SLM (SLM) 10-Q 22 Apr 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	SLM
Entity Registrant Name	SLM CORPORATION
Entity Central Index Key	1032033
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)	425,180,591

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Assets
Cash and cash equivalents	$875,622	$2,359,780
Available-for-sale investments at fair value (cost of $168,964 and $167,740, respectively)	170,831	168,934
Loans held for investment (net of allowance for losses of $89,805 and $83,842, respectively)	10,909,014	9,509,786
Other interest-earning assets	62,383	77,283
Accrued interest receivable	541,355	469,697
Premises and equipment, net	79,822	78,470
Acquired intangible assets, net	2,855	3,225
Tax indemnification receivable	227,157	240,311
Other assets	64,485	64,757
Total assets	12,933,524	12,972,243
Liabilities
Deposits	10,467,753	10,540,555
Income taxes payable, net	194,345	191,499
Upromise related liabilities	285,104	293,004
Other liabilities	120,409	117,227
Total liabilities	11,067,611	11,142,285
Commitments and contingencies
Equity
Common stock, par value $0.20 per share, 1.125 billion shares authorized: 428 million and 425 million shares issued, respectively	85,587	84,961
Additional paid-in capital	1,106,415	1,090,511
Accumulated other comprehensive loss (net of tax benefit of $13,012 and $7,186, respectively)	-20,584	-11,393
Retained earnings	154,824	113,066
Total SLM Corporation stockholders' equity before treasury stock	1,891,242	1,842,145
Less: Common stock held in treasury at cost: 3 million and 1 million shares, respectively	-25,329	-12,187
Total equity	1,865,913	1,829,958
Total liabilities and equity	12,933,524	12,972,243
Series A Preferred Stock
Equity
Preferred stock value outstanding	165,000	165,000
Series B Preferred Stock
Equity
Preferred stock value outstanding	$400,000	$400,000

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Amortized Cost	$168,964	$167,740
Allowance for loan losses	89,805	83,842
Tax benefit for accumulated other comprehensive (loss) income	($13,012)	($7,186)
Preferred Stock, stated value (in dollars per share)	$0.20	$0.20
Preferred stock shares authorized (in shares)	20,000,000	20,000,000
Common stock par value (in dollars per share)	$0.20	$0.20
Common stock, shares authorized (in shares)	1,125,000,000	1,125,000,000
Common stock shares issued (in shares)	428,000,000	425,000,000
Common stock held in treasury (in shares)	3,000,000	1,000,000
Series A Preferred Stock
Preferred Stock, stated value (in dollars per share)	$50	$50
Preferred stock shares outstanding (in shares)	3,300,000	3,300,000
Series B Preferred Stock
Preferred Stock, stated value (in dollars per share)	$100	$100
Preferred stock shares outstanding (in shares)	4,000,000	4,000,000

CONSOLIDATED_STATEMENTS_OF_INC

CONSOLIDATED STATEMENTS OF INCOME (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest income:
Loans	$197,856	$160,035
Investments	2,720	968
Cash and cash equivalents	780	866
Total interest income	201,356	161,869
Interest expense:
Deposits	29,570	22,591
Other interest expense	832	40
Total interest expense	30,402	22,631
Net interest income	170,954	139,238
Less: provisions for loan losses	16,618	39,159
Net interest income after provisions for loan losses	154,336	100,079
Noninterest income:
Gains on sales of loans, net	0	33,888
Gains (losses) on derivatives and hedging activities, net	3,292	-764
Other	8,007	8,136
Total noninterest income	11,299	41,260
Expenses:
Compensation and benefits	41,203	29,667
Other operating expenses	39,984	34,004
Total operating expenses	81,187	63,671
Acquired intangible asset amortization expense	370	1,767
Restructuring and other reorganization expenses	4,657	229
Total expenses	86,214	65,667
Income before income tax expense	79,421	75,672
Income tax expense	31,722	28,658
Net income	47,699	47,014
Less: net loss attributable to noncontrolling interest	0	-434
Net income attributable to SLM Corporation	47,699	47,448
Preferred stock dividends	4,823	0
Net income attributable to SLM Corporation common stock	$42,876	$47,448
Basic earnings per common share attributable to SLM Corporation (in dollars per share)	$0.10	$0.11
Average common shares outstanding (in shares)	424,428	426,717
Diluted earnings per common share attributable to SLM Corporation (in dollars per share)	$0.10	$0.11
Average common and common equivalent shares outstanding (in shares)	432,302	434,650

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$47,699	$47,014
Other comprehensive income (loss):
Unrealized gains on investments	673	1,406
Unrealized losses on cash flow hedges	-15,689	0
Total unrealized gains (losses)	-15,016	1,406
Income tax (expense) benefit	5,825	-534
Other comprehensive income (loss), net of tax benefit (expense)	-9,191	872
Comprehensive income	38,508	47,886
Less: comprehensive loss attributable to noncontrolling interest	0	-434
Total comprehensive income attributable to SLM Corporation	$38,508	$48,320

CONSOLIDATED_STATEMENTS_OF_CHA

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	Series A Preferred Stock	Series B Preferred Stock	Series B Preferred Stock	Navient's subsidiary investment
												Retained Earnings	Total SLM Corporation Equity	Retained Earnings	Total SLM Corporation Equity	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.

CONSOLIDATED_STATEMENTS_OF_CHA1

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (Parenthetical) (USD $)	3 Months Ended
	Mar. 31, 2015
Series A Preferred Stock
Preferred stock dividend rate (in dollars per share)	$0.87
Series B Preferred Stock
Preferred stock dividend rate (in dollars per share)	$0.49

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating activities
Net income	$47,699	$47,014
Adjustments to reconcile net income to net cash used in operating activities:
Provision for loan losses	16,618	39,159
Tax provision	31,722	28,658
Amortization of brokered deposit placement fee	2,695	2,750
Amortization of deferred loan origination costs and fees, net	641	298
Net amortization of discount on investments	324	88
Depreciation of premises and equipment	1,659	1,182
Amortization and impairment of acquired intangibles	370	1,767
Stock-based compensation expense	6,140	7,248
Unrealized (gains)/losses on derivative and hedging activities, net	-2,417	1,107
Gains on sale of loans, net	0	-33,888
Changes in operating assets and liabilities:
Net decrease in loans held for sale	55	5,426
Origination of loans held for sale	-55	-5,426
Increase in accrued interest receivable	-121,815	-76,069
Decrease (increase) in other interest-earning assets	14,900	-21,257
Decrease in tax indemnification receivable	13,154	0
(Increase) decrease in other assets	-2,079	3,999
Decrease in income tax payable, net	-23,049	-122,829
Increase in accrued interest payable	6,541	3,907
Decrease in payable due to entity that is a subsidiary of Navient	-1,655	0
(Decrease) increase in other liabilities	-10,629	-1,381
Total adjustments	-66,880	-165,261
Total net cash used in operating activities	-19,181	-118,247
Investing activities
Loans acquired and originated	-1,663,149	-1,524,455
Net proceeds from sales of loans held for investment	6,387	679,023
Proceeds from claim payments	46,442	27,303
Net decrease in loans held for investment	243,990	183,590
Purchases of available-for-sale securities	-8,178	-25,190
Proceeds from sales and maturities of available-for-sale securities	6,630	1,510
Total net cash used in investing activities	-1,367,878	-658,219
Financing activities
Net decrease in certificates of deposit	-74,457	-324,487
Net (decrease) increase in other deposits	-22,415	135,628
Net decrease in deposits with entity that is a subsidiary of Navient	0	-3,631
Net capital contributions from entity that is a subsidiary of Navient	0	21,230
Excess tax benefit from the exercise of stock-based awards	4,596	0
Preferred stock dividends paid	-4,823	0
Net cash provided by financing activities	-97,099	-171,260
Net decrease in cash and cash equivalents	-1,484,158	-947,726
Cash and cash equivalents at beginning of period	2,359,780	2,182,865
Cash and cash equivalents at end of period	875,622	1,235,139
Cash disbursements made for:
Interest	25,368	16,180
Income taxes paid	$17,811	$99,267

Significant_Accounting_Policie

Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies
	Basis of Presentation
	The accompanying unaudited, consolidated financial statements of SLM Corporation (“we,” “us,” “our,” or the “Company”) have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. The consolidated financial statements include the accounts of SLM Corporation and its majority-owned and controlled subsidiaries after eliminating the effects of intercompany accounts and transactions. In the opinion of management, all adjustments considered necessary for a fair statement of the results for the interim periods have been included. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Operating results for the three months ended March 31, 2015 are not necessarily indicative of the results for the year ending December 31, 2015 or for any other period. These unaudited financial statements should be read in conjunction with the audited financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2014 (the “2014 Form 10-K”).
	On April 30, 2014, we completed our plan to legally separate into two distinct publicly traded entities - an education loan management, servicing and asset recovery business, Navient Corporation (“Navient”), and a consumer banking business, SLM Corporation. The separation of Navient from SLM Corporation (the “Spin-Off”) was preceded by an internal corporate reorganization, which was the first step to separate the education loan management, servicing and asset recovery business from the consumer banking business.
	For periods before the Spin-Off, the financial statements are presented on a basis of accounting that reflects a change in reporting entity and have been adjusted for the effects of the Spin-Off. These carve-out financial statements and selected financial information represent only those operations, assets, liabilities and equity that form Sallie Mae on a stand-alone basis. Because the Spin-Off occurred on April 30, 2014, the balances as of and for the three months ending March 31, 2014 include the carved out financial results.
	Consolidation
	The consolidated financial statements include the accounts of the Company and its majority-owned and controlled subsidiaries after eliminating the effects of intercompany accounts and transactions.
	Recently Issued Accounting Pronouncements
	On February 18, 2015, the FASB issued Accounting Standards Update (“ASU”) No. 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis,” which amends the current consolidation guidance. The amendments reduce the number of consolidation models through the elimination of the indefinite deferral of ASC 810 and place more emphasis on risk of loss when determining a controlling financial interest.  The standard is effective for fiscal periods beginning after December 15, 2015. We do not expect this new guidance to have a material impact to our financial results.

Loans_Held_for_Investment

Loans Held for Investment	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Loans Held for Investment	Loans Held for Investment
	Loans Held for Investment consist of Private Education Loans and FFELP Loans.
	"Private Education Loans" are education loans to students or their families that are not issued, insured or guaranteed by any state or federal government. Our Private Education Loans are made largely to bridge the gap between the cost of higher education and the amount funded through financial aid, government loans or customers’ resources. Private Education Loans bear the full credit risk of the borrower and any cosigners. We manage this risk through risk-performance underwriting strategies and the addition of qualified cosigners. Our Private Education Loans generally carry a variable interest rate indexed to LIBOR. As of March 31, 2015, 82 percent of all Private Education Loans were indexed to LIBOR. We provide incentives for customers to include a cosigner on our Private Education Loans, and the vast majority of Private Education Loans in our portfolio are cosigned. We also encourage our Private Education Loan customers to make payments while in school.
	FFELP Loans are insured by the federal government as to their principal and accrued interest in the event of default subject to a risk sharing level based on the date of loan disbursement. These insurance obligations are supported by contractual rights against the United States. For loans disbursed on or after July 1, 2006, we receive 97 percent reimbursement on all qualifying claims. For loans disbursed after October 1, 1993, and before July 1, 2006, we receive 98 percent reimbursement on all qualifying claims. For loans disbursed prior to October 1, 1993, we receive 100 percent reimbursement on all qualifying claims.
	Loans held for investment are summarized as follows:
		March 31,			December 31,
		2015			2014
	Private Education Loans	$	9,768,761		$	8,311,376
	Deferred origination costs	17,627			13,845
	Allowance for loan losses	(85,236		)	(78,574		)
	Total Private Education Loans, net	9,701,152			8,246,647
	FFELP Loans	1,208,977			1,264,807
	Unamortized acquisition costs, net	3,454			3,600
	Allowance for loan losses	(4,569		)	(5,268		)
	Total FFELP Loans, net	1,207,862			1,263,139
	Loans held for investment, net	$	10,909,014		$	9,509,786
	The estimated weighted average life of education loans in our portfolio was approximately 6.4 years and 6.2 years at March 31, 2015 and December 31, 2014, respectively.
	The average balance and the respective weighted average interest rates are summarized as follows:
		Three Months Ended
		March 31,
		2015						2014
		Average Balance			Weighted Average Interest Rate			Average Balance		Weighted Average Interest Rate
	Private Education Loans	$	9,454,579		8.07	%		$	7,419,714	8.14	%
	FFELP Loans	1,234,682			3.19			1,404,595		3.19
	Total portfolio	$	10,689,261					$	8,824,309

