Business Combinations (Narrative) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended			0 Months Ended			0 Months Ended		12 Months Ended						0 Months Ended		12 Months Ended
	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009	Jun. 25, 2010 Sepps Gourmet Foods Ltd [Member]	Jul. 27, 2010 American Italian Pasta Company [Member]	Sep. 30, 2010 American Italian Pasta Company [Member]	May 31, 2010 J.T. Bakeries Inc. And North American Banking Ltd. [Member]	Mar. 20, 2009 Harvest Manor Farms, LLC [Member] years	Sep. 30, 2011 Harvest Manor Farms, LLC [Member]	Sep. 30, 2010 Harvest Manor Farms, LLC [Member]	Sep. 30, 2009 Harvest Manor Farms, LLC [Member]	Sep. 30, 2011 Parent Company [Member]	Sep. 30, 2010 Parent Company [Member]	Sep. 30, 2009 Parent Company [Member]	Jul. 27, 2010 Customer Relationships [Member] American Italian Pasta Company [Member] years	Jul. 27, 2010 Trademarks/Brands [Member] American Italian Pasta Company [Member] years	Sep. 30, 2011 Fiscal Year 2010 [Member]	Sep. 30, 2010 Fiscal Year 2010 [Member]
Business Acquisition [Line Items]
Date of acquisition												June 25, 2010	July 27, 2010		May 31, 2010	March 20, 2009
Number of businesses acquired																										3
Net sales from acquisition included in statement of earnings																	$ 246.8	$ 210.8	$ 90.5						$ 138.0	$ 46.6
Operating profit, net of amortization expense									78.2	49.3	42.3									10.7	6.3	5.6			4.1	1.2
Operating profit from acquisition included in statement of earnings																	17.5	13.2	5.5						6.6	2.0
Merger and integration costs	1.0	1.2	0.1	0.2	14.5	13.5	4.5	0.6	2.5	33.1	32.0
Cash paid per common stock													$ 53.00
Acquired finite-lived intangible assets																							372.2	12.2
Other intangible assets														568.2										193.0
Weighted average useful life (years)																13							16	15
Acquired indefinite-lived intangible assets																								180.8
Inventory valuation adjustment													$ 3.9