Segment Information (Schedule Of Selected Supplemental Balance Sheet Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net sales, excluding intersegment sales	$ 299.4	$ 275.9	$ 827.6	$ 742.8
Intersegment sales	2.2	1.6	5.5	5.4
Operating income (loss)	32.9	25.7	64.1	42.2
Depreciation and amortization	14.6	15.0	44.4	45.2
Restructuring	0.2	0.7	1.3	2.0
Capital expenditures	8.7	7.4	23.0	19.5
Mueller Co. [Member]
Net sales, excluding intersegment sales	199.3	182.6	538.5	465.2
Intersegment sales	2.2	1.5	5.4	5.3
Operating income (loss)	30.2	23.9	61.5	36.8
Depreciation and amortization	10.9	11.3	33.5	34.1
Restructuring	0.2	0.7	1.2	1.9
Capital expenditures	6.3	4.8	14.6	12.0
Anvil [Member]
Net sales, excluding intersegment sales	100.1	93.3	289.1	277.6
Intersegment sales	0	0.1	0.1	0.1
Operating income (loss)	12.3	9.9	27.3	27.5
Depreciation and amortization	3.6	3.6	10.6	10.7
Restructuring	0	0	0.1	0.2
Capital expenditures	2.3	2.6	8.3	7.5
Corporate [Member]
Operating income (loss)	(9.6)	(8.1)	(24.7)	(22.1)
Depreciation and amortization	0.1	0.1	0.3	0.4
Restructuring	0	0	0	(0.1)
Capital expenditures	$ 0.1	$ 0	$ 0.1	$ 0