v3.26.3
Segment Reporting - Segment Results and Reconciliations to GAAP (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Interest income:        
Cash and investments $ 17 $ 21 $ 51 $ 64
Total interest income 669 781 2,045 2,361
Total interest expense 554 639 1,677 1,961
Net interest income (loss) 115 142 368 400
Less: provisions for loan losses 227 168 281 236
Net interest income (loss) after provisions for loan losses (112) (26) 87 164
Other income (loss):        
Servicing revenue 10 13 31 40
Asset recovery and business processing revenue 0 0 0 23
Other revenue (loss) 7 6 34 10
Gains on sales of loans 162 0 162 0
Net fair value changes of loans 23 0 23 0
Total other income (loss) 202 19 250 73
Expenses:        
Direct operating expenses 70 61 182 189
Unallocated shared services expenses 5 44 64 144
Total operating expenses 75 105 246 333
Goodwill and acquired intangible asset impairment and amortization 0 1 5 2
Restructuring/other reorganization expenses 2 4 4 6
Total expenses 77 110 255 341
Income (loss) before income tax expense (benefit) 13 (117) 82 (104)
Income tax expense (benefit) (2) (31) 26 (29)
Net income (loss) 15 (86) 56 (75)
Federal Education Loans [Member]        
Expenses:        
Total operating expenses 13 16 44 54
Business Processing [Member]        
Expenses:        
Total operating expenses 0 0 0 20
Other Segment [Member]        
Expenses:        
Total operating expenses 5 44 64 144
Operating Segments [Member]        
Interest income:        
Net interest income (loss) 111 146 357 421
Less: provisions for loan losses 227 168 281 236
Other income (loss):        
Total other income (loss) 197 23 239 107
Expenses:        
Total operating expenses 75 105 246 333
Goodwill and acquired intangible asset impairment and amortization 0 0 0 0
Restructuring/other reorganization expenses 2 4 4 6
Total expenses 77 109 250 339
Income (loss) before income tax expense (benefit) 4 (108) 65 (47)
Income tax expense (benefit) 1 (25) 15 (11)
Net income (loss) 3 (83) 50 (36)
Operating Segments [Member] | Federal Education Loans [Member]        
Interest income:        
Cash and investments 8 10 24 30
Total interest income 389 494 1,197 1,489
Total interest expense 342 429 1,056 1,321
Net interest income (loss) 47 65 141 168
Less: provisions for loan losses 13 13 30 29
Net interest income (loss) after provisions for loan losses 34 52 111 139
Other income (loss):        
Servicing revenue 8 10 24 32
Asset recovery and business processing revenue 0 0 0 0
Other revenue (loss) 0 0 0 (1)
Gains on sales of loans 0   0  
Net fair value changes of loans 0   0  
Total other income (loss) 8 10 24 31
Expenses:        
Direct operating expenses 13 16 44 54
Unallocated shared services expenses 0 0 0 0
Total operating expenses 13 16 44 54
Goodwill and acquired intangible asset impairment and amortization 0 0 0 0
Restructuring/other reorganization expenses 0 0 0 0
Total expenses 13 16 44 54
Income (loss) before income tax expense (benefit) 29 46 91 116
Income tax expense (benefit) 7 11 21 27
Net income (loss) 22 35 70 89
Operating Segments [Member] | Consumer Lending [Member]        
Interest income:        
Cash and investments 5 5 14 15
Total interest income 276 281 835 853
Total interest expense 189 183 553 547
Net interest income (loss) 87 98 282 306
Less: provisions for loan losses 214 155 251 207
Net interest income (loss) after provisions for loan losses (127) (57) 31 99
Other income (loss):        
Servicing revenue 2 3 7 8
Asset recovery and business processing revenue 0 0 0 0
Other revenue (loss) 0 0 0 1
Gains on sales of loans 162   162  
Net fair value changes of loans 23   23  
Total other income (loss) 187 3 192 9
Expenses:        
Direct operating expenses 57 45 138 115
Unallocated shared services expenses 0 0 0 0
Total operating expenses 57 45 138 115
Goodwill and acquired intangible asset impairment and amortization 0 0 0 0
Restructuring/other reorganization expenses 0 0 0 0
Total expenses 57 45 138 115
Income (loss) before income tax expense (benefit) 3 (99) 85 (7)
Income tax expense (benefit) 1 (23) 20 (3)
Net income (loss) 2 (76) 65 (4)
Operating Segments [Member] | Business Processing [Member]        
Interest income:        
Cash and investments 0 0 0 0
Total interest income 0 0 0 0
Total interest expense 0 0 0 0
Net interest income (loss) 0 0 0 0
Less: provisions for loan losses 0 0 0 0
Net interest income (loss) after provisions for loan losses 0 0 0 0
Other income (loss):        
Servicing revenue 0 0 0 0
Asset recovery and business processing revenue 0 0 0 23
Other revenue (loss) 0 0 0 0
Gains on sales of loans 0   0  
Net fair value changes of loans 0   0  
