Segment information (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
AmerisourceBergen Corporation [Member]
Revenues earned from major customers
Gross product sales	$ 7,574	$ 7,678	$ 7,179
Gross product sales to major customer (as defined) as a percentage of total gross revenues	36.00%	38.00%	37.00%
Gross product sales to major customer (as defined) as a percentage of U.S. gross product sales	45.00%	47.00%	46.00%
McKesson Corporation [Member]
Revenues earned from major customers
Gross product sales	4,591	3,913	3,694
Gross product sales to major customer (as defined) as a percentage of total gross revenues	22.00%	19.00%	19.00%
Gross product sales to major customer (as defined) as a percentage of U.S. gross product sales	27.00%	24.00%	24.00%
Cardinal Health, Inc. [Member]
Revenues earned from major customers
Gross product sales	$ 3,021	$ 2,813	$ 2,841
Gross product sales to major customer (as defined) as a percentage of total gross revenues	14.00%	14.00%	15.00%
Gross product sales to major customer (as defined) as a percentage of U.S. gross product sales	18.00%	17.00%	18.00%