Allowance_for_Loan_Losses

Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Allowance for Loan Losses	Allowance for Loan Losses
	Our provision for loan losses represents the periodic expense of maintaining an allowance sufficient to absorb incurred probable losses in the held-for-investment loan portfolios. The evaluation of the allowance for loan losses is inherently subjective, as it requires material estimates that may be susceptible to significant changes. We believe the allowance for loan losses is appropriate to cover probable losses incurred in the loan portfolios.
	Allowance for Loan Losses Metrics
			Allowance for Loan Losses
			Three Months Ended March 31, 2015
			FFELP Loans			Private Education				Total
						Loans
	Allowance for Loan Losses
	Beginning balance		$	5,268		$	78,574			$	83,842
	Total provision		435			16,183				16,618
	Net charge-offs:
	Charge-offs		(1,134		)	(8,727		)		(9,861		)
	Recoveries		—			1,387				1,387
	Net charge-offs		(1,134		)	(7,340		)		(8,474		)
	Loan sales(1)		—			(2,181		)		(2,181		)
	Ending Balance		$	4,569		$	85,236			$	89,805
	Allowance:
	Ending balance: individually evaluated for impairment		$	—		$	20,105			$	20,105
	Ending balance: collectively evaluated for impairment		$	4,569		$	65,131			$	69,700
	Loans:
	Ending balance: individually evaluated for impairment		$	—		$	122,120			$	122,120
	Ending balance: collectively evaluated for impairment		$	1,208,977		$	9,646,641			$	10,855,618
	Net charge-offs as a percentage of average loans in repayment (annualized)(2)		0.5		%	0.51		%
	Allowance as a percentage of the ending total loan balance		0.38		%	0.87		%
	Allowance as a percentage of the ending loans in repayment(2)		0.52		%	1.42		%
	Allowance coverage of net charge-offs (annualized)		1.01			2.9
	Ending total loans, gross		$	1,208,977		$	9,768,761
	Average loans in repayment(2)		$	898,360		$	5,705,067
	Ending loans in repayment(2)		$	872,579		$	5,995,121
	____________
	(1) Represents fair value write-downs on loans sold.
	(2) Loans in repayment includes in-school loans making interest only and fixed payments as well as loans that have entered full principal and interest repayment status after any applicable grace period.
			Allowance for Loan Losses
			Three Months Ended March 31, 2014
			FFELP Loans			Private Education				Total
						Loans
	Allowance for Loan Losses
	Beginning balance		$	6,318		$	61,763			$	68,081
	Total provision		506			38,653				39,159
	Charge-offs(1)		(643		)	—				(643		)
	Loan sales(2)		—			(28,963		)		(28,963		)
	Ending Balance		$	6,181		$	71,453			$	77,634
	Allowance:
	Ending balance: individually evaluated for impairment		$	—		$	—			$	—
	Ending balance: collectively evaluated for impairment		$	6,181		$	71,453			$	77,634
	Loans:
	Ending balance: individually evaluated for impairment		$	—		$	—			$	—
	Ending balance: collectively evaluated for impairment		$	1,396,776		$	7,274,718			$	8,671,494
	Charge-offs as a percentage of average loans in repayment (annualized)(3)		0.25		%	—		%
	Allowance as a percentage of the ending total loan balance		0.44		%	0.98		%
	Allowance as a percentage of the ending loans in repayment(3)		0.62		%	1.67		%
	Allowance coverage of charge-offs (annualized)		2.4			—
	Ending total loans, gross		$	1,396,776		$	7,274,718
	Average loans in repayment(3)		$	1,023,329		$	4,329,157
	Ending loans in repayment(3)		$	997,538		$	4,278,969
	____________
	(1) Prior to the Spin-Off, Private Education Loans were sold to an entity that is now a subsidiary of Navient prior to being charged-off.
	(2) Represents fair value write-downs on loans sold.
	(3) Loans in repayment includes in-school loans making interest only and fixed payments as well as loans that have entered full principal and interest repayment status after any applicable grace period.
	Troubled Debt Restructurings (“TDRs”)
	All of our loans are collectively assessed for impairment, except for loans classified as TDRs. Prior to the Spin-Off, we did not have TDR loans because the loans generally were sold to a now unrelated affiliate in the same month that the terms were restructured. Subsequent to May 1, 2014, we have individually assessed $122.1 million of Private Education Loans as TDRs. When these TDR loans are determined to be impaired, we provide for an allowance for losses sufficient to cover life-of-loan expected losses through an impairment calculation based on the difference between the loan's basis and the present value of expected future cash flows discounted at the loan's original effective interest rate.
	Within the Private Education Loan portfolio, loans greater than 90 days past due are considered to be nonperforming. FFELP Loans are at least 97 percent guaranteed as to their principal and accrued interest by the federal government in the event of default, and therefore, we do not deem FFELP Loans as nonperforming from a credit risk standpoint at any point in their life cycle prior to claim payment, and we continue to accrue interest on those loans through the date of claim.
	At March 31, 2015 and December 31, 2014, all of our TDR loans had a related allowance recorded. The following table provides the recorded investment, unpaid principal balance and related allowance for our TDR loans.
			Recorded Investment			Unpaid Principal Balance				Allowance
31-Mar-15
TDR Loans		$	123,702		$	122,120			$	20,105
31-Dec-14
TDR Loans		$	60,278		$	59,402			$	9,815
The following table provides the average recorded investment and interest income recognized for our TDR loans.
		Three Months Ended
		31-Mar-15
		Average Recorded Investment			Interest Income Recognized
TDR Loans		$	88,120		$	2,396
The following table provides information regarding the loan status of TDR loans and the aging of TDR loans that are past due.
		March 31,						December 31,
		2015						2014
		Balance			%			Balance				%
TDR loans in in-school/grace/deferment(1)		$	1,481					$	2,915
TDR loans in forbearance(2)		40,128						18,620
TDR loans in repayment and percentage of each status:
Loans current		73,944			91.8	%		34,554				91.2	%
Loans delinquent 31-60 days(3)		3,921			4.9			1,953				5.2
Loans delinquent 61-90 days(3)		1,873			2.3			983				2.6
Loans delinquent greater than 90 days(3)		773			1			377				1
Total TDR loans in repayment		80,511			100	%		37,867				100	%
Total TDR loans, gross		$	122,120					$	59,402
_____
(1)	Deferment includes customers who have returned to school or are engaged in other permitted educational activities and are not yet required to make payments on the loans (e.g., residency periods for medical students or a grace period for bar exam preparation).
(2)	Loans for customers who have requested extension of grace period generally during employment transition or who have temporarily ceased making full payments due to hardship or other factors, consistent with established loan program servicing policies and procedures.
(3)	The period of delinquency is based on the number of days scheduled payments are contractually past due.
The following table provides the amount of modified loans that resulted in a TDR in the periods presented. Additionally, the table summarizes charge-offs occurring in the TDR portfolio, as well as TDRs for which a payment default occurred in the current period and within 12 months of the loan first being designated as a TDR. We define payment default as 60 day past due for this disclosure. The majority of our loans that are considered TDRs involve a temporary forbearance of payments and do not change the contractual interest rate of the loan.
		Three Months Ended
		31-Mar-15
		Modified Loans			Charge-offs				Payment-Default
TDR Loans		$	122,120		$	930			$	4,785
Key Credit Quality Indicators
For Private Education Loans, the key credit quality indicators are FICO scores, the existence of a cosigner, the loan status and loan seasoning. The FICO scores are assessed at origination and maintained through the loan's term. The following table highlights the gross principal balance of our Private Education Loan portfolio stratified by key credit quality indicators.
		Private Education Loans
		Credit Quality Indicators
		31-Mar-15						December 31, 2014
Credit Quality Indicators:		Balance(1)			% of Balance			Balance(1)				% of Balance
Cosigners:
With cosigner		$	8,804,812		90	%		$	7,465,339			90	%
Without cosigner		963,949			10			846,037				10
Total		$	9,768,761		100	%		$	8,311,376			100	%
FICO at Origination:
Less than 670		$	638,195		6	%		$	558,801			7	%
670-699		1,431,436			15			1,227,860				15
700-749		3,103,824			32			2,626,238				32
Greater than or equal to 750		4,595,306			47			3,898,477				46
Total		$	9,768,761		100	%		$	8,311,376			100	%
Seasoning(2):
1-12 payments		$	3,031,655		31	%		$	2,373,117			29	%
13-24 payments		1,650,103			17			1,532,042				18
25-36 payments		812,674			8			755,143				9
37-48 payments		412,865			4			411,493				5
More than 48 payments		257,986			3			212,438				3
Not yet in repayment		3,603,478			37			3,027,143				36
Total		$	9,768,761		100	%		$	8,311,376			100	%
(1)	Balance represents gross Private Education Loans.
(2)	Number of months in active repayment for which a scheduled payment was due.
FFELP Loans are at least 97 percent insured and guaranteed as to their principal and accrued interest in the event of default; therefore, there are no key credit quality indicators associated with FFELP Loans. Included within our FFELP portfolio as of March 31, 2015 are $741 million of FFELP rehabilitation loans. These loans have previously defaulted but have subsequently been brought current according to a loan rehabilitation agreement. The credit performance on rehabilitation loans is worse than the remainder of our FFELP portfolio. At March 31, 2015 and December 31, 2014, 61.3 percent and 62.1 percent, respectively, of our FFELP portfolio consisted of rehabilitation loans.
The following tables provide information regarding the loan status of our Private Education Loans and the aging of our past due Private Education Loans. Loans in repayment includes in-school loans making interest only and fixed payments as well as loans that have entered full principal and interest repayment status after any applicable grace period.
		Private Education Loans
		March 31,						December 31,
		2015						2014
		Balance			%			Balance				%
Loans in-school/grace/deferment(1)		$	3,603,478					$	3,027,143
Loans in forbearance(2)		170,162						135,018
Loans in repayment and percentage of each status:
Loans current		5,896,132			98.4	%		5,045,600				98	%
Loans delinquent 31-60 days(3)		54,883			0.9			63,873				1.2
Loans delinquent 61-90 days(3)		31,202			0.5			29,041				0.6
Loans delinquent greater than 90 days(3)		12,904			0.2			10,701				0.2
Total loans in repayment		5,995,121			100	%		5,149,215				100	%
Total loans, gross		9,768,761						8,311,376
Deferred origination costs		17,627						13,845
Total loans		9,786,388						8,325,221
Allowance for loan losses		(85,236		)				(78,574		)
Total loans, net		$	9,701,152					$	8,246,647
Percentage of loans in repayment					61.4	%						62	%
Delinquencies as a percentage of loans in repayment					1.7	%						2	%
Loans in forbearance as a percentage of loans in repayment and forbearance					2.8	%						2.6	%
-1	Deferment includes customers who have returned to school or are engaged in other permitted educational activities and are not yet required to make payments on the loans (e.g., residency periods for medical students or a grace period for bar exam preparation).
-2	Loans for customers who have requested extension of grace period generally during employment transition or who have temporarily ceased making full payments due to hardship or other factors, consistent with established loan program servicing policies and procedures.
-3	The period of delinquency is based on the number of days scheduled payments are contractually past due.
Accrued Interest Receivable
The following table provides information regarding accrued interest receivable on our Private Education Loans. The table also discloses the amount of accrued interest on loans greater than 90 days past due as compared to our allowance for uncollectible interest. The allowance for uncollectible interest exceeds the amount of accrued interest on our 90 days past due portfolio for all periods presented.
		Private Education Loan
		Accrued Interest Receivable
		Total Interest Receivable			Greater than 90 days Past Due				Allowance for Uncollectible Interest
31-Mar-15		$	512,501		$	473			$	2,634
31-Dec-14		$	445,710		$	443			$	3,517

Deposits

Deposits	3 Months Ended
	Mar. 31, 2015
Banking and Thrift [Abstract]
Deposits	Deposits
	The following table summarizes total deposits at March 31, 2015 and December 31, 2014.
		March 31,		December 31,
		2015		2014
	Deposits - interest bearing	$	10,466,838	$	10,539,953
	Deposits - non-interest bearing	915		602
	Total deposits	$	10,467,753	$	10,540,555
	Interest Bearing
	Interest bearing deposits as of March 31, 2015 and December 31, 2014 consisted of non-maturity savings and money market deposits, brokered and retail certificates of deposit, and brokered money market deposits. These deposit products are serviced by third party providers. Placement fees associated with the brokered certificates of deposit are amortized into interest expense using the effective interest rate method. We recognized placement fee expense of $2,695 and $2,750 for the three months ended March 31, 2015 and 2014, respectively. No fees were paid to third party brokers related to these certificates of deposit during the three months ended March 31, 2015 and 2014, respectively.
	Interest bearing deposits at March 31, 2015 and December 31, 2014 are summarized as follows:
		31-Mar-15				December 31, 2014
		Amount		Qtr.-End Weighted Average Stated Rate		Amount		Year-End Weighted Average Stated Rate
	Money market	$	4,512,730	1.14	%	$	4,527,448	1.15	%
	Savings	695,675		0.81		703,687		0.81
	Certificates of deposit	5,258,433		1.02		5,308,818		1
	Deposits - interest bearing	$	10,466,838			$	10,539,953
	As of March 31, 2015 and December 31, 2014, there were $224,182 and $253,953, respectively, of deposits exceeding Federal Deposit Insurance Corporation (“FDIC”) insurance limits. Accrued interest on deposits was $22,624 and $16,082 at March 31, 2015 and December 31, 2014, respectively.
	Non Interest Bearing
	Non interest bearing deposits were $915 and $602 as of March 31, 2015 and December 31, 2014, respectively. For both periods these were comprised of money market accounts related to our Employee Stock Purchase Plan account.

