Segment Information (Schedule Of Selected Supplemental Balance Sheet Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2013
Segment Reporting Information [Line Items]
Net sales, excluding intercompany	$ 257.4	$ 245.1
2013	1.6	1.4
Operating income	14.0	6.9
Depreciation and amortization	14.7	14.8
Restructuring	0.1	0.7
2013	7.5	6.2
Total assets	1,269.7		1,281.9
Intangible intangible assets, net	545.5		553.1
Mueller Co. [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany	165.0	151.1
2013	1.6	1.4
Operating income	15.9	8.1
Depreciation and amortization	11.1	11.2
Restructuring	0.1	0.7
2013	4.4	3.4
Anvil [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany	92.4	94.0
2013	0	0
Operating income	7.3	5.9
Depreciation and amortization	3.5	3.5
Restructuring	0	0
2013	3.1	2.8
Corporate [Member]
Segment Reporting Information [Line Items]
Net sales, excluding intercompany	0	0
2013	0	0
Operating income	(9.2)	(7.1)
Depreciation and amortization	0.1	0.1
Restructuring	0	0
2013	$ 0	$ 0