Goodwill and other intangible assets - Goodwill (Detail) - USD ($) $ in Millions		6 Months Ended		12 Months Ended
		Jun. 30, 2022		Dec. 31, 2021
Goodwill And Intangible Assets Disclosure [Abstract]
Balance at beginning of year		$ 73,875	[1]	$ 73,734
Business acquisitions		35		353
Other, including foreign currency translation		(292)		(212)
Balance at end of period	[1]	$ 73,618		$ 73,875

[1] Net of accumulated goodwill impairments of $11.0 billion as of June 30, 2022 and December 31, 2021.