Income taxes (Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current provision:
Federal	$ 865	$ 921	$ 1,284
State	18	34	39
Foreign	359	277	277
Total current provision	1,242	1,232	1,600
Deferred benefit:
Federal	(308)	(321)	(276)
State	(9)	9	(22)
Foreign	(117)	(51)	(6)
Total deferred benefit	(434)	(363)	(304)
Total provision for income taxes	$ 808	$ 869	$ 1,296