Post (POST) 10-Q 3 May 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Mar. 31, 2019	Apr. 30, 2019
Document and Entity Information [Abstract]
Entity Registrant Name	Post Holdings, Inc.
Entity Central Index Key	0001530950
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		73,305,955
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net Sales	$ 1,387.8	$ 1,586.1	$ 2,799.1	$ 3,019.2
Cost of goods sold	936.5	1,113.7	1,921.3	2,098.3
Gross Profit	451.3	472.4	877.8	920.9
Selling, general and administrative expenses	225.8	264.6	442.9	510.6
Amortization of intangible assets	40.4	46.4	80.7	87.9
Gain on sale of business	(2.6)	0	(127.3)	0
Other operating expenses, net	1.4	0.7	1.3	0.7
Operating Profit	186.3	160.7	480.2	321.7
Interest expense, net	85.5	98.8	144.9	189.3
Loss on extinguishment of debt, net	0	0.3	6.1	37.6
Expense (income) on swaps, net	63	(50.5)	114.7	(53.2)
Other income, net	(3.7)	(3.6)	(7.4)	(7.1)
Earnings before Income Taxes and Equity Method Loss	41.5	115.7	221.9	155.1
Income tax (benefit) expense	(11.6)	23.9	32.2	(231.9)
Equity method loss, net of tax	8.8	0	19.5	0
Net Earnings Including Noncontrolling Interest	44.3	91.8	170.2	387
Less: Net earnings attributable to noncontrolling interest	0.3	0.3	0.6	0.6
Net Earnings	44	91.5	169.6	386.4
Less: Preferred stock dividends	1	2.6	3	6
Net Earnings Available to Common Shareholders	$ 43	$ 88.9	$ 166.6	$ 380.4
Earnings per Share, Basic (in usd per share)	$ 0.61	$ 1.33	$ 2.43	$ 5.73
Earnings per Share, Diluted (in usd per share)	$ 0.58	$ 1.20	$ 2.26	$ 5.04
Weighted-Average Common Shares Outstanding, Basic (in shares)	70.6	66.8	68.6	66.4
Weighted-Average Common Shares Outstanding, Diluted (in shares)	75.3	76	75.2	76.6

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Earnings Including Noncontrolling Interest	$ 44.3	$ 91.8	$ 170.2	$ 387
Pension and postretirement benefits adjustments:
Reclassifications to net earnings	(1.1)	(0.8)	(2.3)	(1.6)
Hedging adjustments:
Unrealized net (loss) gain on derivatives	(11.9)	5.4	12.5	3.9
Reclassifications to net earnings	(0.4)	(1.8)	(30.5)	(1.5)
Other reclassifications	0	(0.5)	0	(0.5)
Foreign currency translation adjustments:
Unrealized foreign currency translation adjustments	37.7	70	(2.5)	83.9
Reclassifications to net earnings	0	0	42.1	0
Tax benefit (expense) on other comprehensive income:
Pension and postretirement benefits	0.2	1.2	0.5	1.4
Hedging	11.2	(3.1)	12.6	(2.8)
Total Other Comprehensive Income	35.7	70.4	32.4	82.8
Less: Comprehensive income attributable to noncontrolling interest	0.6	0.3	0.9	0.6
Total Comprehensive Income	$ 79.4	$ 161.9	$ 201.7	$ 469.2

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
ASSETS
Cash and cash equivalents	$ 149.7	$ 989.7
Restricted cash	2.2	4.8
Receivables, net	500.4	462.3
Inventories	555.1	484.2
Current assets held for sale	0	195
Prepaid expenses and other current assets	46.4	64.3
Total Current Assets	1,253.8	2,200.3
Property, net	1,718.7	1,709.7
Goodwill	4,498.9	4,499.6
Other intangible assets, net	3,458.6	3,539.3
Equity method investments	163.1	5.2
Other assets held for sale	0	856.6
Other assets	189.7	246.8
Total Assets	11,282.8	13,057.5
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current portion of long-term debt	6.7	22.1
Accounts payable	325.5	365.1
Current liabilities held for sale	0	65.6
Other current liabilities	317.2	339.3
Total Current Liabilities	649.4	792.1
Long-term debt	6,326.2	7,232.1
Deferred income taxes	751.6	778.4
Other liabilities held for sale	0	695.1
Other liabilities	310.7	499.3
Total Liabilities	8,037.9	9,997
Preferred stock	0	0
Common stock	0.8	0.8
Additional paid-in capital	3,643.1	3,590.9
Retained earnings	252.7	88
Accumulated other comprehensive loss	(7)	(39.4)
Treasury stock, at cost	(655.7)	(589.9)
Total Shareholders’ Equity Excluding Noncontrolling Interest	3,233.9	3,050.4
Noncontrolling interest	11	10.1
Total Shareholders’ Equity	3,244.9	3,060.5
Total Liabilities and Shareholders’ Equity	$ 11,282.8	$ 13,057.5

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Cash Flows from Operating Activities:
Net Earnings Including Noncontrolling Interest	$ 44.3	$ 91.8	$ 170.2	$ 387
Adjustments to reconcile net earnings including noncontrolling interest to net cash flow provided by operating activities:
Depreciation and amortization	97.8	104.6	191.4	195.1
Unrealized loss (gain) on interest rate swaps			114.4	(54)
Gain on sale of business	(2.6)	0	(127.3)	0
Loss on extinguishment of debt, net	0	0.3	6.1	37.6
Non-cash stock-based compensation expense			18.1	15.8
Equity method loss, net of tax	8.8	0	19.5	0
Deferred income taxes			(12.6)	(246.1)
Other, net			2.9	5.5
Other changes in operating assets and liabilities, net of business acquisitions:
Increase in receivables, net			(34.8)	(30.8)
(Increase) decrease in inventories			(71.6)	10.6
Decrease (increase) in prepaid expenses and other current assets			10.3	(9.5)
Decrease (increase) in other assets			4.4	(11.7)
Decrease in accounts payable and other current liabilities			(91.2)	(39)
Increase in non-current liabilities			5	3.1
Net Cash Provided by Operating Activities			204.8	263.6
Cash Flows from Investing Activities:
Business acquisitions, net of cash acquired			0	(1,454)
Additions to property			(135.5)	(86.1)
Proceeds from sale of property and assets held for sale			2	0.2
Proceeds from sale of business			266.8	0
Cross-currency swap cash settlements			29.6	0
Other, net			0	(1.2)
Net Cash Provided by (Used in) Investing Activities			162.9	(1,541.1)
Cash Flows from Financing Activities:
Proceeds from issuance of long-term debt			0	1,000
Repayments of long-term debt			(919.1)	(751.7)
Payments to appraisal rights holders			(253.6)	0
Purchases of treasury stock			(65.8)	(138.8)
Payments of preferred stock dividends			(4)	(6.8)
Payments of debt issuance and modification costs			(8.7)	(10.5)
Refund of debt issuance costs			7.8	0
Payment of debt extinguishment costs			0	(33.5)
Proceeds from exercises of stock awards	41.5		41.5	4
Other, net			(7.5)	(5.8)
Net Cash (Used in) Provided by Financing Activities			(1,209.4)	56.9
Effect of Exchange Rate Changes on Cash, Cash Equivalents and Restricted Cash			(0.9)	2
Net Decrease in Cash, Cash Equivalents and Restricted Cash			(842.6)	(1,218.6)
Cash, Cash Equivalents and Restricted Cash, Beginning of Year			994.5	1,530.1	$ 1,530.1
Cash, Cash Equivalents and Restricted Cash, End of Period	$ 151.9	$ 311.5	$ 151.9	$ 311.5	$ 994.5

