Value	0			403.0
Long-term Debt, Fair Value	0	[2]		405.5
Stated Interest Rate	4.25%
Debt Maturity Date	Mar. 15, 2023
4.25% Notes, Amount Retired	400.0
4.25% Notes, Amount Retired for Cash	399.6
4.25% Notes Retirement, Accrued Interest Paid	0.5
Conversion of 4.25% Notes, Amount	0.4
Conversion of 4.25% Notes, Shares Issued	30,000
4.25% Notes, Incremental Common Shares if Converted	33,000,000
Current conversion ratio	82.4612
Other notes payable and capitalized leases
Debt Instrument
Book Value	63.2			65.1
Long-term Debt, Fair Value	$ 59.9	[2]

[1] On March 15, 2013, holders of our 4.75% Convertible Senior Notes due 2023 (the “4.75% Notes”) may require us to repurchase their notes for cash at par, and accordingly, we included these notes in the current portion of long-term debt on our June 30, 2012 unaudited Consolidated Balance Sheet. The 4.75% Notes are redeemable in whole or in part at our option beginning March 15, 2013. Any 4.75% Notes not repurchased on March 15, 2013 or called for redemption by us will be reclassified to long-term debt. We included our 4.25% Convertible Senior Notes due 2023 (the “4.25% Notes”) in the current portion of long-term debt on our December 31, 2011 Consolidated Balance Sheet because holders of the 4.25% Notes had a repurchase option on March 15, 2012 for cash at par.

[2] See Note 11 for information on the fair value measurement of our long-term debt.