Stockholders' equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Billions	3 Months Ended
	Sep. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Mar. 31, 2023	Oct. 31, 2024
Class of Stock [Line Items]
Amount available for stock repurchases under a board approved stock repurchase plan	$ 7.0
Dividends declared per share (in usd per share)	$ 2.25	$ 2.25	$ 2.25	$ 2.13	$ 2.13
Subsequent Event
Class of Stock [Line Items]
Dividends payable per share (in usd per share)						$ 2.25