Restructuring Charges (Estimated Restructuring Costs) (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
2024 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	$ 34
Restructuring costs incurred during period		$ 22	$ 3
Total expected costs remaining	3
2023 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	78
Restructuring costs incurred during period	(2)	1	6	$ 71
Total expected costs remaining	2
2021 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred during period	6
Operating Segments | Water Infrastructure | 2024 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	6
Restructuring costs incurred during period		0	0
Total expected costs remaining	3
Operating Segments | Water Infrastructure | 2023 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	20
Restructuring costs incurred during period	0	1	5	13
Total expected costs remaining	1
Operating Segments | Water Infrastructure | 2021 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred during period	3
Operating Segments | Applied Water | 2024 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	1
Restructuring costs incurred during period		0	1
Total expected costs remaining	0
Operating Segments | Applied Water | 2023 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	7
Restructuring costs incurred during period	1	0	0	6
Total expected costs remaining	0
Operating Segments | Applied Water | 2021 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred during period	0
Operating Segments | Measurement and Control Solutions | 2024 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	0
Restructuring costs incurred during period		0	0
Total expected costs remaining	0
Operating Segments | Measurement and Control Solutions | 2023 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	7
Restructuring costs incurred during period	(3)	0	0	10
Total expected costs remaining	0
Operating Segments | Measurement and Control Solutions | 2021 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred during period	0
Operating Segments | Water Solutions and Services | 2024 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	27
Restructuring costs incurred during period		22	2
Total expected costs remaining	0
Operating Segments | Water Solutions and Services | 2023 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	7
Restructuring costs incurred during period	0	0	0	7
Total expected costs remaining	0
Operating Segments | Water Solutions and Services | 2021 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred during period	3
Corporate and other | 2024 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	0
Restructuring costs incurred during period		0	0
Total expected costs remaining	0
Corporate and other | 2023 Plan
Restructuring Cost and Reserve [Line Items]
Total expected costs	37
Restructuring costs incurred during period	0	$ 0	$ 1	$ 35
Total expected costs remaining	1
Corporate and other | 2021 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring costs incurred during period	$ 0