Document and Entity Information Document	3 Months Ended
	Mar. 31, 2013	Apr. 30, 2013	Dec. 31, 2012
Entity Information [Line Items]
Entity Registrant Name	Health Net Inc
Entity Central Index Key	0000916085
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		79,345,249
Treasury Stock, Shares	70,646,000	70,647,270	67,426,000