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 (Accumulated Deficit)	Retirement Benefit Adjustments, net of tax	Hedging Adjustments, net of tax	Foreign Currency Translation Adjustments	Treasury Stock	Noncontrolling Interest
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Sep. 30, 2017		$ 0	$ 0.7	$ 3,566.5	$ (376)	$ 35.1	$ (11.1)	$ (64)	$ (371.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock conversion			0.1
Preferred stock dividends declared				(6.8)	0
Activity under stock and deferred compensation plans				(1.5)
Stock-based compensation expense				15.8
Preferred Stock Conversion				0
Net earnings	$ 386.4				386.4
Adoption of Accounting Standards Updates					1.4
Net change in retirement benefits, net of tax						(0.2)
Net change in hedges, net of tax							(0.9)
Foreign currency translation adjustments								83.9		$ 0
Purchases of treasury stock									(138.8)
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Mar. 31, 2018	3,119.4	0	0.8	3,574	11.8	34.9	(12)	19.9	(510)
Total Shareholders' Equity, Beginning of period at Sep. 30, 2017										9.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to noncontrolling interest	0.6									0.6
Total Shareholders' Equity, End of period at Mar. 31, 2018	3,129.7									10.3
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Dec. 31, 2017		0	0.7	3,565.6	(81.1)	34.5	(12)	(50.1)	(427.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock conversion			0.1
Preferred stock dividends declared				(3.4)	0
Activity under stock and deferred compensation plans				2.8
Stock-based compensation expense				9
Preferred Stock Conversion				0
Net earnings	91.5				91.5
Adoption of Accounting Standards Updates					1.4
Net change in retirement benefits, net of tax						0.4
Net change in hedges, net of tax							0
Foreign currency translation adjustments								70		0
Purchases of treasury stock									(82.8)
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Mar. 31, 2018	3,119.4	0	0.8	3,574	11.8	34.9	(12)	19.9	(510)
Total Shareholders' Equity, Beginning of period at Dec. 31, 2017										10
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to noncontrolling interest	0.3									0.3
Total Shareholders' Equity, End of period at Mar. 31, 2018	3,129.7									10.3
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Sep. 30, 2018	3,050.4	0	0.8	3,590.9	88	37.9	37.4	(114.7)	(589.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock conversion			0
Preferred stock dividends declared				0	(4)
Activity under stock and deferred compensation plans				34.2
Stock-based compensation expense				18.1
Preferred Stock Conversion				(0.1)
Net earnings	169.6				169.6
Adoption of Accounting Standards Updates					(0.9)
Net change in retirement benefits, net of tax						(1.8)
Net change in hedges, net of tax							(5.4)
Foreign currency translation adjustments								39.6		0.3
Purchases of treasury stock									(65.8)
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Mar. 31, 2019	3,233.9	0	0.8	3,643.1	252.7	36.1	32	(75.1)	(655.7)
Total Shareholders' Equity, Beginning of period at Sep. 30, 2018	3,060.5									10.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to noncontrolling interest	0.6									0.6
Total Shareholders' Equity, End of period at Mar. 31, 2019	3,244.9									11
Shareholders' Equity Excluding Noncontrolling Interest, Beginning of period at Dec. 31, 2018		0	0.8	3,592.4	210.7	37	33.1	(112.8)	(615.2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred stock conversion			0
Preferred stock dividends declared				0	(2)
Activity under stock and deferred compensation plans				41.4
Stock-based compensation expense				9.4
Preferred Stock Conversion				(0.1)
Net earnings	44				44
Adoption of Accounting Standards Updates					0
Net change in retirement benefits, net of tax						(0.9)
Net change in hedges, net of tax							(1.1)
Foreign currency translation adjustments								37.7		0.3
Purchases of treasury stock									(40.5)
Shareholders' Equity Excluding Noncontrolling Interest, End of period at Mar. 31, 2019	3,233.9	$ 0	$ 0.8	$ 3,643.1	$ 252.7	$ 36.1	$ 32	$ (75.1)	$ (655.7)
Total Shareholders' Equity, Beginning of period at Dec. 31, 2018										10.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings attributable to noncontrolling interest	0.3									0.3
Total Shareholders' Equity, End of period at Mar. 31, 2019	$ 3,244.9									$ 11

Basis of Presentation

Basis of Presentation	6 Months Ended
	Mar. 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”) as of and for the fiscal year ended September 30, 2018. 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, 2018, filed with the SEC on November 16, 2018. 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 position, 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. Certain prior year amounts have been reclassified to conform with the fiscal 2019 presentation. These reclassifications had no impact on net earnings or shareholders’ equity as previously reported. On October 1, 2018, Post and affiliates of Thomas H. Lee Partners, L.P. (collectively, “THL”) separately capitalized 8th Avenue Food & Provisions, Inc. (“8th Avenue,” and such transactions, the “8th Avenue Transactions”), and 8th Avenue became the holding company for Post’s historical private brands business. Post received gross proceeds of $875.0 , as well as $16.8 related to final working capital adjustments, from the 8th Avenue Transactions, and the Company retained shares of common stock equal to 60.5% of the common equity in 8th Avenue. Effective October 1, 2018, 8th Avenue was no longer consolidated in the Company's financial statements and the 60.5% common equity retained interest in 8th Avenue is accounted for using the equity method. 8th Avenue is reported historically herein as Post’s Private Brands segment. For additional information, see Notes 4, 6, 9 and 17.

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Standards (Notes)	6 Months Ended
	Mar. 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 an impact on the Company’s results of operations, comprehensive income, financial condition, cash flows or shareholders’ equity based on current information. Recently Issued In February 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842).” This ASU requires a company to recognize right-of-use 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. This ASU is effective for annual periods beginning after December 15, 2018 and interim periods therein (i.e., Post’s financial statements for the year ending September 30, 2020), with early adoption permitted. The Company will adopt this ASU on October 1, 2019 and expects to use the modified retrospective method of adoption. The Company has selected a software vendor and is in the process of assessing its lease agreements to identify those that fall within the scope of this guidance. This ASU will result in a material increase in both assets and liabilities; however, the Company is unable to quantify the impact at this time. In addition, the Company expects to provide expanded disclosures to present additional information related to its leasing arrangements. Recently Adopted In August 2018, the FASB issued ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract.” This ASU largely aligns the guidance for recognizing implementation costs incurred in a cloud computing arrangement that is a service contract with that for recognizing implementation costs incurred to develop or obtain internal-use software, including hosting arrangements that include an internal-use software license. The Company adopted this ASU on October 1, 2018 on a prospective basis, as permitted by the ASU. The adoption of this ASU did not have a material impact on the Company’s financial statements. In June 2018, the FASB issued ASU 2018-07, “Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting.” This ASU largely aligns the accounting for share-based payment awards issued to employees and nonemployees, whereby the existing employee guidance will apply to nonemployee share-based transactions (as long as the transaction is not effectively a form of financing), with the exception of specific guidance related to the attribution of compensation cost. The cost of nonemployee awards will continue to be recorded as if the grantor had paid cash for the goods or services, and the contractual term will be able to be used in lieu of an expected term in the option-pricing model for nonemployee awards. The Company adopted this ASU on October 1, 2018 on a prospective basis, as permitted by the ASU. In accordance with this ASU, historical share-based payment awards that were granted to employees of 8th Avenue are accounted for as nonemployee compensation. The adoption of this ASU did not have an impact on the Company’s financial statements. In March 2017, the FASB issued ASU 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost.” This ASU requires an entity to report the service cost component of periodic net benefit cost as an operating expense in the same line item or items as other compensation costs arising from services rendered by employees during the period. Other components of net benefit cost are to be presented outside of income from operations in the income statement separately from the service cost component. This ASU also allows only the service cost component to be eligible for capitalization when applicable. The Company adopted this ASU on October 1, 2018 and used the retrospective method of adoption, as required by the ASU. The adoption of this ASU resulted in an increase in “Cost of goods sold” and “Selling, general and administrative expenses” of $3.3 and $0.3 , respectively, and a corresponding increase in “Other income, net” of $3.6 , for the three months ended March 31, 2018, and an increase in “Cost of goods sold” and “Selling, general and administrative expenses” of $6.5 and $0.6 , respectively, and a corresponding increase in “Other income, net” of $7.1 , for the six months ended March 31, 2018, to reflect the exclusion of all components of benefit cost, with the exception of service cost, from operating profit. For additional disclosures about pension and other postretirement benefits, refer to Note 18. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash.” This ASU requires that a statement of cash flows explain the change in the total of cash, cash equivalents and amounts generally described as restricted cash or restricted cash equivalents, and therefore, restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning of year cash balance to the end of year cash balance as shown on the statement of cash flows. The Company adopted this ASU on October 1, 2018 and used the retrospective method of adoption, as required by the ASU. The adoption of this ASU resulted in an increase in “Net Cash Used in Investing Activities” of $1.9 for the six months ended March 31, 2018. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” which superseded all previously existing revenue recognition guidance under GAAP. This ASU’s core principle is that a company will recognize revenue when it transfers promised goods or services to a customer in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. This ASU also calls for additional disclosures around the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The Company adopted this ASU on October 1, 2018 and used the modified retrospective transition method of adoption. The adoption of this ASU did not have a material impact on the Company’s financial statements as the impact of this ASU was limited to recognition timing and classification changes of immaterial amounts within the statement of operations and on the balance sheet. For additional information, refer to Note 3.

