Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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Carrying amount of finite-lived intangible assets, indefinite-lived intangible assets and goodwill. Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Intangible assets are assets, not including financial assets, lacking physical substance.

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The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

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Amount, after cash payment, of expenses associated with exit or disposal activities pursuant to an authorized plan and expenses resulting from the write-down of assets. Excludes expenses related to a business combination, a discontinued operation or an asset retirement obligation.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Segment Information (Schedule Of Selected Supplemental Balance Sheet Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Net sales, excluding intercompany	$ 311.4	$ 301.0	$ 290.3	$ 261.8	$ 320.7	$ 318.5	$ 288.1	$ 257.4	$ 1,164.5	$ 1,184.7	$ 1,120.8
Operating income	44.4	$ 31.5	$ 25.6	$ 8.1	43.0	$ 41.8	$ 25.3	$ 14.0	109.6	124.1	97.3
Depreciation and amortization									58.1	56.7	59.2
Restructuring									20.8	3.1	1.5
Capital expenditures									(37.5)	(36.9)	(36.5)
Total assets	1,229.8				1,312.5				1,229.8	1,312.5
Total intangible assets net book value	507.3				533.6				507.3	533.6
Mueller Co. [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany									702.2	679.1	632.5
Operating income									136.9	126.7	100.3
Depreciation and amortization									38.8	38.0	38.3
Restructuring									8.2	2.1	1.5
Capital expenditures									(20.5)	(18.8)	(16.6)
Total assets	757.7				767.9				757.7	767.9
Total intangible assets net book value	435.5				459.7				435.5	459.7
Anvil [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany									371.1	401.4	391.3
Operating income									30.0	41.3	40.2
Depreciation and amortization									14.7	14.2	14.2
Restructuring									0.4	0.9	0.1
Capital expenditures									(10.3)	(11.6)	(12.3)
Total assets	255.3				263.9				255.3	263.9
Total intangible assets net book value	54.5				57.9				54.5	57.9
Mueller Technologies [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany									91.2	104.2	97.0
Operating income									(12.9)	(4.4)	(9.0)
Depreciation and amortization									4.2	4.1	6.3
Restructuring									0.1	0.1	0.0
Capital expenditures									(6.5)	(6.1)	(7.4)
Total assets	77.2				67.9				77.2	67.9
Total intangible assets net book value	17.3				16.0				17.3	16.0
Corporate [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany									0.0	0.0	0.0
Operating income									(44.4)	(39.5)	(34.2)
Depreciation and amortization									0.4	0.4	0.4
Restructuring									12.1	0.0	(0.1)
Capital expenditures									(0.2)	(0.4)	(0.2)
Total assets	139.6				212.8				139.6	212.8
Total intangible assets net book value	$ 0.0				$ 0.0				0.0	0.0
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intercompany sales									7.3	6.8	7.5
Intersegment Eliminations [Member] \| Mueller Co. [Member]
Segment Reporting Information [Line Items]
Intercompany sales									7.2	6.7	7.4
Intersegment Eliminations [Member] \| Anvil [Member]
Segment Reporting Information [Line Items]
Intercompany sales									0.1	0.1	0.1
Intersegment Eliminations [Member] \| Mueller Technologies [Member]
Segment Reporting Information [Line Items]
Intercompany sales									0.0	0.0	0.0
Intersegment Eliminations [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Intercompany sales									$ 0.0	$ 0.0	$ 0.0