Goodwill and other intangible assets - Goodwill (Detail) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
		Mar. 31, 2023		Dec. 31, 2022
Goodwill And Intangible Assets Disclosure [Abstract]
Balance at beginning of year		$ 78,119	[1]	$ 73,875
Business acquisitions		6,112		4,657
Other, including foreign currency translation		(729)		(413)
Balance at end of period	[1]	$ 83,502		$ 78,119

[1] Net of accumulated goodwill impairments of $11.0 billion as of March 31, 2023 and December 31, 2022.