Document and Entity Information - Jun. 30, 2015 - shares	Total
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
Trading Symbol	HUM
Entity Registrant Name	HUMANA INC
Entity Central Index Key	0000049071
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding	148,143,674