Revenue from Contracts with Cus

Revenue from Contracts with Customers (Notes)	6 Months Ended
	Mar. 31, 2019
Revenue from Contracts with Customers [Abstract]
Revenue from Contracts with Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS In conjunction with the adoption of ASU 2014-09 (see Note 2), the Company updated its policy for recognizing revenue. The Company utilized a comprehensive approach to assess the impact of this ASU by reviewing its customer contract portfolio and existing accounting policies and procedures in order to identify potential differences that would result from applying the new requirements of Accounting Standards Codification (“ASC”) Topic 606, “Revenue from Contracts with Customers.” A summary of the updated policy is included below. Revenue Recognition Policy The Company recognizes revenue when performance obligations have been satisfied by transferring control of the goods to customers. Control is generally transferred upon delivery of the goods to the customer. At the time of delivery, the customer is invoiced using previously agreed-upon credit terms. Shipping and/or handling costs that occur before the customer obtains control of the goods are deemed fulfillment activities and are accounted for as fulfillment costs. The Company’s contracts with customers generally contain one performance obligation. Many of the Company’s contracts with customers include some form of variable consideration. The most common forms of variable consideration are trade promotions, rebates and discounts. Variable consideration is treated as a reduction of revenue at the time product revenue is recognized. Depending on the nature of the variable consideration, the Company uses either the “expected value” or the “most likely amount” method to determine variable consideration. The Company does not believe that there will be significant changes to its estimates of variable consideration when any uncertainties are resolved with customers. The Company reviews and updates estimates of variable consideration each period. Uncertainties related to the estimate of variable consideration are resolved in a short time frame and do not require any additional constraint on variable consideration. The Company’s products are sold with no right of return, except in the case of goods which do not meet product specifications or are damaged. No services beyond this assurance-type warranty are provided to customers. Customer remedies include either a cash refund or an exchange of the product. As a result, the right of return and related refund liability is estimated and recorded as a reduction of revenue based on historical sales return experience. Impacts of Adoption The Company used the modified retrospective transition method of adoption and, accordingly, recorded an adjustment to retained earnings to reflect the application of its updated revenue recognition policy, which resulted in changes to the timing of when variable consideration payments are recognized. The cumulative adjustment resulted in a reduction of retained earnings and deferred income taxes of $0.9 and $0.3 , respectively, and a corresponding increase in other current liabilities of $1.2 at October 1, 2018. The Company elected the following practical expedients in accordance with ASC Topic 606: • Significant financing component — The Company elected not to adjust the promised amount of consideration for the effects of a significant financing component as the Company expects, at contract inception, the period between the transfer of a promised good or service to a customer and when the customer pays for that good or service will be one year or less. • Shipping and handling costs — The Company elected to account for shipping and handling activities that occur before the customer has obtained control of a good as fulfillment activities (i.e., an expense), rather than as promised services. • Measurement of transaction price — The Company elected to exclude from the measurement of transaction price all taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction and collected by the Company from a customer for sales taxes. The following tables summarize the impact of the Company’s adoption of ASC Topic 606 on a modified retrospective basis in the Company’s Condensed Consolidated Statements of Operations. As a result of the adoption, certain payments to customers totaling $7.6 and $12.3 in the three and six months ended March 31, 2019, respectively, previously classified in “Selling, general, and administrative expenses” were classified as “Net Sales” in the Condensed Consolidated Statements of Operations. These payments to customers relate to trade advertisements that support the Company’s sales to customers. In accordance with ASC Topic 606, these payments were determined not to be distinct within the customer contracts and, as such, require classification within net sales. Additionally, in the three and six months ended March 31, 2019, the Company has recognized revenue of $0.3 and $0.7 , respectively, that was deferred upon the adoption of ASC Topic 606 in accordance with the satisfaction of the related performance obligation. The recognition of unearned revenue is included in “Net Sales” in the Company’s Condensed Consolidated Statements of Operations. No material changes to the balance sheet were required by the adoption of ASC Topic 606. Three Months Ended March 31, 2019 As Reported Under Topic 606 As Reported Under Prior Guidance Impact of Adoption Net Sales $ 1,387.8 $ 1,395.1 $ (7.3 ) Cost of goods sold 936.5 936.5 — Gross Profit 451.3 458.6 (7.3 ) Selling, general and administrative expenses 225.8 233.4 (7.6 ) Amortization of intangible assets 40.4 40.4 — Gain on sale of business (2.6 ) (2.6 ) — Other operating expenses, net 1.4 1.4 — Operating Profit $ 186.3 $ 186.0 $ 0.3 Six Months Ended March 31, 2019 As Reported Under Topic 606 As Reported Under Prior Guidance Impact of Adoption Net Sales $ 2,799.1 $ 2,810.7 $ (11.6 ) Cost of goods sold 1,921.3 1,921.3 — Gross Profit 877.8 889.4 (11.6 ) Selling, general and administrative expenses 442.9 455.2 (12.3 ) Amortization of intangible assets 80.7 80.7 — Gain on sale of business (127.3 ) (127.3 ) — Other operating expenses, net 1.3 1.3 — Operating Profit $ 480.2 $ 479.5 $ 0.7 Disaggregated Revenues The following table presents net sales by product. The amounts for the three and six months ended March 31, 2019 are presented under ASC Topic 606 “Revenue from Contracts with Customers,” and the amounts for the three and six months ended March 31, 2018 are presented under ASC Topic 605 “Revenue Recognition.” Three Months Ended Six Months Ended 2019 2018 2019 2018 Cereal and granola $ 563.2 $ 595.1 $ 1,119.4 $ 1,150.8 Egg and egg products 381.1 380.2 775.8 761.3 Side dishes 123.4 111.9 269.1 168.1 Cheese and dairy 53.7 59.6 124.0 131.3 Sausage 36.7 28.7 80.3 28.7 Protein-based products and supplements 216.5 205.2 402.3 391.2 Nut butters and dried fruit and nut — 118.3 — 232.6 Pasta — 68.8 — 136.4 Other 13.7 19.6 29.1 21.2 Eliminations (0.5 ) (1.3 ) (0.9 ) (2.4 ) Net Sales $ 1,387.8 $ 1,586.1 $ 2,799.1 $ 3,019.2

