Guarantee Arrangements, Pledged Assets and Repurchase Agreements - Narrative (Detail) - USD ($)		3 Months Ended	36 Months Ended
		Jun. 30, 2022	Dec. 31, 2007	Sep. 30, 2022	Dec. 31, 2021
Guarantor Obligations [Line Items]
Deferred fees				$ 3,000,000	$ 4,000,000
Carrying value of swap				1,518,906,000,000	1,395,345,000,000
Lease not yet commenced, lease term		20 years
Operating leases, not yet commenced		$ 230,000,000
Estimate of reasonably possible loss				150,000,000
Securities available-for-sale	[1]			28,082,000,000	35,298,000,000
Trading assets	[1]			21,082,000,000	24,043,000,000
Collateral accepted under security resale agreements, fair value				35,419,000,000	12,848,000,000
Collateral accepted under security repurchase agreements but not reported on the balance sheet that can be sold or repledged, fair value				35,044,000,000	12,848,000,000
Collateral accepted under security repurchase agreements that has been sold or repledged under repurchase agreements or to cover short sales				4,342,000,000	538,000,000
Asset Pledged as Collateral with Right
Guarantor Obligations [Line Items]
Securities available-for-sale				261,000,000	2,410,000,000
Trading assets				1,160,000,000	1,749,000,000
Obligation to Repurchase Receivables Sold
Guarantor Obligations [Line Items]
Estimated repurchase liability				12,000,000	3,000,000
Obligation to Repurchase Receivables Sold | Minimum
Guarantor Obligations [Line Items]
Estimate of reasonably possible loss				0
Obligation to Repurchase Receivables Sold | Maximum
Guarantor Obligations [Line Items]
Estimate of reasonably possible loss				30,000,000
HSBC Securities
Guarantor Obligations [Line Items]
Whole loan securitization			$ 24,000,000,000
HSBC Securities | Mortgage Securitization Activity Related Litigation
Guarantor Obligations [Line Items]
Mortgage securitization outstanding loan purchase and sold				2,500,000,000	2,700,000,000
Other liabilities
Guarantor Obligations [Line Items]
Allowance for credit losses on unfunded standby letters of credit				15,000,000	14,000,000
Other liabilities | Standby Letters of Credit
Guarantor Obligations [Line Items]
Deferred fees				50,000,000	51,000,000
Swap
Guarantor Obligations [Line Items]
Carrying value of swap				$ 34,000,000	$ 38,000,000
Changes in fair value		$ (31,000,000)

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at September 30, 2022 and December 31, 2021. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 17, "Variable Interest Entities," for additional information. September 30, 2022December 31, 2021(in millions)AssetsLoans$127 $46 Other assets44 55 Total assets$171 $101 LiabilitiesInterest, taxes and other liabilities$26 $9 Total liabilities$26 $9