Allowance for Credit Losses and Unfunded Loan Commitments - Age Analysis of Past Due Loans Delinquencies (Details) - USD ($)
$ in Thousands |
Jun. 30, 2026 |
Dec. 31, 2025 |
| Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
| Private Education Loans allowance for losses |
$ (1,354,014)
|
$ (1,430,318)
|
| Private Education Loans, net |
$ 19,531,493
|
$ 20,332,124
|
| Percentage of Private Education Loans in repayment, Year 1 |
55.10%
|
59.10%
|
| Percentage of Private Education Loans in repayment, Year 2 |
61.50%
|
63.60%
|
| Percentage of Private Education Loans in repayment, Year 3 |
67.10%
|
72.40%
|
| Percentage of Private Education Loans in repayment, Year 4 |
75.40%
|
79.40%
|
| Percentage of Private Education Loans in repayment, Year 5 |
81.50%
|
83.90%
|
| Percentage of Private Education Loans in repayment, After Year 5 |
89.40%
|
89.80%
|
| Percentage of Private Education Loans in repayment |
73.90%
|
73.40%
|
| Delinquent Private Education Loans in repayment as a percentage of Private Education Loans in repayment, Year 1 |
0.50%
|
0.60%
|
| Delinquent Private Education Loans in repayment as a percentage of Private Education Loans in repayment, Year 2 |
0.80%
|
1.50%
|
| Delinquent Private Education Loans in repayment as a percentage of Private Education Loans in repayment, Year 3 |
2.30%
|
4.50%
|
| Delinquent Private Education Loans in repayment as a percentage of Private Education Loans in repayment, Year 4 |
4.30%
|
4.90%
|
| Delinquent Private Education Loans in repayment as a percentage of Private Education Loans in repayment, Year 5 |
4.70%
|
5.10%
|
| Delinquent Private Education Loans in repayment as a percentage of Private Education Loans in repayment, After Year 5 |
6.00%
|
6.80%
|
| Delinquent Private Education Loans in repayment as a percentage of Private Education Loans in repayment |
3.70%
|
4.00%
|
| Loans in forbearance as a percentage of loans in repayment and forbearance, Year 1 |
0.40%
|
0.90%
|
| Loans in forbearance as a percentage of loans in repayment and forbearance, Year 2 |
1.10%
|
3.60%
|
| Loans in forbearance as a percentage of loans in repayment and forbearance, Year 3 |
3.10%
|
4.10%
|
| Loans in forbearance as a percentage of loans in repayment and forbearance, Year 4 |
3.00%
|
3.60%
|
| Loans in forbearance as a percentage of loans in repayment and forbearance, Year 5 |
2.60%
|
3.20%
|
| Loans in forbearance as a percentage of loans in repayment and forbearance, After Year 5 |
2.00%
|
1.80%
|
| Loans in forbearance as a percentage of loans in repayment and forbearance |
2.10%
|
2.70%
|
| Consumer Portfolio Segment | Student Loan |
|
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
| Total Private Education Loans in Repayment, Year 1 |
$ 623,597
|
$ 2,561,439
|
| Total Private Education Loans in Repayment, Year 2 |
3,288,835
|
3,458,164
|
| Total Private Education Loans in Repayment, Year 3 |
2,602,439
|
1,950,308
|
| Total Private Education Loans in Repayment, Year 4 |
1,676,261
|
1,812,638
|
| Total Private Education Loans in Repayment, Year 5 |
1,657,688
|
1,353,804
|
| Total Private Education Loans in Repayment, After Year 5 |
5,517,776
|
4,758,474
|
| Total Private Education Loans in repayment |
15,366,596
|
15,894,827
|
| Total Private Education Loans, gross, Year 1 |
1,131,734
|
4,331,374
|
| Total Private Education Loans, gross, Year 2 |
5,347,952
|
5,440,721
|
| Total Private Education Loans, gross, Year 3 |
3,880,911
|
2,693,020
|
| Total Private Education Loans, gross, Year 4 |
2,223,093
|
2,282,218
|
| Total Private Education Loans, gross, Year 5 |
2,034,115
|
1,613,592
|
| Total Private Education Loans, gross, After Year 5 |
6,173,692
|
5,299,509
|
| Total Private Education Loans, gross |
20,791,497
|
21,660,434
|
| Private Education Loans deferred origination costs and unamortized premium/(discount), Year 1 |
14,208
|
37,495
|
| Private Education Loans deferred origination costs and unamortized premium/(discount), Year 2 |
30,074
|
30,562
|
| Private Education Loans deferred origination costs and unamortized premium/(discount), Year 3 |
21,206
|
12,936
|
| Private Education Loans deferred origination costs and unamortized premium/(discount), Year 4 |
10,434
|
7,122
|
