CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 193,785us-gaap_ProfitLoss	$ 257,593us-gaap_ProfitLoss	$ 215,726us-gaap_ProfitLoss
Unrealized gains (losses) on investments:
Unrealized gain on investments	6,066us-gaap_UnrealizedGainLossOnInvestments	35,802us-gaap_UnrealizedGainLossOnInvestments	22,264us-gaap_UnrealizedGainLossOnInvestments
Reclassification adjustments for (gain) on sale of available-for-sale securities included in other income	0	(63,813)	(129)
Total unrealized gains (losses) on investments	6,066	(28,011)	22,135
Unrealized losses on cash flow hedges	(19,772)	0	0
Total unrealized gains (losses)	(13,706)	(28,011)	22,135
Income tax benefit (expense)	5,337us-gaap_OtherComprehensiveIncomeLossTax	10,639us-gaap_OtherComprehensiveIncomeLossTax	(8,409)us-gaap_OtherComprehensiveIncomeLossTax
Other comprehensive income (loss), net of tax benefit (expense)	(8,369)	(17,372)	13,726
Comprehensive income	185,416	240,221	229,452
Less: comprehensive loss attributable to noncontrolling interest	(434)	(1,352)	(1,894)
Total comprehensive income attributable to SLM Corporation	$ 185,850	$ 241,573	$ 231,346

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

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