v3.26.1
Allowance for Loan Losses - Education Loans - Private Education Loan Portfolio Stratified by Key Credit Quality Indicators (Detail) - USD ($)
$ in Millions
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Accounts Notes And Loans Receivable [Line Items]            
Loan allowance for losses $ (426) $ (479) $ (537) $ (530) $ (579) $ (621)
Private Education Loans [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Loans, gross 15,409     15,878    
Loan allowance for losses (263) $ (314) $ (364) (348) $ (397) $ (441)
Loans, net 15,146     15,530    
Loan, Net Charge-Offs in Year One 0     0    
Loan, Net Charge-Offs in Year Two (3)     (2)    
Loan, Net Charge-Offs in Year Three (4)     (3)    
Loan, Net Charge-Offs in Year Four (5)     (6)    
Loan, Net Charge-Offs in Year Five (7)     (12)    
Loan, Net Charge-Offs in Year Prior (124)     (129)    
Total Net Charge-Offs (143)     (152)    
FICO Scores [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One 1,531     954    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,992     1,194    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 927     681    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 519     1,269    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 1,035     3,157    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 9,405     8,623    
Total Loans, gross $ 15,409     $ 15,878    
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 $ 1,522     $ 940    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,947     1,146    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 869     635    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 472     1,167    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 936     2,991    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 7,884     7,020    
Total Loans, gross $ 13,630     $ 13,899    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 88.00%     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 $ 9     $ 14    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 45     48    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 58     46    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 47     102    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 99     166    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 1,521     1,603    
Total Loans, gross $ 1,779     $ 1,979    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 12.00%     12.00%    
Loan Status [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 1,531     $ 954    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,992     1,194    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 927     681    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 519     1,269    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 1,035     3,157    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 9,405     8,623    
Total Loans, gross $ 15,409     $ 15,878    
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 $ 38     $ 29    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 99     91    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 81     55    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 41     51    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 43     73    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 326     312    
Total Loans, gross $ 628     $ 611    
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 $ 1,493     $ 924    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,885     1,097    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 838     618    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 469     1,201    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 977     3,063    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 8,770     7,905    
Total Loans, gross $ 14,432     $ 14,808    
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 $ 0     $ 1    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 8     6    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 8     8    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 9     17    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 15     21    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 309     406    
Total Loans, gross $ 349     $ 459    
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 $ 1,531     $ 954    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,992     1,194    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 927     681    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 519     1,269    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 1,035     3,157    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 9,405     8,623    
Total Loans, gross $ 15,409     $ 15,878    
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 $ 1,503     $ 932    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,462     879    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 36     28    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 19     22    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 10     11    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 24     30    
Total Loans, gross $ 3,054     $ 1,902    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 20.00%     12.00%    
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 455     238    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 664     484    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 31     48    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 23     37    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 40     41    
Total Loans, gross $ 1,213     $ 848    
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 166     125    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 351     524    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 56     107    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 93     85    
Total Loans, gross $ 666     $ 841    
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 89     645    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 412     2,182    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 209     160    
Total Loans, gross $ 710     $ 2,987    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 5.00%     19.00%    
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 512     784    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 8,897     8,155    
Total Loans, gross $ 9,409     $ 8,939    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 61.00%     56.00%    
Seasoning [Member] | School/Grace/Deferment [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 28     $ 22    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 75     77    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 61     44    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 29     30    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 22     36    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 142     152    
Total Loans, gross $ 357     $ 361    
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 $ 1,531     $ 954    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,992     1,194    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 927     681    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 519     1,269    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 1,035     3,157    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 9,405     8,623    
Total Loans, gross $ 15,409     $ 15,878    
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 13     6    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 41     27    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 50     98    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 126     203    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 4,648     5,077    
Total Loans, gross $ 4,878     $ 5,411    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 32.00%     34.00%    
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 $ 1,531     $ 954    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,979     1,188    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 886     654    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 469     1,171    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 909     2,954    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 4,757     3,546    
Total Loans, gross $ 10,531     $ 10,467    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 68.00%     66.00%    
Cosigners [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 1,531     $ 954    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,992     1,194    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 927     681    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 519     1,269    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 1,035     3,157    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 9,405     8,623    
Total Loans, gross $ 15,409     $ 15,878    
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 $ 204     $ 152    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 473     342    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 281     225    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 172     136    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 105     70    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 3,263     4,179    
Total Loans, gross $ 4,498     $ 5,104    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 29.00%     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 $ 1,327     $ 802    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,519     852    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 646     456    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 347     1,133    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 930     3,087    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 6,142     4,444    
Total Loans, gross $ 10,911     $ 10,774    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 71.00%     68.00%    
School Type [Member]            
Accounts Notes And Loans Receivable [Line Items]            
Total Private Education Loan Credit Quality Indicators by Origination Year One $ 1,531     $ 954    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,992     1,194    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 927     681    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 519     1,269    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 1,035     3,157    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 9,405     8,623    
Total Loans, gross $ 15,409     $ 15,878    
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 $ 1,531     $ 893    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 1,992     1,127    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 917     643    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 506     1,201    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 1,017     2,971    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 8,546     7,489    
Total Loans, gross $ 14,509     $ 14,324    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 94.00%     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 $ 0     $ 61    
Total Private Education Loan Credit Quality Indicators by Origination Year Two 0     67    
Total Private Education Loan Credit Quality Indicators by Origination Year Three 10     38    
Total Private Education Loan Credit Quality Indicators by Origination Year Four 13     68    
Total Private Education Loan Credit Quality Indicators by Origination Year Five 18     186    
Total Private Education Loan Credit Quality Indicators by Origination Year Prior 859     1,134    
Total Loans, gross $ 900     $ 1,554    
Total Private Education Loan Credit Quality Indicators by Origination Year, Percent 6.00%     10.00%