v3.26.3
Allowance for Loan Losses - Education Loans - Loan Type (Detail) - FFELP Loans [Member] - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Financing Receivable Recorded Investment Past Due [Line Items]    
Total loans, gross $ 26,063 $ 29,138
Change (3,075)  
Stafford Loans [Member]    
Financing Receivable Recorded Investment Past Due [Line Items]    
Total loans, gross 8,615 9,528
Change (913)  
Consolidation Loans [Member]    
Financing Receivable Recorded Investment Past Due [Line Items]    
Total loans, gross 14,796 16,649
Change (1,853)  
Rehab Loans [Member]    
Financing Receivable Recorded Investment Past Due [Line Items]    
Total loans, gross 2,652 $ 2,961
Change $ (309)