| Cover | Jan. 26, 2021 | Jul. 23, 2020 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Jan. 26, 2021 | |
| Entity Registrant Name | ALASKA AIR GROUP, INC. | |
| Entity Central Index Key | 0000766421 | |
| Amendment Flag | false | |
| Entity Incorporation, State or Country Code | DE | |
| Entity File Number | 1-8957 | |
| Entity Tax Identification Number | 91-1292054 | |
| Title of 12(b) Security | Common stock, $0.01 par value | |
| Security Exchange Name | NYSE | |
| Trading Symbol | ALK | |
| Entity Address, Address Line One | 19300 International Boulevard | |
| Entity Address, City or Town | Seattle | |
| Entity Address, State or Province | WA | |
| Entity Address, Postal Zip Code | 98188 | |
| City Area Code | 206 | |
| Local Phone Number | 392-5040 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Entity Emerging Growth Company | false |