Business Combinations

Business Combinations	6 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Business Combinations	BUSINESS COMBINATIONS AND DIVESTITURES The Company accounts for business combinations using the acquisition method of accounting, whereby the results of operations are included in the financial statements from the date of acquisition. The purchase price is allocated to acquired assets and assumed liabilities based on their estimated fair values at the date of acquisition, and any excess is allocated to goodwill. Goodwill represents the value the Company expects to achieve through the implementation of operational synergies and the expansion of the business into new or growing segments of the industry. The Company includes results of operations for business divestitures from the date of acquisition through the date of sale. On October 1, 2018, the Company completed the 8th Avenue Transactions in which Post and THL separately capitalized 8th Avenue and 8th Avenue became the holding company for Post’s private brands business. Post received gross proceeds of $875.0 from the 8th Avenue Transactions, as well as $16.8 related to final working capital adjustments, retaining shares of common stock equal to 60.5% of the common equity in 8th Avenue. Post’s gross proceeds consisted of (i) $250.0 from THL and (ii) $625.0 from a committed senior increasing rate bridge loan (the “Bridge Loan”), which was funded in fiscal 2018 prior to the closing of the 8th Avenue Transactions (see Note 17). THL received 2.5 shares of 8th Avenue preferred stock with an 11% cumulative, quarterly compounding dividend and a $100.00 per share liquidation value and shares of common stock equal to 39.5% of the common equity in 8th Avenue. During the three and six months ended March 31, 2019, the Company recorded gains of $2.6 and $127.3 , respectively, related to the 8th Avenue Transactions, which were reported as “Gain on sale of business” in the Condensed Consolidated Statements of Operations. Such gains recorded in the six months ended March 31, 2019 included foreign exchange losses previously recorded in accumulated other comprehensive income (“OCI”) of $42.1 . Effective October 1, 2018, 8th Avenue was no longer consolidated in the Company's financial statements and the 60.5% common equity retained interest in 8th Avenue is accounted for using the equity method. For additional information regarding the Company’s equity method investment in 8th Avenue, refer to Note 9. In order to calculate the recorded gains related to the 8th Avenue Transactions of $127.3 , management was required to estimate the fair value of the Company’s equity method investment in 8th Avenue. In making this estimate, management used an approach combining the estimated implied value from the 8th Avenue Transactions, an income approach and a market approach, in which the greatest value was placed on the implied value from the 8th Avenue Transactions. In order to calculate the fair value implied by the 8th Avenue Transactions, management was required to estimate the value of the 8th Avenue equity. In making this estimate, management used a lattice model, which required significant assumptions, including estimates for the term, credit spread, yield volatility and risk free rates associated with 8th Avenue’s preferred stock. The income approach was based on discounted future cash flows and required significant assumptions, including estimates regarding future revenue, profitability and capital requirements. The market approach was based on a market multiple (revenue and EBITDA, which stands for earnings before interest, income taxes, depreciation and amortization) and required an estimate of appropriate multiples based on the market data. On January 12, 2018, the Company completed its acquisition of Bob Evans Farms, Inc. (“Bob Evans”), resulting in the Company owning all of the outstanding shares of Bob Evans common stock. At closing, the Company paid each holder of shares of Bob Evans common stock, other than holders who demanded appraisal of their shares under Delaware law and had not withdrawn their demands as of the closing date, $77.00 per share, resulting in a payment at closing of $1,381.2 (which, in addition to the amounts paid to Bob Evans stockholders, includes amounts paid to retire certain debt and other obligations of Bob Evans). Any shares of Bob Evans common stock subject to appraisal as of the closing date were canceled and no longer outstanding after closing. The closing payment did not include any amounts due to former holders of approximately 4.35 shares of Bob Evans common stock who demanded appraisal under Delaware law and had not withdrawn their demands as of the closing date. At September 30, 2018, former holders of 3.3 shares of Bob Evans common stock had not withdrawn their appraisal demands and had not been paid for their shares of Bob Evans common stock. Related to these shares, the Company accrued $267.0 at September 30, 2018, which was the number of shares of Bob Evans common stock for which former Bob Evans stockholders demanded appraisal and had not withdrawn their demands multiplied by the $77.00 per share merger consideration, plus accrued interest at the Federal Reserve Discount Rate plus a spread of 5.00% . In December 2018, the Company made payments of $257.6 to the former holders of Bob Evans common stock who had demanded appraisal and had not been paid for their shares. The payments constitute a settlement with one former stockholder as well as prepayments of the $77.00 per share merger consideration to the remaining former stockholders. At March 31, 2019, the Company had a remaining accrual of $14.0 , which represents the accrued interest at the Federal Reserve Discount Rate plus a spread of 5.00% related to 2.5 shares for which the $77.00 per share merger consideration was paid. Additional payments related to these 2.5 shares could be made in the future. The liabilities were reported in “Other current liabilities” and “Other liabilities” on the Condensed Consolidated Balance Sheets at March 31, 2019 and September 30, 2018, respectively. For additional information regarding the proceedings brought by former holders of Bob Evans common stock who demanded appraisal under Delaware law, refer to Note 16. Bob Evans is a producer of refrigerated potato and pasta side dishes, pork sausage and a variety of refrigerated and frozen convenience food items. Bob Evans is reported in two reportable segments. The results of Bob Evans’s foodservice operations are reported in the Foodservice segment and the results of Bob Evans’s retail operations are reported in the Refrigerated Retail segment (see Note 20). Based upon the purchase price allocation, the Company recorded $376.0 of customer relationships to be amortized over a weighted-average period of 18 years, $6.0 of definite-lived trademarks to be amortized over a weighted-average period of 10 years and $400.0 of indefinite-lived trademarks. The goodwill generated by the Company’s acquisition of Bob Evans is not deductible for U.S. federal income tax purposes; however, $13.8 of goodwill generated by business combinations completed by Bob Evans in periods prior to its acquisition was transferred to Post and is tax deductible. The following table provides the final allocation of the purchase price related to the fiscal 2018 acquisition of Bob Evans based upon the fair value of assets and liabilities assumed, including the provisional amounts recognized related to the acquisition as of September 30, 2018, as well as measurement period adjustments made during fiscal 2019. The allocation of purchase price was finalized as of December 31, 2018, and no additional adjustments have been or will be made. Acquisition Date Amounts Recognized as of September 30, 2018 (a) Adjustments During Fiscal 2019 Acquisition Date Amounts Recognized (as Adjusted) Cash and cash equivalents $ 15.6 $ — $ 15.6 Receivables 58.5 — 58.5 Inventories 27.1 — 27.1 Prepaid expenses and other current assets 34.3 — 34.3 Property 184.3 — 184.3 Goodwill 898.3 (0.7 ) 897.6 Other intangible assets 782.0 — 782.0 Other assets 0.4 — 0.4 Accounts payable (18.2 ) — (18.2 ) Other current liabilities (58.5 ) — (58.5 ) Deferred tax liability - long-term (194.9 ) 0.7 (194.2 ) Other liabilities (5.3 ) — (5.3 ) Total acquisition cost $ 1,723.6 $ — $ 1,723.6 (a) As previously reported in Post’s Annual Report on Form 10-K for fiscal 2018 filed with the SEC on November 16, 2018. Transaction-related Expenses The Company incurs transaction-related expenses in connection with both completed and contemplated acquisitions, divestitures and mergers. These expenses generally include third party costs for due diligence, advisory services and transaction success fees. Transaction-related expenses of $3.8 and $14.5 were incurred during the three and six months ended March 31, 2019, respectively, and $20.9 and $24.0 were incurred during the three and six months ended March 31, 2018, respectively. These expenses were recorded as “Selling, general and administrative expenses” in the Condensed Consolidated Statements of Operations. Transaction-related expenses included costs attributable to the 8th Avenue Transactions of $0.8 and $9.9 for the three and six months ended March 31, 2019, respectively, and $1.3 and $2.0 for the three and six months ended March 31, 2018, respectively. Pro Forma Information The following unaudited pro forma information presents a summary of the results of operations of the Company combined with the results of Bob Evans for the periods presented as if the fiscal 2018 acquisition had occurred on October 1, 2016, along with certain pro forma adjustments. Additionally, the impact of the 8th Avenue Transactions is presented in this unaudited pro forma information as if the transactions had occurred on October 1, 2017. These pro forma adjustments give effect to the amortization of certain definite-lived intangible assets, adjusted depreciation based upon the fair value of assets acquired, interest expense related to the financing of the business combinations, inventory revaluation adjustments on acquired businesses, transaction and extinguished debt costs and related income taxes. Additionally, gains of $2.6 and $127.3 in the three and six months ended March 31, 2019, respectively, related to the 8th Avenue Transactions have been adjusted out of the current year results. The following unaudited pro forma information has been prepared for comparative purposes only and is not necessarily indicative of the results of operations as they would have been had the transactions occurred on the assumed dates, nor is it necessarily an indication of future operating results. Three Months Ended Six Months Ended 2019 2018 2019 2018 Pro forma net sales $ 1,387.8 $ 1,392.0 $ 2,799.1 $ 2,771.4 Pro forma net earnings available to common shareholders $ 42.0 $ 96.8 $ 84.3 $ 373.9 Pro forma basic earnings per common share $ 0.59 $ 1.45 $ 1.23 $ 5.63 Pro forma diluted earnings per common share $ 0.57 $ 1.31 $ 1.16 $ 4.96

Restructuring (Notes)

Restructuring (Notes)	6 Months Ended
	Mar. 31, 2019
Restructuring [Abstract]
Restructuring	RESTRUCTURING In February 2018, the Company announced its plan to close its cereal manufacturing facility in Clinton, Massachusetts, which manufactures certain Weetabix products distributed in North America. The transfer of production capabilities to other Post Consumer Brands facilities and the closure of the facility is expected to be completed by September 2019. Restructuring charges and the related liabilities are shown in the following table. Employee-Related Costs Accelerated Depreciation Total Balance at September 30, 2017 $ — $ — $ — Charge to expense 1.5 0.3 1.8 Cash payments — — — Non-cash charges — (0.3 ) (0.3 ) Balance at March 31, 2018 $ 1.5 $ — $ 1.5 Balance, September 30, 2018 $ 2.7 $ — $ 2.7 Charge to expense 1.5 4.3 5.8 Cash payments (0.1 ) — (0.1 ) Non-cash charges — (4.3 ) (4.3 ) Balance, March 31, 2019 $ 4.1 $ — $ 4.1 Total expected restructuring charge $ 5.2 $ 10.5 $ 15.7 Cumulative restructuring charges incurred to date 4.2 6.8 11.0 Remaining expected restructuring charge $ 1.0 $ 3.7 $ 4.7 The Company incurred total restructuring charges of $3.3 and $5.8 in the three and six months ended March 31, 2019, respectively, and $1.8 in the three and six months ended March 31, 2018. 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 Statements of Operations. These expenses are not included in the measure of segment performance (see Note 20).

Assets and Liabilities Held for

Assets and Liabilities Held for Sale (Notes)	6 Months Ended
	Mar. 31, 2019
Assets and Liabilities Held for Sale [Abstract]
Asset and Liabilities Held for Sale	ASSETS AND LIABILITIES HELD FOR SALE The major classes of assets and liabilities comprising “Current assets held for sale,” “Other assets held for sale,” “Current liabilities held for sale” and “Other liabilities held for sale” on the Condensed Consolidated Balance Sheet as of September 30, 2018 are shown in the following table. There were no assets or liabilities held for sale at March 31, 2019. September 30, 2018 Current assets held for sale Restricted cash $ 0.7 Receivables, net 79.8 Inventories 111.6 Prepaid expenses and other current assets 1.5 Property, net (a) 1.4 $ 195.0 Other assets held for sale Property, net (a) $ 165.1 Goodwill 417.1 Other intangible assets, net 270.4 Other assets 4.0 $ 856.6 Current liabilities held for sale Accounts payable $ 37.4 Other current liabilities 28.2 $ 65.6 Other liabilities held for sale Long-term debt $ 614.6 Deferred income taxes 79.9 Other liabilities 0.6 $ 695.1 (a) In accordance with ASC Topic 360, “Property, Plant, and Equipment,” the building classified as held for sale related to the closure of the Company’s Post Consumer Brands cereal warehouse in Clinton, Massachusetts and the 8th Avenue properties held for sale are classified as current and noncurrent, respectively, on the Condensed Consolidated Balance Sheet. In connection with the 8th Avenue Transactions, the Company had assets and liabilities held for sale at September 30, 2018. On October 1, 2018, the Company completed the 8th Avenue Transactions, and effective on that date, 8th Avenue was no longer consolidated in the Company's financial statements (see Notes 4 and 9). Additionally, at September 30, 2018, the Company had a building classified as held for sale related to the closure of the Company’s Post Consumer Brands cereal warehouse in Clinton, Massachusetts. The building was sold in November 2018. In connection with the 8th Avenue Transactions, the Company recorded gains of $2.6 and $127.3 in the three and six months ended March 31, 2019, respectively, which were reported as “Gain on sale of business” in the Condensed Consolidated Statements of Operations, as well as a loss of $2.6 in the six months ended March 31, 2019, which was included in “Loss on extinguishment of debt, net” in the Condensed Consolidated Statement of Operations. During the six months ended March 31, 2019, a gain of $0.6 was recorded related to the sale of the Company’s Post Consumer Brands cereal warehouse in Clinton, Massachusetts and was included in “Other operating expense, net” in the Condensed Consolidated Statement of Operations. There were no held for sale gains or losses recorded in the three or six months ended March 31, 2018.

