Document and Entity Information	3 Months Ended
	Mar. 31, 2017 shares
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q1
Trading Symbol	SLM
Entity Registrant Name	SLM CORPORATION
Entity Central Index Key	0001032033
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)	431,038,789