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Geographic and Product Information (Revenue by Product) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues by Product
Total net product sales									$ 7,563.8us-gaap_SalesRevenueGoodsNet	$ 6,362.3us-gaap_SalesRevenueGoodsNet	$ 5,385.6us-gaap_SalesRevenueGoodsNet
Other revenue									106.6us-gaap_OtherSalesRevenueNet	131.6us-gaap_OtherSalesRevenueNet	121.1us-gaap_OtherSalesRevenueNet
Total revenue	2,085.5us-gaap_Revenues	1,982.2us-gaap_Revenues	1,872.7us-gaap_Revenues	1,730.0us-gaap_Revenues	1,755.9us-gaap_Revenues	1,674.4us-gaap_Revenues	1,599.0us-gaap_Revenues	1,464.6us-gaap_Revenues	7,670.4us-gaap_Revenues	6,493.9us-gaap_Revenues	5,506.7us-gaap_Revenues
REVLIMID
Revenues by Product
Total net product sales									4,980.0	4,280.3	3,766.6
ABRAXANE
Revenues by Product
Total net product sales									848.2	648.9	426.7
POMALYST/IMNOVID
Revenues by Product
Total net product sales									679.7	305.4	12.0
VIDAZA
Revenues by Product
Total net product sales									611.9	803.3	823.2
Azacitidine
Revenues by Product
Total net product sales									78.2	23.3	0
THALOMID
Revenues by Product
Total net product sales									221.2	244.5	302.1
OTEZLA
Revenues by Product
Total net product sales									69.8	0	0
ISTODAX
Revenues by Product
Total net product sales									65.6	54.0	50.0
Other
Revenues by Product
Total net product sales									$ 9.2	$ 2.6	$ 5.0