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Subsequent Event (Details) - shares
Oct. 26, 2021
Sep. 30, 2021
Sep. 30, 2020
BellRing Brands, Inc. | BellRing Brands, LLC unit      
Subsequent Event [Line Items]      
Noncontrolling interest, ownership percentage by parent   28.80% 28.80%
Common Class B      
Subsequent Event [Line Items]      
Common stock, shares outstanding   1 1
Subsequent Event [Member] | Common Class B      
Subsequent Event [Line Items]      
Common stock, shares outstanding 1    
Subsequent Event [Member] | New BellRing Common Stock      
Subsequent Event [Line Items]      
Common stock, shares outstanding 1    
Subsequent Event [Member] | New BellRing Common Stock | Existing BellRing Brands, Inc. Stockholders      
Subsequent Event [Line Items]      
Sale of Stock, Percentage of Ownership after Transaction 28.80%    
Subsequent Event [Member] | New BellRing Common Stock | Post Holdings, Inc.      
Subsequent Event [Line Items]      
Distribution of ownership in subsidiary, percentage 80.10%    
Sale of Stock, Percentage of Ownership after Transaction 14.20%    
Subsequent Event [Member] | New BellRing Common Stock | Post Holdings, Inc. Stockholders      
Subsequent Event [Line Items]      
Sale of Stock, Percentage of Ownership after Transaction 57.00%