Segment Information (Summary of Operations by Segment) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Financial information for each reportable segment
Revenues		$ 1,160	$ 1,345	$ 2,283	$ 2,582
Operating income		54	171	115	280
Interest Expense		18	18	34	36
Other Nonoperating Income (Expense)		(1)	3	(4)	5
Gain from sale of business		0	0	0	1
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest		35	156	77	250
Depreciation and amortization		62	63	126	127
Capital expenditures		44	60	95	129
Water Infrastructure
Financial information for each reportable segment
Revenues		501	561	939	1,043
Operating income		73	98	112	149
Depreciation and amortization		16	16	31	31
Capital expenditures		8	21	18	51
Applied Water
Financial information for each reportable segment
Revenues		337	394	675	773
Operating income		41	62	88	118
Depreciation and amortization		5	6	11	12
Capital expenditures		3	4	12	10
Measurement & Control Solutions
Financial information for each reportable segment
Revenues		322	390	669	766
Operating income		(46)	26	(58)	42
Depreciation and amortization		34	35	70	71
Capital expenditures		24	29	51	53
Regional Selling Locations
Financial information for each reportable segment
Depreciation and amortization	[1]	7	4	11	8
Capital expenditures	[2]	8	5	12	9
Corporate and other
Financial information for each reportable segment
Operating income		(14)	(15)	(27)	(29)
Depreciation and amortization		0	2	3	5
Capital expenditures		$ 1	$ 1	$ 2	$ 6

[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.