Goodwill (Notes)

Goodwill (Notes)	6 Months Ended
	Mar. 31, 2019
Goodwill [Abstract]
Goodwill	GOODWILL The changes in the carrying amount of goodwill by segment are noted in the following table. Goodwill for the historical Private Brands segment was classified as held for sale at September 30, 2018 (see Note 6). On October 1, 2018, the Company completed the reorganization of its refrigerated foods businesses, which resulted in the assignment of the foodservice and retail components previously included in the historical Refrigerated Food segment to its Foodservice and Refrigerated Retail segments. In connection with the reorganization, the Company assigned goodwill previously reported within the historical Refrigerated Food segment to reporting units within the Foodservice and Refrigerated Retail segments. The historical Refrigerated Food segment contained two reporting units: refrigerated food and cheese and dairy. The Company’s cheese and dairy reporting unit was not impacted by the reorganization and is now reported within the Refrigerated Retail segment. The remaining goodwill balance within the refrigerated food reporting unit was allocated between the Foodservice and Refrigerated Retail segments based on the relative fair value of the businesses. The fair values of the foodservice and refrigerated retail businesses were determined using methodologies consistent with the Company’s annual goodwill impairment assessment. Post Consumer Brands Weetabix Foodservice Refrigerated Retail Active Nutrition Total Balance, September 30, 2018 Goodwill (gross) $ 2,012.0 $ 900.9 $ 1,336.1 $ 793.8 $ 180.7 $ 5,223.5 Accumulated impairment losses (609.1 ) — — — (114.8 ) (723.9 ) Goodwill (net) $ 1,402.9 $ 900.9 $ 1,336.1 $ 793.8 $ 65.9 $ 4,499.6 Acquisition related adjustment — — (0.5 ) (0.2 ) — (0.7 ) Currency translation adjustment (0.2 ) 0.2 — — — — Balance, March 31, 2019 Goodwill (gross) $ 2,011.8 $ 901.1 $ 1,335.6 $ 793.6 $ 180.7 $ 5,222.8 Accumulated impairment losses (609.1 ) — — — (114.8 ) (723.9 ) Goodwill (net) $ 1,402.7 $ 901.1 $ 1,335.6 $ 793.6 $ 65.9 $ 4,498.9

Intangible Assets, net

Intangible Assets, net	6 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets, net	INTANGIBLE ASSETS, NET Total intangible assets are as follows: March 31, 2019 September 30, 2018 Carrying Accumulated Amortization Net Carrying Accumulated Amortization Net Subject to amortization: Customer relationships $ 2,307.0 $ (503.9 ) $ 1,803.1 $ 2,307.0 $ (444.4 ) $ 1,862.6 Trademarks and brands 815.2 (209.4 ) 605.8 768.5 (188.2 ) 580.3 Other intangible assets 3.1 (3.1 ) — 3.1 (3.1 ) — 3,125.3 (716.4 ) 2,408.9 3,078.6 (635.7 ) 2,442.9 Not subject to amortization: Trademarks and brands 1,049.7 — 1,049.7 1,096.4 — 1,096.4 $ 4,175.0 $ (716.4 ) $ 3,458.6 $ 4,175.0 $ (635.7 ) $ 3,539.3

Equity Interests and Related Pa

Equity Interests and Related Party Transactions (Notes)	6 Months Ended
	Mar. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Interests and Related Party Transactions	EQUITY INTERESTS AND RELATED PARTY TRANSACTIONS 8th Avenue In connection with the 8th Avenue Transactions, the Company has a 60.5% common equity retained interest in 8th Avenue that is accounted for using the equity method. In determining the accounting treatment of the retained 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 THL 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 Six Months Ended 8th Avenue’s net loss available to 8th Avenue’s common shareholders $ (11.3 ) $ (22.8 ) 60.5 % 60.5 % Equity method loss available to Post $ (6.8 ) $ (13.8 ) Less: Amortization of basis difference, net of tax (a) 1.8 5.4 Equity method loss, net of tax $ (8.6 ) $ (19.2 ) (a) The Company adjusted the historical basis of 8th Avenue’s assets and liabilities to fair value and recognized a total basis difference of $70.3 , which represents Post’s retained portion of the gain on sale. The basis difference related to inventory of $2.0 , net of tax, was included in equity method loss in the six months ended March 31, 2019. 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 March 31, 2019, the remaining basis difference to be amortized was $64.9 . Summarized financial information of 8th Avenue is presented in the following table. Three Months Ended Six Months Ended Net sales $ 213.7 $ 427.8 Gross profit $ 35.5 $ 69.2 Net loss $ (4.2 ) $ (8.7 ) Less: Preferred stock dividend 7.1 14.1 Net Loss Available to 8th Avenue Common Shareholders $ (11.3 ) $ (22.8 ) Prior to the 8th Avenue Transactions, Post’s historical private brands business used certain functions and services performed by the Company. These functions and services included information systems, procurement, accounting shared services, legal, tax, human resources, payroll and cash management. After the completion of the 8th Avenue Transactions, the Company continued to provide many of these services to 8th Avenue under a master services agreement (“MSA”). In addition, Post and THL both provide certain advisory services to 8th Avenue for a fee. During the three and six months ended March 31, 2019, the Company recorded MSA and advisory income of $1.1 and $2.1 , respectively, which were recorded in “Selling, general and administrative expenses” in the Condensed Consolidated Statements of Operations. No such income was recorded in the three and six months ended March 31, 2018. During the three and six months ended March 31, 2019, the Company had net sales to 8th Avenue of $0.9 and $2.0 , respectively, and purchases from and royalties paid to 8th Avenue of $2.8 and $5.1 , respectively. The investment in 8th Avenue was $158.3 at March 31, 2019 and was included in “Equity method investments” on the Condensed Consolidated Balance Sheet. The Company had receivables and payables with 8th Avenue of $3.0 and $0.7 , respectively, at March 31, 2019, related to the separation of 8th Avenue from the Company, the closing of the 8th Avenue Transactions, including the MSA fees owed by 8th Avenue to the Company and related party sales and purchases. The receivables and payables were included in “Receivables, net” and “Accounts payable,” respectively, on the Condensed Consolidated Balance Sheet. Alpen and Weetabix East Africa The Company holds an equity interest in two legal entities, Alpen Food Company South Africa (Proprietary) Limited (“Alpen”) and Weetabix East Africa Limited (“Weetabix East Africa”), whose assets are reported in the Weetabix segment (see Note 20). Alpen is a South African-based company that produces ready-to-eat (“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 $4.8 and $5.2 at March 31, 2019 and September 30, 2018, respectively, and was included in “Equity method investments” on the Condensed Consolidated Balance Sheets. The Company had a note receivable balance with Alpen of $1.0 and $1.0 at March 31, 2019 and September 30, 2018, 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.

Income Taxes (Notes)

Income Taxes (Notes)	6 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The effective income tax rate was (28.0)% and 14.5% during the three and six months ended March 31, 2019, respectively, and 20.7% and (149.5)% for the three and six months ended March 31, 2018, respectively. In accordance with ASC Topic 740, “Income Taxes,” the Company records income tax (benefit) expense for interim periods using the estimated annual effective income tax rate for the full fiscal year adjusted for the impact of discrete items occurring during the interim periods. In the fiscal 2019 periods, the effective income tax rates differed significantly from the statutory rate as a result of $21.2 of discrete tax benefit items occurring in the three months ended March 31, 2019, of which $17.6 related to excess tax benefits for share-based payments. In the six months ended March 31, 2018, the Company recorded an income tax benefit of $231.9 . This benefit was driven by the Tax Cuts and Jobs Act (the “Tax Act”), which was enacted on December 22, 2017. The Tax Act resulted in significant impacts to the Company’s accounting for income taxes with the most significant of these impacts resulting from the reduction of the U.S. federal corporate income tax rate, a one-time transition tax on unrepatriated foreign earnings and full expensing of certain qualified depreciable assets placed in service after September 27, 2017 and before January 1, 2023. The Tax Act enacted a new U.S. federal corporate income tax rate of 21% that went into effect for the Company’s 2019 tax year and was prorated with the pre-December 22, 2017 U.S. federal corporate income tax rate of 35% for the Company’s 2018 tax year. This proration resulted in a blended U.S. federal corporate income tax rate of 24.5% for fiscal 2018. During the six months ended March 31, 2018, the Company (i) remeasured its existing deferred tax assets and liabilities considering both the 2018 fiscal year blended rate and the 21% rate for periods beyond fiscal 2018 and recorded a provisional tax benefit of $272.4 (adjusted to $281.2 during the year ended September 30, 2018) and (ii) calculated the one-time transition tax and recorded provisional tax expense of $7.1 (adjusted to $10.3 during the year ended September 30, 2018). Full expensing of certain depreciable assets resulted in temporary differences, which were analyzed throughout fiscal 2018 as assets were placed in service. Included in (i) above is a tax benefit adjustment of $1.7 , recorded in the three months ended March 31, 2018, to further refine the remeasurement made in the first quarter of fiscal 2018 of the Company’s existing deferred tax assets and liabilities considering both the 2018 fiscal year blended rate and the 21% rate for periods beyond fiscal 2018. The impacts of the Tax Act have been finalized, and no additional adjustments were or will be recorded in fiscal 2019.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Earnings (Loss) 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 is calculated using the “if-converted” method. In the second quarter of fiscal 2019, the Company completed the redemption of its 2.5% Series C Cumulative Perpetual Convertible Preferred Stock (“Series C Preferred”). Substantially all of the 3.2 shares of Series C Preferred outstanding as of January 10, 2019, the date the Series C Preferred redemption was announced, were converted into 5.9 shares of the Company’s common stock pursuant to the conversion rights applicable to the Series C Preferred, and the remaining shares of Series C Preferred were redeemed. In the second quarter of fiscal 2018, the Company completed the redemption of its 3.75% Series B Cumulative Perpetual Convertible Preferred Stock (“Series B Preferred”). Substantially all of the 1.5 shares of Series B Preferred outstanding as of January 10, 2018, the date the Series B Preferred redemption was announced, were converted into 3.1 shares of the Company’s common stock pursuant to the conversion rights applicable to the Series B Preferred, and the remaining shares of Series B Preferred were redeemed. For additional information regarding the Series B Preferred and Series C Preferred redemptions, refer to Note 19. The following table sets forth the computation of basic and diluted earnings per share. Three Months Ended Six Months Ended 2019 2018 2019 2018 Net earnings for basic earnings per share $ 43.0 $ 88.9 $ 166.6 $ 380.4 Dilutive preferred stock dividends 1.0 2.6 3.0 6.0 Net earnings for diluted earnings per share $ 44.0 $ 91.5 $ 169.6 $ 386.4 Weighted-average shares for basic earnings per share 70.6 66.8 68.6 66.4 Effect of dilutive securities: Stock options 1.7 1.7 1.9 1.7 Stock appreciation rights 0.1 0.1 0.1 0.1 Restricted stock awards 0.4 0.2 0.4 0.3 Preferred shares conversion to common 2.5 7.2 4.2 8.1 Total dilutive securities 4.7 9.2 6.6 10.2 Weighted-average shares for diluted earnings per share 75.3 76.0 75.2 76.6 Basic earnings per common share $ 0.61 $ 1.33 $ 2.43 $ 5.73 Diluted earnings per common share $ 0.58 $ 1.20 $ 2.26 $ 5.04 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 Six Months Ended 2019 2018 2019 2018 Stock options 0.1 0.6 0.4 0.6

