Significant Accounting Policies - Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle
Net sales	$ 8,390	$ 7,810	$ 16,668	$ 15,495
Operating expenses
Cost of sales	4,227	4,020	8,463	7,902
Selling, general and administrative expenses	1,800	1,620	4,373	3,234
Research, development and related expenses	468	478	954	954
Gain on sale of businesses	(506)	(461)	(530)	(490)
Total operating expenses	5,989	5,657	13,260	11,600
Operating income	2,401	2,153	3,408	3,895
Other expense (income), net	51	11	93	16
Income before income taxes	$ 2,350	2,142	$ 3,315	3,879
Previously Reported | ASU 2017-07 Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost
New Accounting Pronouncements or Change in Accounting Principle
Net sales		7,810		15,495
Operating expenses
Cost of sales		4,007		7,876
Selling, general and administrative expenses		1,607		3,207
Research, development and related expenses		473		944
Gain on sale of businesses		(461)		(490)
Total operating expenses		5,626		11,537
Operating income		2,184		3,958
Other expense (income), net		42		79
Income before income taxes		2,142		3,879
Change | ASU 2017-07 Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost
Operating expenses
Cost of sales		13		26
Selling, general and administrative expenses		13		27
Research, development and related expenses		5		10
Total operating expenses		31		63
Operating income		(31)		(63)
Other expense (income), net		$ (31)		$ (63)