Borrowed_Funds

Borrowed Funds	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Borrowed Funds	Borrowed Funds
	We maintain discretionary uncommitted Federal Funds lines of credit with various correspondent banks, which totaled $100,000 at March 31, 2015. The interest rate we are charged on these lines of credit is priced at Fed Funds plus a spread at the time of borrowing, and is payable daily. We did not utilize these lines of credit in the three months ended March 31, 2015 and 2014.
	We established an account at the Federal Reserve Bank (“FRB”) to meet eligibility requirements for access to the Primary Credit borrowing facility at the FRB’s Discount Window (“Window”). The Primary Credit borrowing facility is a lending program available to depository institutions that are in generally sound financial condition. All borrowings at the Window must be fully collateralized. We can pledge asset-backed and mortgage-backed securities, as well as FFELP Loans and Private Education Loans, to the FRB as collateral for borrowings at the Window. Generally, collateral value is assigned based on the estimated fair value of the pledged assets. At March 31, 2015 and December 31, 2014, the value of our pledged collateral at the FRB totaled $1,361,879 and $1,398,286, respectively. The interest rate charged to us is the discount rate set by the FRB. We did not utilize this facility in the three months ended March 31, 2015 and 2014.

Derivative_Financial_Instrumen

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments
	We maintain an overall interest rate risk management strategy that incorporates the use of derivative instruments to minimize the economic effect of interest rate changes. Our goal is to manage interest rate sensitivity by modifying the repricing frequency and underlying index characteristics of certain balance sheet assets and liabilities so the net interest margin is not, on a material basis, adversely affected by movements in interest rates. We do not use derivative instruments to hedge credit risk associated with debt we issued. As a result of interest rate fluctuations, hedged assets and liabilities will appreciate or depreciate in market value. Income or loss on the derivative instruments that are linked to the hedged assets and liabilities will generally offset the effect of this unrealized appreciation or depreciation for the period the item is being hedged. We view this strategy as a prudent management of interest rate sensitivity. Please refer to “Note 11 - Derivative Financial Instruments” in our 2014 Form 10-K for a full discussion of our risk management strategy.
	Although we use derivatives to offset (or minimize) the risk of interest rate changes, the use of derivatives does expose us to both market and credit risk. Market risk is the chance of financial loss resulting from changes in interest rates, foreign exchange rates and market liquidity. Credit risk is the risk that a counterparty will not perform its obligations under a contract and it is limited to the loss of the fair value gain in a derivative that the counterparty owes us. When the fair value of a derivative contract is negative, we owe the counterparty and, therefore, have no credit risk exposure to the counterparty; however, the counterparty has exposure to us. We minimize the credit risk in derivative instruments by entering into transactions with highly rated counterparties that are reviewed regularly by our Credit Department. We also maintain a policy of requiring that all derivative contracts be governed by an International Swaps and Derivative Association Master Agreement. Depending on the nature of the derivative transaction, bilateral collateral arrangements generally are required as well. When we have more than one outstanding derivative transaction with the counterparty, and there exists legally enforceable netting provisions with the counterparty (i.e., a legal right to offset receivable and payable derivative contracts), the “net” mark-to-market exposure, less collateral the counterparty has posted to us, represents exposure with the counterparty. When there is a net negative exposure, we consider our exposure to the counterparty to be zero. At March 31, 2015 and December 31, 2014, we had a net positive exposure (derivative gain positions to us less collateral which has been posted by counterparties to us) related to derivatives of $60,826 and $60,784, respectively.
	Summary of Derivative Financial Statement Impact
	The following tables summarize the fair values and notional amounts of all derivative instruments at March 31, 2015 and December 31, 2014, and their impact on earnings and other comprehensive income for the three months ended March 31, 2015 and 2014.
	Impact of Derivatives on the Consolidated Balance Sheet
				Cash Flow Hedges								Fair Value Hedges							Trading						Total
				March 31,				December 31,				March 31,				December 31,			March 31,			December 31,			March 31,			December 31,
				2015				2014				2015				2014			2015			2014			2015			2014
	Fair Values(1)	Hedged Risk Exposure
	Derivative Assets:(2)
	Interest rate swaps	Interest rate		$	—			$	—			$	24,377			$	5,012		$	1,033		$	226		$	25,410		$	5,238
	Derivative Liabilities:(2)
	Interest rate swaps	Interest rate		(37,295		)		(21,435		)		(738		)		(5,883		)	(30		)	(1,370		)	(38,063		)	(28,688		)
	Total net derivatives			$	(37,295	)		$	(21,435	)		$	23,639			$	(871	)	$	1,003		$	(1,144	)	$	(12,653	)	$	(23,450	)
	___________
	-1	Fair values reported are exclusive of collateral held and pledged and accrued interest. Assets and liabilities are presented without consideration of master netting agreements. Derivatives are carried on the balance sheet based on net position by counterparty under master netting agreements, and classified in other assets or other liabilities depending on whether in a net positive or negative position.
	-2	The following table reconciles gross positions with the impact of master netting agreements to the balance sheet classification:
			Other Assets								Other Liabilities
			March 31,				December 31,				March 31,				December 31,
			2015				2014				2015				2014
	Gross position		$	25,410			$	5,238			$	(38,063	)		$	(28,688	)
	Impact of master netting agreement		(11,003		)		(4,045		)		11,003				4,045
	Derivative values with impact of master netting agreements (as carried on balance sheet)		14,407				1,193				(27,060		)		(24,643		)
	Cash collateral (held) pledged(1)		(3,283		)		(900		)		58,625				72,478
	Net position		$	11,124			$	293			$	31,565			$	47,835
	-1	Cash collateral amount calculations include outstanding accrued interest payable/receivable.
				Cash Flow								Fair Value							Trading						Total
				March 31,				December 31,				March 31,				December 31,			March 31,			December 31,			March 31,			December 31,
				2015				2014				2015				2014			2015			2014			2015			2014
	Notional Values
	Interest rate swaps			$	1,110,072			$	1,106,920			$	2,992,821			$	3,044,492		$	973,539		$	973,539		$	5,076,432		$	5,124,951
	Impact of Derivatives on the Consolidated Statements of Income
			Three Months Ended
			March 31,
			2015				2014
	Fair Value Hedges
	Interest rate swaps:
	Hedge ineffectiveness gains (losses) recorded in earnings		$	427			$	(122	)
	Realized gains recorded in interest expense		7,491				5,672
	Total		$	7,918			$	5,550
	Cash Flow Hedges
	Interest rate swaps:
	Hedge ineffectiveness losses recorded in earnings		(304		)		—
	Realized losses recorded in interest expense		(5,353		)		—
	Total		$	(5,657	)		$	—
	Trading
	Interest rate swaps:
	Interest reclassification		$	1,023			$	459
	Change in fair value of future interest payments recorded in earnings		2,146				(1,101		)
	Total(1)		3,169				(642		)
	Total		$	5,430			$	4,908
	________
	-1	Amounts included in "gains (losses) on derivatives and hedging activities, net. in the consolidated statements of income".
	Impact of Derivatives on the Statements of Changes in Stockholders' Equity
			Three Months Ended
			March 31,
			2015				2014
	Amount of loss recognized in other comprehensive income		$	(21,042	)		$	—
	Amount of loss reclassified in interest expense(1)		(5,353		)		—
	Total change in other comprehensive income for unrealized losses on derivatives		$	(15,689	)		$	—
	___________
	(1) Amounts included in “realized gains (losses) recorded in interest expense” in the “Impact of Derivatives on the Consolidated Statements of Income” table.
	Cash Collateral
Cash collateral held related to derivative exposure between us and our derivatives counterparties was $3,283 and $900 at March 31, 2015 and December 31, 2014, respectively. Collateral held is recorded in “Other Liabilities.” Cash collateral pledged related to derivative exposure between us and our derivatives counterparties was $58,625 and $72,478 at March 31, 2015 and December 31, 2014, respectively.

Stockholders_Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity
	The following table summarizes our common share repurchases and issuances.
			Three Months Ended March 31,
	(Shares and per share amounts in actuals)		2015			2014
	Shares repurchased related to employee stock-based compensation plans(1)		1,389,096			2,115,470
	Average purchase price per share		$	9.46		$	23.56
	Common shares issued(2)		3,130,839			4,238,182
	__________________
	(1)	Comprises shares withheld from stock option exercises and vesting of restricted stock for employees’ tax withholding obligations and shares tendered by employees to satisfy option exercise costs.
	(2)	Common shares issued under our various compensation and benefit plans.
	The closing price of our common stock on March 31, 2015 was $9.28.
	Investment with entities that are now subsidiaries of Navient
	Prior to the Spin-Off, there were transactions between us and affiliates of pre-Spin-Off SLM that are now subsidiaries of Navient. As part of the carve-out, expenses of those transactions were included in our results even though the actual payments for the expenses were paid by the aforementioned affiliates. As such, amounts equal to these payments have been treated as equity contributions in the table below. Certain payments made by us to these affiliates prior to the Spin-Off transaction were treated as dividends.
	Net transfers (to)/from the entity that is now a subsidiary of Navient are included within Navient's subsidiary investment on the consolidated statements of changes in equity. There were no transfers (to)/from the entity that is now a subsidiary of Navient during the three months ended March 31, 2015. The components of the net transfers (to)/from the entity that is now a subsidiary of Navient for the three months ended March 31, 2014 are summarized below:
			Three Months Ended
			March 31,
			2014
	Capital contributions:
	Loan origination activities		$	25,268
	Loan sales		45
	Corporate overhead activities		17,755
	Other		432
	Total capital contributions		43,500
	Corporate push-down		5,738
	Net change in income tax accounts		15,659
	Net change in receivable/payable		(47,622		)
	Other		(31		)
	Total net transfers from the entity that is now a subsidiary of Navient		$	17,244
	Capital Contributions
	During the first four months of 2014, pre-Spin-Off SLM contributed capital to the Bank by funding loan origination activities, purchases of loans in excess of the loans' fair values, providing corporate overhead functions and other activities.
	Capital contributed for loan origination activities reflects the fact that loan origination functions were conducted by a subsidiary of pre-Spin-Off SLM (now a subsidiary of Navient). The Bank did not pay for the costs incurred by pre-Spin-Off SLM in connection with these functions. The costs eligible to be capitalized are recorded on the respective balance sheets and the costs not eligible for capitalization have been recognized as expenses in the respective statements of income.
	Certain general corporate overhead expenses of the Bank were incurred and paid for by pre-Spin-Off SLM.
	Corporate Push-Down
	The consolidated balance sheet of the Company includes certain assets and liabilities that historically were held at pre-Spin-Off SLM but which are specifically identifiable or otherwise allocable to the Company. The cash and cash equivalents held by pre-Spin-Off SLM at the corporate level were not allocated to the Bank for any of the periods presented.
	Receivable/Payable with Affiliate
	All significant intercompany payable/receivable balances between the Bank and pre-Spin-Off SLM are considered to be effectively settled for cash in the combined financial statements at the time the transaction is recorded.

Earnings_per_Common_Share

Earnings per Common Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings per Common Share	Earnings per Common Share
	Basic earnings per common share (“EPS”) are calculated using the weighted average number of shares of common stock outstanding during each period. The determination of the weighted-average shares and diluted potential common shares for the March 31, 2014 period is based on the activity at pre-Spin-Off SLM. A reconciliation of the numerators and denominators of the basic and diluted EPS calculations follows.
			Three Months Ended
			March 31,
	(In thousands, except per share data)		2015		2014
	Numerator:
	Net income attributable to SLM Corporation		$	47,699	$	47,448
	Preferred stock dividends		4,823		—
	Net income attributable to SLM Corporation common stock		$	42,876	$	47,448
	Denominator:
	Weighted average shares used to compute basic EPS		424,428		426,717
	Effect of dilutive securities:
	Dilutive effect of stock options, restricted stock and restricted stock units and Employee Stock Purchase Plan ("ESPP") (1)(2)		7,874		7,933
	Weighted average shares used to compute diluted EPS		432,302		434,650
	Basic earnings per common share attributable to SLM Corporation		$	0.1	$	0.11
	Diluted earnings per common share attributable to SLM Corporation		$	0.1	$	0.11
	_________________
	(1)	Includes the potential dilutive effect of additional common shares that are issuable upon exercise of outstanding stock options, restricted stock, restricted stock units, and the outstanding commitment to issue shares under the ESPP, determined by the treasury stock method.
	(2)	For the three months ended March 31, 2015 and 2014, securities covering approximately 2 million and 3 million shares, respectively, were outstanding but not included in the computation of diluted earnings per share because they were anti-dilutive.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	We use estimates of fair value in applying various accounting standards for our financial statements.
	We categorize our fair value estimates based on a hierarchical framework associated with three levels of price transparency utilized in measuring financial instruments at fair value. For additional information regarding our policies for determining fair value and the hierarchical framework, see Note 2, “Significant Accounting Policies - Fair Value Measurement” in our 2014 Form 10-K for a full discussion.
	During the three months ended March 31, 2015, there were no significant transfers of financial instruments between levels or changes in our methodology or assumptions used to value our financial instruments.
	The following table summarizes the valuation of our financial instruments that are marked-to-fair value on a recurring basis.
		Fair Value Measurements on a Recurring Basis
		March 31, 2015													December 31, 2014
		Level 1			Level 2			Level 3				Total			Level 1			Level 2				Level 3		Total
	Assets
	Mortgage-backed securities	$	—		$	170,831		$	—			$	170,831		$	—		$	168,934			$	—	$	168,934
	Derivative instruments	—			25,410			—				25,410			—			5,238				—		5,238
	Total	$	—		$	196,241		$	—			$	196,241		$	—		$	174,172			$	—	$	174,172
	Liabilities
	Derivative instruments	—			(38,063		)	—				(38,063		)	$	—		$	(28,688	)		$	—	$	(28,688	)
	Total	$	—		$	(38,063	)	$	—			$	(38,063	)	$	—		$	(28,688	)		$	—	$	(28,688	)
	The following table summarizes the fair values of our financial assets and liabilities, including derivative financial instruments.
			March 31, 2015										December 31, 2014
			Fair			Carrying			Difference				Fair			Carrying			Difference
			Value			Value							Value			Value
	Earning assets
	Loans held for investment, net		$	11,878,508		$	10,909,014		$	969,494			$	10,228,399		$	9,509,786		$	718,613
	Cash and cash equivalents		875,622			875,622			—				2,359,780			2,359,780			—
	Available for sale investments		170,831			170,831			—				168,934			168,934			—
	Accrued interest receivable		541,355			541,355			—				469,697			469,697			—
	Tax indemnification receivable		227,157			227,157			—				240,311			240,311			—
	Derivative instruments		25,410			25,410			—				5,238			5,238			—
	Total earning assets		$	13,718,883		$	12,749,389		$	969,494			$	13,472,359		$	12,753,746		$	718,613
	Interest-bearing liabilities
	Money-market, savings and NOW accounts		$	5,209,320		$	5,209,320		$	—			$	5,231,736		$	5,231,736		$	—
	Certificates of deposit		5,274,481			5,258,433			(16,048		)		5,313,645			5,308,818			(4,827		)
	Accrued interest payable		22,624			22,624			—				16,082			16,082			—
	Derivative instruments		38,063			38,063			—				28,688			28,688			—
	Total interest-bearing liabilities		$	10,544,488		$	10,528,440		$	(16,048	)		$	10,590,151		$	10,585,324		$	(4,827	)
	Excess of net asset fair value over carrying value								$	953,446									$	713,786
	Please refer to “Note 15 - Fair Value Measurements” in our 2014 Form 10-K for a full discussion of the methods and assumptions used to estimate the fair value of each class of financial instruments.

