Commitments to originate real estate loans for sale.

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Commitments to sell real estate loans net.

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Interest rate swap agreements used for interest rate risk management.

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Amount before allowance of consumer installment revolving and home equity loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts.

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Other credit-related commitments.

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Other financial instruments.

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Amount of domestic interest-bearing checking and savings accounts, which may include money market accounts, NOW accounts, interest-bearing corporate checking accounts, brokered deposits and other savings accounts.

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Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

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Amount after offset of short term borrowing where a bank borrows, at the federal funds rate, from another bank and securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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The amount outstanding of funds lent to other depository institutions, securities brokers, or securities dealers in the form of Federal Funds sold; for example, immediately available funds lent under agreements or contracts that mature in one business day or roll over under a continuing contract, regardless of the nature of the transaction or the collateral involved, excluding overnight lending for commercial and industrial purposes. Also include Federal Funds sold under agreements to resell on a gross basis, excluding (1) sales of term Federal Funds, (2) due bills representing purchases of securities or other assets by the reporting bank that have not yet been delivered and similar instruments, (3) resale agreements that mature in more than one business day involving assets other than securities, and (4) yield maintenance dollar repurchase agreements.

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For banks and other depository institutions (including Federal Reserve Banks, if applicable): Interest-bearing deposits in other financial institutions for relatively short periods of time including, for example, certificates of deposits, which are presented separately from cash on the balance sheet.

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Sum of the carrying amounts as of the balance sheet date of all investments.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of domestic noninterest-bearing deposits held by the entity, which may include demand deposits, checking, brokered and retail deposits.

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Amount, before allowance for credit loss, of financing receivable.

