Document and Entity Information Document - shares	9 Months Ended
	Sep. 30, 2015	Oct. 29, 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-Q
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		77,294,127
Treasury Stock, Shares	76,445,000	76,447,690	74,378,000