Inventories

Inventories	6 Months Ended
	Mar. 31, 2019
Inventory [Abstract]
Inventories	INVENTORIES March 31, September 30, Raw materials and supplies $ 97.6 $ 107.8 Work in process 17.0 17.8 Finished products 406.3 324.1 Flocks 34.2 34.5 $ 555.1 $ 484.2

Property, net

Property, net	6 Months Ended
	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Property, net	PROPERTY, NET March 31, September 30, Property, at cost $ 2,647.4 $ 2,543.0 Accumulated depreciation (928.7 ) (833.3 ) $ 1,718.7 $ 1,709.7

Derivative Financial Instrument

Derivative Financial Instruments and Hedging	6 Months Ended
	Mar. 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 acquisition of raw materials and supplies, interest rate risks relating to floating 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 March 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; • foreign currency forward contracts maturing within the next year that have the effect of hedging currency fluctuations between the Euro and the U.S. Dollar; • a pay-fixed, receive-variable interest rate swap maturing in May 2021 that requires monthly settlements and has 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 December 2019 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 with maturities 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 • a pay-fixed, receive-variable interest rate swap maturing in May 2024 that requires monthly settlements and is used as a cash flow hedge of forecasted interest payments on the Company’s variable rate term loan. 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 six months ended March 31, 2019. 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. As of January 1, 2018, the Company changed the designation of its foreign currency forward contracts from a cash flow hedge to a non-designated hedging instrument. In connection with the new designation, the Company reclassified gains previously recorded in accumulated OCI of $1.8 , of which $1.3 was reclassified to “Selling, general and administrative expenses” in the Condensed Consolidated Statements of Operations for the three and six months ended March 31, 2018. The following table shows the notional amounts of derivative instruments held. March 31, September 30, Not designated as hedging instruments under ASC Topic 815: Commodity contracts $ 33.0 $ 64.3 Energy contracts 49.3 20.8 Foreign exchange contracts - Forward contracts 4.0 9.3 Interest rate swap 73.9 74.6 Interest rate swaps - Rate-lock swaps 1,649.3 1,649.3 Designated as hedging instruments under ASC Topic 815: Foreign exchange contracts - Cross-currency swaps 448.7 662.9 Interest rate swap 200.0 1,000.0 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 March 31, September 30, March 31, September 30, Asset Derivatives: Commodity contracts Prepaid expenses and other current assets $ 1.1 $ 1.9 $ — $ — Energy contracts Prepaid expenses and other current assets 4.7 4.9 — — Commodity contracts Other assets 1.5 0.2 — — Energy contracts Other assets — 0.3 — — Foreign exchange contracts Prepaid expenses and other current assets — 1.2 — 1.1 Foreign exchange contracts Other assets — 17.6 — 17.6 Interest rate swaps Prepaid expenses and other current assets — 6.4 — 6.4 Interest rate swaps Other assets — 33.9 — 30.6 $ 7.3 $ 66.4 $ — $ 55.7 Liability Derivatives: Commodity contracts Other current liabilities $ 0.9 $ 2.2 $ — $ — Energy contracts Other current liabilities 0.9 0.4 — — Foreign exchange contracts Other current liabilities 0.9 1.5 0.9 1.4 Foreign exchange contracts Other liabilities 11.2 19.4 11.2 19.4 Interest rate swaps Other current liabilities 53.4 23.6 0.1 — Interest rate swaps Other liabilities 176.2 94.3 0.5 — $ 243.5 $ 141.4 $ 12.7 $ 20.8 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 March 31, 2019 and 2018. Derivatives Not Designated as Hedging Instruments Statement of Operations Location Loss (Gain) Recognized in Statement of Operations 2019 2018 Commodity contracts Cost of goods sold $ 3.2 $ (5.1 ) Energy contracts Cost of goods sold (8.3 ) (0.7 ) Interest rate swaps Expense (income) on swaps, net 63.0 (50.5 ) Derivatives Designated as Hedging Instruments Loss (Gain) Recognized in OCI Gain Reclassified from Accumulated OCI into Earnings Statement of Operations Location 2019 2018 2019 2018 Foreign exchange contracts $ — $ — $ — $ (1.3 ) Selling, general and administrative expenses Interest rate swaps 2.5 (20.6 ) (0.4 ) (0.5 ) Interest expense, net Cross-currency swaps 9.4 15.2 — — Expense (income) on swaps, net 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 six months ended March 31, 2019 and 2018. Derivatives Not Designated as Hedging Instruments Statement of Operations Location Loss (Gain) Recognized in Statement of Operations 2019 2018 Commodity contracts Cost of goods sold $ 3.0 $ (4.7 ) Energy contracts Cost of goods sold — (2.9 ) Foreign exchange contracts Selling, general and administrative expenses — 0.2 Interest rate swaps Expense (income) on swaps, net 114.7 (53.2 ) Derivatives Designated as Hedging Instruments Loss (Gain) Recognized in OCI Gain Reclassified from Accumulated OCI into Earnings Statement of Operations Location 2019 2018 2019 2018 Foreign exchange contracts $ — $ (0.2 ) $ — $ (1.3 ) Selling, general and administrative expenses Interest rate swaps 7.1 (29.6 ) (30.5 ) (0.2 ) Interest expense, net Cross-currency swaps (19.6 ) 25.9 — — Expense (income) on swaps, net Accumulated OCI included a $32.0 net gain on hedging instruments before taxes ( $32.0 after taxes) at March 31, 2019, compared to a $50.0 net gain before taxes ( $37.4 after taxes) at September 30, 2018. Approximately $0.1 of the net hedging losses reported in accumulated OCI at March 31, 2019 are 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 $34.4 and $4.8 at March 31, 2019 and September 30, 2018, respectively. In connection with the settlements of cross-currency swaps, the Company recognized gains in accumulated OCI of $1.3 and $29.6 during the three and six months ended March 31, 2019, respectively, and $0.7 and $1.5 during the three and six months ended March 31, 2018, respectively. At March 31, 2019 and September 30, 2018 , the Company had pledged collateral of $1.9 and $4.5 , respectively, related to its commodity and energy contracts. These amounts are classified as “Restricted cash” on the Condensed Consolidated Balance Sheets.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Mar. 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. March 31, 2019 September 30, 2018 Total Level 1 Level 2 Total Level 1 Level 2 Assets: Deferred compensation investments $ 10.6 $ 10.6 $ — $ 43.6 $ 43.6 $ — Derivative assets 7.3 — 7.3 66.4 — 66.4 $ 17.9 $ 10.6 $ 7.3 $ 110.0 $ 43.6 $ 66.4 Liabilities: Deferred compensation liabilities $ 30.4 $ — $ 30.4 $ 52.2 $ — $ 52.2 Derivative liabilities 243.5 — 243.5 141.4 — 141.4 $ 273.9 $ — $ 273.9 $ 193.6 $ — $ 193.6 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 or funds that employ a similar investment strategy, 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. In connection with the acquisition of Bob Evans (see Note 4), the Company had current deferred compensation investments of $24.3 and current deferred compensation liabilities of $24.1 at September 30, 2018. The Bob Evans deferred compensation plans have been terminated, the investments have been liquidated and amounts previously accrued by the Company were paid in January 2019. 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 14 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. Based on current market rates, the fair value of the Company’s debt (Level 2) was $6,320.0 and $7,790.9 as of March 31, 2019 and September 30, 2018, respectively. At September 30, 2018, the fair value of the Company’s debt included amounts classified as held for sale. Certain assets and liabilities, including long-lived assets, goodwill, indefinite-lived intangibles and assets held for sale, are measured at fair value on a non-recurring basis. As stated previously (see Note 6), the Company had assets and liabilities held for sale at September 30, 2018 related to (i) the 8th Avenue Transactions and (ii) the closure of the Company’s Post Consumer Brands cereal warehouse in Clinton, Massachusetts. On October 1, 2018, the Company completed the 8th Avenue Transactions, and effective as of that date, 8th Avenue was no longer consolidated in the Company's financial statements and the 60.5% common equity retained interest in 8th Avenue is accounted for using the equity method. The Post Consumer Brands cereal warehouse was sold in November 2018. The fair value of assets and liabilities held for sale were measured at fair value on a nonrecurring 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 and liabilities. The fair value measurement was categorized as Level 3, as the fair values utilize significant unobservable inputs. The following table summarizes the Level 3 activity. Balance, September 30, 2018 $ 290.9 Gains related to assets and liabilities held for sale 125.3 Proceeds from the sale of assets and liabilities held for sale (276.6 ) Investment in 8th Avenue, working capital and other adjustments (139.6 ) Balance, March 31, 2019 $ —

