Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2021	Feb. 08, 2022	Jun. 30, 2021
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-35229
Entity Registrant Name	Xylem Inc.
Entity Incorporation, State or Country Code	IN
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
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 22.6
Entity Common Stock, Shares Outstanding		179,901,139
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement for its 2022 Annual Meeting of Shareowners, to be held in May 2022, are incorporated by reference into Part II and Part III of this Report.
Entity Central Index Key	0001524472
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Common Stock
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	XYL
Security Exchange Name	NYSE
Senior Notes Due 2023
Entity Information [Line Items]
Title of 12(b) Security	2.250% Senior Notes due 2023
Trading Symbol	XYL23
Security Exchange Name	NYSE