Document and Entity Information - USD ($) $ / shares in Units, $ in Billions	12 Months Ended
	Dec. 31, 2015	Jan. 31, 2016	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Document Document And Entity Information [Abstract]
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Entity Registrant Name	CIGNA Corporation
Entity Central Index Key	0000701221
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Trading Symbol	CI
Entity Common Stock Shares Outstanding		255,766,310
Amendment Flag	false
Entity Current Reporting Status	Yes
Entity Well Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Public Float			$ 41.6
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Common stock, par value per share	$ 0.25			$ 0.25	$ 0.25