CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $) In Thousands, except Share data, unless otherwise specified		Total		Preferred Stock [Member]	Treasury Stock [Member]	Common Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Navient's Subsidiary Investment	Retained Earnings [Member]	Total SLM Corporation Equity [Member]	Non-controlling Interest [Member]	Series A Preferred Stock	Series A Preferred Stock Retained Earnings [Member]	Series A Preferred Stock Total SLM Corporation Equity [Member]	Series B Preferred Stock	Series B Preferred Stock Retained Earnings [Member]	Series B Preferred Stock Total SLM Corporation Equity [Member]
Beginning Balance at Dec. 31, 2011		$ 1,243,858					$ 622		$ 1,235,318		$ 1,235,940	$ 7,918
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		215,726					0		217,620		217,620	(1,894)
Other comprehensive loss, net of tax		13,726					13,726		0		13,726	0
Comprehensive income		229,452									231,346	(1,894)
Net transfers from affiliate		(384,010)					0		(384,010)		(384,010)	0
Cash dividends:
Issuance of common shares (in shares)	[1]	6,432,643
Ending Balance at Dec. 31, 2012		1,089,300					14,348		1,068,928		1,083,276	6,024
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		257,593					0		258,945		258,945	(1,352)
Other comprehensive loss, net of tax		(17,372)					(17,372)		0		(17,372)	0
Comprehensive income		240,221									241,573	(1,352)
Net transfers from affiliate		(163,378)					0		(163,378)		(163,378)	0
Cash dividends:
Issuance of common shares (in shares)	[1]	9,702,976
Ending Balance at Dec. 31, 2013		1,166,143		0	0	0	(3,024)	0	1,164,495	0	1,161,471	4,672
Beginning balance (in shares) at Dec. 31, 2013					0	0
Beginning balance, shares issued (in shares) at Dec. 31, 2013				0		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		193,785							68,173	126,046	194,219	(434)
Other comprehensive loss, net of tax		(8,369)					(8,369)				(8,369)
Comprehensive income		185,416									185,850	(434)
Net transfers from affiliate		479,409							479,409		479,409
Separation adjustments related to Spin-Off of Navient Corporation (in shares)				7,300,000	0	422,790,320
Separation adjustments related to Spin-Off of Navient Corporation		0		565,000		84,558		1,062,519	(1,712,077)
Sale of non-controlling interest		(4,238)										(4,238)
Cash dividends:
Preferred stock													(7,667)	(7,667)	(7,667)	(5,266)	(5,266)	(5,266)
Dividend equivalent units related to employee stock-based compensation plans		0						47		(47)
Issuance of common shares (in shares)		2,013,805	[1]			2,013,805
Issuance of common shares		8,683				403		8,280			8,683
Tax benefit related to employee stock-based compensation		3,271						3,271			3,271
Stock-based compensation expense		16,394						16,394			16,394
Shares repurchased related to employee stock-based compensation plans (in shares)					(1,365,277)	(1,365,277)
Shares repurchased related to employee stock-based compensation plans		(12,187)			(12,187)						(12,187)
Ending Balance at Dec. 31, 2014		$ 1,829,958		$ 565,000	$ (12,187)	$ 84,961	$ (11,393)	$ 1,090,511	$ 0	$ 113,066	$ 1,829,958	$ 0
Ending balance, shares issued (in shares) at Dec. 31, 2014				7,300,000		424,804,125
Ending balance (in shares) at Dec. 31, 2014					(1,365,277)	423,438,848

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