CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $)		Total		Preferred Stock	Common Stock	Treasury Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Total SLM Corporation Equity	Non-controlling interest	Series A Preferred Stock Retained Earnings	Series A Preferred Stock Total SLM Corporation Equity	Series B Preferred Stock Retained Earnings	Series B Preferred Stock Total SLM Corporation Equity	Navient's subsidiary investment Additional Paid-In Capital
Beginning Balance at Dec. 31, 2013		$ 1,166,143,000						$ (3,024,000)		$ 1,161,471,000	$ 4,672,000					$ 1,164,495,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		47,014,000								47,448,000	(434,000)					47,448,000
Other comprehensive income (loss), net of tax		872,000						872,000		872,000
Comprehensive income		47,886,000								48,320,000	(434,000)
Net transfers (to) from affiliate		17,244,000								17,244,000						17,244,000
Cash dividends:
Issuance of common shares (in shares)	[1]	4,238,182
Ending Balance at Mar. 31, 2014		1,231,273,000						(2,152,000)		1,227,035,000	4,238,000					1,229,187,000
Beginning Balance at Dec. 31, 2014		1,829,958,000		565,000,000	84,961,000	(12,187,000)	1,090,511,000	(11,393,000)	113,066,000	1,829,958,000
Beginning Balance (in shares) at Dec. 31, 2014				7,300,000	423,438,848	(1,365,277)
Beginning Balance, shares issued (in shares) at Dec. 31, 2014					424,804,125
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		47,699,000							47,699,000	47,699,000
Other comprehensive income (loss), net of tax		(9,191,000)						(9,191,000)		(9,191,000)
Comprehensive income		38,508,000								38,508,000
Net transfers (to) from affiliate		0
Cash dividends:
Cash dividends, preferred stock												(2,875,000)	(2,875,000)	(1,948,000)	(1,948,000)
Dividend equivalent units related to employee stock-based compensation plans							1,118,000		(1,118,000)	0
Issuance of common shares (in shares)		3,130,839	[1]		3,130,839
Issuance of common shares					626,000		4,050,000			4,676,000
Tax benefit related to employee stock-based compensation							4,596,000			4,596,000
Stock-based compensation expense							6,140,000			6,140,000
Shares repurchased related to employee stock-based compensation plans (in shares)					(1,389,096)	(1,389,096)
Shares repurchased related to employee stock-based compensation plans						(13,142,000)				(13,142,000)
Ending Balance at Mar. 31, 2015		$ 1,865,913,000		$ 565,000,000	$ 85,587,000	$ (25,329,000)	$ 1,106,415,000	$ (20,584,000)	$ 154,824,000	$ 1,865,913,000
Ending Balance (in shares) at Mar. 31, 2015				7,300,000	425,180,591	(2,754,373)
Ending Balance, shares issued (in shares) at Mar. 31, 2015					427,934,964

[1] Common shares issued under our various compensation and benefit plans.