Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Interest income:
Cash and investments	$ 153	$ 62	$ 3
Total interest income	4,419	3,223	2,648
Total interest expense	3,557	2,102	1,316
Net interest income	862	1,121	1,332
Less: provisions for loan losses	123	79	(61)
Net interest income after provisions for loan losses	739	1,042	1,393
Other income (loss):
Servicing revenue	64	77	168
Asset recovery and business processing revenue	321	336	539
Other income	21	32	30
Gains on sales of loans	0	0	78
Losses on debt repurchases	(8)	0	(73)
Gains (losses) on derivative and hedging activities, net	11	171	64
Total other income	409	616	806
Expenses:
Salaries and benefits	401	444	569
Other operating expenses	399	332	638
Total operating expenses	800	776	1,207
Goodwill and acquired intangible asset impairment and amortization expense	10	19	30
Restructuring/other reorganization expenses	25	36	26
Total expenses	835	831	1,263
Income before income tax expense	313	827	936
Income tax expense	85	182	219
Net income	$ 228	$ 645	$ 717
Basic earnings per common share	$ 1.87	$ 4.54	$ 4.23
Average common shares outstanding	122	142	170
Diluted earnings per common share	$ 1.85	$ 4.49	$ 4.18
Average common and common equivalent shares outstanding	123	144	172
Dividends per common share	$ 0.64	$ 0.64	$ 0.64
FFELP Loans [Member]
Interest income:
Total interest income	$ 2,897	$ 1,966	$ 1,464
Less: provisions for loan losses	56	0	0
Private Education Loans [Member]
Interest income:
Total interest income	1,369	1,195	1,181
Less: provisions for loan losses	$ 67	$ 79	$ (61)