Arrangements_with_Navient_Corp

Arrangements with Navient Corporation	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Arrangements with Navient Corporation	Arrangements with Navient Corporation
	In connection with the Spin-Off, we entered into a separation and distribution agreement and other ancillary agreements with Navient. Please refer to “Note 16 - Arrangements with Navient Corporation” in our 2014 Form 10-K for a full discussion of these agreements.
	Amended Loan Participation and Purchase Agreement
	Prior to the Spin-Off, the Bank sold substantially all of its Private Education Loans to several former affiliates, now subsidiaries of Navient (collectively, the “Purchasers”), pursuant to a Loan Participation and Purchase Agreement. This agreement predated the Spin-Off, but was significantly amended and reduced in scope in connection with the Spin-Off. Post-Spin-Off, the Bank retains only the right to require the Purchasers to purchase loans (at fair value) for which the borrower also has a separate lending relationship with Navient (“Split Loans”) when the Split Loans either (1) are more than 90 days past due; (2) have been restructured; (3) have been granted a hardship forbearance or more than 6 months of administrative forbearance; or (4) have a borrower or cosigner who has filed for bankruptcy. At March 31, 2015, we held approximately $108 million of Split Loans.
	During the three months ended March 31, 2015, the Bank sold loans to the Purchasers in the amount of $8,714 in principal and $168 in accrued interest income. During the three months ended March 31, 2014, the Bank sold loans to the Purchasers in the amount of $671,819 in principal and $24,027 in accrued interest income.
	There was no gain as a result of the loans sold in the three months ended March 31, 2015. The gain resulting from loans sold was $33,888 in the three months ended March 31, 2014. Total write-downs to fair value for loans sold with a fair value lower than par totaled $2,181 and $28,963 in the three months ended March 31, 2015 and 2014, respectively. Navient is the servicer for all of these loans.

Regulatory_Capital

Regulatory Capital	3 Months Ended
	Mar. 31, 2015
Banking and Thrift [Abstract]
Regulatory Capital	Regulatory Capital
	The Bank is subject to various regulatory capital requirements administered by federal banking authorities. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material adverse effect on our financial condition. Under the regulatory framework for prompt corrective action, we must meet specific capital guidelines that involve quantitative measures of our assets, and certain off-balance sheet items as calculated under regulatory accounting practices. The Bank’s capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk-weightings and other factors.
	As of the first quarter 2015, the Bank was required by federal banking authorities to report regulatory capital and ratios based on the U.S. Basel III rule. U.S. Basel III implemented changes to capital, risk weighted assets, and “well capitalized” definitions and added a reporting requirement of Common Equity Tier 1 Capital (to risk-weighted assets). Regulatory capital reported as of December 31, 2014 was calculated according to regulatory guidelines in effect at that date.
	“Well capitalized” regulatory requirements are the quantitative measures established by regulation to ensure capital adequacy. The Bank is required to maintain minimum amounts and ratios (set forth in the table below) of Total and Tier I Capital to risk-weighted assets, Common Equity Tier I capital to risk-weighted assets and of Tier I Capital to average assets, as defined by the regulation. The following amounts and ratios are based upon the Bank's assets.
						Well Capitalized Regulatory Requirements
		Amount		Ratio		Amount			Ratio
	As of March 31, 2015:
	Tier I Capital (to Average Assets)	$	1,482,856	11.5	%	$	642,524	>	5	%
	Tier I Capital (to Risk Weighted Assets)	$	1,482,856	13.6	%	$	873,897	>	8	%
	Total Capital (to Risk Weighted Assets)	$	1,572,661	14.4	%	$	1,092,371	>	10	%
	Common Equity Tier I Capital (to Risk Weighted Assets)	$	1,482,856	13.6	%	$	710,041	>	6.5	%
	As of December 31, 2014:
	Tier I Capital (to Average Assets)	$	1,413,988	11.5	%	$	614,709	>	5	%
	Tier I Capital (to Risk Weighted Assets)	$	1,413,988	15	%	$	565,148	>	6	%
	Total Capital (to Risk Weighted Assets)	$	1,497,830	15.9	%	$	941,913	>	10	%
	Bank Dividends
	The Bank is chartered under the laws of the State of Utah and its deposits are insured by the Federal Deposit Insurance Corporation (“FDIC”). The Bank’s ability to pay dividends is subject to the laws of Utah and the regulations of the FDIC. Generally, under Utah’s industrial bank laws and regulations as well as FDIC regulations, the Bank may pay dividends from its net profits without regulatory approval if, following the payment of the dividend, the Bank’s capital and surplus would not be impaired. The Bank paid no dividends for the three months ended March 31, 2015 and 2014, respectively. For the foreseeable future, we expect the Bank to only pay dividends to the Company as may be necessary to provide for regularly scheduled dividends payable on the Company’s Series A and Series B Preferred Stock.

Commitments_Contingencies_and_

Commitments, Contingencies and Guarantees	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Guarantees	Commitments, Contingencies and Guarantees
	Regulatory Matters
	At the time of this filing, the Bank remains subject to the 2014 FDIC Order. Specifically, on May 13, 2014, the Bank reached settlements with the FDIC and the DOJ regarding disclosures and assessments of certain late fees, as well as compliance with the Servicemembers’ Civil Relief Act ("SCRA"). The Department of Justice ("DOJ") Order was approved by the U.S. District Court for the District of Delaware on September 29, 2014. Under the FDIC’s 2014 Order, the Bank agreed to pay $3.3 million in fines and oversee the refund of up to $30 million in late fees assessed on loans owned or originated by the Bank since its inception in November 2005.
	Under the terms of the Separation and Distribution Agreement between the Company and Navient, Navient is responsible for funding all liabilities under the regulatory orders, other than fines directly levied against the Bank in connection with these matters. Under the DOJ Order, Navient is solely responsible for reimbursing SCRA benefits and related compensation on behalf of both its subsidiary, Navient Solutions, Inc., and the Bank.
	In May 2014, the Bank received a Civil Investigative Demand from the Consumer Financial Protection Bureau ("CFPB") in the Bank’s capacity as a former affiliate of Navient as part of the CFPB’s separate investigation relating to fees and policies of pre-Spin-Off SLM during the period prior to the Spin-Off of Navient. We are cooperating fully with the CFPB, but are not in a position at this time to predict the duration or outcome of the investigation. Given the timeframe covered by this demand, Navient would be responsible for all costs, expenses, losses or remediation likely to arise from this investigation.
	Contingencies
	In the ordinary course of business, we and our subsidiaries are routinely defendants in or parties to pending and threatened legal actions and proceedings, including actions brought on behalf of various classes of claimants. These actions and proceedings may be based on alleged violations of consumer protection, securities, employment and other laws. In certain of these actions and proceedings, claims for substantial monetary damage may be asserted against us and our subsidiaries.
	We and our subsidiaries and affiliates are subject to various claims, lawsuits and other actions that arise in the ordinary course of business. In addition, it is common for the Company, our subsidiaries and affiliates to receive information and document requests and investigative demands from state attorneys general, legislative committees, and administrative agencies. These requests may be for informational or regulatory purposes and may relate to our business practices, the industries in which we operate, or other companies with whom we conduct business. Our practice has been and continues to be to cooperate with these bodies and be responsive to any such requests.
	In view of the inherent difficulty of predicting the outcome of litigation, regulatory and investigative actions, we cannot predict what the eventual outcome of the pending matters will be, what the timing or the ultimate resolution of these matters will be, or what the eventual loss, fines or penalties, if any, related to each pending matter may be.
	We are required to establish reserves for litigation and regulatory matters where those matters present loss contingencies that are both probable and estimable. When loss contingencies are not both probable and estimable, we do not establish reserves.
	Based on current knowledge, management does not believe there are loss contingencies, if any, arising from pending investigations, litigation or regulatory matters that could have a material adverse effect on our consolidated financial position, liquidity, results of operations or cash flows.

Subsequent_Event

Subsequent Event	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event
	On April 17, 2015, we announced plans to sell approximately $753 million of Private Education Loans through a securitization transaction to qualified institutional buyers. The transaction will remove the principal balance of the loans backing the securitization trust from our balance sheet on the settlement date. We will continue to service the loans in the trust. We expect to record a pre-tax gain on the sale of approximately $78 million, net of estimated closing adjustments and transaction costs, a 10.5 percent premium over the loans’ book value. The transaction is expected to settle on or about April 23, 2015, and will be reflected in our second quarter 2015 results.

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The accompanying unaudited, consolidated financial statements of SLM Corporation (“we,” “us,” “our,” or the “Company”) have been prepared in accordance with generally accepted accounting principles in the United States of America (“GAAP”) for interim financial information. Accordingly, they do not include all of the information and footnotes required by GAAP for complete consolidated financial statements. The consolidated financial statements include the accounts of SLM Corporation and its majority-owned and controlled subsidiaries after eliminating the effects of intercompany accounts and transactions. In the opinion of management, all adjustments considered necessary for a fair statement of the results for the interim periods have been included. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Operating results for the three months ended March 31, 2015 are not necessarily indicative of the results for the year ending December 31, 2015 or for any other period. These unaudited financial statements should be read in conjunction with the audited financial statements and related notes included in our Annual Report on Form 10-K for the year ended December 31, 2014 (the “2014 Form 10-K”).
	On April 30, 2014, we completed our plan to legally separate into two distinct publicly traded entities - an education loan management, servicing and asset recovery business, Navient Corporation (“Navient”), and a consumer banking business, SLM Corporation. The separation of Navient from SLM Corporation (the “Spin-Off”) was preceded by an internal corporate reorganization, which was the first step to separate the education loan management, servicing and asset recovery business from the consumer banking business.
	For periods before the Spin-Off, the financial statements are presented on a basis of accounting that reflects a change in reporting entity and have been adjusted for the effects of the Spin-Off. These carve-out financial statements and selected financial information represent only those operations, assets, liabilities and equity that form Sallie Mae on a stand-alone basis. Because the Spin-Off occurred on April 30, 2014, the balances as of and for the three months ending March 31, 2014 include the carved out financial results.
Consolidation	Consolidation
	The consolidated financial statements include the accounts of the Company and its majority-owned and controlled subsidiaries after eliminating the effects of intercompany accounts and transactions.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements
	On February 18, 2015, the FASB issued Accounting Standards Update (“ASU”) No. 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis,” which amends the current consolidation guidance. The amendments reduce the number of consolidation models through the elimination of the indefinite deferral of ASC 810 and place more emphasis on risk of loss when determining a controlling financial interest.  The standard is effective for fiscal periods beginning after December 15, 2015. We do not expect this new guidance to have a material impact to our financial results.

