CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Interest income:
Loans	$ 483,327,000	$ 442,576,000	$ 1,387,411,000	$ 1,304,479,000
Investments	10,260,000	3,366,000	24,252,000	9,262,000
Cash and cash equivalents	26,324,000	1,613,000	36,317,000	4,662,000
Total interest income	519,911,000	447,555,000	1,447,980,000	1,318,403,000
Interest expense:
Deposits	105,468,000	51,629,000	215,473,000	175,483,000
Interest expense on short-term borrowings	3,054,000	5,458,000	8,902,000	14,360,000
Interest expense on long-term borrowings	41,879,000	32,950,000	116,255,000	101,144,000
Total interest expense	150,401,000	90,037,000	340,630,000	290,987,000
Net interest income	369,510,000	357,518,000	1,107,350,000	1,027,416,000
Less: provisions for credit losses	207,598,000	138,442,000	336,193,000	(17,648,000)
Net interest income after provisions for credit losses	161,912,000	219,076,000	771,157,000	1,045,064,000
Non-interest income:
Gains (losses) on sales of loans, net	74,978,000	(10,000)	324,856,000	402,780,000
Gains (losses) on derivatives and hedging activities, net	0	44,000	(5,000)	161,000
Other income	20,125,000	13,879,000	50,430,000	76,747,000
Total non-interest income	95,103,000	13,913,000	375,281,000	479,688,000
Operating expenses:
Compensation and benefits	65,003,000	66,229,000	202,995,000	200,426,000
FDIC assessment fees	4,592,000	6,521,000	11,501,000	17,634,000
Other operating expenses	80,369,000	67,899,000	199,204,000	175,098,000
Total operating expenses	149,964,000	140,649,000	413,700,000	393,158,000
Acquired intangible assets amortization expense	2,328,000	0	5,478,000	0
Restructuring expenses	0	108,000	0	1,255,000
Total non-interest expenses	152,292,000	140,757,000	419,178,000	394,413,000
Income before income tax expense	104,723,000	92,232,000	727,260,000	1,130,339,000
Income tax expense	29,551,000	19,392,000	181,203,000	276,091,000
Net income	75,172,000	72,840,000	546,057,000	854,248,000
Preferred stock dividends	2,531,000	1,166,000	5,563,000	3,559,000
Net income attributable to SLM Corporation common stock	$ 72,641,000	$ 71,674,000	$ 540,494,000	$ 850,689,000
Basic earnings per common share (in dollars per share)	$ 0.29	$ 0.24	$ 2.05	$ 2.62
Average common shares outstanding (in shares)	251,266	299,890	263,098	324,148
Diluted earnings per common share (in dollars per share)	$ 0.29	$ 0.24	$ 2.03	$ 2.59
Average common and common equivalent shares outstanding (in shares)	253,716	304,511	266,065	329,064
Declared dividends per common share (in dollars per share)	$ 0.11	$ 0.03	$ 0.33	$ 0.09