Segment Information (Summary of Operations by Segment) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financial information for each reportable segment
Revenues		$ 1,296	$ 1,287	$ 3,878	$ 3,821
Operating income		11	176	291	460
Interest Expense		16	21	52	63
Other Nonoperating Income (Expense)		(7)	4	(2)	9
Gain from sale of business		0	2	1	0
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		(12)	161	238	406
Depreciation and amortization		65	63	192	195
Capital expenditures		46	60	175	171
Water Infrastructure
Financial information for each reportable segment
Revenues		531	541	1,574	1,567
Operating income		97	99	246	240
Depreciation and amortization		15	17	46	50
Capital expenditures		14	20	65	60
Applied Water
Financial information for each reportable segment
Revenues		376	378	1,149	1,132
Operating income		61	59	179	170
Depreciation and amortization		5	5	17	16
Capital expenditures		5	5	15	19
Measurement & Control Solutions
Financial information for each reportable segment
Revenues		389	368	1,155	1,122
Operating income		(136)	31	(94)	95
Depreciation and amortization		36	34	107	107
Capital expenditures		21	26	74	72
Regional Selling Locations
Financial information for each reportable segment
Depreciation and amortization	[1]	6	5	14	15
Capital expenditures	[2]	4	3	13	11
Corporate and other
Financial information for each reportable segment
Operating income		(11)	(13)	(40)	(45)
Depreciation and amortization		3	2	8	7
Capital expenditures		$ 2	$ 6	$ 8	$ 9

[1] Depreciation and amortization expense incurred by the Regional selling locations was included in an overall allocation of Regional selling location costs to the segments; however, a certain portion of that expense was not specifically identified to a segment. That expense is captured in this Regional selling location line.

[2] Represents capital expenditures incurred by the Regional selling locations not allocated to the segments.