Segment information (Customer Concentration, Product Sales) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues Earned from Major Customers [Abstract]
Revenues	$ 22,849	$ 22,991	$ 21,662
AmerisourceBergen Corporation [Member]
Revenues Earned from Major Customers [Abstract]
Revenues	$ 10,742	$ 10,100	$ 10,038
Gross product sales to major customer (as defined) as a percentage of total gross revenues	31.00%	31.00%	34.00%
Gross product sales to major customer (as defined) as a percentage of U.S. gross product sales	37.00%	38.00%	42.00%
McKesson Corporation [Member]
Revenues Earned from Major Customers [Abstract]
Revenues	$ 10,625	$ 9,710	$ 8,766
Gross product sales to major customer (as defined) as a percentage of total gross revenues	30.00%	30.00%	30.00%
Gross product sales to major customer (as defined) as a percentage of U.S. gross product sales	35.00%	34.00%	34.00%
Cardinal Health, Inc. [Member]
Revenues Earned from Major Customers [Abstract]
Revenues	$ 7,049	$ 6,520	$ 5,045
Gross product sales to major customer (as defined) as a percentage of total gross revenues	20.00%	20.00%	17.00%
Gross product sales to major customer (as defined) as a percentage of U.S. gross product sales	24.00%	24.00%	21.00%