CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $) In Thousands, except Share data	Total	Total Stockholders Equity Attributable to Cephalon	Common Stock	Additional Paid-in Capital	Treasury Stock	(Accumulated Deficit)/Retained Earnings	Accumulated Other Comprehensive Income	Noncontrolling Interest	Comprehensive Income
BALANCE at Dec. 31, 2009	$ 2,478,073	$ 2,261,958	$ 780	$ 2,534,070	$ (208,427)	$ (178,659)	$ 114,194	$ 216,115
BALANCE (in shares) at Dec. 31, 2009			78,002,764		3,085,844
Increase (Decrease) in Stockholders' Equity
Net income	192,730	199,629				199,629		(6,899)	192,730
Foreign currency translation gains / losses	(67,986)	(67,986)					(67,986)		(67,986)
Prior service costs and gains on retirement-related plans	(49)	(49)					(49)		(49)
Comprehensive income	124,695	131,594						(6,899)	124,695
Stock options exercised	14,370	14,370	3	14,367
Stock options exercised (in shares)			278,163
Tax benefit from equity compensation	(559)	(559)		(559)
Stock-based compensation expense	21,630	21,630		21,630
Stock-based compensation expense (in shares)			1,250
Treasury stock acquired	(33)	(33)			(33)
Treasury stock acquired (in shares)					502
Change in redeemable equity associated with convertible debt	21,152	21,152		21,152
Acquisition of Ception Therapeutics, Inc. noncontrolling interest	(393,991)	(210,072)		(210,072)				(183,919)
Issuance of common stock upon conversion of convertible notes	8,143	8,143	1	8,142
Issuance of common stock upon conversion of convertible notes (in shares)			137,543
Exercise of convertible note hedge associated with conversion of convertible notes	(8,137)	(8,137)			(8,137)
Exercise of convertible note hedge associated with conversion of convertible notes (in shares)					137,441
Acquisition of Mepha GmbH noncontrolling interest	38,902							38,902
Other	(755)							(755)
BALANCE at Jun. 30, 2010	2,303,490	2,240,046	784	2,388,730	(216,597)	20,970	46,159	63,444
BALANCE (in shares) at Jun. 30, 2010			78,419,720		3,223,787
BALANCE at Dec. 31, 2010	2,667,592	2,633,432	791	2,428,450	(225,870)	247,086	182,975	34,160
BALANCE (in shares) at Dec. 31, 2010			79,091,532		3,369,258
Increase (Decrease) in Stockholders' Equity
Net income	326,802	329,263				329,263		(2,461)	326,802
Foreign currency translation gains / losses	133,723	133,723					133,723		133,723
Gains or losses associated with pension benefits and prior service costs on retirement-related plans	(49)	(49)					(49)		(49)
Comprehensive income	460,476	462,937						(2,461)	460,476
Stock options exercised	133,703	133,703	22	133,681
Stock options exercised (in shares)			2,193,280
Tax benefit from equity compensation	11,729	11,729		11,729
Stock-based compensation expense	16,950	16,950		16,950
Treasury stock acquired	(4)	(4)			(4)
Treasury stock acquired (in shares)					438
Stock issued for employee stock purchase plan	349	349		349
Stock issued for employee stock purchase plan (in shares)			5,948
Change in redeemable equity associated with convertible debt	16,583	16,583		16,583
Finalization of acquisition of Ception noncontrolling interest	22,085	22,085		22,085
Finalization of acquisition of BioAssets Development Corp. noncontrolling interest	4,079	4,079		4,079
Alba Therapeutics Inc. noncontrolling interest upon consolidation	33,000							33,000
ChemGenex Pharmaceuticals Limited noncontrolling interest upon consolidation	22,075							22,075
Reduction in ChemGenex noncontrolling interest due to purchase of additional equity interest	(6,602)							(6,602)
Issuance of common stock upon conversion of convertible notes				7	(7)
Issuance of common stock upon conversion of convertible notes (in shares)			85		85
Other	(677)							(677)
BALANCE at Jun. 30, 2011	$ 3,381,338	$ 3,301,843	$ 813	$ 2,633,913	$ (225,881)	$ 576,349	$ 316,649	$ 79,495
BALANCE (in shares) at Jun. 30, 2011			81,290,845		3,369,781