Goodwill and Other Intangible Assets (Rollforward of Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Changes in the carrying value of goodwill by operating segment
Beginning Balance		$ 2,976	$ 2,768
Goodwill acquired		19	279
Goodwill, Impairment Loss	$ (148)	(148)	0	$ 0
Foreign currency and other		(8)	(71)
Ending Balance		2,839	2,976	2,768
Water Infrastructure
Changes in the carrying value of goodwill by operating segment
Beginning Balance		653	667
Goodwill acquired		0	0
Goodwill, Impairment Loss		0
Foreign currency and other		(2)	(14)
Ending Balance		651	653	667
Applied Water
Changes in the carrying value of goodwill by operating segment
Beginning Balance		516	526
Goodwill acquired		0	0
Goodwill, Impairment Loss		0
Foreign currency and other		(3)	(10)
Ending Balance		513	516	526
Measurement & Control Solutions
Changes in the carrying value of goodwill by operating segment
Beginning Balance		1,807	1,575
Goodwill acquired		19	279
Goodwill, Impairment Loss		(148)
Foreign currency and other		(3)	(47)
Ending Balance		$ 1,675	$ 1,807	$ 1,575

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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