v3.10.0.1
Document and Entity Information
9 Months Ended
Sep. 30, 2018
shares
Document And Entity Information [Abstract]  
Document Type 10-Q
Amendment Flag false
Document Period End Date Sep. 30, 2018
Document Fiscal Year Focus 2018
Document Fiscal Period Focus Q3
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) 435,661,454
Entity Emerging Growth Company false
Entity Small Business false