Goodwill and Intangible Assets - Goodwill balance by business segment (Details)	3 Months Ended		12 Months Ended
	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) item
Goodwill Information
Number of business combinations completed			0		0
Purchased goodwill from acquisitions	$ 0		$ 0	$ 3,469,000,000
Goodwill acquired during the period which is deductible for tax purposes				0
Goodwill
Balance at the beginning of the period		$ 13,444,000,000	13,444,000,000	10,051,000,000
Acquisition activity			(34,000,000)	3,469,000,000
Divestiture activity			(29,000,000)	(49,000,000)
Translation and other			421,000,000	(27,000,000)
Balance at the end of the period	13,802,000,000		13,802,000,000	13,444,000,000	$ 10,051,000,000
Amount of Goodwill impairment	0	0		0	0
Safety and Industrial
Goodwill
Balance at the beginning of the period		4,621,000,000	4,621,000,000	4,716,000,000
Divestiture activity				(49,000,000)
Translation and other			66,000,000	(46,000,000)
Balance at the end of the period	4,687,000,000		4,687,000,000	4,621,000,000	4,716,000,000
Transportation and Electronics
Goodwill
Balance at the beginning of the period		1,830,000,000	1,830,000,000	1,857,000,000
Divestiture activity			(10,000,000)
Translation and other			38,000,000	(27,000,000)
Balance at the end of the period	1,858,000,000		1,858,000,000	1,830,000,000	1,857,000,000
Health Care
Goodwill
Balance at the beginning of the period		6,739,000,000	6,739,000,000	3,248,000,000
Acquisition activity			(34,000,000)	3,469,000,000
Divestiture activity			(19,000,000)
Translation and other			306,000,000	22,000,000
Balance at the end of the period	6,992,000,000		6,992,000,000	6,739,000,000	3,248,000,000
Consumer
Goodwill
Balance at the beginning of the period		$ 254,000,000	254,000,000	230,000,000
Translation and other			11,000,000	24,000,000
Balance at the end of the period	$ 265,000,000		$ 265,000,000	$ 254,000,000	$ 230,000,000