Loans - Narrative (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net deferred origination costs (fees)		$ 27		$ 27		$ 17
Net unamortized premium (discount)		(8)		(8)		(13)
Interest income that was recorded on nonaccrual loans and included in interest income during the period		11	$ 0	19	$ 3
Loans modified			57	313	316
Loans, net	[1]	62,014		62,014		58,987
Interest only residential mortgage loans		4,564		4,564		4,392
90+ Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified, subsequently default			0		0
Loans, net		222		222		309
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified		0	2	1	11
Loans, net		20,899		20,899		19,030
Consumer loans | 90+ Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified, subsequently default		0		0
Loans, net		105		105		99
Consumer loans | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral-dependent loans		287		287		278
Loans modified			2	1	11
Loans, net		20,235		20,235		18,341
Consumer loans | Residential mortgages | 90+ Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net		96		96		91
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral-dependent loans		611		611		618
Loans modified		82	$ 55	312	$ 305
Additional commitments for loans modified		43		43		85
Loans, net		41,115		41,115		39,957
Commercial loans | 90+ Days
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified, subsequently default		0		1
Loans, net		$ 117		$ 117		$ 210

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at September 30, 2024 and December 31, 2023. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 15, "Variable Interest Entities," for additional information. September 30, 2024December 31, 2023(in millions)AssetsOther assets$13 $23 Total assets$13 $23 LiabilitiesInterest, taxes and other liabilities$21 $17 Total liabilities$21 $17