v3.26.3
Allowance for Loan Losses - Education Loans - Private Education Loan Portfolio Stratified by Key Credit Quality Indicators (Detail) - USD ($)
$ in Millions
Sep. 30, 2026
Jun. 30, 2026
Dec. 31, 2025
Sep. 30, 2025
Jun. 30, 2025
Dec. 31, 2024
Accounts Notes And Loans Receivable [Line Items]            
Loan allowance for losses $ (464) $ (426) $ (537) $ (592) $ (530) $ (621)
Private Education Loans [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Loans, gross 12,979     15,862    
Loan allowance for losses (299) $ (263) $ (364) (406) $ (348) $ (441)
Loans, net 12,680     15,456    
Loan, Net Charge-Offs in Year One 0     0    
Loan, Net Charge-Offs in Year Two (5)     (4)    
Loan, Net Charge-Offs in Year Three (6)     (4)    
Loan, Net Charge-Offs in Year Four (7)     (10)    
Loan, Net Charge-Offs in Year Five (9)     (19)    
Loan, Net Charge-Offs in Year Prior (175)     (211)    
Total Net Charge-Offs (202)     (248)    
FICO Scores [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One 2,263     1,591    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,515     1,132    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 631     640    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 327     1,213    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 849     3,019    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 7,394     8,267    
Total Loans, gross $ 12,979     $ 15,862    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 100.00%     100.00%    
FICO Scores [Member] | 640 and Above [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,249     $ 1,566    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,481     1,082    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 586     592    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 295     1,109    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 762     2,853    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 6,253     6,688    
Total Loans, gross $ 11,626     $ 13,890    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 90.00%     88.00%    
FICO Scores [Member] | Below 640 [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 14     $ 25    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 34     50    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 45     48    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 32     104    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 87     166    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 1,141     1,579    
Total Loans, gross $ 1,353     $ 1,972    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 10.00%     12.00%    
Loan Status [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,263     $ 1,591    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,515     1,132    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 631     640    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 327     1,213    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 849     3,019    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 7,394     8,267    
Total Loans, gross $ 12,979     $ 15,862    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 100.00%     100.00%    
Loan Status [Member] | In-school/Grace/Deferment/Forbearance [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 60     $ 73    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 51     94    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 35     53    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 18     46    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 33     75    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 263     300    
Total Loans, gross $ 460     $ 641    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 4.00%     4.00%    
Loan Status [Member] | Current/90 Days or Less Delinquent [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,201     $ 1,517    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,458     1,032    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 590     577    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 302     1,150    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 804     2,919    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 6,890     7,593    
Total Loans, gross $ 12,245     $ 14,788    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 94.00%     93.00%    
Loan Status [Member] | Greater than 90 days Delinquent [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2     $ 1    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 6     6    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 6     10    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 7     17    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 12     25    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 241     374    
Total Loans, gross $ 274     $ 433    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 2.00%     3.00%    
Seasoning [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,263     $ 1,591    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,515     1,132    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 631     640    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 327     1,213    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 849     3,019    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 7,394     8,267    
Total Loans, gross $ 12,979     $ 15,862    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 100.00%     100.00%    
Seasoning [Member] | 1-12 Payments [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,224     $ 1,527    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 756     595    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 14     25    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 4     19    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 3     9    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 17     26    
Total Loans, gross $ 3,018     $ 2,201    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 23.00%     14.00%    
Seasoning [Member] | 13-24 Payments [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 0     $ 0    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 735     458    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 328     330    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 17     37    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 12     33    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 31     36    
Total Loans, gross $ 1,123     $ 894    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 8.00%     6.00%    
Seasoning [Member] | 25-36 Payments [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 0     $ 0    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 0     0    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 271     243    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 162     336    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 36     80    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 69     75    
Total Loans, gross $ 538     $ 734    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 4.00%     5.00%    
Seasoning [Member] | 37-48 Payments [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 0     $ 0    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 0     0    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 0     0    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 135     791    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 194     1,443    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 154     131    
Total Loans, gross $ 483     $ 2,365    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 4.00%     15.00%    
Seasoning [Member] | More than 48 Payments [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 0     $ 0    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 0     0    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 0     0    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 0     0    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 591     1,418    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 7,011     7,848    
Total Loans, gross $ 7,602     $ 9,266    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 59.00%     58.00%    
Seasoning [Member] | School/Grace/Deferment [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 39     $ 64    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 24     79    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 18     42    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 9     30    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 13     36    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 112     151    
Total Loans, gross $ 215     $ 402    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 2.00%     2.00%    
Certain Loan Modifications [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,263     $ 1,591    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,515     1,132    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 631     640    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 327     1,213    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 849     3,019    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 7,394     8,267    
Total Loans, gross $ 12,979     $ 15,862    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 100.00%     100.00%    
Certain Loan Modifications [Member] | Modified [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 0     $ 0    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 23     14    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 45     32    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 43     104    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 119     213    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 3,221     4,933    
Total Loans, gross $ 3,451     $ 5,296    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 27.00%     33.00%    
Certain Loan Modifications [Member] | Non-Modified [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,263     $ 1,591    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,492     1,118    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 586     608    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 284     1,109    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 730     2,806    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 4,173     3,334    
Total Loans, gross $ 9,528     $ 10,566    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 73.00%     67.00%    
Cosigners [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,263     $ 1,591    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,515     1,132    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 631     640    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 327     1,213    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 849     3,019    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 7,394     8,267    
Total Loans, gross $ 12,979     $ 15,862    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 100.00%     100.00%    
Cosigners [Member] | With Cosigner [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 273     $ 318    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 197     329    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 80     212    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 31     129    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 1     66    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 2,110     4,017    
Total Loans, gross $ 2,692     $ 5,071    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 21.00%     32.00%    
Cosigners [Member] | Without Cosigner [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 1,990     $ 1,273    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,318     803    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 551     428    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 296     1,084    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 848     2,953    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 5,284     4,250    
Total Loans, gross $ 10,287     $ 10,791    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 79.00%     68.00%    
School Type [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,263     $ 1,591    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,515     1,132    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 631     640    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 327     1,213    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 849     3,019    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 7,394     8,267    
Total Loans, gross $ 12,979     $ 15,862    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 100.00%     100.00%    
School Type [Member] | Not For Profit [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 2,262     $ 1,500    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,515     1,069    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 622     604    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 315     1,148    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 831     2,842    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 6,812     7,185    
Total Loans, gross $ 12,357     $ 14,348    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 95.00%     90.00%    
School Type [Member] | For Profit [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 1     $ 91    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 0     63    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 9     36    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 12     65    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 18     177    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 582     1,082    
Total Loans, gross $ 622     $ 1,514    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 5.00%     10.00%