Post (POST) 10-Q 7 Feb 20 2020 Q1 Quarterly report Financial data

Cover Page

Cover Page - shares	3 Months Ended
	Dec. 31, 2019	Feb. 03, 2020
Cover page.
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-35305
Entity Registrant Name	Post Holdings, Inc.
Entity Incorporation, State or Country Code	MO
Entity Tax Identification Number	45-3355106
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
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	POST
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		69,906,711
Entity Central Index Key	0001530950
Current Fiscal Year End Date	--09-30
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q1
Amendment Flag	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Statement [Abstract]
Net Sales	$ 1,456.8	$ 1,411.3
Cost of goods sold	985.3	984.8
Gross Profit	471.5	426.5
Selling, general and administrative expenses	235.3	217.1
Amortization of intangible assets	40.1	40.3
Gain on sale of business	0	(124.7)
Other operating expenses (income), net	0.1	(0.1)
Operating Profit	196	293.9
Interest expense, net	102.9	59.4
Loss on extinguishment of debt, net	12.9	6.1
(Income) expense on swaps, net	(61.4)	51.7
Other income, net	(3.2)	(3.7)
Earnings before Income Taxes and Equity Method Loss	144.8	180.4
Income tax expense	30.4	43.8
Equity method loss, net of tax	7.3	10.7
Net Earnings Including Noncontrolling Interests	107.1	125.9
Less: Net earnings attributable to noncontrolling interests	7.9	0.3
Net Earnings	99.2	125.6
Less: Preferred stock dividends	0	2
Net Earnings Available to Common Shareholders	$ 99.2	$ 123.6
Earnings per Share, Basic (in usd per share)	$ 1.40	$ 1.85
Earnings per Share, Diluted (in usd per share)	$ 1.38	$ 1.67
Weighted-Average Common Shares Outstanding, Basic (in shares)	70.7	66.7
Weighted-Average Common Shares Outstanding, Diluted (in shares)	72.1	75.1

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Earnings Including Noncontrolling Interests	$ 107.1	$ 125.9
Pension and postretirement benefits adjustments:
Reclassifications to net earnings	(0.5)	(1.2)
Hedging adjustments:
Unrealized net (loss) gain on derivatives	(33.3)	24.4
Reclassifications to net earnings	7.2	(30.1)
Foreign currency translation adjustments:
Unrealized foreign currency translation adjustments	115.1	(40.2)
Reclassifications to net earnings (see Note 4)	0	42.1
Tax benefit (expense) on pension and postretirement benefits adjustments:
Reclassifications to net earnings	0.1	0.3
Tax benefit (expense) on hedging adjustments:
Unrealized gain/loss on derivatives	8.5	(6)
Reclassifications to net earnings	(1.6)	7.4
Total Other Comprehensive Income (Loss) Including Noncontrolling Interests	95.5	(3.3)
Less: Comprehensive income attributable to noncontrolling interests	8.4	0.3
Total Comprehensive Income	$ 194.2	$ 122.3

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2019	Sep. 30, 2019
ASSETS
Cash and cash equivalents	$ 812.6	$ 1,050.7
Restricted cash	2.5	3.8
Receivables, net	451.8	445.1
Inventories	588.2	579.8
Prepaid expenses and other current assets	66.1	46.9
Total Current Assets	1,921.2	2,126.3
Property, net	1,764.2	1,736
Goodwill	4,460.7	4,399.8
Other intangible assets, net	3,328.3	3,338.5
Equity method investments	138.5	145.5
Other assets	330.6	205.5
Total Assets	11,943.5	11,951.6
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current portion of long-term debt	156.5	13.5
Accounts payable	332.1	395.6
Other current liabilities	394.5	393.8
Total Current Liabilities	883.1	802.9
Long-term debt	6,382.6	7,066
Deferred income taxes	842.4	688.5
Other liabilities	523.8	456.9
Total Liabilities	8,631.9	9,014.3
Preferred stock	0	0
Common stock	0.8	0.8
Additional paid-in capital	4,195.6	3,734.8
Retained earnings	307	207.8
Accumulated other comprehensive loss	(1.8)	(96.8)
Treasury stock, at cost	(1,143.8)	(920.7)
Total Shareholders’ Equity Excluding Noncontrolling Interests	3,357.8	2,925.9
Noncontrolling interests	(46.2)	11.4
Total Shareholders’ Equity	3,311.6	2,937.3
Total Liabilities and Shareholders’ Equity	$ 11,943.5	$ 11,951.6

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Cash Flows from Operating Activities:
Net Earnings Including Noncontrolling Interest	$ 107.1	$ 125.9
Adjustments to reconcile net earnings including noncontrolling interests to net cash flow provided by operating activities:
Depreciation and amortization	90.3	93.6
Unrealized (gain) loss on interest rate swaps	(73.3)	51.5
Gain on sale of business	0	(124.7)
Loss on extinguishment of debt, net	12.9	6.1
Non-cash stock-based compensation expense	11.4	8.7
Equity method loss, net of tax	7.3	10.7
Deferred income taxes	19	8.1
Other, net	3.2	0.6
Other changes in operating assets and liabilities:
(Increase) decrease in receivables, net	(6.7)	30.8
Increase in inventories	(6.1)	(16.1)
Increase in prepaid expenses and other current assets	(20)	(0.5)
Decrease in other assets	2.6	0.9
(Decrease) increase in accounts payable and other current liabilities	(41.3)	46.7
Increase (decrease) in non-current liabilities	2	(3.6)
Net Cash Provided by Operating Activities	108.4	238.7
Cash Flows from Investing Activities:
Additions to property	(77.3)	(78.8)
Proceeds from sale of property and assets held for sale	0.1	2
Proceeds from sale of business	0	250
Cross-currency swap cash settlements	1.4	28.3
Net Cash (Used in) Provided by Investing Activities	(75.8)	201.5
Cash Flows from Financing Activities:
Proceeds from issuance of long-term debt	2,031	0
Repayments of long-term debt	(2,574.5)	(919)
Payments to appraisal rights holders	(3.8)	(253.6)
Purchases of treasury stock	(231.8)	(25.3)
Payments of preferred stock dividends	0	(2)
Proceeds from initial public offering	524.4	0
Payments of debt issuance costs and deferred financing fees	(28.2)	(0.3)
Refund of debt issuance costs	15.3	7.8
Proceeds from exercises of stock awards	2.8	0
Other, net	(10.1)	(7.2)
Net Cash Used in Financing Activities	(274.9)	(1,199.6)
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash	2.9	(1.6)
Net Decrease in Cash, Cash Equivalents and Restricted Cash	(239.4)	(761)
Cash, Cash Equivalents and Restricted Cash, Beginning of Year	1,054.5	994.5	$ 994.5
Cash, Cash Equivalents and Restricted Cash, End of Period	$ 815.1	$ 233.5	$ 1,054.5

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Shareholders' Equity Statement - USD ($) $ in Millions	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Retirement Benefit Adjustments, net of tax	Hedging Adjustments, net of tax	Foreign Currency Translation Adjustments	Treasury Stock	Noncontrolling Interests
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Sep. 30, 2018		$ 0	$ 0.8	$ 3,590.9	$ 88	$ 37.9	$ 37.4	$ (114.7)	$ (589.9)
Total Shareholders' Equity, Beginning of period at Sep. 30, 2018										$ 10.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 125.6				125.6
Adoption of accounting standards update					(0.9)
Preferred stock dividends declared					(2)
Activity under stock and deferred compensation plans				(7.2)
Non-cash stock-based compensation expense				8.7						0
Initial public offering				0						0
Purchases of treasury stock									(25.3)
Net earnings attributable to noncontrolling interests	0.3									0.3
Net change in retirement benefits, net of tax						(0.9)
Net change in hedges, net of tax							(4.3)			0
Foreign currency translation adjustments								1.9		0
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Dec. 31, 2018	3,146	0	0.8	3,592.4	210.7	37	33.1	(112.8)	(615.2)
Total Shareholders' Equity, End of period at Dec. 31, 2018	3,156.4									10.4
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Sep. 30, 2019	2,925.9	0	0.8	3,734.8	207.8	26.6	44.5	(167.9)	(920.7)
Total Shareholders' Equity, Beginning of period at Sep. 30, 2019	2,937.3									11.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	99.2				99.2
Adoption of accounting standards update					0
Preferred stock dividends declared					0
Activity under stock and deferred compensation plans				(7.3)
Non-cash stock-based compensation expense				11.1						0.3
Initial public offering				457						(66.3)
Purchases of treasury stock									(223.1)
Net earnings attributable to noncontrolling interests	7.9									7.9
Net change in retirement benefits, net of tax						(0.4)
Net change in hedges, net of tax							(19.4)			0.2
Foreign currency translation adjustments								114.8		0.3
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Dec. 31, 2019	3,357.8	$ 0	$ 0.8	$ 4,195.6	$ 307	$ 26.2	$ 25.1	$ (53.1)	$ (1,143.8)
Total Shareholders' Equity, End of period at Dec. 31, 2019	$ 3,311.6									$ (46.2)

Basis of Presentation

Basis of Presentation	3 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	BASIS OF PRESENTATION These unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”), under the rules and regulations of the United States Securities and Exchange Commission (the “SEC”), and on a basis substantially consistent with the audited consolidated financial statements of Post Holdings, Inc. (herein referred to as “Post,” “the Company,” “us,” “our” or “we,” and unless otherwise stated or context otherwise indicates, all such references herein mean Post Holdings, Inc. and its consolidated subsidiaries) as of and for the fiscal year ended September 30, 2019. These unaudited condensed consolidated financial statements should be read in conjunction with such audited consolidated financial statements, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2019, filed with the SEC on November 22, 2019. These unaudited condensed consolidated financial statements include all adjustments (consisting of normal recurring adjustments and accruals) that management considers necessary for a fair statement of the Company’s results of operations, comprehensive income, financial condition, cash flows and shareholders’ equity for the interim periods presented. Interim results are not necessarily indicative of the results for any other interim period or for the entire fiscal year. On October 21, 2019, BellRing Brands, Inc. (“BellRing”), a subsidiary of the Company, closed its initial public offering (the “IPO”) of 39.4 shares of its Class A common stock, $0.01 par value per share (the “Class A Common Stock”), which number of shares included the underwriters’ exercise in full of their option to purchase up to an additional 5.1 shares of Class A Common Stock. The IPO was completed at an offering price of $14.00 per share and BellRing received net proceeds from the IPO of $524.4 , after deducting underwriting discounts and commissions. As a result of the IPO and certain other transactions completed in connection with the IPO (the “formation transactions”), BellRing is a publicly-traded company whose Class A Common Stock is traded on the New York Stock Exchange under the ticker symbol “BRBR”. BellRing is a holding company of BellRing Brands, LLC, a Delaware limited liability company (“BellRing LLC”), owning 28.8% of its non-voting membership units (the “BellRing LLC units”). Post owns 71.2% of the BellRing LLC units and one share of BellRing’s Class B common stock, $0.01 par value per share (the “Class B Common Stock” and, collectively with the Class A Common Stock, the “BellRing Common Stock”). The Class B Common Stock has voting rights but no rights to dividends or other economic rights. For so long as Post or its affiliates (other than BellRing and its subsidiaries) directly own more than 50% of the BellRing LLC units, the Class B Common Stock represents 67% of the combined voting power of the BellRing Common Stock. BellRing LLC is the holding company for Post’s historical active nutrition business, reported herein as the BellRing Brands segment and reported historically as the Active Nutrition segment. In connection with the IPO, the Company incurred transaction-related expenses of $2.1 and $1.2 during the three months ended December 31, 2019 and 2018, respectively. These expenses generally included third party costs for due diligence, advisory services and government filing fees and were recorded as “Selling, general and administrative expenses” in the Condensed Consolidated Statements of Operations. Effective October 21, 2019, the financial results of BellRing and its subsidiaries were consolidated within Post’s financial results and 28.8% of the consolidated net income and net assets of BellRing and its subsidiaries, representing the percentage of economic interest in BellRing LLC held by BellRing (and therefore indirectly held by the public stockholders of BellRing through their ownership of the Class A Common Stock), is allocated to noncontrolling interest (“NCI”) (see Note 5 ). The term “BellRing” as used herein generally refers to BellRing Brands, Inc.; however, in discussions related to debt facilities, the term “BellRing” refers to BellRing Brands, LLC.

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Standards (Notes)	3 Months Ended
	Dec. 31, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recently Issued and Adopted Accounting Standards	RECENTLY ISSUED AND ADOPTED ACCOUNTING STANDARDS The Company has considered all new accounting pronouncements and has concluded there are no new pronouncements (other than the ones described below) that had or will have a material impact on the Company’s results of operations, comprehensive income, financial condition, cash flows, shareholders’ equity or disclosures based on current information. In February 2016, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842).” This ASU requires a company to recognize right-of-use (“ROU”) assets and lease liabilities on its balance sheet and disclose key information about leasing arrangements. ASU 2016-02 offers specific accounting guidance for lessees, lessors and sale and leaseback transactions. Lessees and lessors are required to disclose qualitative and quantitative information about leasing arrangements to enable a user of the financial statements to assess the amount, timing and uncertainty of cash flows arising from leases. In July 2018, the FASB issued ASU 2018-11, “Leases (Topic 842): Targeted Improvements.” This ASU provides an additional transition method by allowing entities to initially apply the new lease standard at the date of adoption with a cumulative effect adjustment to the opening balance of retained earnings in the period of adoption. This ASU also gives lessors the option of electing, as a practical expedient by class of underlying asset, not to separate the lease and non-lease components of a contract when those lease contracts meet certain criteria. The Company adopted these ASUs on October 1, 2019, as required by the ASUs, and utilized the cumulative effect adjustment approach. At adoption, the Company recognized ROU assets and lease liabilities of $158.1 and $168.2 , respectively, on the balance sheet at October 1, 2019. The new standard did not materially impact the statements of operations or cash flows. In addition, the Company provides expanded disclosures related to its leasing arrangements in accordance with theses ASUs. For additional information, refer to Note 14 .

Restructuring (Notes)

Restructuring (Notes)	3 Months Ended
	Dec. 31, 2019
Restructuring [Abstract]
Restructuring	RESTRUCTURING In February 2018, the Company announced its plan to close its ready-to-eat (“RTE”) cereal manufacturing facility in Clinton, Massachusetts, which manufactured certain Weetabix products distributed in North America. The transfer of production capabilities to other Post Consumer Brands facilities and the closure of the facility was completed at September 30, 2019. Final cash payments for employee-related costs were made in the first quarter of fiscal 2020. No additional restructuring costs have been or are expected to be incurred in fiscal 2020. For additional information on assets held for sale related to the closure, see Note 4 . Restructuring charges and the related liabilities are shown in the following table. Employee-related costs were included in “Selling, general and administrative expenses” and accelerated depreciation expense was included in “Cost of goods sold” in the Condensed Consolidated Statement of Operations for the three months ended December 31, 2018. These expenses are not included in the measure of segment performance (see Note 18 ). Employee-Related Costs Accelerated Depreciation Total Balance, September 30, 2018 $ 2.7 $ — $ 2.7 Charge to expense 0.7 1.8 2.5 Non-cash charges — (1.8 ) (1.8 ) Balance, December 31, 2018 $ 3.4 $ — $ 3.4 Balance, September 30, 2019 $ 0.1 $ — $ 0.1 Cash payments (0.1 ) — (0.1 ) Balance, December 31, 2019 $ — $ — $ — Total expected restructuring charge $ 4.9 $ 9.9 $ 14.8 Cumulative restructuring charges incurred to date 4.9 9.9 14.8 Remaining expected restructuring charge $ — $ — $ —

Divestitures and Amounts Held f

Divestitures and Amounts Held for Sale (Notes)	3 Months Ended
	Dec. 31, 2019
Assets and Liabilities Held for Sale [Abstract]
Divestitures and Amounts Held for Sale	DIVESTITURES AND AMOUNTS HELD FOR SALE Divestiture On October 1, 2018, 8th Avenue Food & Provisions, Inc. (“8th Avenue”) was separately capitalized through a series of transactions (the “8th Avenue Transactions”), and 8th Avenue became the holding company for Post’s historical private brands business. Post received total gross proceeds of $875.0 , as well as $16.8 received in the second quarter of fiscal 2019 related to final working capital adjustments, from the 8th Avenue Transactions. Post’s gross proceeds consisted of (i) $250.0 from a third party and (ii) $625.0 from a committed senior increasing rate bridge loan (the “2018 Bridge Loan”), which was funded in fiscal 2018 prior to the closing of the 8th Avenue Transactions (see Note 15 ). During the three months ended December 31, 2018, the Company recorded a gain of $124.7 (adjusted to $126.6 during the year ended September 30, 2019) related to the 8th Avenue Transactions, which was reported as “Gain on sale of business” in the Condensed Consolidated Statement of Operations. The gain included foreign exchange losses previously recorded in accumulated other comprehensive loss (“OCI”) of $42.1 . In connection with the 8th Avenue Transactions, the Company incurred transaction-related expenses of $9.1 during the three months ended December 31, 2018. These expenses generally included third party costs for advisory services and transaction success fees, and were recorded as “Selling, general and administrative expenses” in the Condensed Consolidated Statement of Operations. No such gain or loss or transaction-related expenses were recorded during the three months ended December 31, 2019. Amounts Held For Sale In connection with the closure of the Company’s Post Consumer Brands RTE cereal manufacturing facility in Clinton, Massachusetts (see Note 3 ), the Company had a manufacturing plant (the “Clinton Plant”) held for sale with a book value of $8.4 at both December 31, 2019 and September 30, 2019. Additionally, the Company had land and a building with a combined book value of $1.5 classified as held for sale at its Post Consumer Brands RTE cereal manufacturing facility in Asheboro, North Carolina (the “Asheboro Facility”) at both December 31, 2019 and September 30, 2019. In accordance with Accounting Standards Codification (“ASC”) Topic 360, “Property, Plant, and Equipment,” these assets held for sale were classified as current, and were reported as “Prepaid expenses and other current assets” on the Condensed Consolidated Balance Sheets. There were no held for sale gains or losses recorded in the three months ended December 31, 2019. During the three months ended December 31, 2018, the Company recorded a held for sale gain of $124.7 (adjusted to $126.6 during the year ended September 30, 2019), which was reported as “Gain on sale of business,” and a held for sale loss of $2.6 , which was included in “Loss on extinguishment of debt, net,” in the Condensed Consolidated Statement of Operations related to the 8th Avenue Transactions. A gain of $0.6

Equity Interests and Related Pa

Equity Interests and Related Party Transactions (Notes)	3 Months Ended
	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Interests and Related Party Transactions	EQUITY INTERESTS AND RELATED PARTY TRANSACTIONS BellRing As a result of the IPO on October 21, 2019 (see Note 1 ), the Company (other than BellRing and its subsidiaries) owned 71.2% of the BellRing LLC units and one share of Class B Common Stock. The Class B Common Stock has voting rights but no rights to dividends or other economic rights. For so long as the Company (other than BellRing and its subsidiaries) directly owns more than 50% of the BellRing LLC units, the Class B Common Stock represents 67% of the combined voting power of the BellRing Common Stock, which provides the Company control over BellRing’s Board of Directors and results in the full consolidation of BellRing and its subsidiaries into the Company’s financial statements. The remaining interest in BellRing’s consolidated net income and net assets will be allocated to NCI. The BellRing LLC units held by the Company include a redemption feature that allows the Company to, at BellRing LLC’s option (as determined by its Board of Managers), redeem BellRing LLC units for either (i) Class A Common Stock of BellRing or (ii) cash equal to the market value of the BellRing Class A Common Stock at the time of redemption. In the event the Company (other than BellRing and its subsidiaries) holds 50% or less of the BellRing LLC units, the holder of the share of Class B Common Stock will be entitled to a number of votes equal to the number of BellRing LLC units held by all persons other than BellRing and its subsidiaries. In such situation, the Company, as the holder of the share of Class B Common Stock, will only be entitled to cast a number of votes equal to the number of BellRing LLC units held by the Company (other than BellRing and its subsidiaries). Also, in such situation, if any BellRing LLC units are held by persons other than the Company, then the Company, as the holder of the share of Class B Common Stock, will cast the remainder of votes to which the share of Class B Common Stock is entitled only in accordance with the instructions and directions from such other holders of the BellRing LLC units. As of December 31, 2019, the Company owned 71.2% of the BellRing LLC units and the net income and net assets of BellRing and its subsidiaries were consolidated within the Company’s financial statements, and the remaining 28.8% of the consolidated net income and net assets of BellRing and its subsidiaries, representing the percentage of economic interest in BellRing LLC held by BellRing (and therefore indirectly held by the public stockholders of BellRing through their ownership of the Class A Common Stock), were allocated to NCI. The following table summarizes the effects of changes in ownership of BellRing on the Company’s equity: Three Months Ended Increase in additional paid-in capital related to net proceeds from IPO $ 524.4 Increase in additional paid-in capital related to establishment of noncontrolling interest 66.3 Decrease in additional paid-in capital related to tax effects of IPO (133.7 ) Net transfers from noncontrolling interest $ 457.0 8th Avenue The Company has a 60.5% common equity interest in 8th Avenue that is accounted for using the equity method. In determining the accounting treatment of the common equity interest, management concluded that 8th Avenue was not a variable interest entity as defined by ASC Topic 810, “Consolidation” and, as such, was evaluated under the voting interest model. Based on the terms of 8th Avenue’s governing documents, management determined that the Company does not have a controlling voting interest in 8th Avenue due to substantive participating rights held by third parties associated with the governance of 8th Avenue. However, Post does retain significant influence, and therefore, the use of the equity method of accounting is required. The following table presents the calculation of the Company’s equity method loss attributable to 8th Avenue: Three Months Ended 2019 2018 8th Avenue’s net loss available to 8th Avenue’s common shareholders $ (8.7 ) $ (11.5 ) 60.5 % 60.5 % Equity method loss available to Post $ (5.3 ) $ (7.0 ) Less: Amortization of basis difference, net of tax (a) 1.7 3.6 Equity method loss, net of tax $ (7.0 ) $ (10.6 ) (a) The Company adjusted the historical basis of 8th Avenue’s assets and liabilities to fair value and recognized a basis difference of $70.3 . The basis difference related to inventory of $2.0 , net of tax, was included in equity method loss in the three months ended December 31, 2018. The basis difference related to property, plant and equipment and other intangible assets is being amortized over the weighted average useful lives of the assets. At December 31, 2019 and September 30, 2019, the remaining basis difference to be amortized was $59.8 and $61.5 , respectively. Summarized financial information of 8th Avenue is presented in the following table. Three Months Ended 2019 2018 Net sales $ 218.4 $ 214.1 Gross profit $ 38.4 $ 33.7 Net loss $ (0.9 ) $ (4.5 ) Less: Preferred stock dividend 7.8 7.0 Net Loss Available to 8th Avenue Common Shareholders $ (8.7 ) $ (11.5 ) The Company provides services to 8th Avenue under a master services agreement (the “MSA”), as well as certain advisory services for a fee. The Company recorded MSA and advisory income of $1.0 during the three months ended December 31, 2019 and 2018, respectively, which was recorded in “Selling, general and administrative expenses” in the Condensed Consolidated Statements of Operations. During the three months ended December 31, 2019 and 2018, the Company had net sales to 8th Avenue of $1.6 and $1.1 , respectively, and purchases from and royalties paid to 8th Avenue of $2.8 and $2.3 , respectively. Sales and purchases between the Company and 8th Avenue were all made at arm’s-length. The investment in 8th Avenue was $133.5 and $140.5 at December 31, 2019 and September 30, 2019, respectively, and was included in “Equity method investments” on the Condensed Consolidated Balance Sheets. The Company had current receivables, current payables and a long-term liability with 8th Avenue of $3.6 , $0.5 and $0.7 , respectively, at December 31, 2019 and current receivables, current payables and a long-term liability of $5.1 , $0.6 and $0.7 , respectively, at September 30, 2019. The current receivables, current payables and long-term liability related to the separation of 8th Avenue from the Company, the closing of the 8th Avenue Transactions, MSA fees, pass through charges owed by 8th Avenue to the Company and related party sales and purchases were included in “Receivables, net,” “Accounts payable” and “Other liabilities,” respectively, on the Condensed Consolidated Balance Sheets. Alpen and Weetabix East Africa The Company holds an equity interest in two legal entities, Alpen Food Company South Africa (Pty) Limited (“Alpen”) and Weetabix East Africa Limited (“Weetabix East Africa”). Alpen is a South African-based company that produces RTE cereal and muesli. The Company owns 50% of Alpen’s common stock with no other indicators of control, and accordingly, the Company accounts for its investment in Alpen using the equity method. The investment in Alpen was $5.0 and $5.0 at December 31, 2019 and September 30, 2019, respectively, and was included in “Equity method investments” on the Condensed Consolidated Balance Sheets. The Company had a note receivable balance with Alpen of $0.6 and $0.5 at December 31, 2019 and September 30, 2019, respectively, which was included in “Other assets” on the Condensed Consolidated Balance Sheets. Weetabix East Africa is a Kenyan-based company that produces RTE cereal and muesli. The Company owns 50.1% of Weetabix East Africa and holds a controlling voting and financial interest through its appointment of management and representation on Weetabix East Africa’s Board of Directors. Accordingly, Weetabix East Africa is fully consolidated into the Company’s financial statements and its assets and results from operations are reported in the Weetabix segment (see Note 18

Earnings Per Share

Earnings Per Share	3 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings per Share	EARNINGS PER SHARE Basic earnings per share is based on the average number of common shares outstanding during the period. Diluted earnings per share is based on the average number of shares used for the basic earnings per share calculation, adjusted for the dilutive effect of stock options, stock appreciation rights and restricted stock equivalents using the “treasury stock” method. The impact of potentially dilutive convertible preferred stock was calculated using the “if-converted” method. In addition, diluted earnings per share has been adjusted for the effect of BellRing stock awards issued to employees of BellRing and its subsidiaries, to the extent they are dilutive. The following table sets forth the computation of basic and diluted earnings per share. Three Months Ended 2019 2018 Net earnings for basic earnings per share $ 99.2 $ 123.6 Dilutive preferred stock dividends — 2.0 Net earnings for diluted earnings per share $ 99.2 $ 125.6 Weighted-average shares for basic earnings per share 70.7 66.7 Effect of dilutive securities: Stock options 0.7 2.0 Stock appreciation rights 0.1 0.1 Restricted stock units 0.5 0.4 Performance-based restricted stock awards 0.1 — Preferred shares conversion to common — 5.9 Total dilutive securities 1.4 8.4 Weighted-average shares for diluted earnings per share 72.1 75.1 Basic earnings per common share $ 1.40 $ 1.85 Diluted earnings per common share $ 1.38 $ 1.67 The following table details the securities that have been excluded from the calculation of weighted-average shares for diluted earnings per share as they were anti-dilutive. Three Months Ended 2019 2018 Stock options 0.1 0.3 Restricted stock units 0.1 0.2 Performance-based restricted stock awards 0.1 0.1

Inventories

Inventories	3 Months Ended
	Dec. 31, 2019
Inventory [Abstract]
Inventories	INVENTORIES December 31, September 30, 2019 Raw materials and supplies $ 105.7 $ 99.4 Work in process 20.0 19.4 Finished products 429.3 425.4 Flocks 33.2 35.6 $ 588.2 $ 579.8

Property, net

Property, net	3 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, net	PROPERTY, NET December 31, September 30, 2019 Property, at cost $ 2,818.5 $ 2,736.9 Accumulated depreciation (1,054.3 ) (1,000.9 ) $ 1,764.2 $ 1,736.0

Goodwill (Notes)

Goodwill (Notes)	3 Months Ended
	Dec. 31, 2019
Goodwill [Abstract]
Goodwill	GOODWILL The changes in the carrying amount of goodwill by segment are noted in the following table. Post Consumer Brands Weetabix Foodservice Refrigerated Retail BellRing Brands Total Balance, September 30, 2019 Goodwill (gross) $ 2,011.8 $ 850.7 $ 1,335.6 $ 793.6 $ 180.7 $ 5,172.4 Accumulated impairment losses (609.1 ) — — (48.7 ) (114.8 ) (772.6 ) Goodwill (net) $ 1,402.7 $ 850.7 $ 1,335.6 $ 744.9 $ 65.9 $ 4,399.8 Currency translation adjustment 0.1 60.8 — — — 60.9 Balance, December 31, 2019 Goodwill (gross) $ 2,011.9 $ 911.5 $ 1,335.6 $ 793.6 $ 180.7 $ 5,233.3 Accumulated impairment losses (609.1 ) — — (48.7 ) (114.8 ) (772.6 ) Goodwill (net) $ 1,402.8 $ 911.5 $ 1,335.6 $ 744.9 $ 65.9 $ 4,460.7

Intangible Assets, net

Intangible Assets, net	3 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets, net	INTANGIBLE ASSETS, NET Total intangible assets are as follows: December 31, 2019 September 30, 2019 Carrying Accumulated Amortization Net Carrying Accumulated Amortization Net Subject to amortization: Customer relationships $ 2,309.0 $ (593.3 ) $ 1,715.7 $ 2,297.2 $ (562.2 ) $ 1,735.0 Trademarks and brands 795.7 (235.9 ) 559.8 793.7 (225.2 ) 568.5 Other intangible assets 3.1 (3.1 ) — 3.1 (3.1 ) — 3,107.8 (832.3 ) 2,275.5 3,094.0 (790.5 ) 2,303.5 Not subject to amortization: Trademarks and brands 1,052.8 — 1,052.8 1,035.0 — 1,035.0 $ 4,160.6 $ (832.3 ) $ 3,328.3 $ 4,129.0 $ (790.5 ) $ 3,338.5

Derivative Financial Instrument

Derivative Financial Instruments and Hedging	3 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments and Hedging	DERIVATIVE FINANCIAL INSTRUMENTS AND HEDGING In the ordinary course of business, the Company is exposed to commodity price risks relating to the purchases of raw materials and supplies, interest rate risks relating to variable rate debt and foreign currency exchange rate risks. The Company utilizes derivative financial instruments, including (but not limited to) futures contracts, option contracts, forward contracts and swaps, to manage certain of these exposures by hedging when it is practical to do so. The Company does not hold or issue financial instruments for speculative or trading purposes. At December 31, 2019 , the Company’s derivative instruments consisted of: Not designated as hedging instruments under ASC Topic 815 • Commodity and energy futures and option contracts, which relate to inputs that generally will be utilized within the next year; • pay-fixed, receive-variable interest rate swaps maturing in May 2021 and May 2024 that require monthly settlements and have the effect of hedging interest payments on debt expected to be issued but not yet priced; and • rate-lock interest rate swaps that require six lump sum settlements with the first settlement occurring in July 2020 and the last in July 2023 and have the effect of hedging interest payments on debt expected to be issued but not yet priced. Designated as hedging instruments under ASC Topic 815 • Pay-fixed, receive-fixed cross-currency swaps maturing in July 2022 that require quarterly cash settlements and are used as net investment hedges of the Company’s investment in Weetabix, which is denominated in Pounds Sterling; and • pay-fixed, receive-variable interest rate swaps maturing in December 2022 that require monthly settlements beginning in January 2020 and are used as cash flow hedges of forecasted interest payments on BellRing’s variable rate debt. In the first quarter of fiscal 2020, contemporaneously with the repayment of its term loan, the Company changed the designation of one of its interest rate swap contracts from a cash flow hedge to a non-designated hedging instrument. In connection with the de-designation, the Company reclassified losses previously recorded in accumulated OCI of $7.2 to “Interest expense, net” in the Condensed Consolidated Statement of Operations for the three months ended December 31, 2019. In the first quarter of fiscal 2019, the Company terminated $800.0 and $214.2 notional value of its interest rate swap and cross-currency swap contracts, respectively, that were designated as hedging instruments. In connection with the interest rate swap terminations, the Company received cash proceeds of $29.8 , and reclassified previously recorded gains from accumulated OCI to “Interest expense, net” in the Condensed Consolidated Statement of Operations for the three months ended December 31, 2018. In connection with the cross-currency swap terminations, the Company received cash proceeds of $26.2 , which were recorded to accumulated OCI. Reclassification of amounts recorded in accumulated OCI into earnings will only occur in the event all United Kingdom-based operations are liquidated. The following table shows the notional amounts of derivative instruments held. December 31, September 30, 2019 Not designated as hedging instruments under ASC Topic 815: Commodity contracts $ 63.8 $ 47.1 Energy contracts 38.5 39.8 Interest rate swaps 272.8 73.1 Interest rate swaps - Rate-lock swaps 1,399.3 1,531.0 Designated as hedging instruments under ASC Topic 815: Foreign exchange contracts - Cross-currency swaps 448.7 448.7 Interest rate swaps 350.0 200.0 The following table presents the balance sheet location and fair value of the Company’s derivative instruments, along with the portion designated as hedging instruments under ASC Topic 815. The Company does not offset derivative assets and liabilities within the Condensed Consolidated Balance Sheets. Fair Value Portion Designated as Hedging Instruments Balance Sheet Location December 31, September 30, 2019 December 31, September 30, 2019 Asset Derivatives: Commodity contracts Prepaid expenses and other current assets $ 2.8 $ 1.9 $ — $ — Energy contracts Prepaid expenses and other current assets 2.6 0.7 — — Commodity contracts Other assets — 0.1 — — Foreign exchange contracts Prepaid expenses and other current assets — 1.3 — 1.3 Foreign exchange contracts Other assets — 19.2 — 19.2 Interest rate swaps Prepaid expenses and other current assets 0.4 — 0.4 — Interest rate swaps Other assets 0.2 — 0.2 — $ 6.0 $ 23.2 $ 0.6 $ 20.5 Liability Derivatives: Commodity contracts Other current liabilities $ 0.9 $ 1.0 $ — $ — Energy contracts Other current liabilities 1.4 1.5 — — Energy contracts Other liabilities — 0.1 — — Foreign exchange contracts Other current liabilities 1.0 — 1.0 — Foreign exchange contracts Other liabilities 14.5 — 14.5 — Interest rate swaps Other current liabilities 58.8 85.1 — 1.6 Interest rate swaps Other liabilities 275.6 330.4 — 6.2 $ 352.2 $ 418.1 $ 15.5 $ 7.8 The following tables present the effects of the Company’s derivative instruments on the Condensed Consolidated Statements of Operations and Condensed Consolidated Statements of Comprehensive Income for the three months ended December 31, 2019 and 2018. Derivatives Not Designated as Hedging Instruments Statement of Operations Location (Gain) Loss Recognized in Statement of Operations 2019 2018 Commodity contracts Cost of goods sold $ (1.9 ) $ (0.2 ) Energy contracts Cost of goods sold (2.5 ) 8.3 Interest rate swaps (a) (Income) expense on swaps, net (61.4 ) 51.7 (a) For the three months ended December 31, 2019 and 2018, “(Income) expense on swaps, net” related to our interest rate swaps not designated as hedging instruments included cash settlements paid of $19.1 and $0.2 , respectively. Derivatives Designated as Hedging Instruments (Gain) Loss Recognized in OCI including NCI Loss (Gain) Reclassified from Accumulated OCI including NCI into Earnings Statement of Operations Location 2019 2018 2019 2018 Interest rate swaps $ (1.3 ) $ 4.6 $ 7.2 $ (30.1 ) Interest expense, net Cross-currency swaps 34.6 (29.0 ) — — (Income) expense on swaps, net Accumulated OCI, including amounts reported as NCI, included a $33.4 net gain on hedging instruments before taxes ( $25.3 after taxes) at December 31, 2019, compared to a $59.5 net gain before taxes ( $44.5 after taxes) at September 30, 2019. Approximately $0.4 of the net hedging gain reported in accumulated OCI at December 31, 2019 is expected to be reclassified into earnings within the next 12 months. For gains or losses associated with interest rate swaps, the reclassification will occur over the term of the related debt. Reclassification of gains and losses reported in accumulated OCI into earnings related to the cross-currency swaps will only occur in the event all United Kingdom-based operations are liquidated. Accumulated OCI included settlements of cross-currency swaps of $37.9 and $36.5 at December 31, 2019 and September 30, 2019, respectively. In connection with the settlements of cross-currency swaps, the Company recognized gains in accumulated OCI of $1.4 and $28.3 during the three months ended December 31, 2019 and 2018, respectively. At December 31, 2019 and September 30, 2019 , the Company had pledged collateral of $2.4 and $3.7

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The following table represents the Company’s assets and liabilities measured at fair value on a recurring basis and the basis for that measurement according to the levels in the fair value hierarchy in ASC Topic 820. December 31, 2019 September 30, 2019 Total Level 1 Level 2 Total Level 1 Level 2 Assets: Deferred compensation investments $ 13.0 $ 13.0 $ — $ 11.2 $ 11.2 $ — Derivative assets 6.0 — 6.0 23.2 — 23.2 $ 19.0 $ 13.0 $ 6.0 $ 34.4 $ 11.2 $ 23.2 Liabilities: Deferred compensation liabilities $ 33.6 $ — $ 33.6 $ 31.0 $ — $ 31.0 Derivative liabilities 352.2 — 352.2 418.1 — 418.1 $ 385.8 $ — $ 385.8 $ 449.1 $ — $ 449.1 The deferred compensation investments are primarily invested in mutual funds, and the fair value is measured using the market approach. These investments are in the same funds, and are purchased in substantially the same amounts, as the participants’ selected investment options (excluding Post common stock equivalents), which represent the underlying liabilities to participants in the Company’s deferred compensation plans. Deferred compensation liabilities are recorded at amounts due to participants in cash, based on the fair value of participants’ selected investment options (excluding certain Post common stock equivalents to be distributed in shares) using the market approach. The Company utilizes the income approach to measure fair value for its commodity and energy derivatives. The income approach uses pricing models that rely on market observable inputs such as yield curves and forward prices. Foreign exchange contracts are valued using the spot rate less the forward rate multiplied by the notional amount. The Company’s calculation of the fair value of interest rate swaps is derived from a discounted cash flow analysis based on the terms of the contract and the interest rate curve. Refer to Note 11 for the classification of changes in fair value of derivative assets and liabilities measured at fair value on a recurring basis within the Condensed Consolidated Statements of Operations. The Company’s financial assets and liabilities also include cash and cash equivalents, receivables and accounts payable for which the carrying value approximates fair value due to their short maturities (less than 12 months). The Company does not record its current portion of long-term debt and long-term debt at fair value on the Condensed Consolidated Balance Sheets. The fair value of the outstanding borrowings under BellRing’s Revolving Credit Facility (as defined in Note 15 ) as of December 31, 2019 approximated its carrying value. Based on current market rates, the fair value of the Company’s debt, excluding outstanding borrowings under BellRing’s Revolving Credit Facility, (Level 2) was $6,899.0 and $7,412.0 as of December 31, 2019 and September 30, 2019, respectively. Certain assets and liabilities, including property, plant and equipment, goodwill and other intangible assets and assets held for sale, are measured at fair value on a non-recurring basis. At both December 31, 2019 and September 30, 2019, the Company had $9.9 of land and buildings classified as assets held for sale related to the closures of the Company’s Clinton Plant and Asheboro Facility, both of which are reported in the Post Consumer Brands segment. For additional information on assets and liabilities held for sale, see Note 4 . The fair value of assets held for sale was measured on a non-recurring basis based on the lower of book value or third party valuations. When applicable, the fair value is adjusted to reflect an offer to purchase the assets. In the three months ended December 31, 2019, the book values of the land and buildings related to the closures of the Clinton Plant and Asheboro Facility were both lower than fair value; therefore, no fair value adjustment was recorded to the assets that were classified as held for sale. The fair value measurement was categorized as Level 3, as the fair values utilize significant unobservable inputs.

Commitments and Contingencies (

Commitments and Contingencies (Notes)	3 Months Ended
	Dec. 31, 2019
Legal Proceedings [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Legal Proceedings Antitrust claims In late 2008 and early 2009, approximately 22 class action lawsuits were filed in various federal courts against Michael Foods, Inc. (“MFI”), a wholly-owned subsidiary of the Company, and approximately 20 other defendants (producers of shell eggs and egg products and egg industry organizations), alleging violations of federal and state antitrust laws in connection with the production and sale of shell eggs and egg products, and seeking unspecified damages. All cases were transferred to the Eastern District of Pennsylvania for coordinated and/or consolidated pretrial proceedings. The cases involved three plaintiff groups: (i) a nationwide class of direct purchasers of shell eggs (the “direct purchaser class”); (ii) individual companies (primarily large grocery chains and food companies that purchase considerable quantities of eggs) that opted out of various settlements and filed their own complaints related to their purchases of shell eggs and egg products (“opt-out plaintiffs”); and (iii) indirect purchasers of shell eggs (“indirect purchaser plaintiffs”). Resolution of claims: To date, MFI has resolved the following claims, including all class claims: (i) in December 2016, MFI settled all claims asserted against it by the direct purchaser class for a payment of $75.0 , which was approved by the district court in December 2017; (ii) in January 2017, MFI settled all claims asserted against it by opt-out plaintiffs related to shell egg purchases on confidential terms; (iii) in June 2018, MFI settled all claims asserted against it by indirect purchaser plaintiffs on confidential terms; and (iv) between June 2019 and September 2019, MFI individually settled on confidential terms egg product opt-out claims asserted against it by four separate opt-out plaintiffs. MFI has at all times denied liability in this matter, and no settlement contains any admission of liability by MFI. Remaining portion of the cases: MFI remains a defendant only with respect to claims that seek damages based on purchases of egg products by three opt-out plaintiffs. The district court had granted summary judgment precluding any claims for egg products purchases by such opt-out plaintiffs, but the Third Circuit Court of Appeals reversed and remanded these claims for further pre-trial proceedings. Defendants filed a second motion for summary judgment seeking dismissal of the claims, which was denied in June 2019. The remaining opt-out plaintiffs have not yet been assigned trial dates. Although the likelihood of a material adverse outcome in the egg antitrust litigation has been significantly reduced as a result of the MFI settlements described above, the remaining portion of the cases could still result in a material adverse outcome. No expense was recorded related to these matters in the three months ended December 31, 2019 or 2018. At December 31, 2019 and September 30, 2019, the Company had $3.5 and $6.2 , respectively, accrued for this matter, which was included in “Other current liabilities” on the Condensed Consolidated Balance Sheets. The Company records reserves for litigation losses in accordance with ASC Topic 450, “Contingencies.” Under ASC Topic 450, a loss contingency is recorded if a loss is probable and can be reasonably estimated. The Company records probable loss contingencies based on the best estimate of the loss. If a range of loss can be reasonably estimated, but no single amount within the range appears to be a better estimate than any other amount within the range, the minimum amount in the range is accrued. These estimates are often initially developed earlier than when the ultimate loss is known, and the estimates are adjusted if additional information becomes known. Although the Company believes its accruals for this matter are appropriate, the final amounts required to resolve such matter could differ materially from recorded estimates and the Company’s financial condition, results of operations and cash flows could be materially affected. Under current law, any settlement paid, including the settlements with the direct purchaser class, the opt-out plaintiffs and the indirect purchaser plaintiffs, is deductible for federal income tax purposes. Bob Evans Appraisal Proceedings Prior to completion of the Company’s acquisition of Bob Evans Farms, Inc. (“Bob Evans”) on January 12, 2018, Bob Evans received demands from certain stockholders demanding appraisal of their shares of Bob Evans common stock. After the completion of the acquisition, several such former stockholders filed petitions in the Delaware Court of Chancery ( Arbitrage Fund v. Bob Evans Farms, Inc. filed on January 23, 2018; Blue Mountain Credit Alternatives Master Fund L.P., et al. v. Bob Evans Farms, Inc. filed on April 30, 2018; and 2017 Clarendon LLC, et al. v. Bob Evans Farms, Inc. filed on April 30, 2018) seeking appraisal of their shares of Bob Evans common stock pursuant to Section 262 of the Delaware General Corporation Law (“Section 262”). The lawsuits sought appraisal for such shares, plus statutory interest, as well as the costs of the proceedings and such other relief as appropriate. Under Section 262, persons who were stockholders at the time of the closing were entitled to have their shares appraised by the Delaware Court of Chancery and receive payment of the “fair value” of such shares (plus statutory interest) as determined by the Delaware Court of Chancery. In May 2018, the court consolidated the lawsuits into one action. In December 2018, the Company settled with one petitioner, Arbitrage Fund, and Arbitrage Fund was dismissed with prejudice from the consolidated action. In addition, in December 2018, the Company pre-paid the $77.00 per share merger consideration to the Blue Mountain and 2017 Clarendon petitioners, effectively stopping the continued accrual of statutory interest on that amount. The Company made total payments of $257.6 , inclusive of the aforementioned prepayment of $77.00 per share merger consideration, related to these matters in fiscal 2019. In September 2019, the Company reached settlement terms on a confidential basis with the remaining petitioners regarding their outstanding appraisal claims. The settlement was finalized and paid in October 2019, and the remaining portion of the case was dismissed on October 3, 2019. All former Bob Evans stockholders who demanded appraisal of their shares of Bob Evans common stock were paid for their shares. During the three months ended December 31, 2018, the Company expensed $4.3 related to these matters, which was included in “Interest expense, net” in the Condensed Consolidated Statement of Operations. At September 30, 2019, the Company had an accrual of $19.1 , which was reported in “Other current liabilities” on the Condensed Consolidated Balance Sheet. All remaining cash payments related to this matter were made in October 2019 and there was no accrual reported on the Condensed Consolidated Balance Sheet as of December 31, 2019. In addition, no expense was recorded in the Condensed Consolidated Statement of Operations related to these matters for the three months ended December 31, 2019. Weetabix Limited Environmental Matter In March 2019, Weetabix Limited, one of the Company’s wholly-owned subsidiaries, received notification from the United Kingdom Environment Agency (the “Environment Agency”) that the Environment Agency intended to charge Weetabix Limited in relation to a spill of diesel fuel into the ground at Weetabix Limited’s Burton Latimer site in the United Kingdom that occurred in November 2016, prior to the Company’s acquisition of the Weetabix business. Upon discovery of the spill, Weetabix Limited informed the Environment Agency and took all necessary steps to address the spill, including putting in place monitoring and improvement measures. Weetabix Limited has fully cooperated with the Environment Agency at all times regarding the containment and assessment of the incident. The matter was allocated to the Northampton Crown Court and was heard on November 20, 2019, during which Weetabix Limited pleaded guilty to the offense under the Environmental Permitting Regulations 2010 and the Court imposed a fine of $0.1 , plus costs. Other The Company is subject to various other legal proceedings and actions arising in the normal course of business. In the opinion of management, based upon the information presently known, the ultimate liability, if any, arising from such pending legal proceedings, as well as from asserted legal claims and known potential legal claims which are likely to be asserted, taking into account established accruals for estimated liabilities (if any), are not expected to be material individually or in the aggregate to the financial condition, results of operations or cash flows of the Company. In addition, although it is difficult to estimate the potential financial impact of actions regarding expenditures for compliance with regulatory matters, in the opinion of management, based upon the information currently available, the ultimate liability arising from such compliance matters is not expected to be material to the financial condition, results of operations or cash flows of the Company.

Leases (Notes)

Leases (Notes)	3 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	LEASES In conjunction with the adoption of ASUs 2016-02 and 2018-11 (see Note 2 ), the Company updated its policy for recognizing leases under ASC Topic 842. The Company assessed the impact of these ASUs by reviewing its lease portfolio, implementing lease accounting software, developing related business processes and implementing internal controls. A summary of the updated policy is included below. Prior to October 1, 2019, the Company accounted for leases under ASC Topic 840, “Leases.” Lease Portfolio The Company leases office space, certain warehouses and equipment primarily through operating lease agreements. The Company has no material finance lease agreements. Leases have remaining terms which range from 1 to 57 years and most leases provide the Company with the option to exercise one or more renewal terms. Lease Policy The Company determines if an arrangement is a lease at its inception. When the arrangements include lease and non-lease components, the Company accounts for them as a single lease component. Leases with an initial term of less than 12 months are not reported on the balance sheet, but rather recognized as lease expense on a straight-line basis over the lease term. Arrangements may include options to extend or terminate the lease arrangement. These options are included in the lease term used to establish ROU assets and lease liabilities when it is reasonably certain they will be exercised. The Company will reassess expected lease terms based on changes in circumstances that indicate options may be more or less likely to be exercised. The Company has certain lease arrangements that include variable rental payments. The future variability of these payments and adjustments are unknown and therefore are not included in minimum rental payments used to determine ROU assets and lease liabilities. The Company has lease arrangements where it makes separate payments to the lessor based on the lessor's common area maintenance expenses, property and casualty insurance costs, property taxes assessed on the property and other variable expenses. As the Company has elected the practical expedient not to separate lease and non-lease components, these variable amounts are captured in operating lease expense in the period in which they are incurred. Variable rental payments are recognized in the period in which their associated obligation is incurred. As most of the Company’s lease arrangements do not provide an implicit interest rate, an incremental borrowing rate (“IBR”) is applied in determining the present value of future payments. The Company’s IBR is selected based upon information available at the lease commencement date. ROU assets are recorded as “Other assets,” and lease liabilities are recorded as “Other current liabilities” and “Other liabilities” on the Condensed Consolidated Balance Sheet. Operating lease expense is recognized on a straight-line basis over the lease term and is included in either “Cost of goods sold” or “Selling, general and administrative expenses” in the Condensed Consolidated Statement of Operations. Costs associated with finance leases and lease income do not have a material impact on the Company’s financial statements. Impact of Adoption The Company utilized the cumulative effect adjustment method of adoption and, accordingly, recorded ROU assets and lease liabilities of $158.1 and $168.2 , respectively, on the balance sheet at October 1, 2019. The Company elected the following practical expedients in accordance with ASC Topic 842: • Reassessment elections — The Company elected the package of practical expedients, and did not reassess whether any existing contracts are or contain a lease, provided a lease analysis was conducted under ASC Topic 840. To the extent leases were identified under ASC Topic 840, the Company did not reassess the classification of those leases. Additionally, to the extent initial direct costs were capitalized under ASC Topic 840 and are not amortized as a result of the implementation of ASC Topic 842, they were not reassessed. • Short-term lease election — ASC Topic 842 allows lessees an option to not recognize ROU assets and lease liabilities arising from short-term leases. A short-term lease is defined as a lease with an initial term of 12 months or less. The Company elected to not recognize short-term leases as ROU assets and lease liabilities on the balance sheet. All short-term leases which are not included on the Company’s balance sheet will be recognized within lease expense. Leases that have an initial term of 12 months or less with an option for renewal will need to be assessed in order to determine if the lease qualifies for the short-term lease exception. If the option is reasonably certain to be exercised, the lease does not qualify as a short-term lease. • Lease vs non-lease components — The Company elected to combine lease and non-lease components as a single component and the total consideration for the arrangements were accounted for as a lease. The following table presents the balance sheet location of the Company’s operating leases. December 31, 2019 ROU assets: Other assets $ 128.8 Lease liabilities: Other current liabilities $ 23.4 Other liabilities 116.1 Total lease liabilities $ 139.5 The following table presents maturities of the Company’s operating lease liabilities as of December 31, 2019 , presented under ASC Topic 842. December 31, 2019 Remaining fiscal 2020 $ 21.8 Fiscal 2021 27.2 Fiscal 2022 26.3 Fiscal 2023 23.3 Fiscal 2024 17.2 Thereafter 51.1 Total future minimum payments $ 166.9 Less: Implied interest 27.4 Total lease liabilities $ 139.5 The following table presents future minimum rental payments under the Company’s noncancelable operating lease agreements as of September 30, 2019 , presented under ASC Topic 840. September 30, 2019 Fiscal 2020 $ 28.3 Fiscal 2021 29.0 Fiscal 2022 28.1 Fiscal 2023 25.4 Fiscal 2024 19.2 Thereafter 77.3 Total future minimum payments (a) $ 207.3 (a) Future minimum payments as of September 30, 2019 included $36.0 related to a real estate lease, consisting of land and a building, that was purchased by the Company in December 2019. As of December 31, 2019, the Company de-recognized both a ROU asset and lease liability of $23.1 and recognized the assets as property on the Condensed Consolidated Balance Sheet. As reported under ASC Topic 842, operating lease expense for the three months ended December 31, 2019 was $11.0 , of which $1.2 and $2.0 related to variable lease costs and short-term lease costs, respectively. As reported under ASC Topic 840, rent expense during the three months ended December 31, 2018 was $9.9 . Operating cash flows for amounts included in the measurement of the Company’s operating lease liabilities for the three months ended December 31, 2019 were $7.4 . ROU assets obtained in exchange for operating lease liabilities during the three months ended December 31, 2019 were $0.1 . The weighted average remaining lease term of the Company’s operating leases as of December 31, 2019 was approximately seven years and the weighted average incremental borrowing rate was 4.40% as of December 31, 2019.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Long-Term Debt	LONG-TERM DEBT Long-term debt as of the dates indicated consisted of the following: December 31, September 30, 2019 5.50% Senior Notes maturing December 2029 $ 750.0 $ 750.0 5.625% Senior Notes maturing January 2028 940.9 940.9 5.50% Senior Notes maturing March 2025 1,000.0 1,000.0 5.75% Senior Notes maturing March 2027 1,299.3 1,299.3 5.00% Senior Notes maturing August 2026 1,697.3 1,697.3 8.00% Senior Notes maturing July 2025 122.2 122.2 Term Loan — 1,309.5 BellRing Term B Facility 700.0 — BellRing Revolving Credit Facility 80.0 — Capital lease — 0.1 $ 6,589.7 $ 7,119.3 Less: Current portion of long-term debt (156.5 ) (13.5 ) Debt issuance costs, net (65.6 ) (69.0 ) Plus: Unamortized premium and discount, net 15.0 29.2 Total long-term debt $ 6,382.6 $ 7,066.0 Senior Notes On December 18, 2019, the Company provided notice that it elected to redeem all of its remaining outstanding 8.00% senior notes, which had an aggregate outstanding principal amount of $122.2 . On January 8, 2020, subsequent to the end of the period, the Company completed the previously announced redemption of the 8.00% senior notes and made a payment of $135.5 , which included accrued and unpaid interest and a tender premium, using cash on hand. As of December 31, 2019, the Company reclassified the outstanding principal balance of $122.2 and associated debt issuance costs of $0.7 to “Current portion of long-term debt” on the Condensed Consolidated Balance Sheet. In connection with the January 8, 2020 repayment, the Company will record a write-off of the associated debt issuance costs and a tender premium payment of $9.3 , which will be reported as loss on extinguishment of debt. Credit Agreement On March 28, 2017, the Company entered into an amended and restated credit agreement (as further amended, the “Credit Agreement”). The Credit Agreement provides for a revolving credit facility in an aggregate principal amount of $800.0 (the “Revolving Credit Facility”), with the commitments thereunder to be made available to the Company in U.S. Dollars, Canadian Dollars, Euros and Pounds Sterling. The issuance of letters of credit is available under the Credit Agreement in an aggregate amount of up to $50.0 . The Revolving Credit Facility has outstanding letters of credit of $22.0 , which reduced the available borrowing capacity under the Credit Agreement to $778.0 at December 31, 2019 . The Credit Agreement also provides for potential incremental revolving and term facilities at the request of the Company and at the discretion of the lenders, in each case on terms to be determined, and permits the Company, subject to certain conditions, to incur incremental equivalent debt, in an aggregate maximum amount (for incremental revolving and term facilities and incremental equivalent debt combined) not to exceed the greater of (i) $700.0 and (ii) the maximum amount at which (a) the Company’s pro forma consolidated leverage ratio (as defined in the Credit Agreement) would not exceed 6.50 to 1.00 and (b) the Company’s pro forma senior secured leverage ratio (as defined in the Credit Agreement) would not exceed 3.00 to 1.00 as of the date such indebtedness is incurred. The outstanding amounts under the Revolving Credit Facility must be repaid on or before March 28, 2022. The Credit Agreement permits the Company to designate certain of its subsidiaries as unrestricted subsidiaries and once so designated, permits the disposition of (and authorizes the release of liens on) the assets of, and the equity interests in, such unrestricted subsidiaries and permits the release of such unrestricted subsidiaries as guarantors under the Credit Agreement. Borrowings under the Revolving Credit Facility will bear interest, at the option of the Company, at an annual rate equal to either the Base Rate, Eurodollar Rate or CDOR Rate (as such terms are defined in the Credit Agreement) plus an applicable margin ranging from 1.75% to 2.25% for Eurodollar Rate-based loans and CDOR Rate-based loans and from 0.75% to 1.25% for Base Rate-based loans, depending in each case on the Company’s senior secured leverage ratio. Commitment fees on the daily unused amount of commitments under the Revolving Credit Facility will accrue at rates ranging from 0.25% to 0.375% , also depending on the Company’s senior secured leverage ratio. The Credit Agreement provides for customary events of default, including material breach of representations and warranties, failure to make required payments, failure to comply with certain agreements or covenants, failure to pay, or default under, indebtedness in excess of $75.0 , certain events of bankruptcy and insolvency, inability to pay debts, the occurrence of one or more unstayed or undischarged judgments in excess of $75.0 , attachments issued against a material part of the Company’s property, change in control, the invalidity of any loan document, the failure of the collateral documents to create a valid and perfected first priority lien and certain events under the Employee Retirement Income Security Act of 1974. Upon the occurrence of an event of default, the maturity of the loans under the Credit Agreement may be accelerated and the agent and lenders under the Credit Agreement may exercise other rights and remedies available at law or under the loan documents, including with respect to the collateral and guarantees for the Company’s obligations under the Credit Agreement. 2020 Bridge Loan On October 11, 2019, in connection with the IPO and the formation transactions, the Company entered into a $1,225.0 Bridge Facility Agreement (the “2020 Bridge Loan Facility”) and borrowed $1,225.0 under the 2020 Bridge Loan Facility (the “2020 Bridge Loan”). On October 21, 2019, BellRing entered into a Borrower Assignment and Assumption Agreement with the Company and the administrative agent under the 2020 Bridge Loan Facility, under which BellRing became the borrower under the 2020 Bridge Loan and assumed all interest of $2.2 thereunder, and the Company and its subsidiary guarantors (other than BellRing and its domestic subsidiaries) were released from all material obligations thereunder. The Company retained the net cash proceeds of the 2020 Bridge Loan, and following the assumption by BellRing of the 2020 Bridge Loan Facility, used the cash proceeds of the 2020 Bridge Loan to repay a portion of the $1,309.5 outstanding balance of its term loan. The domestic subsidiaries of BellRing continued to guarantee the 2020 Bridge Loan, and BellRing’s obligations under the 2020 Bridge Loan became secured by a first priority security interest in substantially all of the assets (other than real estate) of BellRing and in substantially all of the assets of its subsidiary guarantors. On October 21, 2019, the 2020 Bridge Loan was repaid in full by BellRing. In connection with the 2020 Bridge Loan Facility, the Company incurred issuance costs of $19.1 , of which $15.3 were refunded to the Company at the closing of the IPO on October 21, 2019, and the remaining $3.8 of issuance costs were written off and included in “Loss on extinguishment of debt, net” in the Condensed Consolidated Statement of Operations for the three months ended December 31, 2019. 2018 Bridge Loan On September 24, 2018, in connection with the 8th Avenue Transactions, the Company entered into a $625.0 bridge facility agreement (the “2018 Bridge Loan Facility”) and borrowed $625.0 under the 2018 Bridge Loan. In connection with the 2018 Bridge Loan Facility, the Company incurred issuance costs of $10.4 , of which $7.8 were refunded to the Company at the closing of the 8th Avenue Transactions on October 1, 2018, and the remaining $2.6 of issuance costs were written off and included in “Loss on extinguishment of debt, net” in the Condensed Consolidated Statement of Operations for the three months ended December 31, 2018. Upon the closing of the 8th Avenue Transactions on October 1, 2018, the 2018 Bridge Loan was assumed by 8th Avenue and the Company was released from its repayment obligations thereunder while retaining the proceeds from the 2018 Bridge Loan. Term Loan As discussed above, the Company used the cash proceeds from the 2020 Bridge Loan to repay a portion of the $1,309.5 outstanding principal balance of its term loan. Subsequent to this repayment, the Company used cash on hand to repay the remaining outstanding principal balance of its term loan. In connection with these repayments, the Company recorded a write-off of debt issuance costs of $9.1 , which was included in “Loss on extinguishment of debt, net” in the Condensed Consolidated Statement of Operations for the three months ended December 31, 2019. The term loan bore interest at an annual rate equal to either the Base Rate or Eurodollar Rate plus an applicable margin of 2.00% for Eurodollar Rate-based loans and 1.00% for Base Rate-based loans. The interest rate on the term loan was 4.04% at September 30, 2019. BellRing’s Credit Agreement and Senior Debt Facilities On October 21, 2019, BellRing entered into a credit agreement (the “BellRing Credit Agreement”) by and among BellRing, the institutions from time to time party thereto as lenders (the “Lenders”), Credit Suisse Loan Funding LLC, BofA Securities, Inc., Morgan Stanley Senior Funding, Inc., Barclays Bank PLC, Citibank, N.A., Goldman Sachs Bank USA and JPMorgan Chase Bank, N.A., as joint lead arrangers and joint bookrunners, and BMO Capital Markets Corp., Coöperatieve Rabobank U.A., New York Branch, Nomura Securities International, Inc., Suntrust Robinson Humphrey, Inc., UBS Securities LLC and Wells Fargo Securities, LLC, as co-managers, and Credit Suisse AG, Cayman Islands Branch, as administrative agent for the Lenders (in such capacity, the “Agent”). The BellRing Credit Agreement provides for a term B loan facility in an aggregate principal amount of $700.0 (the “BellRing Term B Facility”) and a revolving credit facility in an aggregate principal amount of $200.0 (the “BellRing Revolving Credit Facility”), with the commitments under the BellRing Revolving Credit Facility to be made available to BellRing in U.S. Dollars, Euros and Pounds Sterling. Letters of credit are available under the BellRing Credit Agreement in an aggregate amount of up to $20.0 . The outstanding amounts under the BellRing Revolving Credit Facility and BellRing Term B Facility must be repaid on or before October 21, 2024. On October 21, 2019, BellRing borrowed the full amount under the BellRing Term B Facility and $100.0 under the BellRing Revolving Credit Facility. The BellRing Term B Facility was issued at 98.0% of par and BellRing received $776.4 from the BellRing Term B Facility and BellRing Revolving Credit Facility after accounting for the original issue discount of $14.0 and paying investment banking and other fees of $9.6 , which were deferred and will be amortized to interest expense over the terms of the loans. BellRing used the proceeds, together with the net proceeds of the IPO that were contributed to it by BellRing Brands, Inc., (i) to repay in full the $1,225.0 of borrowings under the 2020 Bridge Loan and all interest thereunder and related costs and expenses, (ii) to pay directly, or reimburse the Company for, as applicable, all fees and expenses incurred by BellRing Brands, Inc., BellRing or the Company in connection with the IPO and the formation transactions, (iii) to reimburse the Company for the amount of cash on BellRing’s balance sheet immediately prior to the completion of the IPO and (iv) for general corporate and working capital purposes, as well as to repay $20.0 of outstanding borrowings under the BellRing Revolving Credit Facility. During the three months ended December 31, 2019, BellRing borrowed $120.0 and repaid $40.0 on the BellRing Revolving Credit Facility. The available borrowing capacity under the BellRing Revolving Credit Facility was $120.0 at December 31, 2019, and there were no outstanding letters of credit at December 31, 2019. Borrowings under the BellRing Term B Facility bear interest, at the option of BellRing, at an annual rate equal to either (a) the Eurodollar Rate or (b) the Base Rate (as such terms are defined in the BellRing Credit Agreement) determined by reference to the greatest of (i) the Prime Rate (as defined in the BellRing Credit Agreement), (ii) the Federal Funds Effective Rate (as defined in the BellRing Credit Agreement) plus 0.50% per annum and (iii) the one-month Eurodollar Rate plus 1.00% per annum, in each case plus an applicable margin of 5.00% for Eurodollar Rate-based loans and 4.00% for Base Rate-based loans. The BellRing Term B Facility requires quarterly scheduled amortization payments of $8.75 beginning on March 31, 2020, with the balance to be paid at maturity on October 21, 2024. The BellRing Term B Facility contains customary mandatory prepayment provisions, including provisions for mandatory prepayment (a) from the net cash proceeds of certain asset sales and (b) beginning with the fiscal year ending September 30, 2020, of 75% of Consolidated Excess Cash Flow (as defined in the BellRing Credit Agreement) (which percentage will be reduced to 50% if the secured net leverage ratio (as defined in the BellRing Credit Agreement) is less than or equal to 3.35 :1.00 as of a fiscal year end). The BellRing Term B Facility may be optionally prepaid at 101% of the principal amount prepaid at any time during the first 12 months following the closing of the BellRing Term B Facility, and without premium or penalty thereafter. Borrowings under the BellRing Revolving Credit Facility bear interest, at the option of BellRing, at an annual rate equal to either the Eurodollar Rate or the Base Rate (determined as described above) plus a margin, which initially will be 4.25% for Eurodollar Rate-based loans and 3.25% for Base Rate-based loans, and thereafter, will be determined by reference to the secured net leverage ratio, with the applicable margin for Eurodollar Rate-based loans and Base Rate-based loans being (i) 4.25% and 3.25% , respectively, if the secured net leverage ratio is greater than or equal to 3.50 :1.00, (ii) 4.00% and 3.00% , respectively, if the secured net leverage ratio is less than 3.50 :1.00 and greater than or equal to 2.50 :1.00 or (iii) 3.75% and 2.75% , respectively, if the secured net leverage ratio is less than 2.50 :1.00. Facility fees on the daily unused amount of commitments under the BellRing Revolving Credit Facility will initially accrue at the rate of 0.50% per annum and thereafter, depending on BellRing’s secured net leverage ratio, will accrue at rates ranging from 0.25% to 0.50% per annum. The BellRing Credit Agreement provides for incremental revolving and term facilities, and also permits other secured or unsecured debt, if, among other conditions, certain financial ratios are met, as defined and specified in the BellRing Credit Agreement. The BellRing Credit Agreement provides for customary events of default, including material breach of representations and warranties, failure to make required payments, failure to comply with certain agreements or covenants, failure to pay or default under certain other material indebtedness, certain events of bankruptcy and insolvency, inability to pay debts, the occurrence of one or more unstayed or undischarged judgments in excess of $65.0 , certain events under the Employee Retirement Income Security Act of 1974, the invalidity of any loan document, a change in control and the failure of the collateral documents to create a valid and perfected first priority lien. Upon the occurrence and during the continuance of an event of default, the maturity of the loans under the BellRing Credit Agreement may accelerate and the Agent and Lenders under the BellRing Credit Agreement may exercise other rights and remedies available at law or under the loan documents, including with respect to the collateral and guarantees of BellRing’s obligations under the BellRing Credit Agreement. Obligations under the BellRing Credit Agreement are guaranteed by the existing and subsequently acquired or organized domestic subsidiaries of BellRing LLC (other than immaterial subsidiaries and certain excluded subsidiaries) and are secured by security interests in substantially all of the assets of BellRing LLC and the assets of its subsidiary guarantors (other than real estate), subject to limited exceptions. The Company and its subsidiaries (other than BellRing LLC and certain of its subsidiaries) are not obligors or guarantors under the BellRing debt facilities. Repayments of Long-Term Debt The following tables show the Company’s repayments of long-term debt and associated gain or loss included in “Loss on extinguishment of debt, net” in the Condensed Consolidated Statements of Operations. Repayments of Long-Term Debt Loss on Extinguishment of Debt, net Three Months Ended Issuance or Borrowing Principal Amount Repaid Debt Repurchased at a Discount Write-off of Debt Issuance Costs Write-off of Unamortized Premium Term Loan $ 1,309.5 $ — $ 9.1 $ — 2020 Bridge Loan 1,225.0 — 3.8 — BellRing Revolving Credit Facility 40.0 $ — — $ — 2019 Total $ 2,574.5 $ — $ 12.9 $ — Term Loan $ 863.0 $ — $ 7.6 $ — 5.75% Senior Notes 27.0 (1.5 ) 0.3 (0.7 ) 5.625% Senior Notes 20.0 (1.3 ) 0.2 — 5.00% Senior Notes 13.0 (1.2 ) 0.1 — 2018 Bridge Loan — — 2.6 — 2018 Total $ 923.0 $ (4.0 ) $ 10.8 $ (0.7 ) Debt Covenants Credit Agreement Under the terms of the Credit Agreement, the Company is required to comply with a financial covenant consisting of a ratio for quarterly maximum senior secured leverage (as defined in the Credit Agreement) not to exceed 4.25 to 1.00, measured as of the last day of any fiscal quarter, if, as of the last day of such fiscal quarter, the aggregate outstanding amount of all revolving credit loans, swing line loans and letter of credit obligations (subject to certain exceptions specified in the Credit Agreement) exceeds 30% of the Company’s revolving credit commitments. As of December 31, 2019 , the Company was not required to comply with such financial covenant as the aggregate amount of the aforementioned obligations did not exceed 30% . The Credit Agreement permits the Company to incur additional unsecured debt if, among other conditions, the pro forma consolidated interest coverage ratio, calculated as provided in the Credit Agreement, would be greater than or equal to 2.00 to 1.00 after giving effect to such new debt. As of December 31, 2019 , the pro forma consolidated interest coverage ratio exceeded this threshold. BellRing Credit Agreement Under the terms of the BellRing Credit Agreement, BellRing is required to comply with a financial covenant requiring BellRing to maintain a total net leverage ratio (as defined in the BellRing Credit Agreement) not to exceed 6.00 to 1.00, measured as of the last day of each fiscal quarter, beginning with the quarter ending March 31, 2020. The total net leverage ratio of BellRing would not have exceeded this threshold had BellRing been required to comply with the financial covenant as of December 31, 2019 . The BellRing Credit Agreement provides for incremental revolving and term facilities, and also permits other secured or unsecured debt, if, among other conditions, certain financial ratios are met, as defined and specified in the BellRing Credit Agreement.

Pension and Other Postretiremen

Pension and Other Postretirement Benefits	3 Months Ended
	Dec. 31, 2019
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Pension and Other Postretirement benefits	PENSION AND OTHER POSTRETIREMENT BENEFITS The Company maintains qualified defined benefit plans in the United States, the United Kingdom and Canada for certain employees primarily within its Post Consumer Brands and Weetabix segments. Certain of the Company’s employees are eligible to participate in the Company’s postretirement benefit plans (partially subsidized retiree health and life insurance). Amounts for the Canadian plans are included in the North America disclosures and are not disclosed separately because they do not constitute a significant portion of the combined amounts. The following tables provide the components of net periodic benefit cost (gain) for the pension plans. North America Three Months Ended 2019 2018 Service cost $ 1.1 $ 1.0 Interest cost 0.9 1.0 Expected return on plan assets (1.6 ) (1.6 ) Recognized net actuarial loss 0.5 — Net periodic benefit cost $ 0.9 $ 0.4 Other International Three Months Ended 2019 2018 Service cost $ — $ 1.4 Interest cost 3.7 4.8 Expected return on plan assets (6.2 ) (7.3 ) Net periodic benefit gain $ (2.5 ) $ (1.1 ) The following table provides the components of net periodic benefit gain for the North American other postretirement benefit plans. Three Months Ended 2019 2018 Service cost $ 0.1 $ 0.1 Interest cost 0.5 0.6 Recognized net actuarial loss 0.2 — Recognized prior service credit (1.2 ) (1.2 ) Net periodic benefit gain $ (0.4 ) $ (0.5 )

Shareholders' Equity

Shareholders' Equity	3 Months Ended
	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Shareholders' Equity	SHAREHOLDERS’ EQUITY During the three months ended December 31, 2019, the Company repurchased 2.2 shares of its common stock at an average share price of $102.99 per share for a total cost of $223.1 , including broker’s commissions. Purchases of treasury stock in the Condensed Consolidated Statement of Cash Flows for the three months ended December 31, 2019 included $8.7 of repurchases of common stock that were accrued at September 30, 2019 and did not settle until fiscal 2020. During the three months ended December 31, 2018, the Company repurchased 0.3 shares of its common stock at an average share price of $88.14 per share for a total cost of $25.3 , including broker’s commissions.

Segments

Segments	3 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segments	SEGMENTS At December 31, 2019, the Company’s reportable segments were as follows: • Post Consumer Brands: North American RTE cereal business; • Weetabix: primarily United Kingdom RTE cereal and muesli business; • Foodservice: primarily egg and potato products; • Refrigerated Retail: refrigerated retail products, inclusive of side dishes and egg, cheese and sausage products; and • BellRing Brands: ready-to-drink (“RTD”) protein shakes, other RTD beverages, powders and nutrition bars. Due to the level of integration between the Foodservice and Refrigerated Retail segments, it is impracticable to present total assets separately for each segment. An allocation has been made between the two segments for depreciation based on inventory costing. Management evaluates each segment’s performance based on its segment profit, which is its earnings before income taxes and equity method earnings/loss before impairment of property, goodwill and other intangible assets, facility closure related costs, restructuring expenses, gain/loss on assets and liabilities held for sale, gain/loss on sale of businesses and facilities, interest expense and other unallocated corporate income and expenses. The following tables present information about the Company’s reportable segments. Three Months Ended 2019 2018 Net Sales Post Consumer Brands $ 441.2 $ 455.3 Weetabix 101.5 100.9 Foodservice 420.6 408.1 Refrigerated Retail 249.9 261.6 BellRing Brands 244.0 185.8 Eliminations (0.4 ) (0.4 ) Total $ 1,456.8 $ 1,411.3 Segment Profit Post Consumer Brands $ 80.6 $ 84.0 Weetabix 23.7 18.9 Foodservice 47.0 52.7 Refrigerated Retail 26.0 30.5 BellRing Brands 49.3 35.2 Total segment profit 226.6 221.3 General corporate expenses and other 27.4 48.4 Gain on sale of business — (124.7 ) Interest expense, net 102.9 59.4 Loss on extinguishment of debt, net 12.9 6.1 (Income) expense on swaps, net (61.4 ) 51.7 Earnings before income taxes and equity method loss $ 144.8 $ 180.4 Net sales by product Cereal and granola $ 542.5 $ 556.2 Eggs and egg products 395.3 394.7 Side dishes 148.5 145.7 Cheese and dairy 67.6 70.3 Sausage 45.9 43.6 Protein-based products and supplements 244.1 185.8 Other 13.2 15.4 Eliminations (0.3 ) (0.4 ) Total $ 1,456.8 $ 1,411.3 Depreciation and amortization Post Consumer Brands $ 27.9 $ 29.5 Weetabix 8.7 8.7 Foodservice 29.0 27.0 Refrigerated Retail 17.4 18.0 BellRing Brands 6.4 6.4 Total segment depreciation and amortization 89.4 89.6 Corporate and accelerated depreciation 0.9 4.0 Total $ 90.3 $ 93.6 Assets December 31, September 30, 2019 Post Consumer Brands $ 3,340.4 $ 3,296.3 Weetabix 1,908.8 1,779.1 Foodservice and Refrigerated Retail 5,063.9 5,033.8 BellRing Brands 670.9 594.0 Corporate 959.5 1,248.4 Total $ 11,943.5 $ 11,951.6

Leases (Policies)

Leases (Policies)	3 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	The Company determines if an arrangement is a lease at its inception. When the arrangements include lease and non-lease components, the Company accounts for them as a single lease component. Leases with an initial term of less than 12 months are not reported on the balance sheet, but rather recognized as lease expense on a straight-line basis over the lease term. Arrangements may include options to extend or terminate the lease arrangement. These options are included in the lease term used to establish ROU assets and lease liabilities when it is reasonably certain they will be exercised. The Company will reassess expected lease terms based on changes in circumstances that indicate options may be more or less likely to be exercised. The Company has certain lease arrangements that include variable rental payments. The future variability of these payments and adjustments are unknown and therefore are not included in minimum rental payments used to determine ROU assets and lease liabilities. The Company has lease arrangements where it makes separate payments to the lessor based on the lessor's common area maintenance expenses, property and casualty insurance costs, property taxes assessed on the property and other variable expenses. As the Company has elected the practical expedient not to separate lease and non-lease components, these variable amounts are captured in operating lease expense in the period in which they are incurred. Variable rental payments are recognized in the period in which their associated obligation is incurred. As most of the Company’s lease arrangements do not provide an implicit interest rate, an incremental borrowing rate (“IBR”) is applied in determining the present value of future payments. The Company’s IBR is selected based upon information available at the lease commencement date.

Restructuring (Tables)

Restructuring (Tables)	3 Months Ended
	Dec. 31, 2019
Restructuring [Abstract]
Restructuring charges and related liabilities	Employee-Related Costs Accelerated Depreciation Total Balance, September 30, 2018 $ 2.7 $ — $ 2.7 Charge to expense 0.7 1.8 2.5 Non-cash charges — (1.8 ) (1.8 ) Balance, December 31, 2018 $ 3.4 $ — $ 3.4 Balance, September 30, 2019 $ 0.1 $ — $ 0.1 Cash payments (0.1 ) — (0.1 ) Balance, December 31, 2019 $ — $ — $ — Total expected restructuring charge $ 4.9 $ 9.9 $ 14.8 Cumulative restructuring charges incurred to date 4.9 9.9 14.8 Remaining expected restructuring charge $ — $ — $ —

Equity Interests and Related _2

Equity Interests and Related Party Transactions (Tables)	3 Months Ended
	Dec. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Effects of changes in ownership of BellRing on Post equity	Three Months Ended Increase in additional paid-in capital related to net proceeds from IPO $ 524.4 Increase in additional paid-in capital related to establishment of noncontrolling interest 66.3 Decrease in additional paid-in capital related to tax effects of IPO (133.7 ) Net transfers from noncontrolling interest $ 457.0
Equity method loss attributable to 8th Avenue	Three Months Ended 2019 2018 8th Avenue’s net loss available to 8th Avenue’s common shareholders $ (8.7 ) $ (11.5 ) 60.5 % 60.5 % Equity method loss available to Post $ (5.3 ) $ (7.0 ) Less: Amortization of basis difference, net of tax (a) 1.7 3.6 Equity method loss, net of tax $ (7.0 ) $ (10.6 ) (a) The Company adjusted the historical basis of 8th Avenue’s assets and liabilities to fair value and recognized a basis difference of $70.3 . The basis difference related to inventory of $2.0 , net of tax, was included in equity method loss in the three months ended December 31, 2018. The basis difference related to property, plant and equipment and other intangible assets is being amortized over the weighted average useful lives of the assets. At December 31, 2019 and September 30, 2019, the remaining basis difference to be amortized was $59.8 and $61.5 , respectively.
8th Avenue Summarized Financial Information	Three Months Ended 2019 2018 Net sales $ 218.4 $ 214.1 Gross profit $ 38.4 $ 33.7 Net loss $ (0.9 ) $ (4.5 ) Less: Preferred stock dividend 7.8 7.0 Net Loss Available to 8th Avenue Common Shareholders $ (8.7 ) $ (11.5 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Computation of basic and diluted earnings per share	Three Months Ended 2019 2018 Net earnings for basic earnings per share $ 99.2 $ 123.6 Dilutive preferred stock dividends — 2.0 Net earnings for diluted earnings per share $ 99.2 $ 125.6 Weighted-average shares for basic earnings per share 70.7 66.7 Effect of dilutive securities: Stock options 0.7 2.0 Stock appreciation rights 0.1 0.1 Restricted stock units 0.5 0.4 Performance-based restricted stock awards 0.1 — Preferred shares conversion to common — 5.9 Total dilutive securities 1.4 8.4 Weighted-average shares for diluted earnings per share 72.1 75.1 Basic earnings per common share $ 1.40 $ 1.85 Diluted earnings per common share $ 1.38 $ 1.67
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Securities Excluded from Computation of Diluted Earnings Per Share	Three Months Ended 2019 2018 Stock options 0.1 0.3 Restricted stock units 0.1 0.2 Performance-based restricted stock awards 0.1 0.1

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Dec. 31, 2019
Inventory [Abstract]
Inventories	December 31, September 30, 2019 Raw materials and supplies $ 105.7 $ 99.4 Work in process 20.0 19.4 Finished products 429.3 425.4 Flocks 33.2 35.6 $ 588.2 $ 579.8

Property, net (Tables)

Property, net (Tables)	3 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, net	December 31, September 30, 2019 Property, at cost $ 2,818.5 $ 2,736.9 Accumulated depreciation (1,054.3 ) (1,000.9 ) $ 1,764.2 $ 1,736.0

Goodwill (Tables)

Goodwill (Tables)	3 Months Ended
	Dec. 31, 2019
Goodwill
Carrying Amount of Goodwill	Post Consumer Brands Weetabix Foodservice Refrigerated Retail BellRing Brands Total Balance, September 30, 2019 Goodwill (gross) $ 2,011.8 $ 850.7 $ 1,335.6 $ 793.6 $ 180.7 $ 5,172.4 Accumulated impairment losses (609.1 ) — — (48.7 ) (114.8 ) (772.6 ) Goodwill (net) $ 1,402.7 $ 850.7 $ 1,335.6 $ 744.9 $ 65.9 $ 4,399.8 Currency translation adjustment 0.1 60.8 — — — 60.9 Balance, December 31, 2019 Goodwill (gross) $ 2,011.9 $ 911.5 $ 1,335.6 $ 793.6 $ 180.7 $ 5,233.3 Accumulated impairment losses (609.1 ) — — (48.7 ) (114.8 ) (772.6 ) Goodwill (net) $ 1,402.8 $ 911.5 $ 1,335.6 $ 744.9 $ 65.9 $ 4,460.7

Intangible Assets, net (Tables)

Intangible Assets, net (Tables)	3 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Total Intangible Assets	December 31, 2019 September 30, 2019 Carrying Accumulated Amortization Net Carrying Accumulated Amortization Net Subject to amortization: Customer relationships $ 2,309.0 $ (593.3 ) $ 1,715.7 $ 2,297.2 $ (562.2 ) $ 1,735.0 Trademarks and brands 795.7 (235.9 ) 559.8 793.7 (225.2 ) 568.5 Other intangible assets 3.1 (3.1 ) — 3.1 (3.1 ) — 3,107.8 (832.3 ) 2,275.5 3,094.0 (790.5 ) 2,303.5 Not subject to amortization: Trademarks and brands 1,052.8 — 1,052.8 1,035.0 — 1,035.0 $ 4,160.6 $ (832.3 ) $ 3,328.3 $ 4,129.0 $ (790.5 ) $ 3,338.5

Derivative Financial Instrume_2

Derivative Financial Instruments and Hedging (Tables)	3 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional amounts of derivatives held	December 31, September 30, 2019 Not designated as hedging instruments under ASC Topic 815: Commodity contracts $ 63.8 $ 47.1 Energy contracts 38.5 39.8 Interest rate swaps 272.8 73.1 Interest rate swaps - Rate-lock swaps 1,399.3 1,531.0 Designated as hedging instruments under ASC Topic 815: Foreign exchange contracts - Cross-currency swaps 448.7 448.7 Interest rate swaps 350.0 200.0
Derivative Instruments in Condensed Consolidated Balance Sheets	Fair Value Portion Designated as Hedging Instruments Balance Sheet Location December 31, September 30, 2019 December 31, September 30, 2019 Asset Derivatives: Commodity contracts Prepaid expenses and other current assets $ 2.8 $ 1.9 $ — $ — Energy contracts Prepaid expenses and other current assets 2.6 0.7 — — Commodity contracts Other assets — 0.1 — — Foreign exchange contracts Prepaid expenses and other current assets — 1.3 — 1.3 Foreign exchange contracts Other assets — 19.2 — 19.2 Interest rate swaps Prepaid expenses and other current assets 0.4 — 0.4 — Interest rate swaps Other assets 0.2 — 0.2 — $ 6.0 $ 23.2 $ 0.6 $ 20.5 Liability Derivatives: Commodity contracts Other current liabilities $ 0.9 $ 1.0 $ — $ — Energy contracts Other current liabilities 1.4 1.5 — — Energy contracts Other liabilities — 0.1 — — Foreign exchange contracts Other current liabilities 1.0 — 1.0 — Foreign exchange contracts Other liabilities 14.5 — 14.5 — Interest rate swaps Other current liabilities 58.8 85.1 — 1.6 Interest rate swaps Other liabilities 275.6 330.4 — 6.2 $ 352.2 $ 418.1 $ 15.5 $ 7.8
Effect of Derivative Instruments on the Condensed Consolidated Statements of Operations and Condensed Consolidated Statements of Other Comprehensive Income	The following tables present the effects of the Company’s derivative instruments on the Condensed Consolidated Statements of Operations and Condensed Consolidated Statements of Comprehensive Income for the three months ended December 31, 2019 and 2018. Derivatives Not Designated as Hedging Instruments Statement of Operations Location (Gain) Loss Recognized in Statement of Operations 2019 2018 Commodity contracts Cost of goods sold $ (1.9 ) $ (0.2 ) Energy contracts Cost of goods sold (2.5 ) 8.3 Interest rate swaps (a) (Income) expense on swaps, net (61.4 ) 51.7 (a) For the three months ended December 31, 2019 and 2018, “(Income) expense on swaps, net” related to our interest rate swaps not designated as hedging instruments included cash settlements paid of $19.1 and $0.2 , respectively. Derivatives Designated as Hedging Instruments (Gain) Loss Recognized in OCI including NCI Loss (Gain) Reclassified from Accumulated OCI including NCI into Earnings Statement of Operations Location 2019 2018 2019 2018 Interest rate swaps $ (1.3 ) $ 4.6 $ 7.2 $ (30.1 ) Interest expense, net Cross-currency swaps 34.6 (29.0 ) — — (Income) expense on swaps, net

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets and liabilities measured at fair value on a recurring basis	December 31, 2019 September 30, 2019 Total Level 1 Level 2 Total Level 1 Level 2 Assets: Deferred compensation investments $ 13.0 $ 13.0 $ — $ 11.2 $ 11.2 $ — Derivative assets 6.0 — 6.0 23.2 — 23.2 $ 19.0 $ 13.0 $ 6.0 $ 34.4 $ 11.2 $ 23.2 Liabilities: Deferred compensation liabilities $ 33.6 $ — $ 33.6 $ 31.0 $ — $ 31.0 Derivative liabilities 352.2 — 352.2 418.1 — 418.1 $ 385.8 $ — $ 385.8 $ 449.1 $ — $ 449.1

Leases (Tables)

Leases (Tables)	3 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Balance Sheet location of Operating Leases	December 31, 2019 ROU assets: Other assets $ 128.8 Lease liabilities: Other current liabilities $ 23.4 Other liabilities 116.1 Total lease liabilities $ 139.5
Maturities of Lease Liabilities, under ASC Topic 842	December 31, 2019 Remaining fiscal 2020 $ 21.8 Fiscal 2021 27.2 Fiscal 2022 26.3 Fiscal 2023 23.3 Fiscal 2024 17.2 Thereafter 51.1 Total future minimum payments $ 166.9 Less: Implied interest 27.4 Total lease liabilities $ 139.5
Future Minimum Rental Payments, under ASC Topic 840	September 30, 2019 Fiscal 2020 $ 28.3 Fiscal 2021 29.0 Fiscal 2022 28.1 Fiscal 2023 25.4 Fiscal 2024 19.2 Thereafter 77.3 Total future minimum payments (a) $ 207.3 (a) Future minimum payments as of September 30, 2019 included $36.0 related to a real estate lease, consisting of land and a building, that was purchased by the Company in December 2019. As of December 31, 2019, the Company de-recognized both a ROU asset and lease liability of $23.1 and recognized the assets as property on the Condensed Consolidated Balance Sheet.

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Long-term Debt	December 31, September 30, 2019 5.50% Senior Notes maturing December 2029 $ 750.0 $ 750.0 5.625% Senior Notes maturing January 2028 940.9 940.9 5.50% Senior Notes maturing March 2025 1,000.0 1,000.0 5.75% Senior Notes maturing March 2027 1,299.3 1,299.3 5.00% Senior Notes maturing August 2026 1,697.3 1,697.3 8.00% Senior Notes maturing July 2025 122.2 122.2 Term Loan — 1,309.5 BellRing Term B Facility 700.0 — BellRing Revolving Credit Facility 80.0 — Capital lease — 0.1 $ 6,589.7 $ 7,119.3 Less: Current portion of long-term debt (156.5 ) (13.5 ) Debt issuance costs, net (65.6 ) (69.0 ) Plus: Unamortized premium and discount, net 15.0 29.2 Total long-term debt $ 6,382.6 $ 7,066.0
Repayments of Long-term Debt	Repayments of Long-Term Debt Loss on Extinguishment of Debt, net Three Months Ended Issuance or Borrowing Principal Amount Repaid Debt Repurchased at a Discount Write-off of Debt Issuance Costs Write-off of Unamortized Premium Term Loan $ 1,309.5 $ — $ 9.1 $ — 2020 Bridge Loan 1,225.0 — 3.8 — BellRing Revolving Credit Facility 40.0 $ — — $ — 2019 Total $ 2,574.5 $ — $ 12.9 $ — Term Loan $ 863.0 $ — $ 7.6 $ — 5.75% Senior Notes 27.0 (1.5 ) 0.3 (0.7 ) 5.625% Senior Notes 20.0 (1.3 ) 0.2 — 5.00% Senior Notes 13.0 (1.2 ) 0.1 — 2018 Bridge Loan — — 2.6 — 2018 Total $ 923.0 $ (4.0 ) $ 10.8 $ (0.7 )

Pension and Other Postretirem_2

Pension and Other Postretirement Benefits (Tables)	3 Months Ended
	Dec. 31, 2019
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Components of net periodic benefit cost (gain)	North America Three Months Ended 2019 2018 Service cost $ 1.1 $ 1.0 Interest cost 0.9 1.0 Expected return on plan assets (1.6 ) (1.6 ) Recognized net actuarial loss 0.5 — Net periodic benefit cost $ 0.9 $ 0.4 Other International Three Months Ended 2019 2018 Service cost $ — $ 1.4 Interest cost 3.7 4.8 Expected return on plan assets (6.2 ) (7.3 ) Net periodic benefit gain $ (2.5 ) $ (1.1 ) The following table provides the components of net periodic benefit gain for the North American other postretirement benefit plans. Three Months Ended 2019 2018 Service cost $ 0.1 $ 0.1 Interest cost 0.5 0.6 Recognized net actuarial loss 0.2 — Recognized prior service credit (1.2 ) (1.2 ) Net periodic benefit gain $ (0.4 ) $ (0.5 )

Segments (Tables)

Segments (Tables)	3 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Segment Reporting Information, by Segment and Disaggregated Revenue	Three Months Ended 2019 2018 Net Sales Post Consumer Brands $ 441.2 $ 455.3 Weetabix 101.5 100.9 Foodservice 420.6 408.1 Refrigerated Retail 249.9 261.6 BellRing Brands 244.0 185.8 Eliminations (0.4 ) (0.4 ) Total $ 1,456.8 $ 1,411.3 Segment Profit Post Consumer Brands $ 80.6 $ 84.0 Weetabix 23.7 18.9 Foodservice 47.0 52.7 Refrigerated Retail 26.0 30.5 BellRing Brands 49.3 35.2 Total segment profit 226.6 221.3 General corporate expenses and other 27.4 48.4 Gain on sale of business — (124.7 ) Interest expense, net 102.9 59.4 Loss on extinguishment of debt, net 12.9 6.1 (Income) expense on swaps, net (61.4 ) 51.7 Earnings before income taxes and equity method loss $ 144.8 $ 180.4 Net sales by product Cereal and granola $ 542.5 $ 556.2 Eggs and egg products 395.3 394.7 Side dishes 148.5 145.7 Cheese and dairy 67.6 70.3 Sausage 45.9 43.6 Protein-based products and supplements 244.1 185.8 Other 13.2 15.4 Eliminations (0.3 ) (0.4 ) Total $ 1,456.8 $ 1,411.3 Depreciation and amortization Post Consumer Brands $ 27.9 $ 29.5 Weetabix 8.7 8.7 Foodservice 29.0 27.0 Refrigerated Retail 17.4 18.0 BellRing Brands 6.4 6.4 Total segment depreciation and amortization 89.4 89.6 Corporate and accelerated depreciation 0.9 4.0 Total $ 90.3 $ 93.6 Assets December 31, September 30, 2019 Post Consumer Brands $ 3,340.4 $ 3,296.3 Weetabix 1,908.8 1,779.1 Foodservice and Refrigerated Retail 5,063.9 5,033.8 BellRing Brands 670.9 594.0 Corporate 959.5 1,248.4 Total $ 11,943.5 $ 11,951.6

Basis of Presentation (Details)

Basis of Presentation (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Oct. 21, 2019	Dec. 31, 2019	Dec. 31, 2018
Proceeds from initial public offering		$ 524.4	$ 0
BellRing Brands, Inc.
Offering Price, Per Share of Initial Public Offering	$ 14
Proceeds from initial public offering	$ 524.4
BellRing Brands, Inc. | BellRing Brands, LLC
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	28.80%
Post Holdings, Inc.
Third Party Costs		$ 2.1	$ 1.2
Post Holdings, Inc. | BellRing Brands, LLC
Noncontrolling Interest, Ownership Percentage by Parent	71.20%
Common Class A | BellRing Brands, Inc.
Common Stock, Shares, Issued	39.4
Common Stock, Par or Stated Value Per Share	$ 0.01
Common Stock, Shares, Underwriter Option	5.1
Common Class B | BellRing Brands, Inc.
Common Stock, Par or Stated Value Per Share	$ 0.01
Initial Public Offering, Percentage of Voting Interests	67.00%
Minimum | Post Holdings, Inc. | BellRing Brands, LLC
Noncontrolling Interest, Ownership Percentage by Parent	50.00%

Recently Issued and Adopted A_2

Recently Issued and Adopted Accounting Standards (Details) - Accounting Standards Update 2016-02 $ in Millions	Oct. 01, 2019USD ($)
Right-of-use assets
New Accounting Pronouncement, Early Adoption
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 158.1
Lease liabilities
New Accounting Pronouncement, Early Adoption
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 168.2

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Restructuring Reserve
Balance, Beginning of Period	$ 0.1	$ 2.7
Charge to expense		2.5
Cash payments	(0.1)
Non-cash charges		(1.8)
Balance, End of Period	0	3.4
Total expected restructuring charge	14.8
Cumulative restructuring charges incurred to date	14.8
Remaining expected restructuring charge	0
Employee Severance
Restructuring Reserve
Balance, Beginning of Period	0.1	2.7
Charge to expense		0.7
Cash payments	(0.1)
Non-cash charges		0
Balance, End of Period	0	3.4
Total expected restructuring charge	4.9
Cumulative restructuring charges incurred to date	4.9
Remaining expected restructuring charge	0
Accelerated depreciation
Restructuring Reserve
Balance, Beginning of Period	0	0
Charge to expense		1.8
Cash payments	0
Non-cash charges		(1.8)
Balance, End of Period	0	$ 0
Total expected restructuring charge	9.9
Cumulative restructuring charges incurred to date	9.9
Remaining expected restructuring charge	$ 0

Divestitures and Amounts Held_2

Divestitures and Amounts Held for Sale (Details) - USD ($) $ in Millions	Oct. 01, 2018	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of business related to 8th Avenue Transactions		$ 0		$ (124.7)
Foreign currency losses reclassified from accumulated OCI		0		(42.1)
Loss (gain) on assets held for sale		0
8th Avenue | Sale of Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of business related to 8th Avenue Transactions				124.7	$ 126.6
Foreign currency losses reclassified from accumulated OCI				42.1
8th Avenue | Sale of Business | (Gain) loss on extinguishment of debt, net
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss (gain) on assets held for sale				2.6
8th Avenue
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries	$ 875
Business Divestiture, Purchase Price Adjustment, Net Working Capital Settlement			$ 16.8
Third Party Costs				9.1
2018 Bridge Loan | 8th Avenue
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries	625
Post Consumer Brands | Clinton, Massachusetts facility
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Property, net		8.4			8.4
Post Consumer Brands | Clinton, Massachusetts facility | Facility Closing
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss (gain) on assets held for sale				$ (0.6)
Post Consumer Brands | Asheboro, North Carolina facility
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Property, net		$ 1.5			$ 1.5
Third party | 8th Avenue
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from Divestiture of Interest in Consolidated Subsidiaries	$ 250

Equity Interests and Related _3

Equity Interests and Related Party Transactions (Details) $ in Millions	Oct. 21, 2019USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Sep. 30, 2019USD ($)	Oct. 01, 2018USD ($)
Schedule of Equity Method Investments
Net Earnings		$ 99.2	$ 123.6
Proceeds from initial public offering		524.4	0
Equity method loss, net of tax		(7.3)	$ (10.7)
Equity method investments		$ 138.5		$ 145.5
Number of Joint Ventures Held		2
8th Avenue
Schedule of Equity Method Investments
Equity Method Investment, Ownership Percentage		60.50%	60.50%
Net Loss Available to 8th Avenue Common Shareholders		$ (8.7)	$ (11.5)
Equity method loss available to Common Shareholders		(5.3)	(7)
Amortization of basis difference, net of tax		1.7	3.6
Equity method loss, net of tax		(7)	(10.6)
Total Basis Difference Recognized					$ 70.3
Remaining Basis Difference to be Amortized		59.8		61.5
Net sales		218.4	214.1
Gross profit		38.4	33.7
Net loss		(0.9)	(4.5)
Less: Preferred stock dividend		7.8	7
Revenue from Related Parties		1.6	1.1
Purchases from and Royalties paid to Related Party		$ 2.8	2.3
Alpen Food Company South Africa (Pty) Limited
Schedule of Equity Method Investments
Equity Method Investment, Ownership Percentage		50.00%
Weetabix East Africa Limited
Schedule of Equity Method Investments
Noncontrolling Interest, Ownership Percentage by Parent		50.10%
Inventory | 8th Avenue
Schedule of Equity Method Investments
Amortization of basis difference, net of tax			2
Equity Method Investments | 8th Avenue
Schedule of Equity Method Investments
Equity method investments		$ 133.5		140.5
Equity Method Investments | Alpen Food Company South Africa (Pty) Limited
Schedule of Equity Method Investments
Equity method investments		5		5
Accounts Receivable | 8th Avenue
Schedule of Equity Method Investments
Accounts Receivable, Related Parties		3.6		5.1
Accounts Payable | 8th Avenue
Schedule of Equity Method Investments
Accounts Payable, Related Parties		0.5		0.6
Other Liabilities | 8th Avenue
Schedule of Equity Method Investments
Due to Related Parties		0.7		0.7
Other Assets | Alpen Food Company South Africa (Pty) Limited
Schedule of Equity Method Investments
Notes Receivable, Related Parties, Noncurrent		0.6		$ 0.5
BellRing Brands, Inc.
Schedule of Equity Method Investments
Proceeds from initial public offering	$ 524.4
Selling, General and Administrative Expenses | 8th Avenue
Schedule of Equity Method Investments
MSA and Advisory Income		1	1
BellRing Brands, LLC | BellRing Brands, Inc.
Schedule of Equity Method Investments
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	28.80%
BellRing Brands, LLC | Post Holdings, Inc.
Schedule of Equity Method Investments
Noncontrolling Interest, Ownership Percentage by Parent	71.20%
Additional Paid-in Capital
Schedule of Equity Method Investments
Increase in additional paid-in capital related to net proceeds from IPO		457	0
Non-cash stock-based compensation expense		11.1	$ 8.7
Additional Paid-in Capital | BellRing
Schedule of Equity Method Investments
Proceeds from initial public offering		524.4
Increase in additional paid-in capital related to net proceeds from IPO		457
Tax Effects of Initial Public Offering		(133.7)
Additional Paid-in Capital related to noncontrolling interest | BellRing
Schedule of Equity Method Investments
Increase in additional paid-in capital related to net proceeds from IPO		$ 66.3
Minimum | BellRing Brands, LLC | Post Holdings, Inc.
Schedule of Equity Method Investments
Noncontrolling Interest, Ownership Percentage by Parent	50.00%
Common Class B | BellRing Brands, Inc.
Schedule of Equity Method Investments
Initial Public Offering, Percentage of Voting Interests	67.00%

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Net Earnings Available to Common Shareholders	$ 99.2	$ 123.6
Dilutive preferred stock dividends	0	2
Net earnings for diluted earnings per share	$ 99.2	$ 125.6
Weighted-average shares for basic earnings per share	70.7	66.7
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	1.4	8.4
Weighted-average shares for diluted earnings per share	72.1	75.1
Basic earnings per share (in usd per share)	$ 1.40	$ 1.85
Diluted earnings per share (in usd per share)	$ 1.38	$ 1.67
Stock Options
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	0.7	2
Stock Appreciation Rights
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	0.1	0.1
Restricted Stock Awards
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	0.5	0.4
Performance-based restricted stock awards
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	0.1	0
Preferred shares conversion to common
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	0	5.9

Earnings Per Share Antidilutive

Earnings Per Share Antidilutive shares excluded from earnings per share (Details) - shares shares in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.1	0.3
Restricted Stock Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.1	0.2
Performance-based restricted stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.1	0.1

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2019	Sep. 30, 2019
Inventory [Abstract]
Raw materials and supplies	$ 105.7	$ 99.4
Work in process	20	19.4
Finished products	429.3	425.4
Flocks	33.2	35.6
Inventories	$ 588.2	$ 579.8

Property, net (Details)

Property, net (Details) - USD ($) $ in Millions	Dec. 31, 2019	Sep. 30, 2019
Property, Plant and Equipment [Abstract]
Property, at cost	$ 2,818.5	$ 2,736.9
Accumulated depreciation	(1,054.3)	(1,000.9)
Property, net	$ 1,764.2	$ 1,736

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Sep. 30, 2019
Goodwill
Goodwill (gross)	$ 5,233.3	$ 5,172.4
Accumulated impairment losses	(772.6)	(772.6)
Goodwill	4,460.7	4,399.8
Currency translation adjustment	60.9
Post Consumer Brands
Goodwill
Goodwill (gross)	2,011.9	2,011.8
Accumulated impairment losses	(609.1)	(609.1)
Goodwill	1,402.8	1,402.7
Currency translation adjustment	0.1
Weetabix
Goodwill
Goodwill (gross)	911.5	850.7
Accumulated impairment losses	0	0
Goodwill	911.5	850.7
Currency translation adjustment	60.8
Foodservice
Goodwill
Goodwill (gross)	1,335.6	1,335.6
Accumulated impairment losses	0	0
Goodwill	1,335.6	1,335.6
Currency translation adjustment	0
Refrigerated Retail
Goodwill
Goodwill (gross)	793.6	793.6
Accumulated impairment losses	(48.7)	(48.7)
Goodwill	744.9	744.9
Currency translation adjustment	0
BellRing Brands, Inc.
Goodwill
Goodwill (gross)	180.7	180.7
Accumulated impairment losses	(114.8)	(114.8)
Goodwill	65.9	$ 65.9
Currency translation adjustment	$ 0

Intangible Assets, net (Details

Intangible Assets, net (Details) - USD ($) $ in Millions	Dec. 31, 2019	Sep. 30, 2019
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets, Gross	$ 3,107.8	$ 3,094
Finite-Lived Intangible Assets, Accumulated Amortization	(832.3)	(790.5)
Finite-Lived Intangible Assets, Net	2,275.5	2,303.5
Intangible Assets, Net (Excluding Goodwill)
Carrying amount, total	4,160.6	4,129
Other intangible assets, net	3,328.3	3,338.5
Trademarks and brands
Indefinite-Lived Intangible Assets (Excluding Goodwill)
Carrying amount	1,052.8	1,035
Customer Relationships
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets, Gross	2,309	2,297.2
Finite-Lived Intangible Assets, Accumulated Amortization	(593.3)	(562.2)
Finite-Lived Intangible Assets, Net	1,715.7	1,735
Trademarks and brands
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets, Gross	795.7	793.7
Finite-Lived Intangible Assets, Accumulated Amortization	(235.9)	(225.2)
Finite-Lived Intangible Assets, Net	559.8	568.5
Other Intangible Assets
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets, Gross	3.1	3.1
Finite-Lived Intangible Assets, Accumulated Amortization	(3.1)	(3.1)
Finite-Lived Intangible Assets, Net	$ 0	$ 0

Derivative Financial Instrume_3

Derivative Financial Instruments and Hedging (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Derivatives, Fair Value
Losses (gains) reclassified to net earnings	$ 7.2	$ (30.1)
Assets, Total
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	6		$ 23.2
Liabilities, Total
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	352.2		418.1
Portion Designated as Hedging Instruments | Assets, Total
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0.6		20.5
Portion Designated as Hedging Instruments | Liabilities, Total
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	15.5		7.8
Commodity contracts | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	2.8		1.9
Commodity contracts | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0.1
Commodity contracts | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0.9		1
Commodity contracts | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value
Notional Amount of Derivative	63.8		47.1
Commodity contracts | Portion Designated as Hedging Instruments | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0
Commodity contracts | Portion Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0
Commodity contracts | Portion Designated as Hedging Instruments | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0		0
Energy Contracts | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	2.6		0.7
Energy Contracts | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	1.4		1.5
Energy Contracts | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0		0.1
Energy Contracts | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value
Notional Amount of Derivative	38.5		39.8
Energy Contracts | Portion Designated as Hedging Instruments | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0
Energy Contracts | Portion Designated as Hedging Instruments | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0		0
Energy Contracts | Portion Designated as Hedging Instruments | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0		0
Foreign Exchange Contract - Forward Contracts | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		1.3
Foreign Exchange Contract - Forward Contracts | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		19.2
Foreign Exchange Contract - Forward Contracts | Portion Designated as Hedging Instruments | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		1.3
Foreign Exchange Contract - Forward Contracts | Portion Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		19.2
Interest Rate Swap | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0.4		0
Interest Rate Swap | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0.2		0
Interest Rate Swap | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	58.8		85.1
Interest Rate Swap | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	275.6		330.4
Interest Rate Swap | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value
Notional Amount of Derivative	272.8		73.1
Interest Rate Swap | Derivatives Not Designated as Hedging Instruments | Interest expense, net
Derivatives, Fair Value
Losses (gains) reclassified to net earnings	(7.2)
Interest Rate Swap | Portion Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount of Terminated Contracts		800
Notional Amount of Derivative	350		200
Interest Rate Swap | Portion Designated as Hedging Instruments | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0.4		0
Interest Rate Swap | Portion Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0.2		0
Interest Rate Swap | Portion Designated as Hedging Instruments | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0		1.6
Interest Rate Swap | Portion Designated as Hedging Instruments | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0		6.2
Interest Rate Swap | Portion Designated as Hedging Instruments | Interest expense, net
Derivatives, Fair Value
Derivative, Cash Received on Hedge		29.8
Interest rate swap, rate lock swaps | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value
Notional Amount of Derivative	1,399.3		1,531
Currency Swap | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	1		0
Currency Swap | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	14.5		0
Currency Swap | Portion Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount of Terminated Contracts		214.2
Notional Amount of Derivative	448.7		448.7
Currency Swap | Portion Designated as Hedging Instruments | Accumulated Other Comprehensive Income
Derivatives, Fair Value
Derivative, Cash Received on Hedge		$ 26.2
Currency Swap | Portion Designated as Hedging Instruments | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	1		0
Currency Swap | Portion Designated as Hedging Instruments | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	$ 14.5		$ 0

Derivative Financial Instrume_4

Derivative Financial Instruments and Hedging (Gain) Loss recognized in Statement of Operations from derivative instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Interest rate swaps | Expense (income) on swaps, net
Derivative Instruments, (Gain) Loss
Derivative Instruments Not Designated as Hedging Instruments, Cash Paid	$ 19.1	$ 0.2
Derivatives Not Designated as Hedging Instruments | Commodity contracts | Cost of Goods Sold
Derivative Instruments, (Gain) Loss
(Gain) Loss Recognized in Statement of Operations	(1.9)	(0.2)
Derivatives Not Designated as Hedging Instruments | Energy Contracts | Cost of Goods Sold
Derivative Instruments, (Gain) Loss
(Gain) Loss Recognized in Statement of Operations	(2.5)	8.3
Derivatives Not Designated as Hedging Instruments | Interest rate swaps | Expense (income) on swaps, net
Derivative Instruments, (Gain) Loss
(Gain) Loss Recognized in Statement of Operations	$ (61.4)	$ 51.7

Derivative Financial Instrume_5

Derivative Financial Instruments and Hedging Derivatives designated as hedges (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Derivative Instruments, (Gain) Loss
Loss (Gain) Recognized in OCI	$ 33.3	$ (24.4)
Cross Currency Swap Settlements Included in AOCI	37.9		$ 36.5
Cross Currency Swap Settlements Recognized in AOCI	1.4	28.3
Collateral Already Posted	2.4		3.7
Hedging Instruments
Derivative Instruments, (Gain) Loss
Accumulated Other Comprehensive Income, Cumulative Changes in Net Gain from Hedges, Before Tax	33.4		59.5
Accumulated Other Comprehensive Income, Cumulative Changes in Net Gain from Hedges, Effect Net of Tax	25.3		$ 44.5
Interest Rate Swap | Hedging Instruments
Derivative Instruments, (Gain) Loss
Loss (Gain) Recognized in OCI	(1.3)	4.6
Interest Rate Swap Losses to be Reclassified During Next 12 Months	0.4
Interest Rate Swap | Interest expense, net | Hedging Instruments
Derivative Instruments, (Gain) Loss
(Gain) Loss Reclassified from Accumulated OCI into Earnings	7.2	(30.1)
Currency Swap | Hedging Instruments
Derivative Instruments, (Gain) Loss
Loss (Gain) Recognized in OCI	34.6	(29)
Currency Swap | Expense (income) on swaps, net | Hedging Instruments
Derivative Instruments, (Gain) Loss
(Gain) Loss Reclassified from Accumulated OCI into Earnings	$ 0	$ 0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred Compensation Investment	$ 13	$ 11.2
Derivative Asset	6	23.2
Assets, Fair Value Disclosure	19	34.4
Deferred Compensation Liabilities	33.6	31
Derivative Liability	352.2	418.1
Other Liabilities, Fair Value Disclosure	385.8	449.1
Gains related to assets and liabilities held for sale	0
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred Compensation Investment	13	11.2
Derivative Asset	0	0
Assets, Fair Value Disclosure	13	11.2
Deferred Compensation Liabilities	0	0
Derivative Liability	0	0
Other Liabilities, Fair Value Disclosure	0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred Compensation Investment	0	0
Derivative Asset	6	23.2
Assets, Fair Value Disclosure	6	23.2
Deferred Compensation Liabilities	33.6	31
Derivative Liability	352.2	418.1
Other Liabilities, Fair Value Disclosure	385.8	449.1
Debt, Fair Value	6,899	7,412
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets Held for Sale, Fair Value	$ 9.9	$ 9.9

Commitments and Contingencies_2

Commitments and Contingencies (Details)	Nov. 20, 2019USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2019USD ($)defendant	Dec. 31, 2018USD ($)	Sep. 30, 2019USD ($)	Jan. 12, 2018$ / shares
Bob Evans Farms
Loss Contingencies
Business Acquisition, Share Price | $ / shares						$ 77
Payments to appraisal rights holders, including interest				$ 257,600,000
Bob Evans Farms | Other Current Liabilities
Loss Contingencies
Estimated Litigation Liability, Current					$ 19,100,000
Michael Foods
Loss Contingencies
Claims filed, number			22
Loss Contingency, Number of Defendants | defendant			20
Loss Contingency, Pending Claims, Number of Plaintiff Groups			3
Litigation Settlement, Amount Awarded to Other Party		$ 75,000,000
Estimated Litigation Liability, Current			$ 3,500,000		$ 6,200,000
Weetabix
Loss Contingencies
Litigation Settlement, Amount Awarded to Other Party	$ 100,000
Interest expense, net
Loss Contingencies
Litigation Settlement, Expense			$ 0	$ 4,300,000

Leases (Details)

Leases (Details) - USD ($) $ in Millions	Oct. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset		$ 128.8
Operating Lease, Liability, Current		23.4
Operating Lease, Liability, Noncurrent		116.1
Operating Lease, Liability		139.5
Lessee, Operating Lease, Liability, Payments, Remainder of Fiscal Year		21.8
Lessee, Operating Lease, Liability, Payments, Due Year Two		27.2
Lessee, Operating Lease, Liability, Payments, Due Year Three		26.3
Lessee, Operating Lease, Liability, Payments, Due Year Four		23.3
Lessee, Operating Lease, Liability, Payments, Due Year Five		17.2
Lessee, Operating Lease, Liability, Payments, Due after Year Five		51.1
Lessee, Operating Lease, Liability, Payments, Due		166.9
Lessee, Operating Lease, Liability, Undiscounted Excess Amount		27.4
Operating Leases, Future Minimum Payments Due, Next Twelve Months				$ 28.3
Operating Leases, Future Minimum Payments, Due in Two Years				29
Operating Leases, Future Minimum Payments, Due in Three Years				28.1
Operating Leases, Future Minimum Payments, Due in Four Years				25.4
Operating Leases, Future Minimum Payments, Due in Five Years				19.2
Operating Leases, Future Minimum Payments, Due Thereafter				77.3
Operating Leases, Future Minimum Payments Due				207.3
De-recognition of right of use asset		23.1
De-recognition of lease liability		23.1
Operating Lease, Cost		11
Variable Lease, Cost		1.2
Short-term Lease, Cost		2
Operating Leases, Rent Expense, Net			$ 9.9
Operating Lease, Payments		7.4
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability		$ 0.1
Operating Lease, Weighted Average Remaining Lease Term		7 years
Operating Lease, Weighted Average Discount Rate, Percent		4.40%
Minimum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		1 year
Maximum
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		57 years
Accounting Standards Update 2016-02 | Right-of-use assets
Lessee, Lease, Description [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 158.1
Accounting Standards Update 2016-02 | Lease liabilities
Lessee, Lease, Description [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 168.2
Real Estate
Lessee, Lease, Description [Line Items]
Operating Leases, Future Minimum Payments Due				$ 36

Long-Term Debt (Details)

Long-Term Debt (Details) - USD ($)	Dec. 31, 2019	Oct. 21, 2019	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2018	Dec. 18, 2019	Oct. 11, 2019	Sep. 30, 2019
Debt Instrument
Repayments of Long-term Debt				$ 2,574,500,000	$ 919,000,000
Capital Lease Obligations	$ 0			0						$ 100,000
Long-term Debt, Including Current Maturities	6,589,700,000			6,589,700,000						7,119,300,000
Current portion of long-term debt	(156,500,000)			(156,500,000)						(13,500,000)
Unamortized Debt Issuance Expense	(65,600,000)			(65,600,000)						(69,000,000)
Plus: Unamortized premium and discount, net	15,000,000			15,000,000						29,200,000
Total Long-term Debt	$ 6,382,600,000			6,382,600,000						7,066,000,000
Payments of Debt Issuance Costs				28,200,000	300,000
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal				$ 0
Debt Covenant, Leverage Ratio	4.25			4.25
Debt Covenant, Percentage of Revolving Credit Commitments	30.00%			30.00%
Debt covenant, interest coverage ratio				2
Refund of debt issuance costs				$ 15,300,000	7,800,000
Gross Repayments of Long-term debt				$ 2,574,500,000	923,000,000
Debt Instruments, Covenant Compliance, Percentage of Revolving Credit Commitments	30.00%			30.00%
Term Loan
Debt Instrument
Long-term Debt	$ 0	$ 1,309,500,000		$ 0						$ 1,309,500,000
Debt Instrument, Interest Rate, Effective Percentage										4.04%
Gross Repayments of Long-term debt				$ 1,309,500,000	863,000,000
Term Loan | Base Rate
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate				1.00%
Term Loan | Eurodollar
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate				2.00%
Revolving Credit Facility
Debt Instrument
Line of Credit Facility, Current Borrowing Capacity	800,000,000			$ 800,000,000
Letters of Credit Outstanding, Amount	22,000,000			22,000,000
Line of Credit Facility, Remaining Borrowing Capacity	778,000,000			778,000,000
Debt Covenant, Maximum Undischarged Judgments	75,000,000			$ 75,000,000
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 | Minimum
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate				0.75%
Revolving Credit Facility | Base Rate | Maximum
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate				1.25%
Revolving Credit Facility | Eurodollar | Minimum
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate				1.75%
Revolving Credit Facility | Eurodollar | Maximum
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate				2.25%
2020 Bridge Loan
Debt Instrument
Debt Issuance Costs, Net		19,100,000
Refund of debt issuance costs		15,300,000
Gross Repayments of Long-term debt				$ 1,225,000,000
Line of Credit
Debt Instrument
Line of Credit Facility, Current Borrowing Capacity	50,000,000			50,000,000
BellRing Term B Facility
Debt Instrument
Long-term Debt	700,000,000			$ 700,000,000						$ 0
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	80,000,000			$ 80,000,000						0
2018 Bridge Loan
Debt Instrument
Payments of Debt Issuance Costs							$ 10,400,000
Refund of debt issuance costs					7,800,000
Gross Repayments of Long-term debt					0
5.50% Senior Notes Maturing in December 2029 | Senior Notes
Debt Instrument
Long-term Debt	750,000,000			750,000,000						750,000,000
5.625% Senior Notes maturing January 2028 | Senior Notes
Debt Instrument
Long-term Debt	940,900,000			940,900,000						940,900,000
Gross Repayments of Long-term debt					20,000,000
5.50% Senior Notes maturing March 2025 | Senior Notes
Debt Instrument
Long-term Debt	1,000,000,000			1,000,000,000						1,000,000,000
5.75% Senior Notes maturing March 2027 | Senior Notes
Debt Instrument
Long-term Debt	1,299,300,000			1,299,300,000						1,299,300,000
Gross Repayments of Long-term debt					27,000,000
5.00% Senior Notes maturing August 2026 | Senior Notes
Debt Instrument
Long-term Debt	$ 1,697,300,000			$ 1,697,300,000						1,697,300,000
Gross Repayments of Long-term debt					13,000,000
8.00% Senior Notes maturing July 2025 | Senior Notes
Debt Instrument
Debt Instrument, Interest Rate, Stated Percentage	8.00%			8.00%
Long-term Debt	$ 122,200,000			$ 122,200,000				$ 122,200,000		$ 122,200,000
Debt Issuance Costs, Net	700,000			700,000
Revolver Incremental Borrowing Capacity
Debt Instrument
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases	700,000,000			700,000,000
Debt Covenant, Proforma Consolidated Leverage Ratio	6.50			6.50
Debt Covenant, Proforma Senior Secured Leverage Ratio	3			3
(Gain) loss on extinguishment of debt, net
Debt Instrument
Write off of Debt Issuance Costs and Other Expenses				12,900,000	10,800,000
Gain on Debt Repurchased at a Discount				0	(4,000,000)
Write-off of Unamortized Debt Discount/(Premium)				0	(700,000)
(Gain) loss on extinguishment of debt, net | Term Loan
Debt Instrument
Write off of Debt Issuance Costs and Other Expenses				9,100,000	7,600,000
Gain on Debt Repurchased at a Discount				0	0
Write-off of Unamortized Debt Discount/(Premium)				0	0
(Gain) loss on extinguishment of debt, net | 2020 Bridge Loan
Debt Instrument
Write off of Debt Issuance Costs and Other Expenses		3,800,000		3,800,000
Gain on Debt Repurchased at a Discount				0
Write-off of Unamortized Debt Discount/(Premium)				0
(Gain) loss on extinguishment of debt, net | BellRing Revolving Credit Facility
Debt Instrument
Write off of Debt Issuance Costs and Other Expenses				0
Gain on Debt Repurchased at a Discount				0
Write-off of Unamortized Debt Discount/(Premium)				0
(Gain) loss on extinguishment of debt, net | 2018 Bridge Loan
Debt Instrument
Write off of Debt Issuance Costs and Other Expenses					2,600,000
Gain on Debt Repurchased at a Discount					0
Write-off of Unamortized Debt Discount/(Premium)					0
(Gain) loss on extinguishment of debt, net | 5.625% Senior Notes maturing January 2028 | Senior Notes
Debt Instrument
Write off of Debt Issuance Costs and Other Expenses					200,000
Gain on Debt Repurchased at a Discount					(1,300,000)
Write-off of Unamortized Debt Discount/(Premium)					0
(Gain) loss on extinguishment of debt, net | 5.75% Senior Notes maturing March 2027 | Senior Notes
Debt Instrument
Write off of Debt Issuance Costs and Other Expenses					300,000
Gain on Debt Repurchased at a Discount					(1,500,000)
Write-off of Unamortized Debt Discount/(Premium)					(700,000)
(Gain) loss on extinguishment of debt, net | 5.00% Senior Notes maturing August 2026 | Senior Notes
Debt Instrument
Write off of Debt Issuance Costs and Other Expenses					100,000
Gain on Debt Repurchased at a Discount					(1,200,000)
Write-off of Unamortized Debt Discount/(Premium)					0
8th Avenue | 2018 Bridge Loan
Debt Instrument
Loans Payable to Bank						$ 625,000,000	$ 625,000,000
Proceeds from bridge loan						$ 625,000,000
Subsequent Event | 8.00% Senior Notes maturing July 2025 | Senior Notes
Debt Instrument
Repayments of Long-term Debt			$ 135,500,000
Subsequent Event | (Gain) loss on extinguishment of debt, net | 8.00% Senior Notes maturing July 2025
Debt Instrument
Write of deferred debt issuance cost and tender premium			$ 9,300,000
8th Avenue | Sale of Business | (Gain) loss on extinguishment of debt, net
Debt Instrument
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal					$ 2,600,000
BellRing Brands, LLC | 2020 Bridge Loan
Debt Instrument
Loans Payable to Bank									$ 1,225,000,000
Proceeds from bridge loan				$ 1,225,000,000
BellRing
Debt Instrument
Debt Instrument, Redemption Price, Percentage				98.00%
Proceeds from Debt, Net of Issuance Costs				$ 776,400,000
Debt Instrument, Unamortized Discount		14,000,000
BellRing | Revolving Credit Facility
Debt Instrument
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage				0.50%
BellRing | Revolving Credit Facility | Minimum
Debt Instrument
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage				0.25%
BellRing | Revolving Credit Facility | Maximum
Debt Instrument
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage				0.50%
BellRing | 2020 Bridge Loan
Debt Instrument
Interest Costs Incurred				$ 2,200,000
Gross Repayments of Long-term debt				1,225,000,000
BellRing | BellRing Term B Facility
Debt Instrument
Debt Instrument, Periodic Payment, Principal	8,750,000
Loans Payable to Bank	700,000,000			$ 700,000,000
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			$ 200,000,000
Line of Credit Facility, Maximum Borrowing Capacity	20,000,000			20,000,000
Letters of Credit Outstanding, Amount	0	$ 100,000,000		0
Line of Credit Facility, Remaining Borrowing Capacity	$ 120,000,000			$ 120,000,000
Debt Covenant, Leverage Ratio	6			6
Debt Covenant, Maximum Undischarged Judgments	$ 65,000,000			$ 65,000,000
Gross Repayments of Long-term debt				40,000,000
Line of Credit Facility, Periodic Payment				20,000,000
Proceeds from Lines of Credit				$ 120,000,000
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 | BellRing Term B Facility and BellRing Revolving Credit Facility
Debt Instrument
Payments of Debt Issuance Costs				$ 9,600,000
Less than or equal to 3.35 | BellRing | BellRing Revolving Credit Facility
Debt Instrument
Debt Covenant, Leverage Ratio	3.35			3.35
High-End Ratio | BellRing | BellRing Revolving Credit Facility
Debt Instrument
Debt Covenant, Leverage Ratio	3.50			3.50
Low-End Ratio | BellRing | BellRing Revolving Credit Facility
Debt Instrument
Debt Covenant, Leverage Ratio	2.50			2.50

Pension and Other Postretirem_3

Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Gain) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits | North America
Components of net periodic benefit cost (gain)
Service cost	$ 1.1	$ 1
Interest cost	0.9	1
Expected return on plan assets	(1.6)	(1.6)
Recognized net actuarial loss	0.5	0
Net periodic benefit cost (gain)	0.9	0.4
Pension Benefits | Non-North America
Components of net periodic benefit cost (gain)
Service cost	0	1.4
Interest cost	3.7	4.8
Expected return on plan assets	(6.2)	(7.3)
Net periodic benefit cost (gain)	(2.5)	(1.1)
Other Postretirement Benefit Plan | North America
Components of net periodic benefit cost (gain)
Service cost	0.1	0.1
Interest cost	0.5	0.6
Recognized net actuarial loss	0.2	0
Recognized prior service cost (credit)	(1.2)	(1.2)
Net periodic benefit cost (gain)	$ (0.4)	$ (0.5)

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Purchases of treasury stock	$ 231,800,000	$ 25,300,000
Payments for accrued repurchases of common stock	$ 8,700,000
Common Stock
Class of Stock [Line Items]
Purchases of treasury stock, shares	2.2	0.3
Treasury Stock Acquired, Average Cost Per Share (in USD per share)	$ 102.99	$ 88.14
Purchases of treasury stock	$ 223,100,000	$ 25,300,000

Segments (Details)

Segments (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Segment Reporting Information
Net Sales	$ 1,456.8	$ 1,411.3
Gain on sale of business	0	(124.7)
Interest expense, net	102.9	59.4
Loss on extinguishment of debt, net	12.9	6.1
(Income) expense on swaps, net	(61.4)	51.7
Earnings before income taxes and equity method loss	144.8	180.4
Depreciation and amortization	90.3	93.6
Assets	11,943.5		$ 11,951.6
Corporate
Segment Reporting Information
General corporate expenses and other	27.4	48.4
Depreciation and amortization	0.9	4
Assets	959.5		1,248.4
Operating Segments
Segment Reporting Information
Net Sales	1,456.8	1,411.3
Segment Profit	226.6	221.3
Depreciation and amortization	89.4	89.6
Operating Segments | Post Consumer Brands
Segment Reporting Information
Net Sales	441.2	455.3
Segment Profit	80.6	84
Depreciation and amortization	27.9	29.5
Assets	3,340.4		3,296.3
Operating Segments | Weetabix
Segment Reporting Information
Net Sales	101.5	100.9
Segment Profit	23.7	18.9
Depreciation and amortization	8.7	8.7
Assets	1,908.8		1,779.1
Operating Segments | Foodservice
Segment Reporting Information
Net Sales	420.6	408.1
Segment Profit	47	52.7
Depreciation and amortization	29	27
Operating Segments | Refrigerated Retail
Segment Reporting Information
Net Sales	249.9	261.6
Segment Profit	26	30.5
Depreciation and amortization	17.4	18
Operating Segments | Foodservice and Refrigerated Retail
Segment Reporting Information
Assets	5,063.9		5,033.8
Operating Segments | BellRing Brands, Inc.
Segment Reporting Information
Net Sales	244	185.8
Segment Profit	49.3	35.2
Depreciation and amortization	6.4	6.4
Assets	670.9		$ 594
Eliminations | Eliminations
Segment Reporting Information
Net Sales	(0.4)	(0.4)
Cereal and Granola | Operating Segments
Segment Reporting Information
Net Sales	542.5	556.2
Egg and Egg Products | Operating Segments
Segment Reporting Information
Net Sales	395.3	394.7
Side Dishes | Operating Segments
Segment Reporting Information
Net Sales	148.5	145.7
Cheese and Dairy | Operating Segments
Segment Reporting Information
Net Sales	67.6	70.3
Sausage | Operating Segments
Segment Reporting Information
Net Sales	45.9	43.6
Protein-based Products and Supplements | Operating Segments
Segment Reporting Information
Net Sales	244.1	185.8
Other | Operating Segments
Segment Reporting Information
Net Sales	13.2	15.4
Product Eliminations | Eliminations
Segment Reporting Information
Net Sales	$ (0.3)	$ (0.4)