Loans_Held_for_Investment_Tabl

Loans Held for Investment (Tables)	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Loans held for investment	Loans held for investment are summarized as follows:
		March 31,			December 31,
		2015			2014
	Private Education Loans	$	9,768,761		$	8,311,376
	Deferred origination costs	17,627			13,845
	Allowance for loan losses	(85,236		)	(78,574		)
	Total Private Education Loans, net	9,701,152			8,246,647
	FFELP Loans	1,208,977			1,264,807
	Unamortized acquisition costs, net	3,454			3,600
	Allowance for loan losses	(4,569		)	(5,268		)
	Total FFELP Loans, net	1,207,862			1,263,139
	Loans held for investment, net	$	10,909,014		$	9,509,786
	The estimated weighted average life of education loans in our portfolio was approximately 6.4 years and 6.2 years at March 31, 2015 and December 31, 2014, respectively.
	The average balance and the respective weighted average interest rates are summarized as follows:
		Three Months Ended
		March 31,
		2015						2014
		Average Balance			Weighted Average Interest Rate			Average Balance		Weighted Average Interest Rate
	Private Education Loans	$	9,454,579		8.07	%		$	7,419,714	8.14	%
	FFELP Loans	1,234,682			3.19			1,404,595		3.19
	Total portfolio	$	10,689,261					$	8,824,309

Allowance_for_Loan_Losses_Tabl

Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Allowance for Credit Losses and Recorded Investments in Loans	Allowance for Loan Losses Metrics
			Allowance for Loan Losses
			Three Months Ended March 31, 2015
			FFELP Loans			Private Education				Total
						Loans
	Allowance for Loan Losses
	Beginning balance		$	5,268		$	78,574			$	83,842
	Total provision		435			16,183				16,618
	Net charge-offs:
	Charge-offs		(1,134		)	(8,727		)		(9,861		)
	Recoveries		—			1,387				1,387
	Net charge-offs		(1,134		)	(7,340		)		(8,474		)
	Loan sales(1)		—			(2,181		)		(2,181		)
	Ending Balance		$	4,569		$	85,236			$	89,805
	Allowance:
	Ending balance: individually evaluated for impairment		$	—		$	20,105			$	20,105
	Ending balance: collectively evaluated for impairment		$	4,569		$	65,131			$	69,700
	Loans:
	Ending balance: individually evaluated for impairment		$	—		$	122,120			$	122,120
	Ending balance: collectively evaluated for impairment		$	1,208,977		$	9,646,641			$	10,855,618
	Net charge-offs as a percentage of average loans in repayment (annualized)(2)		0.5		%	0.51		%
	Allowance as a percentage of the ending total loan balance		0.38		%	0.87		%
	Allowance as a percentage of the ending loans in repayment(2)		0.52		%	1.42		%
	Allowance coverage of net charge-offs (annualized)		1.01			2.9
	Ending total loans, gross		$	1,208,977		$	9,768,761
	Average loans in repayment(2)		$	898,360		$	5,705,067
	Ending loans in repayment(2)		$	872,579		$	5,995,121
	____________
	(1) Represents fair value write-downs on loans sold.
	(2) Loans in repayment includes in-school loans making interest only and fixed payments as well as loans that have entered full principal and interest repayment status after any applicable grace period.
			Allowance for Loan Losses
			Three Months Ended March 31, 2014
			FFELP Loans			Private Education				Total
						Loans
	Allowance for Loan Losses
	Beginning balance		$	6,318		$	61,763			$	68,081
	Total provision		506			38,653				39,159
	Charge-offs(1)		(643		)	—				(643		)
	Loan sales(2)		—			(28,963		)		(28,963		)
	Ending Balance		$	6,181		$	71,453			$	77,634
	Allowance:
	Ending balance: individually evaluated for impairment		$	—		$	—			$	—
	Ending balance: collectively evaluated for impairment		$	6,181		$	71,453			$	77,634
	Loans:
	Ending balance: individually evaluated for impairment		$	—		$	—			$	—
	Ending balance: collectively evaluated for impairment		$	1,396,776		$	7,274,718			$	8,671,494
	Charge-offs as a percentage of average loans in repayment (annualized)(3)		0.25		%	—		%
	Allowance as a percentage of the ending total loan balance		0.44		%	0.98		%
	Allowance as a percentage of the ending loans in repayment(3)		0.62		%	1.67		%
	Allowance coverage of charge-offs (annualized)		2.4			—
	Ending total loans, gross		$	1,396,776		$	7,274,718
	Average loans in repayment(3)		$	1,023,329		$	4,329,157
	Ending loans in repayment(3)		$	997,538		$	4,278,969
	____________
	(1) Prior to the Spin-Off, Private Education Loans were sold to an entity that is now a subsidiary of Navient prior to being charged-off.
	(2) Represents fair value write-downs on loans sold.
	(3) Loans in repayment includes in-school loans making interest only and fixed payments as well as loans that have entered full principal and interest repayment status after any applicable grace period.
Impaired Financing Receivables	At March 31, 2015 and December 31, 2014, all of our TDR loans had a related allowance recorded. The following table provides the recorded investment, unpaid principal balance and related allowance for our TDR loans.
			Recorded Investment			Unpaid Principal Balance				Allowance
	31-Mar-15
	TDR Loans		$	123,702		$	122,120			$	20,105
	31-Dec-14
	TDR Loans		$	60,278		$	59,402			$	9,815
Average Recorded Investment And Interest Income Recognized For Troubled Debt Restructuring Loans	The following table provides the average recorded investment and interest income recognized for our TDR loans.
			Three Months Ended
			31-Mar-15
			Average Recorded Investment			Interest Income Recognized
	TDR Loans		$	88,120		$	2,396
Age Analysis of Past Due Loans Delinquencies	The following tables provide information regarding the loan status of our Private Education Loans and the aging of our past due Private Education Loans. Loans in repayment includes in-school loans making interest only and fixed payments as well as loans that have entered full principal and interest repayment status after any applicable grace period.
			Private Education Loans
			March 31,						December 31,
			2015						2014
			Balance			%			Balance				%
	Loans in-school/grace/deferment(1)		$	3,603,478					$	3,027,143
	Loans in forbearance(2)		170,162						135,018
	Loans in repayment and percentage of each status:
	Loans current		5,896,132			98.4	%		5,045,600				98	%
	Loans delinquent 31-60 days(3)		54,883			0.9			63,873				1.2
	Loans delinquent 61-90 days(3)		31,202			0.5			29,041				0.6
	Loans delinquent greater than 90 days(3)		12,904			0.2			10,701				0.2
	Total loans in repayment		5,995,121			100	%		5,149,215				100	%
	Total loans, gross		9,768,761						8,311,376
	Deferred origination costs		17,627						13,845
	Total loans		9,786,388						8,325,221
	Allowance for loan losses		(85,236		)				(78,574		)
	Total loans, net		$	9,701,152					$	8,246,647
	Percentage of loans in repayment					61.4	%						62	%
	Delinquencies as a percentage of loans in repayment					1.7	%						2	%
	Loans in forbearance as a percentage of loans in repayment and forbearance					2.8	%						2.6	%
	-1	Deferment includes customers who have returned to school or are engaged in other permitted educational activities and are not yet required to make payments on the loans (e.g., residency periods for medical students or a grace period for bar exam preparation).
	-2	Loans for customers who have requested extension of grace period generally during employment transition or who have temporarily ceased making full payments due to hardship or other factors, consistent with established loan program servicing policies and procedures.
	-3	The period of delinquency is based on the number of days scheduled payments are contractually past due.
	The following table provides information regarding the loan status of TDR loans and the aging of TDR loans that are past due.
			March 31,						December 31,
			2015						2014
			Balance			%			Balance				%
	TDR loans in in-school/grace/deferment(1)		$	1,481					$	2,915
	TDR loans in forbearance(2)		40,128						18,620
	TDR loans in repayment and percentage of each status:
	Loans current		73,944			91.8	%		34,554				91.2	%
	Loans delinquent 31-60 days(3)		3,921			4.9			1,953				5.2
	Loans delinquent 61-90 days(3)		1,873			2.3			983				2.6
	Loans delinquent greater than 90 days(3)		773			1			377				1
	Total TDR loans in repayment		80,511			100	%		37,867				100	%
	Total TDR loans, gross		$	122,120					$	59,402
	_____
	(1)	Deferment includes customers who have returned to school or are engaged in other permitted educational activities and are not yet required to make payments on the loans (e.g., residency periods for medical students or a grace period for bar exam preparation).
	(2)	Loans for customers who have requested extension of grace period generally during employment transition or who have temporarily ceased making full payments due to hardship or other factors, consistent with established loan program servicing policies and procedures.
	(3)	The period of delinquency is based on the number of days scheduled payments are contractually past due.
Modified Loans Accounts For Troubled Debt Restructuring	The following table provides the amount of modified loans that resulted in a TDR in the periods presented. Additionally, the table summarizes charge-offs occurring in the TDR portfolio, as well as TDRs for which a payment default occurred in the current period and within 12 months of the loan first being designated as a TDR. We define payment default as 60 day past due for this disclosure. The majority of our loans that are considered TDRs involve a temporary forbearance of payments and do not change the contractual interest rate of the loan.
			Three Months Ended
			31-Mar-15
			Modified Loans			Charge-offs				Payment-Default
	TDR Loans		$	122,120		$	930			$	4,785
Private Education Loan Portfolio Stratified by Key Credit Quality Indicators	The following table highlights the gross principal balance of our Private Education Loan portfolio stratified by key credit quality indicators.
			Private Education Loans
			Credit Quality Indicators
			31-Mar-15						December 31, 2014
	Credit Quality Indicators:		Balance(1)			% of Balance			Balance(1)				% of Balance
	Cosigners:
	With cosigner		$	8,804,812		90	%		$	7,465,339			90	%
	Without cosigner		963,949			10			846,037				10
	Total		$	9,768,761		100	%		$	8,311,376			100	%
	FICO at Origination:
	Less than 670		$	638,195		6	%		$	558,801			7	%
	670-699		1,431,436			15			1,227,860				15
	700-749		3,103,824			32			2,626,238				32
	Greater than or equal to 750		4,595,306			47			3,898,477				46
	Total		$	9,768,761		100	%		$	8,311,376			100	%
	Seasoning(2):
	1-12 payments		$	3,031,655		31	%		$	2,373,117			29	%
	13-24 payments		1,650,103			17			1,532,042				18
	25-36 payments		812,674			8			755,143				9
	37-48 payments		412,865			4			411,493				5
	More than 48 payments		257,986			3			212,438				3
	Not yet in repayment		3,603,478			37			3,027,143				36
	Total		$	9,768,761		100	%		$	8,311,376			100	%
	(1)	Balance represents gross Private Education Loans.
	(2)	Number of months in active repayment for which a scheduled payment was due.
Accrued Interest Receivable	The following table provides information regarding accrued interest receivable on our Private Education Loans. The table also discloses the amount of accrued interest on loans greater than 90 days past due as compared to our allowance for uncollectible interest. The allowance for uncollectible interest exceeds the amount of accrued interest on our 90 days past due portfolio for all periods presented.
			Private Education Loan
			Accrued Interest Receivable
			Total Interest Receivable			Greater than 90 days Past Due				Allowance for Uncollectible Interest
	31-Mar-15		$	512,501		$	473			$	2,634
	31-Dec-14		$	445,710		$	443			$	3,517

Deposits_Tables

Deposits (Tables)	3 Months Ended
	Mar. 31, 2015
Banking and Thrift [Abstract]
Schedule of Deposits	The following table summarizes total deposits at March 31, 2015 and December 31, 2014.
		March 31,		December 31,
		2015		2014
	Deposits - interest bearing	$	10,466,838	$	10,539,953
	Deposits - non-interest bearing	915		602
	Total deposits	$	10,467,753	$	10,540,555
Interest Bearing Deposits	Interest bearing deposits at March 31, 2015 and December 31, 2014 are summarized as follows:
		31-Mar-15				December 31, 2014
		Amount		Qtr.-End Weighted Average Stated Rate		Amount		Year-End Weighted Average Stated Rate
	Money market	$	4,512,730	1.14	%	$	4,527,448	1.15	%
	Savings	695,675		0.81		703,687		0.81
	Certificates of deposit	5,258,433		1.02		5,308,818		1
	Deposits - interest bearing	$	10,466,838			$	10,539,953