Commitments and Contingencies (

Commitments and Contingencies (Notes)	6 Months Ended
	Mar. 31, 2019
Legal Proceedings [Abstract]
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 case involved three plaintiff groups: (i) a nationwide class of direct purchasers of shell eggs (“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) MFI settled all claims asserted against it by opt-out plaintiffs related to shell egg purchases on confidential terms in January 2017; and (iii) in June 2018, MFI settled all claims asserted against it by indirect purchaser plaintiffs on confidential terms. MFI has at all times denied liability in this matter, and no settlement contains any admission of liability by MFI. Remaining portion of the case: MFI remains a defendant only with respect to claims that seek damages based on purchases of egg products by six 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 have filed a second motion for summary judgment seeking dismissal of the claims, and that motion is currently pending. 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 case could still result in a material adverse outcome. Related to these settlements, the Company expensed $2.0 in the three and six months ended March 31, 2018, which was included in “Selling, general, and administrative expenses” in the Condensed Consolidated Statements of Operations. No expense was recorded related to these matters in the three or six months ended March 31, 2019. At March 31, 2019 and September 30, 2018, the Company had $6.0 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 position, results of operations and cash flows could be materially affected. Under current law, any settlement paid, including the settlements with the direct purchaser plaintiffs, 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 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 seek 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 are 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 related to these matters in December 2018. However, the consolidated action remains active with respect to the determination of the fair value of the shares formerly held by the two remaining petitioners. Approximately 2.5 shares of Bob Evans common stock are before the court for appraisal in the consolidated action. As of completion of the acquisition, former Bob Evans stockholders can no longer submit new demands for appraisal. All other former stockholders have been paid for their shares. The Company intends to vigorously defend the consolidated action. At September 30, 2018, former holders of 3.3 shares of Bob Evans common stock had not withdrawn their appraisal demands and had not been paid for their shares of Bob Evans common stock. Related to these shares, the Company accrued $267.0 at September 30, 2018, which was the number of shares of Bob Evans common stock for which former Bob Evans stockholders demanded appraisal and had not withdrawn their demands multiplied by the $77.00 per share merger consideration, plus accrued interest at the Federal Reserve Discount Rate plus a spread of 5.00% . At March 31, 2019, former holders of 2.5 shares of Bob Evans common stock had not withdrawn their appraisal demands, and the Company had a remaining accrual of $14.0 , which represents the accrued interest related to the 2.5 shares for which the $77.00 per share merger consideration was paid. Additional payments related to these 2.5 shares could be made in the future. The liabilities were reported in “Other current liabilities” and “Other liabilities” on the Condensed Consolidated Balance Sheets at March 31, 2019 and September 30, 2018, respectively. While the Company believes its accrual for these matters is appropriate, the final amounts required to resolve such matters could differ materially and the Company’s financial position, results of operations and cash flows could be materially affected. Accordingly, the Company cannot predict what impact, if any, these matters and any results from such matters could have on the Company’s future financial position, results of operations or cash flows. Weetabix Limited Environmental Matter In March 2019, Weetabix Limited, one of the Company’s subsidiaries, received notification from the United Kingdom Environment Agency (the “Environment Agency”) that the Environment Agency intends 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 promptly informed the Environment Agency and took steps to address the spill, including putting in place monitoring and remediation measures. Weetabix Limited has cooperated with the Environment Agency at all times regarding the containment and assessment of the incident. A first court hearing will be scheduled for a future date. The Company does not expect this matter will have a material effect on its financial condition, results of operations or cash flows. 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 position, 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 position, results of operations or cash flows of the Company. Leases Historically, Bob Evans guaranteed certain payment and performance obligations associated with the leases for 143 properties (the “Guarantee”) leased by the restaurant business formerly owned by Bob Evans (the “Bob Evans Restaurant Business”). The Guarantee remained in effect following the Company’s acquisition of Bob Evans. In the event the Bob Evans Restaurant Business fails to meet its payment and performance obligations under these leases, the Company may be required to make rent and other payments to the landlord under the requirements of the Guarantee. Should the Company, as guarantor of the lease obligations, be required to make all lease payments due for the remaining term of the leases subsequent to March 31, 2019, the maximum amount the Company may be required to pay is equal to the annual rent amount for the remainder of the lease terms. The current annual rent on these leases is $13.5 and will increase up to 1.5% annually based on indexed inflation. The lease terms extend for approximately 17 years from March 31, 2019, and the Guarantee would remain in effect in the event the leases are extended for a renewal period. In the event the Company is obligated to make payments under the Guarantee, the Company believes its exposure is limited due to protections and recourse available in the leases associated with the leased properties, including a requirement of the landlord to mitigate damages by re-letting the properties in default. The Bob Evans Restaurant Business continues to meet its obligations under these leases, and there have been no events that would indicate the obligations will not continue to be met. As such, the Company believes the fair value of the Guarantee is immaterial as of March 31, 2019.

