Consolidated Balance Sheets - Supplemental Information - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Loans, net	$ 46,568	$ 54,827
Short-term borrowings, Carrying Value	5,134	4,226
Long-term borrowings, Carrying Value	43,184	53,402
FFELP Loans [Member]
Loans, net	30,852	37,925
Private Education Loans [Member]
Loans, net	15,716	16,902
Assets and Liabilities of Consolidated Variable Interest Entities [Member]
Loans, net	45,258	53,591
Restricted cash	1,364	1,937
Other assets, net	1,224	1,744
Short-term borrowings, Carrying Value	4,532	3,634
Long-term borrowings, Carrying Value	38,497	48,169
Net assets of consolidated variable interest entities	4,817	5,469
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | FFELP Loans [Member]
Loans, net	30,620	37,832
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | Private Education Loans [Member]
Loans, net	$ 14,638	$ 15,759