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Impact of Derivatives on the Consolidated Balance Sheet	Impact of Derivatives on the Consolidated Balance Sheet
				Cash Flow Hedges								Fair Value Hedges							Trading						Total
				March 31,				December 31,				March 31,				December 31,			March 31,			December 31,			March 31,			December 31,
				2015				2014				2015				2014			2015			2014			2015			2014
	Fair Values(1)	Hedged Risk Exposure
	Derivative Assets:(2)
	Interest rate swaps	Interest rate		$	—			$	—			$	24,377			$	5,012		$	1,033		$	226		$	25,410		$	5,238
	Derivative Liabilities:(2)
	Interest rate swaps	Interest rate		(37,295		)		(21,435		)		(738		)		(5,883		)	(30		)	(1,370		)	(38,063		)	(28,688		)
	Total net derivatives			$	(37,295	)		$	(21,435	)		$	23,639			$	(871	)	$	1,003		$	(1,144	)	$	(12,653	)	$	(23,450	)
	___________
	-1	Fair values reported are exclusive of collateral held and pledged and accrued interest. Assets and liabilities are presented without consideration of master netting agreements. Derivatives are carried on the balance sheet based on net position by counterparty under master netting agreements, and classified in other assets or other liabilities depending on whether in a net positive or negative position.
	-2	The following table reconciles gross positions with the impact of master netting agreements to the balance sheet classification:
			Other Assets								Other Liabilities
			March 31,				December 31,				March 31,				December 31,
			2015				2014				2015				2014
	Gross position		$	25,410			$	5,238			$	(38,063	)		$	(28,688	)
	Impact of master netting agreement		(11,003		)		(4,045		)		11,003				4,045
	Derivative values with impact of master netting agreements (as carried on balance sheet)		14,407				1,193				(27,060		)		(24,643		)
	Cash collateral (held) pledged(1)		(3,283		)		(900		)		58,625				72,478
	Net position		$	11,124			$	293			$	31,565			$	47,835
	-1	Cash collateral amount calculations include outstanding accrued interest payable/receivable.
Offsetting Assets	The following table reconciles gross positions with the impact of master netting agreements to the balance sheet classification:
			Other Assets								Other Liabilities
			March 31,				December 31,				March 31,				December 31,
			2015				2014				2015				2014
	Gross position		$	25,410			$	5,238			$	(38,063	)		$	(28,688	)
	Impact of master netting agreement		(11,003		)		(4,045		)		11,003				4,045
	Derivative values with impact of master netting agreements (as carried on balance sheet)		14,407				1,193				(27,060		)		(24,643		)
	Cash collateral (held) pledged(1)		(3,283		)		(900		)		58,625				72,478
	Net position		$	11,124			$	293			$	31,565			$	47,835
	-1	Cash collateral amount calculations include outstanding accrued interest payable/receivable.
Offsetting Liabilities	Impact of Derivatives on the Consolidated Balance Sheet
				Cash Flow Hedges								Fair Value Hedges							Trading						Total
				March 31,				December 31,				March 31,				December 31,			March 31,			December 31,			March 31,			December 31,
				2015				2014				2015				2014			2015			2014			2015			2014
	Fair Values(1)	Hedged Risk Exposure
	Derivative Assets:(2)
	Interest rate swaps	Interest rate		$	—			$	—			$	24,377			$	5,012		$	1,033		$	226		$	25,410		$	5,238
	Derivative Liabilities:(2)
	Interest rate swaps	Interest rate		(37,295		)		(21,435		)		(738		)		(5,883		)	(30		)	(1,370		)	(38,063		)	(28,688		)
	Total net derivatives			$	(37,295	)		$	(21,435	)		$	23,639			$	(871	)	$	1,003		$	(1,144	)	$	(12,653	)	$	(23,450	)
	___________
	-1	Fair values reported are exclusive of collateral held and pledged and accrued interest. Assets and liabilities are presented without consideration of master netting agreements. Derivatives are carried on the balance sheet based on net position by counterparty under master netting agreements, and classified in other assets or other liabilities depending on whether in a net positive or negative position.
	-2	The following table reconciles gross positions with the impact of master netting agreements to the balance sheet classification:
			Other Assets								Other Liabilities
			March 31,				December 31,				March 31,				December 31,
			2015				2014				2015				2014
	Gross position		$	25,410			$	5,238			$	(38,063	)		$	(28,688	)
	Impact of master netting agreement		(11,003		)		(4,045		)		11,003				4,045
	Derivative values with impact of master netting agreements (as carried on balance sheet)		14,407				1,193				(27,060		)		(24,643		)
	Cash collateral (held) pledged(1)		(3,283		)		(900		)		58,625				72,478
	Net position		$	11,124			$	293			$	31,565			$	47,835
	-1	Cash collateral amount calculations include outstanding accrued interest payable/receivable.
Schedule of Notional Amounts of Outstanding Derivative Positions
				Cash Flow								Fair Value							Trading						Total
				March 31,				December 31,				March 31,				December 31,			March 31,			December 31,			March 31,			December 31,
				2015				2014				2015				2014			2015			2014			2015			2014
	Notional Values
	Interest rate swaps			$	1,110,072			$	1,106,920			$	2,992,821			$	3,044,492		$	973,539		$	973,539		$	5,076,432		$	5,124,951
Derivative Instruments, Gain (Loss)	Impact of Derivatives on the Consolidated Statements of Income
			Three Months Ended
			March 31,
			2015				2014
	Fair Value Hedges
	Interest rate swaps:
	Hedge ineffectiveness gains (losses) recorded in earnings		$	427			$	(122	)
	Realized gains recorded in interest expense		7,491				5,672
	Total		$	7,918			$	5,550
	Cash Flow Hedges
	Interest rate swaps:
	Hedge ineffectiveness losses recorded in earnings		(304		)		—
	Realized losses recorded in interest expense		(5,353		)		—
	Total		$	(5,657	)		$	—
	Trading
	Interest rate swaps:
	Interest reclassification		$	1,023			$	459
	Change in fair value of future interest payments recorded in earnings		2,146				(1,101		)
	Total(1)		3,169				(642		)
	Total		$	5,430			$	4,908
	________
	-1	Amounts included in "gains (losses) on derivatives and hedging activities, net. in the consolidated statements of income".
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)	Impact of Derivatives on the Statements of Changes in Stockholders' Equity
			Three Months Ended
			March 31,
			2015				2014
	Amount of loss recognized in other comprehensive income		$	(21,042	)		$	—
	Amount of loss reclassified in interest expense(1)		(5,353		)		—
	Total change in other comprehensive income for unrealized losses on derivatives		$	(15,689	)		$	—
	___________
	(1) Amounts included in “realized gains (losses) recorded in interest expense” in the “Impact of Derivatives on the Consolidated Statements of Income” table.

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Schedule of Common Share Repurchases	The following table summarizes our common share repurchases and issuances.
			Three Months Ended March 31,
	(Shares and per share amounts in actuals)		2015			2014
	Shares repurchased related to employee stock-based compensation plans(1)		1,389,096			2,115,470
	Average purchase price per share		$	9.46		$	23.56
	Common shares issued(2)		3,130,839			4,238,182
	__________________
	(1)	Comprises shares withheld from stock option exercises and vesting of restricted stock for employees’ tax withholding obligations and shares tendered by employees to satisfy option exercise costs.
	(2)	Common shares issued under our various compensation and benefit plans.
Schedule of Net Transfers (to) from Navient	The components of the net transfers (to)/from the entity that is now a subsidiary of Navient for the three months ended March 31, 2014 are summarized below:
			Three Months Ended
			March 31,
			2014
	Capital contributions:
	Loan origination activities		$	25,268
	Loan sales		45
	Corporate overhead activities		17,755
	Other		432
	Total capital contributions		43,500
	Corporate push-down		5,738
	Net change in income tax accounts		15,659
	Net change in receivable/payable		(47,622		)
	Other		(31		)
	Total net transfers from the entity that is now a subsidiary of Navient		$	17,244

Earnings_per_Common_Share_Tabl

Earnings per Common Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	A reconciliation of the numerators and denominators of the basic and diluted EPS calculations follows.
			Three Months Ended
			March 31,
	(In thousands, except per share data)		2015		2014
	Numerator:
	Net income attributable to SLM Corporation		$	47,699	$	47,448
	Preferred stock dividends		4,823		—
	Net income attributable to SLM Corporation common stock		$	42,876	$	47,448
	Denominator:
	Weighted average shares used to compute basic EPS		424,428		426,717
	Effect of dilutive securities:
	Dilutive effect of stock options, restricted stock and restricted stock units and Employee Stock Purchase Plan ("ESPP") (1)(2)		7,874		7,933
	Weighted average shares used to compute diluted EPS		432,302		434,650
	Basic earnings per common share attributable to SLM Corporation		$	0.1	$	0.11
	Diluted earnings per common share attributable to SLM Corporation		$	0.1	$	0.11
	_________________
	(1)	Includes the potential dilutive effect of additional common shares that are issuable upon exercise of outstanding stock options, restricted stock, restricted stock units, and the outstanding commitment to issue shares under the ESPP, determined by the treasury stock method.
	(2)	For the three months ended March 31, 2015 and 2014, securities covering approximately 2 million and 3 million shares, respectively, were outstanding but not included in the computation of diluted earnings per share because they were anti-dilutive.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Valuation of Financial Instruments that are Marked-To-Market on Recurring Basis	The following table summarizes the valuation of our financial instruments that are marked-to-fair value on a recurring basis.
		Fair Value Measurements on a Recurring Basis
		March 31, 2015													December 31, 2014
		Level 1			Level 2			Level 3				Total			Level 1			Level 2				Level 3		Total
	Assets
	Mortgage-backed securities	$	—		$	170,831		$	—			$	170,831		$	—		$	168,934			$	—	$	168,934
	Derivative instruments	—			25,410			—				25,410			—			5,238				—		5,238
	Total	$	—		$	196,241		$	—			$	196,241		$	—		$	174,172			$	—	$	174,172
	Liabilities
	Derivative instruments	—			(38,063		)	—				(38,063		)	$	—		$	(28,688	)		$	—	$	(28,688	)
	Total	$	—		$	(38,063	)	$	—			$	(38,063	)	$	—		$	(28,688	)		$	—	$	(28,688	)
Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments	The following table summarizes the fair values of our financial assets and liabilities, including derivative financial instruments.
			March 31, 2015										December 31, 2014
			Fair			Carrying			Difference				Fair			Carrying			Difference
			Value			Value							Value			Value
	Earning assets
	Loans held for investment, net		$	11,878,508		$	10,909,014		$	969,494			$	10,228,399		$	9,509,786		$	718,613
	Cash and cash equivalents		875,622			875,622			—				2,359,780			2,359,780			—
	Available for sale investments		170,831			170,831			—				168,934			168,934			—
	Accrued interest receivable		541,355			541,355			—				469,697			469,697			—
	Tax indemnification receivable		227,157			227,157			—				240,311			240,311			—
	Derivative instruments		25,410			25,410			—				5,238			5,238			—
	Total earning assets		$	13,718,883		$	12,749,389		$	969,494			$	13,472,359		$	12,753,746		$	718,613
	Interest-bearing liabilities
	Money-market, savings and NOW accounts		$	5,209,320		$	5,209,320		$	—			$	5,231,736		$	5,231,736		$	—
	Certificates of deposit		5,274,481			5,258,433			(16,048		)		5,313,645			5,308,818			(4,827		)
	Accrued interest payable		22,624			22,624			—				16,082			16,082			—
	Derivative instruments		38,063			38,063			—				28,688			28,688			—
	Total interest-bearing liabilities		$	10,544,488		$	10,528,440		$	(16,048	)		$	10,590,151		$	10,585,324		$	(4,827	)
	Excess of net asset fair value over carrying value								$	953,446									$	713,786

Regulatory_Capital_Tables

Regulatory Capital (Tables)	3 Months Ended
	Mar. 31, 2015
Banking and Thrift [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	The following amounts and ratios are based upon the Bank's assets.
						Well Capitalized Regulatory Requirements
		Amount		Ratio		Amount			Ratio
	As of March 31, 2015:
	Tier I Capital (to Average Assets)	$	1,482,856	11.5	%	$	642,524	>	5	%
	Tier I Capital (to Risk Weighted Assets)	$	1,482,856	13.6	%	$	873,897	>	8	%
	Total Capital (to Risk Weighted Assets)	$	1,572,661	14.4	%	$	1,092,371	>	10	%
	Common Equity Tier I Capital (to Risk Weighted Assets)	$	1,482,856	13.6	%	$	710,041	>	6.5	%
	As of December 31, 2014:
	Tier I Capital (to Average Assets)	$	1,413,988	11.5	%	$	614,709	>	5	%
	Tier I Capital (to Risk Weighted Assets)	$	1,413,988	15	%	$	565,148	>	6	%
	Total Capital (to Risk Weighted Assets)	$	1,497,830	15.9	%	$	941,913	>	10	%

Significant_Accounting_Policie2

Significant Accounting Policies Significant Accounting Policies Detail (Details)	Apr. 30, 2014
	entity
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Spin-Off, Number of Legally Separate Publicly Traded Entities	2

Loans_Held_for_Investment_Addi

Loans Held for Investment - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Jul. 01, 2006	Jun. 30, 2006	Sep. 30, 1993
Receivables [Abstract]
Percent of Private Loans indexed to LIBOR	82.00%
Tier One of Government Guarantee	97.00%		97.00%
Tier Two of Government Guarantee				98.00%
Tier 3 of Government Guarantee					100.00%
Estimated weighted average life of student loans	6 years 5 months 6 days	6 years 2 months 6 days

Loans_Held_for_Investment_Stud

Loans Held for Investment - Student Loan Portfolio by Program (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Receivables [Abstract]
Private Education Loans	$9,768,761	$8,311,376
Deferred origination costs	17,627	13,845
Allowance for loan losses	-85,236	-78,574
Total Private Education Loans, net	9,701,152	8,246,647
FFELP Loans	1,208,977	1,264,807
Unamortized acquisition costs, net	3,454	3,600
Allowance for loan losses	-4,569	-5,268
Total FFELP Loans, net	1,207,862	1,263,139
Loans held for investment, net	$10,909,014	$9,509,786

Loans_Held_for_Investment_Stud1

Loans Held for Investment - Student Loan Portfolio Average Balances (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Receivables [Abstract]
Average Balance, Private Education Loans	$9,454,579	$7,419,714
Weighted Average Interest Rate, Private Education Loans	8.07%	8.14%
Average Balance FFELP Loans	1,234,682	1,404,595
Weighted Average Interest Rate FFELP loans	3.19%	3.19%
Average balance, total portfolio	$10,689,261	$8,824,309

