Segment information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended									12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011		Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues [Abstract]
Product sales	$ 4,337	$ 4,201	$ 4,200	$ 3,901	$ 3,907	$ 3,877	[1]	$ 3,893	$ 3,618	$ 16,639	$ 15,295	$ 14,660
Other revenues										626	287	393
Total revenues										17,265	15,582	15,053
Neulasta [Member]
Revenues [Abstract]
Product sales										4,092	3,952	3,558
NEUPOGEN [Member]
Revenues [Abstract]
Product sales										1,260	1,260	1,286
ENBREL [Member]
Revenues [Abstract]
Product sales										4,236	3,701	3,534
Aranesp [Member]
Revenues [Abstract]
Product sales										2,040	2,303	2,486
EPOGEN [Member]
Revenues [Abstract]
Product sales										1,941	2,040	2,524
Sensipar Mimpara [Member]
Revenues [Abstract]
Product sales										950	808	714
Vectibix [Member]
Revenues [Abstract]
Product sales										359	322	288
Nplate [Member]
Revenues [Abstract]
Product sales										368	297	229
XGEVA [Member]
Revenues [Abstract]
Product sales										748	351	8
Prolia [Member]
Revenues [Abstract]
Product sales										472	203	33
Other [Member]
Revenues [Abstract]
Product sales										$ 173	$ 58	$ 0

[1] We recorded a $780 million legal settlement charge ($705 million, net of tax) in connection with an agreement in principle to settle allegations related to our sales and marketing practices.