Accounting for Transfers and Servicing of Financial Assets and Variable Interest Entities - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended			6 Months Ended			12 Months Ended
		Jun. 30, 2023		Jun. 30, 2022	Jun. 30, 2023		Jun. 30, 2022	Dec. 31, 2022
Variable Interest Entity [Line Items]
Assets related to consolidated VIEs		$ 680,825			$ 680,825			$ 674,805
Liabilities related to consolidated VIEs		627,341			627,341			623,573
Available-for-sale securities	[2]	69,221	[1],[3]		69,221	[1],[3]		72,910
Community Development And Tax Advantaged Investments [Member]
Variable Interest Entity [Line Items]
Federal and state income tax credits recognized in tax expense		149		$ 112	287		$ 225
Expense related to investments		135		106	265		208
Investment tax credits		72		162	236		175
Financial Support Waived Fees [Member]
Variable Interest Entity [Line Items]
Financial or other support to money market funds				$ 7			$ 65
Variable Interest Entity Not Primary Beneficiary [Member] | Private Investment Funds and Partnerships [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss		318			318			310
Assets related to consolidated VIEs		198			198			177
Variable Interest Entity Not Primary Beneficiary [Member] | Community Development And Tax Advantaged Investments [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss		9,830			9,830			9,761
Assets related to consolidated VIEs		6,242			6,242			5,452
Liabilities related to consolidated VIEs		3,013			3,013			2,416
Variable Interest Entity Not Primary Beneficiary [Member] | Minimum [Member]
Variable Interest Entity [Line Items]
Aggregate amount of investments in unconsolidated VIEs		1			1			1
Variable Interest Entity Not Primary Beneficiary [Member] | Maximum [Member]
Variable Interest Entity [Line Items]
Aggregate amount of investments in unconsolidated VIEs		91			91			116
Variable Interest Entity Primary Beneficiary [Member] | Senior Notes [Member]
Variable Interest Entity [Line Items]
Available-for-sale securities		6,600			6,600			3,400
Collateral held related to senior notes					7,700			4,000
Variable Interest Entity Primary Beneficiary [Member] | Community Development And Tax Advantaged Investments [Member]
Variable Interest Entity [Line Items]
Assets related to consolidated VIEs		5,900			5,900			5,900
Liabilities related to consolidated VIEs		4,400			4,400			4,200
Variable Interest Entity Primary Beneficiary [Member] | Tender Option Bond Program [Member]
Variable Interest Entity [Line Items]
Assets related to consolidated VIEs		1,000			1,000			1,500
Liabilities related to consolidated VIEs		$ 1,000			$ 1,000			$ 1,000

[1] Amortized cost excludes portfolio level basis adjustments of $(1) million.

[2] Includes only collateral pledged by the Company where counterparties have the right to sell or pledge the collateral.

[3] The weighted-average maturity of total held-to-maturity investment securities was 9.2 years at December 31, 2022, with a corresponding weighted-average yield of 2.18 percent. The weighted-average maturity of total available-for-sale investment securities was 7.4 years at December 31, 2022, with a corresponding weighted-average yield of 2.94 percent.