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Organization (Details) $ in Millions		3 Months Ended		12 Months Ended
	Jul. 31, 2014	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2017
Segment Reporting Information [Line Items]
Beginning balance		$ 0.9	$ 3.3	$ 0.9
Restructuring		3.2	3.9
Payments		1.1	$ 1.4
Number of Reportable Segments			2,000,000
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage	49.00%
Defined Benefit Plan, Net Periodic Benefit Cost other than Service Cost		$ (0.1)	$ 0.2
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	24.50%		35.00%
Mueller Co. [Member]
Segment Reporting Information [Line Items]
Restructuring		$ 0.0	$ 0.0
Scenario, Forecast [Member]
Segment Reporting Information [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				21.00%

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