Total other income (loss) 0 0 0 23
Expenses:        
Direct operating expenses 0 0 0 20
Unallocated shared services expenses 0 0 0 0
Total operating expenses 0 0 0 20
Goodwill and acquired intangible asset impairment and amortization 0 0 0 0
Restructuring/other reorganization expenses 0 0 0 0
Total expenses 0 0 0 20
Income (loss) before income tax expense (benefit) 0 0 0 3
Income tax expense (benefit) 0 0 0 1
Net income (loss) 0 0 0 2
Operating Segments [Member] | Other Segment [Member]        
Interest income:        
Cash and investments 4 6 13 19
Total interest income 4 6 13 19
Total interest expense 27 23 79 72
Net interest income (loss) (23) (17) (66) (53)
Less: provisions for loan losses 0 0 0 0
Net interest income (loss) after provisions for loan losses (23) (17) (66) (53)
Other income (loss):        
Servicing revenue 0 0 0 0
Asset recovery and business processing revenue 0 0 0 0
Other revenue (loss) 2 10 23 44
Gains on sales of loans 0   0  
Net fair value changes of loans 0   0  
Total other income (loss) 2 10 23 44
Expenses:        
Direct operating expenses 0 0 0 0
Unallocated shared services expenses 5 44 64 144
Total operating expenses 5 44 64 144
Goodwill and acquired intangible asset impairment and amortization 0 0 0 0
Restructuring/other reorganization expenses 2 4 4 6
Total expenses 7 48 68 150
Income (loss) before income tax expense (benefit) (28) (55) (111) (159)
Income tax expense (benefit) (7) (13) (26) (36)
Net income (loss) (21) (42) (85) (123)
Adjustments [Member] | Reclassifications [Member]        
Interest income:        
Net interest income (loss) 0 4 3 15
Other income (loss):        
Total other income (loss) 0 (4) (3) (15)
Expenses:        
Total operating expenses 0 0 0 0
Goodwill and acquired intangible asset impairment and amortization 0 0 0 0
Restructuring/other reorganization expenses 0 0 0 0
Total expenses 0 0 0 0
Income (loss) before income tax expense (benefit) 0 0 0 0
Income tax expense (benefit) 0 0 0 0
Net income (loss) 0 0 0 0
Adjustments [Member] | Additions (Subtractions) [Member]        
Interest income:        
Net interest income (loss) (4) 0 (14) 6
Other income (loss):        
Total other income (loss) (5) 8 (8) 49
Expenses:        
Total operating expenses 0 0 0 0
Goodwill and acquired intangible asset impairment and amortization 0 (1) (5) (2)
Restructuring/other reorganization expenses 0 0 0 0
Total expenses 0 (1) (5) (2)
Income (loss) before income tax expense (benefit) (9) 9 (17) 57
Income tax expense (benefit) 3 6 (11) 18
Net income (loss) (12) 3 (6) 39
Adjustments [Member] | Total Adjustments [Member]        
Interest income:        
Net interest income (loss) (4) 4 (11) 21
Net interest income (loss) after provisions for loan losses (4) 4 (11) 21
Other income (loss):        
Total other income (loss) (5) 4 (11) 34
Expenses:        
Total operating expenses 0 0 0 0
Goodwill and acquired intangible asset impairment and amortization 0 (1) (5) (2)
Restructuring/other reorganization expenses 0 0 0 0
Total expenses 0 (1) (5) (2)
Income (loss) before income tax expense (benefit) (9) 9 (17) 57
Income tax expense (benefit) 3 6 (11) 18
Net income (loss) (12) 3 (6) 39
Education Loan Portfolio [Member]        
Interest income:        
Total interest income 651 760 1,993 2,297
Education Loan Portfolio [Member] | Operating Segments [Member] | Federal Education Loans [Member]        
Interest income:        
Total interest income 381 484 1,173 1,459
Education Loan Portfolio [Member] | Operating Segments [Member] | Consumer Lending [Member]        
Interest income:        
Total interest income 270 276 820 838
Education Loan Portfolio [Member] | Operating Segments [Member] | Business Processing [Member]        
Interest income:        
Total interest income 0 0 0 0
Education Loan Portfolio [Member] | Operating Segments [Member] | Other Segment [Member]        
Interest income:        
Total interest income 0 $ 0 0 $ 0
Personal Loan Portfolio [Member]        
Interest income:        
Total interest income 1   1  
Personal Loan Portfolio [Member] | Operating Segments [Member] | Federal Education Loans [Member]        
Interest income:        
Total interest income 0   0  
Personal Loan Portfolio [Member] | Operating Segments [Member] | Consumer Lending [Member]        
Interest income:        
Total interest income 1   1  
Personal Loan Portfolio [Member] | Operating Segments [Member] | Business Processing [Member]        
Interest income:        
Total interest income 0   0  
Personal Loan Portfolio [Member] | Operating Segments [Member] | Other Segment [Member]        
Interest income:        
Total interest income $ 0   $ 0