Related Party Disclosures (Details) (USD $)
In Millions, unless otherwise specified
8 Months Ended 12 Months Ended 12 Months Ended 0 Months Ended 12 Months Ended
Sep. 30, 2012
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2010
Feb. 01, 2010
Sep. 30, 2012
Principal Owner [Member]
Sep. 30, 2011
Principal Owner [Member]
Sep. 30, 2012
Ralcorp [Member]
Sep. 30, 2011
Ralcorp [Member]
Sep. 30, 2010
Ralcorp [Member]
Sep. 29, 2011
Western Waffles [Member]
Sep. 29, 2011
Western Waffles [Member]
U.S. Dollars
Sep. 29, 2011
Western Waffles [Member]
Candian Dollars
Sep. 30, 2012
Net Investment [Member]
Related Party Transactions                            
Shares of common stock retained by former parent in Spin-Off   6.8                        
Repayments of Related Party Debt   $ 900.0 $ 0 $ 0                    
Separation related adjustments   191.0                       182.8
Total allocated costs reported in selling, general and administrative expenses               4.6 21.5 19.6        
Related Party Transaction, Expenses from Transactions with Related Party 8.1                          
Net sales, related party transactions               16.7 10.5 6.7        
Fees paid to related party for procurement services               0.2            
Fees incurred on behalf of and due from related party   0.5                        
Notes payable                       4.0 4.0  
Interest rate on promissory note                     1.00%      
Discount factor on sale of receivables to related party               1.18%            
Discount on receivables sold to related party               3.3 13.0          
Servicing fee income from related party               0.8 3.7          
Intercompany notes receivable 0 0 7.8           41.3          
Separation related expenses               12.5 2.8          
Debt Instrument, Face Amount           0 784.5              
Equity Investment in Affiliate     $ 60.2   $ 58.6