v3.20.4
Long-Term Debt (Details)
3 Months Ended
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Sep. 30, 2020
USD ($)
Debt Instrument      
Long-term Debt, Including Current Maturities $ 7,032,200,000   $ 7,049,700,000
Current portion of long-term debt 36,100,000   64,900,000
Unamortized Debt Issuance Expense 60,300,000   62,600,000
Plus: Unamortized premium and discount, net 36,300,000   36,800,000
Total Long-term Debt 6,972,100,000   6,959,000,000.0
Repayments of Long-term Debt $ 37,500,000 $ 2,574,500,000  
Debt Covenant, Leverage Ratio 4.25    
Debt Covenant, Percentage of Revolving Credit Commitments 30.00%    
Gross Repayments of Long-term debt $ 37,500,000 2,574,500,000  
Term Loan      
Debt Instrument      
Write off of Debt Issuance Costs and Other Expenses   9,100,000  
Gross Repayments of Long-term debt   1,309,500,000  
Revolving Credit Facility      
Debt Instrument      
Line of Credit Facility, Current Borrowing Capacity $ 750,000,000.0    
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.25%    
Letters of Credit Outstanding, Amount $ 19,400,000    
Line of Credit Facility, Remaining Borrowing Capacity 730,600,000    
Debt Covenant, Maximum Undischarged Judgments $ 100,000,000.0    
Revolving Credit Facility | Minimum      
Debt Instrument      
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.25%    
Revolving Credit Facility | Maximum      
Debt Instrument      
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.375%    
Revolving Credit Facility | Base Rate      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 0.50%    
Revolving Credit Facility | Base Rate | Minimum      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 0.50%    
Revolving Credit Facility | Base Rate | Maximum      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 1.00%    
Revolving Credit Facility | Base Rate | Median      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 0.75%    
Revolving Credit Facility | Federal Funds      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 0.50%    
Revolving Credit Facility | One-Month Eurodollar      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 1.00%    
Revolving Credit Facility | Eurodollar      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 1.50%    
Revolving Credit Facility | Eurodollar | Minimum      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 1.50%    
Revolving Credit Facility | Eurodollar | Maximum      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 2.00%    
Revolving Credit Facility | Eurodollar | Median      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 1.75%    
Line of Credit      
Debt Instrument      
Line of Credit Facility, Current Borrowing Capacity $ 75,000,000.0    
2020 Bridge Loan      
Debt Instrument      
Write off of Debt Issuance Costs and Other Expenses   3,800,000  
Gross Repayments of Long-term debt   1,225,000,000.0  
BellRing Term B Facility      
Debt Instrument      
Long-term Debt $ 636,200,000   673,700,000
BellRing Term B Facility | Base Rate      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 4.00%    
BellRing Revolving Credit Facility      
Debt Instrument      
Long-term Debt $ 50,000,000.0   30,000,000.0
Municipal Bonds      
Debt Instrument      
Long-term Debt 8,500,000   8,500,000
4.625% Senior Notes Maturing April 2030 | Senior Notes      
Debt Instrument      
Long-term Debt 1,650,000,000.0   1,650,000,000.0
5.50% Senior Notes Maturing in December 2029 | Senior Notes      
Debt Instrument      
Long-term Debt 750,000,000.0   750,000,000.0
5.625% Senior Notes maturing January 2028 | Senior Notes      
Debt Instrument      
Long-term Debt 940,900,000   940,900,000
5.75% Senior Notes Maturing March 2027 | Senior Notes      
Debt Instrument      
Long-term Debt 1,299,300,000   1,299,300,000
5.00% Senior Notes maturing August 2026 | Senior Notes      
Debt Instrument      
Long-term Debt 1,697,300,000   $ 1,697,300,000
(Gain) loss on extinguishment of debt, net      
Debt Instrument      
Write off of Debt Issuance Costs and Other Expenses 0 12,900,000  
BellRing | BellRing Term B Facility      
Debt Instrument      
Debt Instrument, Periodic Payment, Principal 8,750,000    
Gross Repayments of Long-term debt 37,500,000    
Loans Payable to Bank $ 700,000,000.0    
Debt Instrument, Interest Rate, Effective Percentage 6.00%   6.00%
Excess cash flow prepayment $ 28,800,000    
BellRing | BellRing Term B Facility | Federal Funds      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 0.50%    
BellRing | BellRing Term B Facility | One-Month Eurodollar      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 1.00%    
BellRing | BellRing Term B Facility | Eurodollar      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 5.00%    
BellRing | BellRing Revolving Credit Facility      
Debt Instrument      
Line of Credit Facility, Current Borrowing Capacity $ 200,000,000.0    
Line of Credit Facility, Maximum Borrowing Capacity $ 20,000,000.0    
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.50%    
Letters of Credit Outstanding, Amount $ 0    
Line of Credit Facility, Remaining Borrowing Capacity $ 150,000,000.0   $ 170,000,000.0
Debt Covenant, Leverage Ratio 6.00    
Debt Covenant, Maximum Undischarged Judgments $ 65,000,000.0    
Gross Repayments of Long-term debt 0 40,000,000.0  
Proceeds from Lines of Credit $ 20,000,000.0 120,000,000.0  
Debt Instrument, Interest Rate, Effective Percentage 5.25%   5.25%
BellRing | BellRing Revolving Credit Facility | Minimum      
Debt Instrument      
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.25%    
BellRing | BellRing Revolving Credit Facility | Maximum      
Debt Instrument      
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.50%    
BellRing | BellRing Revolving Credit Facility | Base Rate      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 3.25%    
BellRing | BellRing Revolving Credit Facility | Base Rate | Minimum      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 2.75%    
BellRing | BellRing Revolving Credit Facility | Base Rate | Maximum      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 3.25%    
BellRing | BellRing Revolving Credit Facility | Base Rate | Median      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 3.00%    
BellRing | BellRing Revolving Credit Facility | Eurodollar      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 4.25%    
BellRing | BellRing Revolving Credit Facility | Eurodollar | Minimum      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 3.75%    
BellRing | BellRing Revolving Credit Facility | Eurodollar | Maximum      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 4.25%    
BellRing | BellRing Revolving Credit Facility | Eurodollar | Median      
Debt Instrument      
Debt Instrument, Basis Spread on Variable Rate 4.00%    
BellRing | (Gain) loss on extinguishment of debt, net | BellRing Term B Facility      
Debt Instrument      
Write off of Debt Issuance Costs and Other Expenses $ 0    
BellRing | (Gain) loss on extinguishment of debt, net | BellRing Revolving Credit Facility      
Debt Instrument      
Write off of Debt Issuance Costs and Other Expenses   $ 0  
Less than or equal to 3.35 | BellRing | BellRing Revolving Credit Facility      
Debt Instrument      
Debt Covenant, Leverage Ratio 3.35    
High-End Ratio | Revolving Credit Facility      
Debt Instrument      
Debt Covenant, Leverage Ratio 3.00    
High-End Ratio | BellRing | BellRing Revolving Credit Facility      
Debt Instrument      
Debt Covenant, Leverage Ratio 3.50    
Low-End Ratio | Revolving Credit Facility      
Debt Instrument      
Debt Covenant, Leverage Ratio 1.50    
Low-End Ratio | BellRing | BellRing Revolving Credit Facility      
Debt Instrument      
Debt Covenant, Leverage Ratio 2.50