| Document and Entity Information | Mar. 10, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K12B/A |
| Amendment Flag | true |
| Document Period End Date | Mar. 10, 2022 |
| Entity Registrant Name | BellRing Brands, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39093 |
| Entity Tax Identification Number | 87-3296749 |
| Entity Address, Address Line One | 2503 S. Hanley Road |
| Entity Address, City or Town | St. Louis |
| Entity Address, State or Province | MO |
| Entity Address, Postal Zip Code | 63144 |
| City Area Code | 314 |
| Local Phone Number | 644-7600 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 par value per share |
| Trading Symbol | BRBR |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Amendment Description | As previously reported, on March 10, 2022 (the “Closing Date”), BellRing Brands, Inc. (formerly known as BellRing Distribution, LLC) (“New BellRing”) became the new public parent company of, and successor issuer to, BellRing Intermediate Holdings, Inc. (formerly known as BellRing Brands, Inc.) (“Old BellRing”). On the Closing Date, as previously announced, Old BellRing completed its merger (the “merger”) with BellRing Merger Sub Corporation (“Merger Sub”), a wholly-owned subsidiary of New BellRing, whereby Merger Sub merged with and into Old BellRing with Old BellRing continuing as the surviving corporation in the merger. As a result of the merger, (i) Old BellRing became a wholly-owned subsidiary of New BellRing and (ii) each share of Old BellRing Class A common stock outstanding prior to the merger was converted into the right to receive one share of New BellRing Common Stock and $2.97 in cash. In addition, Post Holdings, Inc. completed the previously announced spin-off of 80.1% of its interest in New BellRing to its shareholders. This Amendment No. 1 to Form 8-K amends the Current Report on Form 8-K12B filed by New BellRing with the Securities and Exchange Commission (the “SEC”) on the Closing Date (the “Original Form 8-K”). The Original Form 8-K did not include the unaudited pro forma financial information of New BellRing to give effect to the transactions described therein (the “transactions”). This Amendment No. 1 to the Original Form 8-K is being filed to include such financial information as required under Items 9.01(a) and 9.01(b) of Form 8-K. |
| Entity Central Index Key | 0001772016 |
