Revenue from Contracts with Customers Accounted for in Accordance with ASC 606 - Summary of Disaggregation of Revenue from Contracts with Customers Accounted Under ASC 606 (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 81	$ 83	$ 158	$ 155
Federal Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	14	17	29	23
Guarantor Agencies [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
State and Local Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	18	17	35	35
Tolling Authorities [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	17	18	33	34
Hospitals and Other Healthcare Providers [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	32	31	61	63
Federal Education Loans [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Federal Education Loans [Member] | Federal Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Federal Education Loans [Member] | Guarantor Agencies [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Federal Education Loans [Member] | State and Local Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Federal Education Loans [Member] | Tolling Authorities [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Federal Education Loans [Member] | Hospitals and Other Healthcare Providers [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Business Processing [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	81	83	158	155
Business Processing [Member] | Federal Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	14	17	29	23
Business Processing [Member] | Guarantor Agencies [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Business Processing [Member] | State and Local Government [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	18	17	35	35
Business Processing [Member] | Tolling Authorities [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	17	18	33	34
Business Processing [Member] | Hospitals and Other Healthcare Providers [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	32	31	61	63
Federal Education Loan Asset Recovery Services [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Federal Education Loan Asset Recovery Services [Member] | Federal Education Loans [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Federal Education Loan Asset Recovery Services [Member] | Business Processing [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Government Services [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	49	52	97	92
Government Services [Member] | Federal Education Loans [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Government Services [Member] | Business Processing [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	49	52	97	92
Healthcare Services [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	32	31	61	63
Healthcare Services [Member] | Federal Education Loans [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	0	0	0	0
Healthcare Services [Member] | Business Processing [Member]
Disaggregation Of Revenue [Line Items]
Total Revenue	$ 32	$ 31	$ 61	$ 63