Income taxes - Provision for income taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
U.S. federal - Current	$ 605	$ 943	$ 1,235
Non-U.S. - Current	244	240	212
U.S. state - Current	15	24	27
Total current income tax expense (benefit)	864	1,207	1,474
U.S. federal - Deferred	(139)	(277)	(223)
Non-U.S. - Deferred	(71)	(22)	32
U.S. state - Deferred	0	0	0
Total deferred income tax expense (benefit)	(210)	(299)	(191)
Total U.S. federal income taxes	466	666	1,012
Total Non-U.S. income taxes	173	218	244
Total U.S. state income taxes	15	24	27
Provision for income taxes	$ 654	$ 908	$ 1,283