v3.26.3
Allowance for Loan Losses - Education Loans - Age Analysis of Past Due Loans Delinquencies (Parenthetical) (Details)
$ in Millions
Sep. 30, 2026
USD ($)
Financing Receivable, Past Due [Line Items]  
Loans held for sale $ 2,400
Private Education Loans [Member]  
Financing Receivable, Past Due [Line Items]  
Loans held for sale 2,400
In-School Education Loans [Member]  
Financing Receivable, Past Due [Line Items]  
Loans held for sale $ 235