v3.26.1
Allowance for Loan Losses - Education Loans - Allowance for Credit Losses and Recorded Investments in Loans (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Allowance for Loan Losses        
Beginning balance $ 479 $ 579 $ 537 $ 621
Provision:        
Total provision 26 37 54 67
Charge-offs:        
Gross charge-offs (92) (101) (192) (189)
Expected future recoveries on current period gross charge-offs 11 13 22 23
Net charge-offs (81) (88) (170) (166)
Decrease in expected future recoveries on previously fully charged-off loans 3 2 7 8
Allowance at end of period 426 530 426 530
Private Education Loans [Member]        
Allowance for Loan Losses        
Beginning balance 314 397 364 441
Provision:        
Total provision 17 29 35 51
Charge-offs:        
Gross charge-offs (82) (93) (165) (175)
Expected future recoveries on current period gross charge-offs 11 13 22 23
Net charge-offs (71) (80) (143) (152)
Decrease in expected future recoveries on previously fully charged-off loans 3 2 7 8
Allowance at end of period $ 263 $ 348 $ 263 $ 348
Net charge-offs as a percentage of average loans in repayment 1.84% 2.08% 1.87% 1.98%
Ending total loans $ 15,409 $ 15,878 $ 15,409 $ 15,878
Average loans in repayment 14,803 15,375 14,792 15,423
Ending loans in repayment 14,781 15,267 14,781 15,267
Provision For Education Loans [Member]        
Provision:        
Total provision 25 37 52 67
FFELP Loans [Member]        
Allowance for Loan Losses        
Beginning balance 165 182 173 180
Provision:        
Total provision 8 8 17 16
Charge-offs:        
Gross charge-offs (10) (8) (27) (14)
Expected future recoveries on current period gross charge-offs 0 0 0 0
Net charge-offs (10) (8) (27) (14)
Decrease in expected future recoveries on previously fully charged-off loans 0 0 0 0
Allowance at end of period $ 163 $ 182 $ 163 $ 182
Net charge-offs as a percentage of average loans in repayment 0.18% 0.14% 0.24% 0.12%
Ending total loans $ 26,738 $ 29,800 $ 26,738 $ 29,800
Average loans in repayment 22,478 25,133 22,850 25,295
Ending loans in repayment $ 22,324 $ 24,867 $ 22,324 $ 24,867