Goodwill and other intangible assets - Goodwill (Detail) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Mar. 31, 2025	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Balance at the beginning of the year	[1]	$ 83,880	$ 84,626
Business acquisitions		58	87
Other, including foreign currency translation		69	(833)
Balance at the end of the period	[1]	$ 84,007	$ 83,880

[1] Net of accumulated goodwill impairments of $11.5 billion as of March 31, 2025 and December 31, 2024 and $11.1 billion as of December 31, 2023.