| Private Education Loans deferred origination costs and unamortized premium/(discount), Year 5 |
6,104
|
4,388
|
| Private Education Loans deferred origination costs and unamortized premium/(discount), After Year 5 |
11,984
|
9,505
|
| Private Education Loans deferred origination costs and unamortized premium/(discount) |
94,010
|
102,008
|
| Total Private Education Loans, Year 1 |
1,145,942
|
4,368,869
|
| Total Private Education Loans, Year 2 |
5,378,026
|
5,471,283
|
| Total Private Education Loans, Year 3 |
3,902,117
|
2,705,956
|
| Total Private Education Loans, Year 4 |
2,233,527
|
2,289,340
|
| Total Private Education Loans, Year 5 |
2,040,219
|
1,617,980
|
| Total Private Education Loans, After Year 5 |
6,185,676
|
5,309,014
|
| Total Private Education Loans |
20,885,507
|
21,762,442
|
| Private Education Loans allowance for losses, Year 1 |
(57,118)
|
(231,497)
|
| Private Education Loans allowance for losses, Year 2 |
(282,369)
|
(312,665)
|
| Private Education Loans allowance for losses, Year 3 |
(241,613)
|
(211,732)
|
| Private Education Loans allowance for losses, Year 4 |
(176,768)
|
(182,408)
|
| Private Education Loans allowance for losses, Year 5 |
(162,087)
|
(122,163)
|
| Private Education Loans allowance for losses, After Year 5 |
(434,059)
|
(369,853)
|
| Private Education Loans allowance for losses |
(1,354,014)
|
(1,430,318)
|
| Private Education Loans, net, Year 1 |
1,088,824
|
4,137,372
|
| Private Education Loans, net, Year 2 |
5,095,657
|
5,158,618
|
| Private Education Loans, net, Year 3 |
3,660,504
|
2,494,224
|
| Private Education Loans, net, Year 4 |
2,056,759
|
2,106,932
|
| Private Education Loans, net, Year 5 |
1,878,132
|
1,495,817
|
| Private Education Loans, net, After Year 5 |
5,751,617
|
4,939,161
|
| Private Education Loans, net |
19,531,493
|
20,332,124
|
| Consumer Portfolio Segment | Student Loan | Loan delinquent, current |
|
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
| Year 1 |
620,435
|
2,545,734
|
| Year 2 |
3,261,987
|
3,404,837
|
| Year 3 |
2,542,458
|
1,863,481
|
| Year 4 |
1,604,502
|
1,723,538
|
| Year 5 |
1,579,515
|
1,284,830
|
| After Year 5 |
5,185,377
|
4,436,303
|
| Loan type |
14,794,274
|
15,258,723
|
| Consumer Portfolio Segment | Student Loan | Loan delinquent 30-59 days |
|
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
| Year 1 |
2,267
|
10,981
|
| Year 2 |
16,491
|
29,336
|
| Year 3 |
30,351
|
41,888
|
| Year 4 |
35,301
|
44,106
|
| Year 5 |
36,292
|
33,983
|
| After Year 5 |
169,062
|
170,013
|
| Loan type |
289,764
|
330,307
|
| Consumer Portfolio Segment | Student Loan | Loan delinquent 60-89 days |
|
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
| Year 1 |
524
|
3,267
|
| Year 2 |
6,396
|
13,265
|
| Year 3 |
15,295
|
22,287
|
| Year 4 |
19,132
|
22,729
|
| Year 5 |
21,480
|
17,118
|
| After Year 5 |
83,297
|
76,017
|
| Loan type |
146,124
|
154,683
|
| Consumer Portfolio Segment | Student Loan | Loan delinquent 90 days or greater past due |
|
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
| Year 1 |
371
|
1,457
|
| Year 2 |
3,961
|
10,726
|
| Year 3 |
14,335
|
22,652
|
| Year 4 |
17,326
|
22,265
|
| Year 5 |
20,401
|
17,873
|
| After Year 5 |
80,040
|
76,141
|
| Loan type |
136,434
|
151,114
|
| Loans In-school/grace/deferment | Consumer Portfolio Segment | Student Loan |
|
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
| Year 1 |
505,842
|
1,747,456
|
| Year 2 |
2,021,505
|
1,855,164
|
| Year 3 |
1,195,933
|
658,750
|
| Year 4 |
495,468
|
402,546
|
| Year 5 |
331,963
|
215,115
|
| After Year 5 |
545,589
|
453,501
|
| Loan type |
5,096,300
|
5,332,532
|
| Loans In forbearance | Consumer Portfolio Segment | Student Loan |
|
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] |
|
|
| Total Private Education Loans in forbearance, Year 1 |
2,295
|
22,479
|
| Total Private Education Loans in forbearance, Year 2 |
37,612
|
127,393
|
| Total Private Education Loans in forbearance, Year 3 |
82,539
|
83,962
|
| Total Private Education Loans in forbearance, Year 4 |
51,364
|
67,034
|
| Total Private Education Loans in forbearance, Year 5 |
44,464
|
44,673
|
| Total Private Education Loans in forbearance, After Year 5 |
110,327
|
87,534
|
| Total Private Education Loans in forbearance |
$ 328,601
|
$ 433,075
|