Loans - Loans HIP in past due status, non-performing status and accruing loans past-due 90 days or more by loan class (Parenthetical) (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unearned Income	$ 306,650	$ 295,156
Loans held-for-sale, at fair value	11,181	5,381
Notes Receivable Gross	32,338,373	32,077,769
Non-accrual with no allowance	176,722	177,104
Asset pledged as collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Receivable Gross	7,700,000	7,400,000
Federal Home Loan Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Line Of Credit Facility Current Borrowing Capacity	2,800,000	2,100,000
Federal Home Loan Bank | Asset pledged as collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Receivable Gross	5,100,000	4,800,000
FRB Advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Receivable Gross	2,600,000	2,600,000
Line Of Credit Facility Current Borrowing Capacity	1,500,000	1,400,000
Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Receivable Gross	31,094,292	30,783,152
Reverse Mortgages | Current
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes Receivable Gross	40,000	42,000
Residential mortgage loans insured By FHA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual with no allowance	$ 167,000	$ 190,000