Restructuring Charges (Accrual Rollfoward) (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Restructuring Reserve [Roll Forward]
Restructuring accruals - January 1		$ 27	$ 5
Restructuring charges		2	8
Cash payments		(8)	(4)
Foreign currency and other		(1)	0
Restructuring accruals - March 31		20	9
Water Infrastructure
Restructuring Reserve [Roll Forward]
Restructuring charges		2	4
Restructuring accruals - March 31		1	2
Applied Water
Restructuring Reserve [Roll Forward]
Restructuring charges		0	0
Restructuring accruals - March 31		1	0
Measurement & Control Solutions
Restructuring Reserve [Roll Forward]
Restructuring charges		0	7
Restructuring accruals - March 31		17	4
Regional Selling Locations
Restructuring Reserve [Roll Forward]
Restructuring accruals - March 31	[1]	$ 1	$ 3

[1] Regional selling locations consist primarily of selling and marketing organizations and related support services that incurred restructuring expense which was allocated to the segments. The liabilities associated with restructuring expense were not allocated to the segments.