Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2020	Apr. 30, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Fiscal Period Focus	Q1
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-38769
Entity Registrant Name	Cigna Corporation
Entity Central Index Key	0001739940
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-4991898
Entity Address, Address Line One	900 Cottage Grove Road
Entity Address, City or Town	Bloomfield
Entity Address, State or Province	CT
Entity Address, Postal Zip Code	06002
City Area Code	860
Local Phone Number	226-6000
Title of 12(b) Security	Common Stock, Par Value $0.01
Trading Symbol	CI
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		368,980,984