Other Borrowings - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Debt [Line Items]
FHLB advances	$ 4,000	$ 0
Other Short-term Borrowings	60	35
Short-term Debt	5,096	727
Senior Notes	316	318
Notes Payable	907	457
Long-term Debt	1,223	775
Other borrowings	6,319	1,502
Customer repurchase agreements	26	17
Federal Funds Purchased	1,010	675
Senior Notes
Debt [Line Items]
Debt Instrument, Face Amount	$ 300
Debt Instrument, Interest Rate, Stated Percentage	6.50%
Credit Linked Notes Maturing July 2059
Debt [Line Items]
Debt Instrument, Face Amount	$ 206	228
Debt Issuance Costs, Net	3	3
Credit Linked Notes Maturing April 2052
Debt [Line Items]
Debt Instrument, Face Amount	191
Debt Issuance Costs, Net	3
Credit Linked Notes Maturing June 2028
Debt [Line Items]
Debt Instrument, Face Amount	300
Debt Issuance Costs, Net	5
Credit Linked Notes Maturing December 2024
Debt [Line Items]
Debt Instrument, Face Amount	242	242
Debt Issuance Costs, Net	2	2
Federal Home Loan Bank Advances [Member]
Debt [Line Items]
Additional available credit with the entity	7,100	7,800
FRB [Member]
Debt [Line Items]
Additional available credit with the entity	5,000	$ 3,400
Unsecured Credit Facility [Member]
Debt [Line Items]
Secured borrowing credit line	4,700
Warehouse Agreement Borrowings
Debt [Line Items]
Additional available credit with the entity	$ 1,000