Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net sales	$ 9,823	$ 9,048	$ 8,386
Cost of products sold	2,813	2,593	2,424
Gross profit	7,011	6,455	5,962
Operating expenses:
Selling, general and administrative expenses	3,569	3,294	3,099
Research and development expenses	1,113	997	920
Royalty expense	70	68	79
Amortization expense	599	565	545
Intangible asset impairment charges	35	4	11
Contingent consideration expense (benefit)	(21)	(80)	29
Restructuring charges (credits)	36	37	28
Litigation-related charges (credits)	103	285	804
Operating expenses	5,504	5,170	5,515
Operating income (loss)	1,506	1,285	447
Other income (expense):
Interest expense	(241)	(229)	(233)
Other, net	156	(124)	(37)
Income (loss) before income taxes	1,422	933	177
Income tax (benefit) expense	(249)	828	(170)
Net income (loss)	$ 1,671	$ 104	$ 347
Net income (loss) per common share — basic	$ 1.21	$ 0.08	$ 0.26
Net income (loss) per common share — assuming dilution	$ 1.19	$ 0.08	$ 0.25
Weighted-average shares outstanding
Basic	1,381.0	1,370.1	1,357.6
Assuming dilution	1,401.4	1,392.7	1,377.2