Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 65	$ 130	$ 283	$ 324
Other comprehensive loss, before tax:
Foreign currency translation adjustment	(20)	(9)	(9)	(61)
Net change in derivative hedge agreements:
Unrealized loss	(5)	0	(14)	(9)
Amount of loss reclassified into net income	3	3	7	1
Net change in postretirement benefit plans:
Net loss	(11)	0	(11)	0
Amortization of prior service credit	(1)	(2)	(3)	(4)
Amortization of net actuarial loss into net income	2	4	8	11
Settlement/Curtailment	8	0	8	1
Other comprehensive loss, before tax	(24)	(4)	(14)	(61)
Income tax expense (benefit) related to items of other comprehensive income	13	(3)	14	7
Other comprehensive loss, net of tax	(37)	(1)	(28)	(68)
Comprehensive income	28	129	255	256
Less: comprehensive loss attributable to noncontrolling interests	0	(2)	0	(2)
Comprehensive income attributable to Xylem	$ 28	$ 131	$ 255	$ 258