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Amount of time deposit liabilities, including certificates of deposit.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Fair Value Measurements - Carrying Amounts and Estimated Fair Value for Financial Instrument Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Financial assets:
Interest-bearing deposits at banks	$ 31,407,227	$ 23,663,810
Investment securities	6,610,667	7,045,697
Federal funds sold	1,000
Loans and leases:
Allowance for credit losses	(1,636,206)	(1,736,387)	$ (1,384,366)	$ (1,051,071)
Loans and leases, net	97,662,874	96,799,480
Financial liabilities:
Noninterest-bearing deposits	(53,641,419)	(47,572,884)
Savings and interest-checking deposits	(70,679,036)	(67,680,840)
Time deposits	(3,514,219)	(3,899,910)
Deposits at Cayman Islands office	(641,691)	(652,104)
Long-term borrowings	(3,498,503)	(4,382,193)
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial assets:
Cash and cash equivalents	1,213,877	1,497,457
Trading account assets	49,115	50,060
Investment securities	64,150	63,129
Significant Observable Inputs (Level 2) [Member]
Financial assets:
Cash and cash equivalents	45,112	55,286
Interest-bearing deposits at banks	31,407,227	23,663,810
Trading account assets	638,244	1,018,521
Investment securities	6,551,036	7,005,571
Federal funds sold	1,000
Loans and leases:
Loans and leases, net	4,113,977	4,413,566
Accrued interest receivable	440,658	419,936
Financial liabilities:
Noninterest-bearing deposits	(53,641,419)	(47,572,884)
Savings and interest-checking deposits	(70,679,036)	(67,680,840)
Time deposits	(3,526,947)	(3,919,367)
Deposits at Cayman Islands office	(641,691)	(652,104)
Short-term borrowings	(58,957)	(59,482)
Long-term borrowings	(3,609,625)	(4,490,433)
Accrued interest payable	(43,745)	(59,916)
Trading account liabilities	(95,239)	(116,902)
Other financial instruments:
Commitments to sell real estate loans	36,698	(18,429)
Interest rate swap agreements used for interest rate risk management	(3,194)	1,076
Significant Unobservable Inputs (Level 3) [Member]
Financial assets:
Investment securities	67,556	70,289
Loans and leases:
Consumer loans	16,781,406	16,554,050
Loans and leases, net	94,339,767	93,266,904
Other financial instruments:
Commitments to originate real estate loans for sale	13,757	43,234
Other credit-related commitments	(134,928)	(133,354)
Commercial Loans And Leases [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Loans and leases:
Commercial loans and leases	27,509,182	27,220,699
Commercial [Member] \| Significant Observable Inputs (Level 2) [Member]
Loans and leases:
Commercial loans and leases	98,513	277,911
Commercial [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Loans and leases:
Commercial loans and leases	36,563,245	36,538,669
Residential Real Estate Loans [Member] \| Significant Observable Inputs (Level 2) [Member]
Loans and leases:
Commercial loans and leases	4,015,464	4,135,655
Residential Real Estate Loans [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Loans and leases:
Commercial loans and leases	13,485,934	12,953,486
Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	1,258,989	1,552,743
Interest-bearing deposits at banks	31,407,227	23,663,810
Trading account assets	687,359	1,068,581
Investment securities	6,610,667	7,045,697
Federal funds sold	1,000
Loans and leases:
Consumer loans	16,712,233	16,570,421
Allowance for credit losses	(1,636,206)	(1,736,387)
Loans and leases, net	97,662,874	96,799,480
Accrued interest receivable	440,658	419,936
Financial liabilities:
Noninterest-bearing deposits	(53,641,419)	(47,572,884)
Savings and interest-checking deposits	(70,679,036)	(67,680,840)
Time deposits	(3,514,219)	(3,899,910)
Deposits at Cayman Islands office	(641,691)	(652,104)
Short-term borrowings	(58,957)	(59,482)
Long-term borrowings	(3,498,503)	(4,382,193)
Accrued interest payable	(43,745)	(59,916)
Trading account liabilities	(95,239)	(116,902)
Other financial instruments:
Commitments to originate real estate loans for sale	13,757	43,234
Commitments to sell real estate loans	36,698	(18,429)
Other credit-related commitments	(134,928)	(133,354)
Interest rate swap agreements used for interest rate risk management	(3,194)	1,076
Carrying Amount [Member] \| Commercial Loans And Leases [Member]
Loans and leases:
Commercial loans and leases	27,811,190	27,574,564
Carrying Amount [Member] \| Commercial [Member]
Loans and leases:
Commercial loans and leases	37,425,974	37,637,889
Carrying Amount [Member] \| Residential Real Estate Loans [Member]
Loans and leases:
Commercial loans and leases	17,349,683	16,752,993
Cumulative Amount of Fair Value Hedging Adjustment Increasing (Decreasing) the Carrying Amount [Member]
Financial assets:
Cash and cash equivalents	1,258,989	1,552,743
Interest-bearing deposits at banks	31,407,227	23,663,810
Trading account assets	687,359	1,068,581
Investment securities	6,682,742	7,138,989
Federal funds sold	1,000
Loans and leases:
Consumer loans	16,781,406	16,554,050
Loans and leases, net	98,453,744	97,680,470
Accrued interest receivable	440,658	419,936
Financial liabilities:
Noninterest-bearing deposits	(53,641,419)	(47,572,884)
Savings and interest-checking deposits	(70,679,036)	(67,680,840)
Time deposits	(3,526,947)	(3,919,367)
Deposits at Cayman Islands office	(641,691)	(652,104)
Short-term borrowings	(58,957)	(59,482)
Long-term borrowings	(3,609,625)	(4,490,433)
Accrued interest payable	(43,745)	(59,916)
Trading account liabilities	(95,239)	(116,902)
Other financial instruments:
Commitments to originate real estate loans for sale	13,757	43,234
Commitments to sell real estate loans	36,698	(18,429)
Other credit-related commitments	(134,928)	(133,354)
Interest rate swap agreements used for interest rate risk management	(3,194)	1,076
Cumulative Amount of Fair Value Hedging Adjustment Increasing (Decreasing) the Carrying Amount [Member] \| Commercial Loans And Leases [Member]
Loans and leases:
Commercial loans and leases	27,509,182	27,220,699
Cumulative Amount of Fair Value Hedging Adjustment Increasing (Decreasing) the Carrying Amount [Member] \| Commercial [Member]
Loans and leases:
Commercial loans and leases	36,661,758	36,816,580
Cumulative Amount of Fair Value Hedging Adjustment Increasing (Decreasing) the Carrying Amount [Member] \| Residential Real Estate Loans [Member]
Loans and leases:
Commercial loans and leases	$ 17,501,398	$ 17,089,141