Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net sales	$ 10,735	$ 9,823	$ 9,048
Cost of products sold	3,116	2,813	2,593
Gross profit	7,620	7,011	6,455
Operating expenses:
Selling, general and administrative expenses	3,941	3,569	3,294
Research and development expenses	1,174	1,113	997
Royalty expense	65	70	68
Amortization expense	699	599	565
Intangible asset impairment charges	105	35	4
Contingent consideration expense (benefit)	(35)	(21)	(80)
Restructuring charges (credits)	38	36	37
Litigation-related charges (credits)	115	103	285
Operating expenses	6,102	5,504	5,170
Operating income (loss)	1,518	1,506	1,285
Other income (expense):
Interest expense	(473)	(241)	(229)
Other, net	(358)	156	(124)
Income (loss) before income taxes	687	1,422	933
Income tax (benefit) expense	(4,013)	(249)	828
Net income (loss)	$ 4,700	$ 1,671	$ 104
Net income (loss) per common share — basic	$ 3.38	$ 1.21	$ 0.08
Net income (loss) per common share — assuming dilution	$ 3.33	$ 1.19	$ 0.08
Weighted-average shares outstanding
Basic	1,391.5	1,381.0	1,370.1
Assuming dilution	1,410.6	1,401.4	1,392.7