v3.26.3
Segment Reporting - Segment Results and Reconciliations to GAAP - Reportable Segment Significant Operating Expenses (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Segment Reporting [Line Items]        
Servicing expenses $ 26 $ 28 $ 83 $ 95
Information technology expenses 14 27 50 86
Corporate expenses 15 21 56 67
Other/remaining expenses 20 29 57 85
Total operating expenses 75 105 246 333
Consumer Lending Segment [Member]        
Segment Reporting [Line Items]        
Servicing expenses 14 12 41 40
Information technology expenses 9 8 29 25
Corporate expenses 0 0 1 1
Other/remaining expenses 34 25 67 49
Total operating expenses 57 45 138 115
Federal Education Loans [Member]        
Segment Reporting [Line Items]        
Servicing expenses 12 16 42 50
Information technology expenses 0 0 0 0
Corporate expenses 0 0 1 2
Other/remaining expenses 1 0 1 2
Total operating expenses 13 16 44 54
Business Processing [Member]        
Segment Reporting [Line Items]        
Servicing expenses 0 0 0 0
Information technology expenses 0 0 0 1
Corporate expenses 0 0 0 0
Other/remaining expenses 0 0 0 19
Total operating expenses 0 0 0 20
Other Segment [Member]        
Segment Reporting [Line Items]        
Servicing expenses 0 0 0 5
Information technology expenses 5 19 21 60
Corporate expenses 15 21 54 64
Other/remaining expenses (15) 4 (11) 15
Total operating expenses $ 5 $ 44 $ 64 $ 144