Loans and finance receivables (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Receivables [Abstract]
Loans and finance receivables before allowances and discounts	$ 22,596	$ 22,065
Allowances for credit losses	(781)	(765)	$ (725)	$ (712)
Unamortized acquisition discounts and points	(550)	(549)
Loans and finance receivables	$ 21,265	$ 20,751

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant