Income Taxes (Notes)	9 Months Ended
Income Taxes (Notes)	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income taxes	INCOME TAXES BellRing Inc. holds 28.8% of the economic interest in BellRing LLC (see Note 1), which, as a result of the IPO and formation transactions, is treated as a partnership for U.S. federal income tax purposes. As a partnership, BellRing LLC is itself generally not subject to U.S. federal income tax under current U.S. tax laws. The effective income tax rate was 7.2% and 12.5% for the three and nine months ended June 30, 2020, respectively, and 23.7% and 23.8% for the three and nine months ended June 30, 2019, respectively. The decreases in the effective income tax rate compared to each of the prior year periods were primarily due to the Company taking into account for U.S. federal, state and local income tax purposes its 28.8% distributive share of the items of income, gain, loss and deduction of BellRing LLC in the periods subsequent to the IPO. Prior to the IPO and formation transactions, the Company reported 100% of the income, gain, loss and deduction of BellRing LLC. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security (“CARES”) Act was enacted and signed into law. Based on the Company’s review of the CARES Act provisions, it has determined that there were no significant tax impacts during the three or nine months ended June 30, 2020, and the Company has accounted for any tax impacts.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.