Allowance_for_Loan_Losses_Allo

Allowance for Loan Losses - Allowance for Credit Losses and Recorded Investments in Loans (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Allowance for Loan Losses
Beginning balance	$83,842		$68,081
Total provision	16,618		39,159
Charge-offs	-9,861		-643	[1]
Recoveries	1,387
Net charge-offs	-8,474
Loan sales	-2,181	[2]	-28,963	[2]
Ending Balance	89,805		77,634
Allowance:
Ending balance: individually evaluated for impairment	20,105		0
Ending balance: collectively evaluated for impairment	69,700		77,634
Loans:
Ending balance: individually evaluated for impairment	122,120		0
Ending balance: collectively evaluated for impairment	10,855,618		8,671,494
FFELP Loans
Allowance for Loan Losses
Beginning balance	5,268		6,318
Total provision	435		506
Charge-offs	-1,134		-643	[1]
Recoveries	0
Net charge-offs	-1,134
Loan sales	0	[2]	0	[2]
Ending Balance	4,569		6,181
Allowance:
Ending balance: individually evaluated for impairment	0		0
Ending balance: collectively evaluated for impairment	4,569		6,181
Loans:
Ending balance: individually evaluated for impairment	0		0
Ending balance: collectively evaluated for impairment	1,208,977		1,396,776
Net charge-offs as a percentage of average loans in repayment (annualized)	0.50%	[3]	0.25%	[3]
Allowance as a percentage of the ending total loan balance	0.38%		0.44%
Allowance as a percentage of the ending loans in repayment	0.52%	[3]	0.62%	[3]
Allowance coverage of net charge-offs (annualized)	1.01		2.4
Ending total loans, gross	1,208,977		1,396,776
Average loans in repayment	898,360	[3]	1,023,329	[3]
Ending loans in repayment	872,579	[3]	997,538	[3]
Private Education Loans
Allowance for Loan Losses
Beginning balance	78,574		61,763
Total provision	16,183		38,653
Charge-offs	-8,727		0	[1]
Recoveries	1,387
Net charge-offs	-7,340
Loan sales	-2,181	[2]	-28,963	[2]
Ending Balance	85,236		71,453
Allowance:
Ending balance: individually evaluated for impairment	20,105		0
Ending balance: collectively evaluated for impairment	65,131		71,453
Loans:
Ending balance: individually evaluated for impairment	122,120		0
Ending balance: collectively evaluated for impairment	9,646,641		7,274,718
Net charge-offs as a percentage of average loans in repayment (annualized)	0.51%	[3]	0.00%	[3]
Allowance as a percentage of the ending total loan balance	0.87%		0.98%
Allowance as a percentage of the ending loans in repayment	1.42%	[3]	1.67%	[3]
Allowance coverage of net charge-offs (annualized)	2.9		0
Ending total loans, gross	9,768,761		7,274,718
Average loans in repayment	5,705,067	[3]	4,329,157	[3]
Ending loans in repayment	$5,995,121	[3]	$4,278,969	[3]
[1]	Prior to the Spin-Off, Private Education Loans were sold to an entity that is now a subsidiary of Navient prior to being charged-off.
[2]	Represents fair value write-downs on loans sold.
[3]	Loans in repayment includes in-school loans making interest only and fixed payments as well as loans that have entered full principal and interest repayment status after any applicable grace period.

Allowance_for_Loan_Losses_Reco

Allowance for Loan Losses - Recorded Investment, Unpaid Principal Balance and Related Allowance for TDR Loans (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Receivables [Abstract]
TDR Loans, Recorded Investment	$123,702	$60,278
TDR Loans, Unpaid Principal Balance	122,120	59,402
TDR Loans, Allowance	$20,105	$9,815

Allowance_for_Loan_Losses_Aver

Allowance for Loan Losses - Average Recorded Investment and Interest Income Recognized for TDR (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Receivables [Abstract]
TDR Loans, Average Recorded Investment	$88,120
TDR Loans, Interest Income Recognized	$2,396

Allowance_for_Loan_Losses_Age_

Allowance for Loan Losses - Age Analysis of Past Due Loans Delinquencies (Detail) (USD $)	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Loans in repayment and percentage of each status:
Allowance for loan losses	($89,805)		($83,842)		($77,634)	($68,081)
Private Education Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in-school/grace/deferment	3,603,478	[1]	3,027,143	[1]
Loans in forbearance	170,162	[2]	135,018	[2]
Loans in repayment and percentage of each status:
Loans current	5,896,132		5,045,600
Loans delinquent 31-60 days	54,883	[3]	63,873	[3]
Loans delinquent 61-90 days	31,202	[3]	29,041	[3]
Loans delinquent greater than 90 days	12,904	[3]	10,701	[3]
Total loans in repayment	5,995,121		5,149,215
Total loans, gross	9,768,761		8,311,376
Deferred origination costs	17,627		13,845
Total loans	9,786,388		8,325,221
Allowance for loan losses	-85,236		-78,574		-71,453	-61,763
Total loans, net	9,701,152		8,246,647
Loans current, in percentage	98.40%		98.00%
Loans delinquent 31-60 days, in percentage	0.90%	[3]	1.20%	[3]
Loans delinquent 61-90 days, in percentage	0.50%	[3]	0.60%	[3]
Loans delinquent greater than 90 days, in percentage	0.20%	[3]	0.20%	[3]
Total loans in repayment, in percentage	100.00%		100.00%
Percentage of loans in repayment	61.40%		62.00%
Delinquencies as a percentage of loans in repayment	1.70%		2.00%
Loans in forbearance as a percentage of loans in repayment and forbearance	2.80%		2.60%
Troubled Debt Restructured Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans in-school/grace/deferment	1,481	[1]	2,915	[1]
Loans in forbearance	40,128	[2]	18,620	[2]
Loans in repayment and percentage of each status:
Loans current	73,944		34,554
Loans delinquent 31-60 days	3,921	[3]	1,953	[3]
Loans delinquent 61-90 days	1,873	[3]	983	[3]
Loans delinquent greater than 90 days	773	[3]	377	[3]
Total loans in repayment	80,511		37,867
Total loans, gross	$122,120		$59,402
Loans current, in percentage	91.80%		91.20%
Loans delinquent 31-60 days, in percentage	4.90%	[3]	5.20%	[3]
Loans delinquent 61-90 days, in percentage	2.30%	[3]	2.60%	[3]
Loans delinquent greater than 90 days, in percentage	1.00%	[3]	1.00%	[3]
Total loans in repayment, in percentage	100.00%		100.00%
[1]	Deferment includes customers who have returned to school or are engaged in other permitted educational activities and are not yet required to make payments on the loans (e.g., residency periods for medical students or a grace period for bar exam preparation).
[2]	Loans for customers who have requested extension of grace period generally during employment transition or who have temporarily ceased making full payments due to hardship or other factors, consistent with established loan program servicing policies and procedures.
[3]	The period of delinquency is based on the number of days scheduled payments are contractually past due.

Allowance_for_Loan_Losses_Modi

Allowance for Loan Losses - Modified Loan Accounts for TDR (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Receivables [Abstract]
Modified Loans	$122,120
Charge-offs	930
Payment-Default	$4,785

Allowance_for_Loan_Losses_Priv

Allowance for Loan Losses - Private Education Loan Portfolio Stratified by Key Credit Quality Indicators (Detail) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$9,768,761		$8,311,376
Private Education Loans | Cosigners
Accounts, Notes, Loans and Financing Receivable [Line Items]
Private Education Loans with cosigner	8,804,812	[1]	7,465,339	[1]
Private Education Loans without cosigner	963,949	[1]	846,037	[1]
Private Education Loans with cosigner in percent	90.00%		90.00%
Private Education Loans without cosigner in percent	10.00%		10.00%
Total	9,768,761	[1]	8,311,376	[1]
Total in percent	100.00%		100.00%
Private Education Loans | FICO at Origination
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	9,768,761	[1]	8,311,376	[1]
Total in percent	100.00%		100.00%
Private Education Loans | Seasoning
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	9,768,761	[1],[2]	8,311,376	[1],[2]
Seasoning - based on monthly scheduled payments due from 1-12 payments	3,031,655	[1],[2]	2,373,117	[1],[2]
Seasoning - based on monthly scheduled payments due from 13-24 payments	1,650,103	[1],[2]	1,532,042	[1],[2]
Seasoning - based on monthly scheduled payments due from 25-36 payments	812,674	[1],[2]	755,143	[1],[2]
Seasoning - based on monthly scheduled payments due from 37-48 payments	412,865	[1],[2]	411,493	[1],[2]
Seasoning - based on monthly scheduled payments due from more than 48 payments	257,986	[1],[2]	212,438	[1],[2]
Seasoning - based on monthly scheduled payments due from not yet in repayment	3,603,478	[1],[2]	3,027,143	[1],[2]
Seasoning based on monthly scheduled payments due from 1-12 payments, in percent	31.00%	[2]	29.00%	[2]
Seasoning based on monthly scheduled payments due from 13 - 24 payments, in percent	17.00%	[2]	18.00%	[2]
Seasoning based on monthly scheduled payments due from 25 - 36 payments, in percent	8.00%	[2]	9.00%	[2]
Seasoning based on monthly scheduled payments due from 37 - 48 payments, in percent	4.00%	[2]	5.00%	[2]
Seasoning based on monthly scheduled payments due from more than 48 payments, in percent	3.00%	[2]	3.00%	[2]
Seasoning - based on monthly scheduled payments due from not yet in repayment, in percent	37.00%	[2]	36.00%	[2]
Total in percent	100.00%	[2]	100.00%	[2]
FICO score less than 670 | Private Education Loans | FICO at Origination
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	638,195	[1]	558,801	[1]
Total in percent	6.00%		7.00%
FICO score 670-699 | Private Education Loans | FICO at Origination
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	1,431,436	[1]	1,227,860	[1]
Total in percent	15.00%		15.00%
FICO score 700-749 | Private Education Loans | FICO at Origination
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,103,824	[1]	2,626,238	[1]
Total in percent	32.00%		32.00%
FICO score greater than or equal to 750 | Private Education Loans | FICO at Origination
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$4,595,306	[1]	$3,898,477	[1]
Total in percent	47.00%		46.00%
[1]	Balance represents gross Private Education Loans.
[2]	Number of months in active repayment for which a scheduled payment was due.

Allowance_for_Loan_Losses_Accr

Allowance for Loan Losses - Accrued Interest Receivable (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Receivables [Abstract]
Accrued Interest Receivable On Private Education Loans	$512,501	$445,710
Greater Than 90 Days Past Due	473	443
Allowance For Uncollectible Accrued Interest	$2,634	$3,517

Allowance_for_Loan_Losses_Addi

Allowance for Loan Losses - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Jul. 01, 2006
Receivables [Abstract]
Troubled Debt Restructuring	$122.10
Criteria for loans to be considered as nonperforming	90 days
TDR payment default period	60 days
Tier One of Government Guarantee	97.00%		97.00%
Ffelp Loans Net	$741
Percentage of FFELP Rehabilitation Loans	61.30%	62.10%
Period of loans past due that have accrued interest	90 days

Deposits_Additional_Informatio

Deposits - Additional Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Banking and Thrift [Abstract]
Brokered deposit placement fee	$2,695,000	$2,750,000
Third Party Broker Fees Paid	0	0
Deposits exceeding FDIC insurance limits	224,182,000		253,953,000
Accrued interest on deposits	$22,624,000		$16,082,000

Deposits_Summary_Details

Deposits - Summary (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Banking and Thrift [Abstract]
Deposits - interest bearing	$10,466,838	$10,539,953
Deposits - non-interest bearing	915	602
Deposits	$10,467,753	$10,540,555

Deposits_Interest_Bearing_Depo

Deposits - Interest Bearing Deposits (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Interest-bearing Deposit Liabilities, Domestic, by Component [Abstract]
Money market	$4,512,730	$4,527,448
Savings	695,675	703,687
Certificates of deposit	5,258,433	5,308,818
Deposits - interest bearing	$10,466,838	$10,539,953
Qtr.-End Weighted Average Stated Rate
Money market	1.14%	1.15%
Savings	0.81%	0.81%
Certificates of deposit	1.02%	1.00%

Deposits_Non_Interest_Bearing_

Deposits - Non Interest Bearing Deposits (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Banking and Thrift [Abstract]
Deposits - non-interest bearing	$915	$602

Borrowed_Funds_Borrowed_Funds_

Borrowed Funds Borrowed Funds (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Debt Disclosure [Abstract]
Uncommitted Fed Funds	$100,000,000
Lendable value of collateral	$1,361,879,000	$1,398,286,000

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Additional Information (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net derivatives	$60,826	$60,784
Cash collateral held	3,283	900
Cash collateral pledged	$58,625	$72,478

