Long-term Debt (Details) (USD $) In Millions, unless otherwise specified					12 Months Ended			12 Months Ended			12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended			12 Months Ended						12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2012 6.25% Senior Unsecured Notes due 2014		Dec. 31, 2011 6.25% Senior Unsecured Notes due 2014	Dec. 31, 2012 10.00% Senior Unsecured Notes due 2017		Dec. 31, 2011 10.00% Senior Unsecured Notes due 2017	Dec. 31, 2012 2.25% Senior Notes due 2017		Nov. 08, 2012 2.25% Senior Notes due 2017	Dec. 31, 2011 2.25% Senior Notes due 2017	Dec. 31, 2012 4.00% Senior Notes due 2022		Mar. 02, 2012 4.00% Senior Notes due 2022	Dec. 31, 2011 4.00% Senior Notes due 2022	Dec. 31, 2012 3.75% Senior Notes due 2023		Nov. 08, 2012 3.75% Senior Notes due 2023	Dec. 31, 2011 3.75% Senior Notes due 2023	Dec. 31, 2012 4.75% Convertible Senior Notes due 2023		Dec. 31, 2011 4.75% Convertible Senior Notes due 2023	Dec. 31, 2012 4.25% Convertible Senior Notes due 2023		Dec. 31, 2011 4.25% Convertible Senior Notes due 2023	Dec. 31, 2012 Other notes payable and capitalized leases		Dec. 31, 2011 Other notes payable and capitalized leases	Dec. 31, 2012 7.25% Senior Notes due 2011
Debt Instrument
Effective Interest Rate					6.29%			10.38%			2.30%				4.13%				4.32%				3.50%
Stated Interest Rate					6.25%			10.00%			2.25%				4.00%				3.75%				4.75%			4.25%						7.25%
Book Value					$ 352.8		$ 354.3	$ 591.9		$ 590.6	$ 299.3			$ 0	$ 247.1			$ 0	$ 498.5			$ 0	$ 200.5	[1]	$ 202.7	$ 0		$ 403.0	$ 87.3		$ 65.1
Fair Value					372.6	[2]	374.5	660.8	[2]	690.0	297.8	[2]		0	258.7	[2]		0	499.7	[2]		0	202.8	[2]	220.5	0	[2]	405.5	90.8	[2]
Total long-term debt	2,277.4		1,615.7
Less: current portion	216.6	[1],[3]	404.8	[1],[3]
Long-term debt, excluding current portion	2,060.8		1,210.9
Face Value								600.0			300.0				250.0				500.0				200.0
Debt Maturity Date					Nov. 15, 2014			Jul. 15, 2017			Nov. 15, 2017				Mar. 15, 2022				Feb. 15, 2023				Mar. 15, 2023			Mar. 15, 2023						Aug. 15, 2011
Unamortized Discount					0.2			8.1			0.7		0.7		2.9		3.2		1.5		1.5
Unamortized Premium																							$ 0.5

[1] See Note 17 for further information regarding subsequent events.

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

[3] 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, stock or a combination, at our election, at par, and accordingly, we included these notes in the current portion of long-term debt on our December 31, 2012 Consolidated Balance Sheet. 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. The 4.25% Notes were retired in the first quarter of 2012.