Earnings Per Share (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net income	$ 561,000,000	$ (34,100,000)	$ 356,200,000	$ 718,900,000	$ 613,900,000	$ 508,500,000	$ 597,800,000	$ 279,700,000	$ 1,602,000,000	$ 1,999,900,000	$ 1,449,900,000
Weighted average shares:
Basic (in shares)	785,800,000	791,100,000	793,000,000	798,900,000	800,200,000	799,600,000	799,600,000	811,500,000	792,200,000	802,700,000	827,700,000
Effect of dilutive securities:
Options, restricted stock units, warrants and other (in shares)									32,700,000	33,300,000	32,900,000
Diluted (in shares)	816,500,000	791,100,000	825,300,000	834,100,000	834,600,000	832,800,000	831,000,000	845,100,000	824,900,000	836,000,000	860,600,000
Net income per share attributable to Celgene:
Basic (in dollars per share)	$ 0.71	$ (0.04)	$ 0.45	$ 0.90	$ 0.77	$ 0.64	$ 0.75	$ 0.34	$ 2.02	$ 2.49	$ 1.75
Diluted (in dollars per share)	$ 0.69	$ (0.04)	$ 0.43	$ 0.86	$ 0.74	$ 0.61	$ 0.72	$ 0.33	$ 1.94	$ 2.39	$ 1.68
Anti-dilutive securities
Antidilutive securities excluded from computation of earnings per share (in shares)									14,100,000	18,700,000	14,300,000
Approved common share repurchase amount	$ 17,500,000,000.0		$ 4,000,000,000.000						$ 17,500,000,000.0
Put option premium net gains (losses)									$ (9,900,000)	$ 11,600,000
Put options outstanding	0								0
Common stock repurchased under the program during the period (in shares)									28,100,000.0
Common stock repurchased under the program during the period									$ 3,257,000,000
Remaining open-ended repurchase authorization	$ 3,890,000,000								$ 3,890,000,000