DEBT - COVERTIBLE SUBORDINATED NOTES (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Zero Coupon Convertible Subordinated Notes [Line Items]
Payments On Zero Coupon Subordinated Notes	$ 155,100,000	$ 11,400,000	$ 289,400,000
Common stock issued upon conversion of zero-coupon subordinated notes (in shares)	1,000,000	0	400,000
Announcement date that none of the zero-coupon subordinated notes were tendered by holders for purchase by the Company	Sep. 12, 2011
Zero-coupon convertible subordinated notes [Member]
Zero Coupon Convertible Subordinated Notes [Line Items]
Principal amount at maturity of zero-coupon subordinated notes outstanding	164,100,000	354,600,000
Issued price per principal amount at maturity	671.65	0
Principal amount of zero-coupon subordinated notes	1,000	1,000
Zero-coupon convertible subordinated notes conversion feature description	Each one thousand dollar principal amount at maturity of the notes is convertible into 13.4108 shares of the Company’s common stock, subject to adjustment in certain circumstances,	Each one thousand dollar principal amount at maturity of the notes is convertible into 13.4108 shares of the Company’s common stock, subject to adjustment in certain circumstances,
Annual yield to maturity	2.00%	2.00%
Stock conversion rate for zero-coupon subordinated notes (per thousand)	13.4108	13.4108
Minimum number of trading days in a period the common stock sale price must meet a specified threshold to trigger conversion price (in days)	20
Number of consecutive trading days ending on the last trading day of the preceding quarter for the common stock sale price to reach a specified threshold to trigger conversion price (in days)	30
Common stock sales price threshold, beginning	120.00%
Common stock sales price threshold, declining per quarter	0.1282%
Common stock sales price threshold, ending	110.00%
Conversion trigger price, current period (per share)	$ 70.35
Principal Amount At Maturity Of Zero Coupon Subordinated Notes Converted	190,600,000
Value Of Cash And Common Stock In Connection With Conversions Of Zero Coupon Subordinated Notes Settled In Current Period	248,900,000
Payments On Zero Coupon Subordinated Notes	155,100,000
Common stock issued upon conversion of zero-coupon subordinated notes (in shares)	1,000,000
Tax Benefit Realized Upon Conversion Of Zero Coupon Convertible Debt	36,200,000
Cash Purchase Price Per Subordinate Note	$ 819.54
Date in which holders of zero-coupon subordinated notes may require the Company to purchase notes at the cash purchase price plus any accrued contingent additional principal and interest	September 12, 2011
Contingent cash interest accrual rate	0.125%
Contingent cash interest accrual rate period	September 12, 2011 to March 11, 2012
Contingent cash interest accrual rate description	no less than 0.125% of the average market price of a zero-coupon subordinated note for the five trading days ended September 7, 2011, in addition to the continued accrual of the original issue discount
Debt Conversion Announcement Date	Jan. 03, 2012
Debt Conversion Date Of Subordinated Notes And Indenture	Oct. 24, 2006
Zero Coupon Subordinated Notes Convertible Earliest Date	Jan. 01, 2012
Zero Coupon Subordinated Notes Convertible Latest Date	Mar. 30, 2012