Collaborations (Details)	1 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended			6 Months Ended		1 Months Ended	10 Months Ended	1 Months Ended					10 Months Ended	1 Months Ended		10 Months Ended	1 Months Ended	3 Months Ended		12 Months Ended	3 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended	1 Months Ended	3 Months Ended	1 Months Ended
	Aug. 31, 2012 USD ($)	Jun. 30, 2013 USD ($)	Jun. 30, 2012 USD ($)	Jun. 30, 2013 USD ($)	Jun. 30, 2012 USD ($)	Jun. 30, 2013 Erbitux [Member] USD ($)	Jun. 30, 2012 Erbitux [Member] USD ($)	Jun. 30, 2013 Erbitux [Member] USD ($)	Jun. 30, 2012 Erbitux [Member] USD ($)	Jun. 30, 2013 Effient [Member] USD ($)	Jun. 30, 2012 Effient [Member] USD ($)	Jun. 30, 2013 Effient [Member] USD ($)	Jun. 30, 2012 Effient [Member] USD ($)	Jun. 30, 2013 Amylin [Member] USD ($)	Jun. 30, 2012 Amylin [Member] USD ($)	Jun. 30, 2013 Amylin [Member] USD ($)	Jun. 30, 2012 Amylin [Member] USD ($)	Jun. 30, 2013 Exenatide [Member] USD ($)	Jun. 30, 2012 Exenatide [Member] USD ($)	Jun. 30, 2013 Exenatide [Member] USD ($)	Jun. 30, 2012 Exenatide [Member] USD ($)	Jun. 30, 2013 Boerhringer Ingelheim (BI) [Member] USD ($)	Jun. 30, 2012 Boerhringer Ingelheim (BI) [Member] USD ($)	Mar. 31, 2011 Boerhringer Ingelheim (BI) [Member] USD ($)	Jun. 30, 2013 Boerhringer Ingelheim (BI) [Member] USD ($)	Jun. 30, 2012 Boerhringer Ingelheim (BI) [Member] USD ($)	Nov. 30, 2011 Sales [Member] Amylin [Member]	Oct. 31, 2011 Sales [Member] Outside the United States [Member] Exenatide [Member]	Aug. 31, 2012 Revenue Share [Member] Amylin [Member] USD ($)	Nov. 30, 2011 Revenue Share [Member] Amylin [Member] USD ($)	Nov. 30, 2011 Revenue Share [Member] United States [Member] Amylin [Member]	Nov. 30, 2011 Revenue Share [Member] Outside the United States [Member] Amylin [Member]	Nov. 30, 2011 Secured Note [Member] Amylin [Member]	Oct. 31, 2011 Gross Margin Share [Member] United States [Member] Exenatide [Member]	Jun. 30, 2001 Profit and Development and Marketing Share [Member] Effient [Member]	Dec. 31, 2009 Research and Development Exp [Member] Baricitinib [Member]	Oct. 31, 2011 Research and Development and Marketing and Selling Expense [Member] United States [Member] Exenatide [Member]	Nov. 30, 2011 Milestone Payments, Development and Regulatory [Member] Amylin [Member] USD ($)	Jun. 30, 2013 Milestone Payments, Development and Regulatory [Member] BI compounds [Member] EUR (€)	Mar. 31, 2013 Milestone Payments, Development and Regulatory [Member] BI compounds [Member] USD ($)	Dec. 31, 2011 Milestone Payments, Development and Regulatory [Member] BI compounds [Member] USD ($)	Mar. 31, 2011 Milestone Payments, Development and Regulatory [Member] LLY compounds [Member] USD ($)	Mar. 31, 2011 Milestone Payments, Development and Regulatory [Member] LLY optional compound [Member] USD ($)	Dec. 31, 2009 Milestone Payments, Development and Regulatory [Member] Baricitinib [Member] USD ($)	Dec. 31, 2012 Milestone Payments, Development and Regulatory [Member] Baricitinib [Member] USD ($)	Dec. 31, 2010 Milestone Payments, Development and Regulatory [Member] Baricitinib [Member] USD ($)	Jun. 30, 2011 Milestone Payments, Sales-based [Member] TPG-Axon [Member] USD ($)	Dec. 31, 2009 Milestone Payments, Sales-based [Member] Baricitinib [Member] USD ($)	Jun. 30, 2011 Royalty Agreement Terms [Member] Solanezumab [Member]	Dec. 31, 2009 Royalty Agreement Terms [Member] Baricitinib [Member]	Jun. 30, 2011 Loan Commitment [Member] Exenatide Once Weekly [Member] USD ($)	Nov. 30, 2011 Upfront Payment [Member] Amylin [Member] USD ($)
Net product sales		$ 5,759,900,000	$ 5,455,500,000	$ 11,208,400,000	$ 10,869,300,000	$ 12,500,000	$ 28,700,000	$ 37,700,000	$ 62,700,000	$ 137,400,000	$ 111,000,000	$ 253,200,000	$ 226,900,000					$ 21,000,000	$ 53,100,000	$ 85,100,000	$ 101,600,000
Collaboration and other revenue		169,800,000	145,200,000	323,300,000	333,400,000	79,300,000	81,400,000	148,900,000	160,600,000									0	14,100,000	0	65,400,000	54,800,000	13,100,000		97,400,000	25,900,000
Revenue		5,929,700,000	5,600,700,000	11,531,700,000	11,202,700,000	91,800,000	110,100,000	186,600,000	223,300,000									21,000,000	67,200,000	85,100,000	167,000,000
Income related to transfer of exenatide rights		0	0	495,400,000	0									0	0	495,400,000	0
Research and development		1,330,400,000	1,320,700,000	2,678,500,000	2,472,200,000
Collaborative Arrangement, Income Statement Classification and Amounts		55,200,000	45,900,000	100,400,000	92,700,000
Collaborative Arrangement, Rights and Obligations, Terms																													1,260,000,000	1,200,000,000								150,000,000	(228,800,000)	(92,200,000)	(478,700,000)	290,000,000	525,000,000	(515,000,000)	(50,000,000)	(49,000,000)	(70,000,000)	(150,000,000)			(165,000,000)	250,000,000
Collaborative Arrangement, Rights and Obligations, Terms of Arrangement, Period																																																	10 years
Debt Instrument, Interest Rate, Stated Percentage																																	9.50%
Collaborative Arrangement, Rights and Obligations Percent																											15.00%	100.00%			65.00%	35.00%		50.00%	50.00%	30.00%	50.00%													20.00%
Proceeds from prepayment of revenue-sharing obligation	1,210,000,000
Acquired in-process research and development																								388,000,000
Amortization of Intangible Assets		$ 145,200,000	$ 133,100,000	$ 291,300,000	$ 280,800,000