Derivative_Financial_Instrumen3

Derivative Financial Instruments - Impact of Derivatives on Consolidated Balance Sheet (Detail) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]
Derivative Assets	$25,410		$5,238
Derivative Liabilities	-38,063		-28,688
Interest rate swaps [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	25,410	[1],[2]	5,238	[1],[2]
Derivative Liabilities	-38,063	[1],[2]	-28,688	[1],[2]
Total net derivatives	-12,653	[1]	-23,450	[1]
Interest rate swaps [Member] | Trading
Derivatives, Fair Value [Line Items]
Derivative Assets	1,033	[1],[2]	226	[1],[2]
Derivative Liabilities	-30	[1],[2]	-1,370	[1],[2]
Total net derivatives	1,003	[1]	-1,144	[1]
Interest rate swaps [Member] | Cash Flow | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	0	[1],[2]	0	[1],[2]
Derivative Liabilities	-37,295	[1],[2]	-21,435	[1],[2]
Total net derivatives	-37,295	[1]	-21,435	[1]
Interest rate swaps [Member] | Fair Value | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	24,377	[1],[2]	5,012	[1],[2]
Derivative Liabilities	-738	[1],[2]	-5,883	[1],[2]
Total net derivatives	$23,639	[1]	($871)	[1]
[1]	Fair values reported are exclusive of collateral held and pledged and accrued interest. Assets and liabilities are presented without consideration of master netting agreements. Derivatives are carried on the balance sheet based on net position by counterparty under master netting agreements, and classified in other assets or other liabilities depending on whether in a net positive or negative position.
[2]	The following table reconciles gross positions with the impact of master netting agreements to the balance sheet classification: Other AssetsB Other Liabilities March 31, December 31,B March 31, December 31, 2015B 2014B 2015B 2014Gross positionB $25,410B $5,238B $(38,063)B $(28,688)Impact of master netting agreementB (11,003)B (4,045)B 11,003B 4,045Derivative values with impact of master netting agreements (as carried on balance sheet)B 14,407B 1,193B (27,060)B (24,643)Cash collateral (held) pledged(1)B (3,283)B (900)B 58,625B 72,478Net positionB $11,124B $293B $31,565B $47,835

Derivative_Financial_Instrumen4

Derivative Financial Instruments - Offsetting Assets and Liabilities (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Other Assets
Gross position	$25,410		$5,238
Impact of master netting agreement	-11,003		-4,045
Derivative values with impact of master netting agreements (as carried on balance sheet)	14,407		1,193
Cash collateral (held) pledged	-3,283	[1]	-900	[1]
Net position	11,124		293
Other Liabilities
Gross position	-38,063		-28,688
Impact of master netting agreement	11,003		4,045
Derivative values with impact of master netting agreements (as carried on balance sheet)	-27,060		-24,643
Cash collateral (held) pledged	58,625	[1]	72,478	[1]
Net position	$31,565		$47,835
[1]	Cash collateral amount calculations include outstanding accrued interest payable/receivable.

Derivative_Financial_Instrumen5

Derivative Financial Instruments - Notional Values (Details) (Interest rate swaps [Member], USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Derivatives, Fair Value [Line Items]
Notional values	$5,076,432	$5,124,951
Trading
Derivatives, Fair Value [Line Items]
Notional values	973,539	973,539
Cash Flow Hedges [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional values	1,110,072	1,106,920
Fair Value Hedges [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Notional values	$2,992,821	$3,044,492

Derivative_Financial_Instrumen6

Derivative Financial Instruments - Impact of Derivatives on Consolidated Statements of Income (Details) (Interest rate swaps [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Trading
Gain (loss) on derivatives, net	$5,430		$4,908
Designated as Hedging Instrument [Member] | Fair Value Hedges [Member]
Fair Value Hedges
Hedge ineffectiveness gains (losses) recorded in earnings	427		-122
Realized gains recorded in interest expense	7,491		5,672
Trading
Gain (loss) on derivatives, net	7,918		5,550
Designated as Hedging Instrument [Member] | Cash Flow Hedges [Member]
Cash Flow Hedges
Hedge ineffectiveness losses recorded in earnings	-304		0
Realized losses recorded in interest expense	-5,353		0
Trading
Gain (loss) on derivatives, net	-5,657		0
Not Designated as Hedging Instrument [Member]
Trading
Interest reclassification	1,023		459
Change in fair value of future interest payments recorded in earnings	2,146		-1,101
Gain (loss) on derivatives, net	$3,169	[1]	($642)	[1]
[1]	Amounts included in "gains (losses) on derivatives and hedging activities, net. in the consolidated statements of income".

Derivative_Financial_Instrumen7

Derivative Financial Instruments - Impact of Derivatives on Consolidated Statement of Changes in Stockholders' Equity (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Amount of loss recognized in other comprehensive income	($21,042)		$0
Amount of loss reclassified to interest expense	-5,353	[1]	0	[1]
Total change in other comprehensive income for unrealized losses on derivatives	($15,689)		$0
[1]	Amounts included in brealized gains (losses) recorded in interest expenseb in the bImpact of Derivatives on the Consolidated Statements of Incomeb table.

Stockholders_Equity_Common_sto

Stockholders' Equity - Common stock repurchased (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Equity [Abstract]
Shares repurchased related to employee stock-based compensation plans (in shares)	1,389,096	[1]	2,115,470	[1]
Average purchase price per share (in dollars per share)	$9.46		$23.56
Common shares issued (in shares)	3,130,839	[2]	4,238,182	[2]
[1]	Comprises shares withheld from stock option exercises and vesting of restricted stock for employeesb tax withholding obligations and shares tendered by employees to satisfy option exercise costs.
[2]	Common shares issued under our various compensation and benefit plans.

Stockholders_Equity_Additional

Stockholders' Equity - Additional Detail (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Class of Stock [Line Items]
Total net transfers from the entity that is now a subsidiary of Navient	$0	$17,244,000
Common Stock
Class of Stock [Line Items]
Common stock closing price (usd per share)	$9.28

Stockholders_Equity_Net_Transf

Stockholders' Equity - Net Transfers (To) From Navient (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions		$43,500,000
Corporate push-down		5,738,000
Net change in income tax accounts		15,659,000
Net change in receivable/payable		-47,622,000
Other		-31,000
Total net transfers from the entity that is now a subsidiary of Navient	0	17,244,000
Loan origination activities
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions		25,268,000
Loan sales
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions		45,000
Corporate overhead activities
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions		17,755,000
Other
Schedule of Transfers To and From Affiliate [Line Items]
Total capital contributions		$432,000

Earnings_per_Common_Share_Deta

Earnings per Common Share (Details) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Numerator [Abstract]
Net income attributable to SLM Corporation	$47,699		$47,448
Preferred stock dividends	4,823		0
Net income attributable to SLM Corporation common stock	$42,876		$47,448
Denominator [Abstract]
Weighted average shares used to compute basic EPS (in shares)	424,428,000		426,717,000
Effect of dilutive securities:
Dilutive effect of stock options, restricted stock and restricted stock units (in shares)	7,874,000	[1],[2]	7,933,000	[1],[2]
Weighted average shares used to compute diluted EPS (in shares)	432,302,000		434,650,000
Basic earnings per common share attributable to SLM Corporation (in dollars per share)	$0.10		$0.11
Diluted earnings per common share attributable to SLM Corporation (in dollars per share)	$0.10		$0.11
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	2,000,000		3,000,000
[1]	For the three months ended MarchB 31, 2015 and 2014, securities covering approximately 2 million and 3 million shares, respectively, were outstanding but not included in the computation of diluted earnings per share because they were anti-dilutive.
[2]	Includes the potential dilutive effect of additional common shares that are issuable upon exercise of outstanding stock options, restricted stock, restricted stock units, and the outstanding commitment to issue shares under the ESPP, determined by the treasury stock method.

Fair_Value_Measurements_Valuat

Fair Value Measurements - Valuation of Financial Instruments that are Marked-to-Market on Recurring Basis (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Assets
Estimated Fair Value	$170,831	$168,934
Fair Value Measurements Recurring
Assets
Estimated Fair Value	170,831	168,934
Derivative instruments	25,410	5,238
Total earning assets	196,241	174,172
Liabilities
Derivative Liability	-38,063	-28,688
Fair Value Measurements Recurring | Level 1
Assets
Estimated Fair Value	0	0
Derivative instruments	0	0
Total earning assets	0	0
Liabilities
Derivative Liability	0	0
Fair Value Measurements Recurring | Level 2
Assets
Estimated Fair Value	170,831	168,934
Derivative instruments	25,410	5,238
Total earning assets	196,241	174,172
Liabilities
Derivative Liability	-38,063	-28,688
Fair Value Measurements Recurring | Level 3
Assets
Estimated Fair Value	0	0
Derivative instruments	0	0
Total earning assets	0	0
Liabilities
Derivative Liability	$0	$0

Fair_value_Measurements_Fair_V

Fair value Measurements - Fair Values of Financial Assets and Liabilities, Including Derivative Financial Instruments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Earning assets
Tax indemnification receivable	$227,157	$240,311
Estimate of Fair Value Measurement [Member]
Earning assets
Loans held for investment, net	11,878,508	10,228,399
Cash and cash equivalents	875,622	2,359,780
Available-for-sale investments	170,831	168,934
Accrued interest receivable	541,355	469,697
Tax indemnification receivable	227,157	240,311
Derivative instruments	25,410	5,238
Total earning assets	13,718,883	13,472,359
Interest-bearing liabilities
Accrued interest payable	22,624	16,082
Derivative instruments	38,063	28,688
Total interest-bearing liabilities	10,544,488	10,590,151
Estimate of Fair Value Measurement [Member] | Money market, savings and NOW accounts
Interest-bearing liabilities
Deposits	5,209,320	5,231,736
Estimate of Fair Value Measurement [Member] | Certificates of Deposit
Interest-bearing liabilities
Deposits	5,274,481	5,313,645
Carrying Value
Earning assets
Loans held for investment, net	10,909,014	9,509,786
Cash and cash equivalents	875,622	2,359,780
Available-for-sale investments	170,831	168,934
Accrued interest receivable	541,355	469,697
Tax indemnification receivable	227,157	240,311
Derivative instruments	25,410	5,238
Total earning assets	12,749,389	12,753,746
Interest-bearing liabilities
Accrued interest payable	22,624	16,082
Derivative instruments	38,063	28,688
Total interest-bearing liabilities	10,528,440	10,585,324
Carrying Value | Money market, savings and NOW accounts
Interest-bearing liabilities
Deposits	5,209,320	5,231,736
Carrying Value | Certificates of Deposit
Interest-bearing liabilities
Deposits	5,258,433	5,308,818
Changes Measurement [Member]
Earning assets
Loans held for investment, net	969,494	718,613
Cash and cash equivalents	0	0
Available-for-sale investments	0	0
Accrued interest receivable	0	0
Tax indemnification receivable	0	0
Derivative instruments	0	0
Total earning assets	969,494	718,613
Interest-bearing liabilities
Accrued interest payable	0	0
Derivative instruments	0	0
Total interest-bearing liabilities	-16,048	-4,827
Excess of net asset fair value over carrying value	953,446	713,786
Changes Measurement [Member] | Money market, savings and NOW accounts
Interest-bearing liabilities
Deposits	0	0
Changes Measurement [Member] | Certificates of Deposit
Interest-bearing liabilities
Deposits	($16,048)	($4,827)

Arrangements_with_Navient_Corp1

Arrangements with Navient Corporation (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
Minimum days past due that company may required spin-off company to purchase loans	90 days
Period of hardship forbearance	6 months
Private Education Loans Net	$9,701,152,000		$8,246,647,000
Interest income from related party	168,000	24,027,000
Gains on loans to related party	0	33,888,000
Write-down to fair value for loans sold to related party	2,181,000	28,963,000
Split Loans
Related Party Transaction [Line Items]
Private Education Loans Net	108,000,000
Participated loans [Member]
Related Party Transaction [Line Items]
Loans sold to related party	$8,714,000	$671,819,000

Regulatory_Capital_Well_Capita

Regulatory Capital - Well Capitalized Regulatory Requirements (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Actual
Tier I Capital (to Average Assets)	$1,482,856	$1,413,988
Tier I Capital (to Risk Weighted Assets)	1,482,856	1,413,988
Total Capital (to Risk Weighted Assets)	1,572,661	1,497,830
Common Equity Tier I Capital (to Risk Weighted Assets)	1,482,856
Actual Ratio
Tier I Capital (to Average Assets)	11.50%	11.50%
Tier I Capital (to Risk Weighted Assets)	13.60%	15.00%
Total Capital (to Risk Weighted Assets)	14.40%	15.90%
Common Equity Tier I Capital (to Risk Weighted Assets)	13.60%
Well Capitalized Regulatory Requirements, Amount
Tier I Capital (to Average Assets)	642,524	614,709
Tier I Capital (to Risk Weighted Assets)	873,897	565,148
Total Capital (to Risk Weighted Assets)	1,092,371	941,913
Common Equity Tier I Capital (to Risk Weighted Assets)	$710,041
Well Capitalized Regulatory Requirements, Ratio
Tier I Capital (to Average Assets)	5.00%	5.00%
Tier I Capital (to Risk Weighted Assets)	8.00%	6.00%
Total Capital (to Risk Weighted Assets)	10.00%	10.00%
Common Equity Tier I Capital (to Risk Weighted Assets)	6.50%

Regulatory_Capital_Additional_

Regulatory Capital - Additional Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Banking and Thrift [Abstract]
Dividends	$0	$0

Commitments_Contingencies_and_1

Commitments, Contingencies and Guarantees - Additional Information (Detail) (USD $)	Sep. 29, 2014
Commitments and Contingencies Disclosure [Abstract]
FDIC civil monetary penalties	$3,300,000
Maximum [Member]
Loss Contingencies [Line Items]
Contingency refund	$30,000,000

Subsequent_Event_Subsequent_Ev

Subsequent Event Subsequent Event (Details) (Subsequent Event [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2015	Apr. 17, 2015
Subsequent Event [Member]
Subsequent Event [Line Items]
Future sale of Private Education Loans		$753
Gain on sale of loans, net of costs and adjustments	$78
Percentage of premium on loan sale		1050.00%