v3.24.2.u1
Segments (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jun. 30, 2024
Jun. 30, 2023
Jun. 30, 2024
Jun. 30, 2023
Sep. 30, 2023
Segment Reporting Information          
Net Sales $ 1,947.7 $ 1,859.4 $ 5,912.6 $ 5,045.6  
Interest expense, net 78.8 72.7 236.9 202.4  
Gain on extinguishment of debt, net (1.8) (6.4) (4.6) (21.2)  
(Income) expense on swaps, net (3.1) (17.1) 4.7 (20.4)  
Earnings before income taxes and equity method loss 131.6 125.1 374.2 318.0  
Depreciation and amortization 120.7 106.5 352.7 293.3  
Assets 12,128.5   12,128.5   $ 11,646.7
Operating Segments          
Segment Reporting Information          
Net Sales 1,947.7 1,859.4 5,912.6 5,045.6  
Segment Profit (Loss) 247.4 226.6 757.1 618.7  
Depreciation and amortization 113.6 104.2 335.6 288.7  
Operating Segments | Post Consumer Brands          
Segment Reporting Information          
Net Sales 1,008.1 871.3 3,062.2 2,025.1  
Segment Profit (Loss) 128.6 83.0 401.0 237.8  
Depreciation and amortization 52.5 44.1 153.7 109.2  
Assets 4,992.0   4,992.0   4,782.2
Operating Segments | Weetabix          
Segment Reporting Information          
Net Sales 136.1 134.2 403.2 377.2  
Segment Profit (Loss) 24.1 17.9 63.2 58.8  
Depreciation and amortization 10.2 9.2 29.6 26.6  
Assets 1,831.1   1,831.1   1,737.8
Operating Segments | Foodservice          
Segment Reporting Information          
Net Sales 589.1 622.7 1,711.0 1,856.4  
Segment Profit (Loss) 89.6 107.7 229.8 264.9  
Depreciation and amortization 33.0 31.8 98.8 95.5  
Operating Segments | Refrigerated Retail          
Segment Reporting Information          
Net Sales 214.4 230.7 735.7 786.4  
Segment Profit (Loss) 5.1 18.0 63.1 57.2  
Depreciation and amortization 17.9 19.1 53.5 57.4  
Operating Segments | Foodservice and Refrigerated Retail          
Segment Reporting Information          
Assets 4,867.1   4,867.1   4,921.6
Eliminations and Corporate          
Segment Reporting Information          
Net Sales 0.0 0.5 0.5 0.5  
Corporate          
Segment Reporting Information          
General corporate expenses and other 41.9 52.3 145.9 139.9  
Depreciation and amortization 7.1 2.3 17.1 4.6  
Assets 438.3   438.3   $ 205.1
Cereal | Operating Segments          
Segment Reporting Information          
Net Sales 677.5 700.8 2,039.3 2,028.5  
Eggs and egg products | Operating Segments          
Segment Reporting Information          
Net Sales 542.2 591.1 1,582.0 1,769.2  
Side dishes (including potato products) | Operating Segments          
Segment Reporting Information          
Net Sales 174.8 171.0 576.6 561.0  
Pet Food | Operating Segments          
Segment Reporting Information          
Net Sales 428.9 275.3 1,316.2 275.3  
Cheese and dairy | Operating Segments          
Segment Reporting Information          
Net Sales 39.9 42.9 129.9 143.9  
Sausage | Operating Segments          
Segment Reporting Information          
Net Sales 34.2 35.5 123.4 127.8  
Peanut butter | Operating Segments          
Segment Reporting Information          
Net Sales 28.8 20.0 83.5 74.9  
Protein-based products and supplements | Operating Segments          
Segment Reporting Information          
Net Sales 9.8 9.4 23.3 23.6  
Other | Operating Segments          
Segment Reporting Information          
Net Sales 11.6 13.4 38.4 42.2  
Eliminations | Eliminations and Corporate          
Segment Reporting Information          
Net Sales $ 0.0 $ 0.0 $ 0.0 $ (0.8)