Restructuring and Asset Impairment Charges - Estimated Restructuring Costs (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Sep. 30, 2026	Jun. 30, 2026	Mar. 31, 2026	Dec. 31, 2025
Actions Commenced in 2026
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	$ 9
Incurred restructuring costs	0	$ 6	$ 0
Expected costs remaining	3
Actions Commenced in 2025
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs				$ 143
Incurred restructuring costs	8	4	31	93
Expected costs remaining				7
Operating Segments \| Applied Water \| Actions Commenced in 2026
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	5
Incurred restructuring costs	1	2	0
Expected costs remaining	2
Operating Segments \| Applied Water \| Actions Commenced in 2025
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs				25
Incurred restructuring costs	0	1	1	23
Expected costs remaining				0
Operating Segments \| Measurement and Control Solutions \| Actions Commenced in 2026
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	1
Incurred restructuring costs	0	1	0
Expected costs remaining	0
Operating Segments \| Measurement and Control Solutions \| Actions Commenced in 2025
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs				22
Incurred restructuring costs	6	1	3	9
Expected costs remaining				3
Operating Segments \| Water Solutions and Services \| Actions Commenced in 2026
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	2
Incurred restructuring costs	(1)	3	0
Expected costs remaining	0
Operating Segments \| Water Solutions and Services \| Actions Commenced in 2025
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs				11
Incurred restructuring costs	1	0	1	6
Expected costs remaining				3
Operating Segments \| Water Infrastructure \| Actions Commenced in 2026
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	0
Incurred restructuring costs	0	0	0
Expected costs remaining	0
Operating Segments \| Water Infrastructure \| Actions Commenced in 2025
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs				85
Incurred restructuring costs	1	2	26	55
Expected costs remaining				1
Corporate \| Actions Commenced in 2026
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs	1
Incurred restructuring costs	0	0	0
Expected costs remaining	1
Corporate \| Actions Commenced in 2025
Restructuring Cost and Reserve [Line Items]
Expected restructuring costs				0
Incurred restructuring costs	$ 0	$ 0	$ 0	0
Expected costs remaining				$ 0