Accounting for Transfers and Servicing of Financial Assets and Variable Interest Entities - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Variable Interest Entity [Line Items]
Assets related to consolidated VIEs	$ 586,517		$ 573,284
Liabilities related to consolidated VIEs	534,849		517,897
Community Development And Tax Advantaged Investments [Member]
Variable Interest Entity [Line Items]
Federal and state income tax credits recognized in tax expense	113	$ 133
Expense related to investments	102	126
Investment tax credits	13	37
Expenses related to investments recognized in tax expense	91	92
Financial Support Waived Fees [Member]
Variable Interest Entity [Line Items]
Financial or other support to money market funds	58	$ 47
Variable Interest Entity Not Primary Beneficiary [Member] | Private Investment Funds and Partnerships [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	84		84
Assets related to consolidated VIEs	41		40
Variable Interest Entity Not Primary Beneficiary [Member] | Community Development And Tax Advantaged Investments [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	9,764		9,899
Assets related to consolidated VIEs	5,106		4,484
Liabilities related to consolidated VIEs	2,331		1,890
Variable Interest Entity Not Primary Beneficiary [Member] | Minimum [Member]
Variable Interest Entity [Line Items]
Aggregate amount of investments in unconsolidated VIEs	1		1
Variable Interest Entity Not Primary Beneficiary [Member] | Maximum [Member]
Variable Interest Entity [Line Items]
Aggregate amount of investments in unconsolidated VIEs	74		75
Variable Interest Entity Primary Beneficiary [Member] | Community Development And Tax Advantaged Investments [Member]
Variable Interest Entity [Line Items]
Assets related to consolidated VIEs	4,900		5,000
Liabilities related to consolidated VIEs	3,300		3,400
Variable Interest Entity Primary Beneficiary [Member] | Tender Option Bond Program [Member]
Variable Interest Entity [Line Items]
Assets related to consolidated VIEs	1,600		1,700
Liabilities related to consolidated VIEs	$ 1,200		$ 1,200