Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenue	$ 5,929.7	$ 5,600.7	$ 11,531.7	$ 11,202.7
Segment Reporting Information, Income (Loss) before Income Taxes	1,514.9	1,185.7	3,466.0	2,521.0
Income related to transfer of exenatide rights	0	0	495.4	0
Asset impairments, restructuring, and other special charges	(63.5)	0	(85.2)	(23.8)
Neuroscience [Member]
Revenue	2,004.5	1,824.5	3,853.4	3,728.2
Endocrinology [Member]
Revenue	1,784.3	1,704.1	3,509.2	3,395.1
Oncology [Member]
Revenue	808.1	846.8	1,572.3	1,650.6
Cardiovascular [Member]
Revenue	731.3	646.9	1,425.3	1,284.9
Animal health [Member]
Revenue	543.5	512.2	1,042.4	1,003.0
Segment Reporting Information, Income (Loss) before Income Taxes	147.7	136.4	277.0	263.9
Other pharmaceuticals [Member]
Revenue	58.0	66.2	129.1	140.9
Pharmaceutical products, total [Member]
Revenue	5,386.2	5,088.5	10,489.3	10,199.7
Segment Reporting Information, Income (Loss) before Income Taxes	1,430.7	1,049.3	2,778.8	2,280.9
Total segment [Member]
Segment Reporting Information, Income (Loss) before Income Taxes	1,578.4	1,185.7	3,055.8	2,544.8
Amylin [Member]
Income related to transfer of exenatide rights	$ 0	$ 0	$ 495.4	$ 0