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 net result for the period of deducting operating expenses from operating revenues.

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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, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Net sales, excluding intercompany	$ 320.7	$ 318.5	$ 288.1	$ 257.4	$ 293.2	$ 299.4	$ 283.1	$ 245.1	$ 1,184.7	$ 1,120.8	$ 1,023.9
Operating income	43.0	41.8	25.3	14.0	33.2	32.9	24.3	6.9	124.1	97.3	64.1
Depreciation and amortization									56.7	59.2	60.6
Restructuring									3.1	1.5	2.8
Capital expenditures									(36.9)	(36.5)	(31.4)
Total assets	1,317.1				1,281.9				1,317.1	1,281.9
Total intangible assets net book value	533.6				553.1				533.6	553.1
Mueller Co. [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany									783.3	729.5	652.4
Operating income									122.3	91.3	57.7
Depreciation and amortization									42.1	44.6	45.7
Restructuring									2.2	1.5	2.5
Capital expenditures									(24.9)	(24.0)	(20.0)
Total assets	835.8				846.8				835.8	846.8
Total intangible assets net book value	475.7				491.6				475.7	491.6
Anvil [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany									401.4	391.3	371.5
Operating income									41.3	40.2	37.3
Depreciation and amortization									14.2	14.2	14.3
Restructuring									0.9	0.1	0.3
Capital expenditures									(11.6)	(12.3)	(11.4)
Total assets	263.9				259.6				263.9	259.6
Total intangible assets net book value	57.9				61.5				57.9	61.5
Corporate [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany									0	0	0
Operating income									(39.5)	(34.2)	(30.9)
Depreciation and amortization									0.4	0.4	0.6
Restructuring									0	(0.1)	0
Capital expenditures									(0.4)	(0.2)	0
Total assets	217.4				175.5				217.4	175.5
Total intangible assets net book value	0				0				0	0
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intercompany sales									6.8	7.5	7.4
Intersegment Eliminations [Member] \| Mueller Co. [Member]
Segment Reporting Information [Line Items]
Intercompany sales									6.7	7.4	7.3
Intersegment Eliminations [Member] \| Anvil [Member]
Segment Reporting Information [Line Items]
Intercompany sales									0.1	0.1	0.1
Intersegment Eliminations [Member] \| Corporate [Member]
Segment Reporting Information [Line Items]
Intercompany sales									$ 0	$ 0	$ 0