| Cover | Oct. 31, 2019 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 31, 2019 |
| Entity File Number | 001-38769 |
| Entity Registrant Name | Cigna Corporation |
| Entity Central Index Key | 0001739940 |
| Entity Tax Identification Number | 82-4991898 |
| Entity Incorporation, State or Country Code | DE |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, Par Value $0.01 |
| Trading Symbol | CI |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
