| Cover Page | Mar. 31, 2020 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Mar. 31, 2020 |
| Entity Registrant Name | XYLEM INC. |
| Entity Incorporation, State or Country Code | IN |
| Entity File Number | 001-35229 |
| Entity Tax Identification Number | 45-2080495 |
| Entity Address, Address Line One | 1 International Drive |
| Entity Address, City or Town | Rye Brook, |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10573 |
| City Area Code | 914 |
| Local Phone Number | 323-5700 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001524472 |
| Amendment Flag | false |
| Common Stock, par value $0.01 per share | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | XYL |
| Security Exchange Name | NYSE |
| 2.250% Senior Notes due 2023 | |
| Document Information [Line Items] | |
| Title of 12(b) Security | 2.250% Senior Notes due 2023 |
| Trading Symbol | XYL23 |
| Security Exchange Name | NYSE |
