Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 23, 2016	Jun. 30, 2015	Dec. 31, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	Health Net Inc
Entity Central Index Key	0000916085
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		77,633,701
Treasury Stock, Shares	76,458,000	76,700,096		74,378,000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 4,858,629,585