Earnings Per Share (Calculations for EPS) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Basic and diluted net earnings per share:
Net income attributable to Xylem (in usd)		$ 194	$ 92	$ 347	$ 191
Shares
Weighted average common shares outstanding (in shares)		242,538	205,505	242,182	192,938
Add: Participating securities (in shares)	[1]	34	34	31	29
Weighted average common shares outstanding - Basic (in shares)		242,572	205,539	242,213	192,967
Plus incremental shares from assumed conversions:
Weighted average common shares outstanding - Diluted (in shares)		243,538	206,740	243,279	194,029
Basic earnings per share (usd per share)		$ 0.80	$ 0.45	$ 1.43	$ 0.99
Diluted earnings per share (usd per share)		$ 0.80	$ 0.45	$ 1.43	$ 0.98
Stock options
Plus incremental shares from assumed conversions:
Dilutive effect of stock options (in shares)	[2]	576	872	651	747
Restricted stock units
Plus incremental shares from assumed conversions:
Dilutive effect of stock options (in shares)	[2]	390	329	415	315

[1] Restricted stock units containing rights to non-forfeitable dividends that participate in undistributed earnings with common stockholders are considered participating securities for purposes of computing earnings per share.

[2] Incremental shares from stock options, restricted stock units and performance share units are computed by the treasury stock method. The weighted average shares listed below were not included in the computation of diluted earnings per share because to do so would have been anti-dilutive for the periods presented or were otherwise excluded under the treasury stock method. The treasury stock method calculates dilution assuming the exercise of all in-the-money options and vesting of restricted stock units and performance share units, reduced by the repurchase of shares with the proceeds from the assumed exercises and unrecognized compensation expense for outstanding awards. Performance share units will be included in the treasury stock calculation of diluted earnings per share upon achievement of underlying performance or market conditions at the end of the reporting period. See Note 15, "Share-Based Compensation Plans," to the condensed consolidated financial statements for further detail on the performance share units.