Consolidated Balance Sheets - Supplemental Information - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Loans, net	$ 54,827	$ 62,250
Short-term borrowings, Carrying Value	4,226	5,870
Long-term borrowings, Carrying Value	53,402	61,026
FFELP Loans [Member]
Loans, net	37,925	43,525
Private Education Loans [Member]
Loans, net	16,902	18,725
Assets and Liabilities of Consolidated Variable Interest Entities [Member]
Loans, net	53,591	60,672
Restricted cash	1,937	3,233
Other assets, net	1,744	1,356
Short-term borrowings, Carrying Value	3,634	4,458
Long-term borrowings, Carrying Value	48,169	55,598
Net assets of consolidated variable interest entities	5,469	5,205
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | FFELP Loans [Member]
Loans, net	37,832	43,465
Assets and Liabilities of Consolidated Variable Interest Entities [Member] | Private Education Loans [Member]
Loans, net	$ 15,759	$ 17,207