Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue	$ 5,772.6		$ 5,443.3	$ 17,304.3	$ 16,646.0
Segment Reporting Information, Income (Loss) before Income Taxes	1,513.4		1,874.7	4,979.4	4,395.7
Income related to the termination of the exenatide collaboratio	0		787.8	495.4	787.8
Asset impairments, restructuring, and other special charges	0		(53.3)	(85.2)	(77.1)
Neuroscience [Member]
Revenue	1,878.1		1,815.8	5,731.5	5,544.0
Endocrinology [Member]
Revenue	1,764.7		1,646.1	5,273.9	5,041.2
Oncology [Member]
Revenue	821.8		791.7	2,394.1	2,442.4
Cardiovascular [Member]
Revenue	715.6		650.9	2,140.9	1,936.4
Animal health [Member]
Revenue	530.3		479.4	1,573.1	1,482.4
Segment Reporting Information, Income (Loss) before Income Taxes	150.9		106.0	427.8	370.0
Other pharmaceuticals [Member]
Revenue	62.1		59.4	190.8	199.6
Pharmaceutical products, total [Member]
Revenue	5,242.3		4,963.9	15,731.2	15,163.6
Segment Reporting Information, Income (Loss) before Income Taxes	1,362.5		1,034.2	4,141.4	3,315.0
Total segment [Member]
Segment Reporting Information, Income (Loss) before Income Taxes	1,513.4		1,140.2	4,569.2	3,685.0
Amylin [Member]
Income related to the termination of the exenatide collaboratio	$ 0	$ 495.4	$ 787.8	$ 495.4	$ 787.8