DEBT (Details 2) (USD $)	3 Months Ended					1 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended	12 Months Ended		1 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Convertible Notes	Mar. 31, 2011 Convertible Notes	Dec. 31, 2011 Convertible Notes	Mar. 31, 2012 1.00% Convertible Senior Notes Due March 2018 [Member] Days	Mar. 31, 2012 1.00% Convertible Senior Notes Due March 2018 [Member]	Mar. 31, 2010 1.25% Convertible Senior Notes due March 2015 [Member] Days	Mar. 31, 2012 1.25% Convertible Senior Notes due March 2015 [Member]	Dec. 31, 2011 1.25% Convertible Senior Notes due March 2015 [Member]	Dec. 31, 2010 1.25% Convertible Senior Notes due March 2015 [Member]	Mar. 31, 2012 Minimum [Member] 1.00% Convertible Senior Notes Due March 2018 [Member]	Mar. 31, 2010 Minimum [Member] 1.25% Convertible Senior Notes due March 2015 [Member]	Mar. 31, 2012 Maximum [Member] 1.00% Convertible Senior Notes Due March 2018 [Member]	Mar. 31, 2010 Maximum [Member] 1.25% Convertible Senior Notes due March 2015 [Member]
Debt Instrument
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt, Subsequent Adjustments									$ 71,800,000	$ 77,400,000
Estimated market value of outstanding convertible debt			2,400,000,000		900,000,000
Description of Senior Notes
Aggregate principal amount						1,000,000,000	1,000,000,000	575,000,000
Interest rate on Convertible Senior Notes						1.00%	1.00%	1.25%
Debt financing costs paid							20,300,000				13,300,000
Convertible debt conversion price (in dollars per share)						$ 944.61	$ 944.61	$ 303.06
Minimum days the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note (in days)						20		20
Maximum consecutive days the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note (in days)						30		30
Ratio of closing share price to conversion price as a condition for conversion of convertible 2015 Senior Notes, minimum						150.00%		150.00%
Additional Payment To Debt Holder Settled In Shares Aggregate Value Of Shares												0	0	344,000,000	132,700,000
Effective interest rate at debt origination or modification						3.50%	3.50%	5.89%
Debt discount related to convertible notes, net of tax						80,900,000	80,900,000
Debt discount related to convertible notes, before tax						135,200,000	135,200,000
Finance costs related to convertible notes, net of tax						2,800,000	2,800,000
Interest expense related to convertible notes			10,600,000	7,500,000
Contractual coupon interest related to convertible notes included in interest expense			2,600,000	1,800,000
Amortization of debt discount included in interest expense	7,241,000	5,239,000	7,200,000	5,200,000
Amortization of debt issuance costs			$ 800,000	$ 500,000
Effective interest rate during the period			5.70%	6.30%