| Document and Entity Information Document | Apr. 30, 2020 | Oct. 24, 2019 |
| Entity Information [Line Items] | ||
| Document Type | 8-K | |
| Document Period End Date | Apr. 30, 2020 | |
| Entity Registrant Name | Baxter International Inc. | |
| Entity Central Index Key | 0000010456 | |
| Amendment Flag | false | |
| Entity Incorporation, State or Country Code | DE | |
| Entity File Number | 1-4448 | |
| Entity Tax Identification Number | 36-0781620 | |
| Entity Address, Address Line One | One Baxter Parkway | |
| Entity Address, City or Town | Deerfield | |
| Entity Address, State or Province | IL | |
| Entity Address, Postal Zip Code | 60015 | |
| City Area Code | 224 | |
| Local Phone Number | 948-2000 | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Entity Emerging Growth Company | false | |
| Common Stock, $1.00 Per Value | ||
| Entity Information [Line Items] | ||
| Title of 12(b) Security | Common Stock, $1.00 par value | |
| Trading Symbol | BAX (NYSE) | |
| 1.3% Global Notes due 2025 | ||
| Entity Information [Line Items] | ||
| Title of 12(b) Security | 1.3% Global Notes due 2025 | |
| Trading Symbol | BAX 25 | |
| 1.3% Global Notes due 2029 | ||
| Entity Information [Line Items] | ||
| Title of 12(b) Security | 1.3% Global Notes due 2029 | |
| Trading Symbol | BAX 29 | |
| 0.4% Global Notes due 2024 | ||
| Entity Information [Line Items] | ||
| Title of 12(b) Security | 0.4% Global Notes due 2024 | |
| Trading Symbol | BAX 24 | |
| NEW YORK STOCK EXCHANGE, INC. | Common Stock, $1.00 Per Value | ||
| Entity Information [Line Items] | ||
| Security Exchange Name | NYSE | |
| NEW YORK STOCK EXCHANGE, INC. | 1.3% Global Notes due 2025 | ||
| Entity Information [Line Items] | ||
| Security Exchange Name | NYSE | |
| NEW YORK STOCK EXCHANGE, INC. | 1.3% Global Notes due 2029 | ||
| Entity Information [Line Items] | ||
| Security Exchange Name | NYSE | |
| NEW YORK STOCK EXCHANGE, INC. | 0.4% Global Notes due 2024 | ||
| Entity Information [Line Items] | ||
| Security Exchange Name | NYSE | |
| CHICAGO STOCK EXCHANGE, INC | Common Stock, $1.00 Per Value | ||
| Entity Information [Line Items] | ||
| Security Exchange Name | CHX |
