Goodwill and other intangible assets - Goodwill (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2022		Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Balance at beginning of year		$ 73,875	[1]	$ 73,734
Business acquisitions		4,657		353
Other, including foreign currency translation		(413)		(212)
Balance at end of year	[1]	$ 78,119		$ 73,875

[1] Net of accumulated goodwill impairments of $11.0 billion as of December 31, 2022 and 2021