Loans and finance receivables - Schedule of reconciliation of allowance for credit losses on loans and finance receivables (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Allowance For Credit Loss [Abstract]
Balance at beginning of year	$ 765	$ 712
Provision for credit losses	22	27
Charge-offs, net of recoveries	(6)	(14)
Balance at March 31	$ 781	$ 725