Long-Term Debt

Long-Term Debt	6 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Long-Term Debt	LONG-TERM DEBT Long-term debt as of the dates indicated consists of the following: March 31, September 30, 2018 5.625% Senior Notes maturing January 2028 $ 940.9 $ 960.9 5.50% Senior Notes maturing March 2025 1,000.0 1,000.0 5.75% Senior Notes maturing March 2027 1,299.3 1,326.3 5.00% Senior Notes maturing August 2026 1,697.3 1,710.3 8.00% Senior Notes maturing July 2025 122.2 122.2 Term Loan 1,309.5 2,172.5 Bridge Loan (a) — — Capital lease 0.1 0.2 $ 6,369.3 $ 7,292.4 Less: Current portion of long-term debt (6.7 ) (22.1 ) Debt issuance costs, net (67.1 ) (71.2 ) Plus: Unamortized premium 30.7 33.0 Total long-term debt $ 6,326.2 $ 7,232.1 (a) In connection with the 8th Avenue Transactions, the Company classified its Bridge Loan and associated debt issuance costs as held for sale at September 30, 2018. See below for more information about the Bridge Loan. See Note 6 for information about assets and liabilities held for sale. Senior Notes On February 8, 2019, the Company received consents (the “Requisite Consents”) from holders of a majority of the outstanding aggregate principal amount of its outstanding 5.00% Senior Notes due August 2026 (the “Notes”) to approve proposed amendments to the indenture relating to the Notes (the “Indenture”). Following receipt of the Requisite Consents, the Company, its subsidiary guarantors and the trustee for the Indenture executed a supplemental indenture documenting the amendments, which more closely aligns certain provisions of the Indenture with the comparable provisions included in the indentures for the Company’s other senior notes, specifically to (i) add an exception to the restricted payments covenant in the Indenture and (ii) revise the “Permitted Investments” definition in the Indenture to add an additional category of Permitted Investments under the Indenture. In connection with the consents, the Company incurred $8.4 of debt modification costs, which were deferred and will be amortized to interest expense over the remaining term of the Notes, and recorded expense of $1.3 in the three and six months ended March 31, 2019, which is included in “Selling, general and administrative expenses” in the Condensed Consolidated Statements of Operations. 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 $22.8 , which reduced the available borrowing capacity under the Credit Agreement to $777.2 at March 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 (1) $700.0 and (2) 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 Employee Retirement Income Security Act of 1974 events. 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. Term Loan In the first quarter of fiscal 2019, the Company utilized a portion of the net proceeds from the 8th Avenue Transactions (see Note 4) to repay $863.0 of the outstanding principal value of its term loan, as required by the Credit Agreement. As a result of the prepayment, quarterly principal installment payments on the term loan are not required until December 31, 2019. Beginning on December 31, 2019, the term loan will require quarterly principal installment payments of $3.3 , compared to the previously required quarterly principal installment payments of $5.5 , which began on September 30, 2017. The term loan bears 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 4.49% and 4.22% at March 31, 2019 and September 30, 2018, respectively. The maturity date for the term loan is May 24, 2024. Bridge Loan On September 24, 2018, in connection with the 8th Avenue Transactions (see Note 4), the Company entered into a $625.0 bridge facility agreement (the “Bridge Loan Facility”) and borrowed $625.0 under the Bridge Loan Facility (the Bridge Loan, as defined in Note 4). In connection with the Bridge Loan Facility, the Company incurred issuance costs of $10.4 in fiscal 2018, of which $7.8 were refunded to the Company at the closing of the 8th Avenue Transactions on October 1, 2018. Upon the closing of the 8th Avenue Transactions on October 1, 2018, the Bridge Loan was assumed by 8th Avenue and the Company was released from its repayment obligations thereunder while retaining the proceeds from the Bridge Loan. 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 Premium and Debt Extinguishment Costs Paid Write-off of Debt Issuance Costs Write-off of Unamortized (Premium)/Discount Capital lease $ 0.1 $ — $ — $ — $ — 2019 Total $ 0.1 $ — $ — $ — $ — 5.75% Senior Notes $ 98.0 $ (1.3 ) $ — $ 1.1 $ (2.7 ) 8.00% Senior Notes 14.0 — 1.8 0.1 — Term Loan (a) 5.5 — 0.9 0.4 — 2018 Total $ 117.5 $ (1.3 ) $ 2.7 $ 1.6 $ (2.7 ) (a) In connection with an amendment to the Credit Agreement entered into on March 8, 2018, the Company paid debt extinguishment costs and recorded a write-off of debt issuance costs. Repayments of Long-Term Debt Loss on Extinguishment of Debt, net Six Months Ended Issuance or Borrowing Principal Amount Repaid Debt Repurchased at a Discount Premium and Debt Extinguishment Costs Paid Write-off of Debt Issuance Costs Write-off of Unamortized (Premium)/Discount 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 — Capital lease 0.1 — — — — Bridge Loan (a) — — — 2.6 — 2019 Total $ 923.1 $ (4.0 ) $ — $ 10.8 $ (0.7 ) 6.00% Senior Notes $ 630.0 $ — $ 30.8 $ 6.5 $ — 5.75% Senior Notes 98.0 (1.3 ) — 1.1 (2.7 ) 8.00% Senior Notes 14.0 — 1.8 0.1 — Term Loan (b) 11.0 — 0.9 0.4 — 2018 Total $ 753.0 $ (1.3 ) $ 33.5 $ 8.1 $ (2.7 ) (a) In connection with the assumption of the Bridge Loan by 8th Avenue discussed above, the Company recorded a write-off of debt issuance costs during the six months ended March 31, 2019 for costs that were not refunded at closing of the 8th Avenue Transactions. (b) In connection with an amendment to the Credit Agreement entered into on March 8, 2018, the Company paid debt extinguishment costs and recorded a write-off of debt issuance costs. Debt Covenants 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 March 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 March 31, 2019 , the pro forma consolidated interest coverage ratio exceeded this threshold.

Pension and Other Postretiremen

Pension and Other Postretirement Benefits	6 Months Ended
	Mar. 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. On October 1, 2018, the Company adopted ASU 2017-07 (see Note 2). The following tables provide the components of net periodic benefit cost (gain) for the pension plans. North America Three Months Ended Six Months Ended 2019 2018 2019 2018 Service cost $ 0.9 $ 1.0 $ 1.9 $ 2.1 Interest cost 1.0 0.9 2.0 1.8 Expected return on plan assets (1.6 ) (1.1 ) (3.2 ) (2.2 ) Recognized net actuarial loss — 0.3 — 0.6 Recognized prior service cost 0.1 — 0.1 — Net periodic benefit cost $ 0.4 $ 1.1 $ 0.8 $ 2.3 Other International Three Months Ended Six Months Ended 2019 2018 2019 2018 Service cost $ 1.5 $ 1.7 $ 2.9 $ 3.4 Interest cost 4.8 5.1 9.6 9.9 Expected return on plan assets (7.3 ) (8.2 ) (14.6 ) (16.0 ) Net periodic benefit gain $ (1.0 ) $ (1.4 ) $ (2.1 ) $ (2.7 ) The following table provides the components of net periodic benefit gain for the North American other postretirement benefit plans. Three Months Ended Six Months Ended 2019 2018 2019 2018 Service cost $ 0.1 $ 0.1 $ 0.2 $ 0.3 Interest cost 0.5 0.5 1.1 1.0 Recognized net actuarial loss — — — 0.1 Recognized prior service credit (1.2 ) (1.1 ) (2.4 ) (2.3 ) Net periodic benefit gain $ (0.6 ) $ (0.5 ) $ (1.1 ) $ (0.9 )

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Mar. 31, 2019
Stockholders' Equity Note [Abstract]
Shareholders' Equity	SHAREHOLDERS’ EQUITY Stock Repurchases During the three months ended March 31, 2019, the Company repurchased 0.4 shares of its common stock at an average share price of $97.68 per share for a total cost of $40.5 , including broker’s commissions. In the six months ended March 31, 2019, the Company repurchased 0.7 shares of its common stock at an average share price of $93.77 for a total cost of $65.8 , including broker’s commissions. During the three months ended March 31, 2018, the Company repurchased 1.1 shares of its common stock at an average share price of $74.03 per share for a total cost of $82.8 , including broker’s commissions. During the six months ended March 31, 2018, the Company repurchased 1.8 shares of its common stock at an average share price of $75.59 per share for a total cost of $138.8 , including broker’s commissions. 2.5% Series C Cumulative Perpetual Convertible Preferred Stock Conversion and Redemption In the second quarter of fiscal 2019, the Company completed the redemption of its Series C Preferred. Substantially all of the 3.2 shares of Series C Preferred outstanding as of January 10, 2019, the date the Series C Preferred redemption was announced, were converted into 5.9 shares of the Company’s common stock pursuant to the conversion rights applicable to the Series C Preferred. The remaining shares of Series C Preferred were redeemed. 3.75% Series B Cumulative Perpetual Convertible Preferred Stock Conversion and Redemption In the second quarter of fiscal 2018, the Company completed the redemption of its Series B Preferred. Substantially all of the 1.5 shares of Series B Preferred outstanding as of January 10, 2018, the date the Series B Preferred redemption was announced, were converted into 3.1 shares of the Company’s common stock pursuant to the conversion rights applicable to the Series B Preferred. The remaining shares of Series B Preferred were redeemed. Exercises of Stock Options In the three and six months ended March 31, 2019, the Company had 1.3 stock options exercised at a weighted average exercise price per share of $32.71 . In connection with the exercises, the Company received proceeds of $41.5 .

Segments

Segments	6 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Segments	SEGMENTS During the first quarter of fiscal 2019, the Company reorganized its reportable segments in accordance with ASC Topic 280, “Segment Reporting.” At March 31, 2019, the Company’s reportable segments were as follows: • Post Consumer Brands: North American RTE cereal business; • Weetabix: the RTE cereal and branded muesli business sold and distributed primarily outside of North America; • Foodservice: primarily egg and potato products; • Refrigerated Retail: refrigerated retail products, inclusive of side dishes, egg, cheese and sausage; and • Active Nutrition: protein shakes and other ready-to-drink beverages, powders, nutrition bars and supplements. Due to the level of integration between the Foodservice and Refrigerated Retail segments, it is impracticable to present total assets separately for each segment. Where practicable, all fiscal 2018 segment results reported herein have been reclassified to conform with the March 31, 2019 presentation. Additionally, effective October 1, 2018, 8th Avenue was no longer consolidated in the Company's financial statements and the 60.5% common equity retained interest in 8th Avenue is accounted for using the equity method. All historical segment results of 8th Avenue are reported herein as Post’s historical Private Brands segment. 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 intangible assets, facility closure related costs, restructuring expenses, gain/loss on assets held for sale, gain/loss on sale of businesses and facilities, interest expense, net and other unallocated corporate income and expenses. The following tables present information about the Company’s reportable segments. Three Months Ended Six Months Ended 2019 2018 2019 2018 Net Sales Post Consumer Brands $ 459.1 $ 462.3 $ 914.4 $ 894.3 Weetabix 104.1 109.0 205.0 208.7 Foodservice 389.1 380.2 797.2 749.1 Refrigerated Retail 219.5 219.8 481.1 361.5 Active Nutrition 216.5 205.2 402.3 391.2 Private Brands — 212.6 — 419.0 Eliminations (0.5 ) (3.0 ) (0.9 ) (4.6 ) Total $ 1,387.8 $ 1,586.1 $ 2,799.1 $ 3,019.2 Segment Profit Post Consumer Brands $ 83.2 $ 91.1 $ 167.2 $ 161.3 Weetabix 23.6 15.7 42.5 32.5 Foodservice 47.4 42.9 100.1 88.8 Refrigerated Retail 26.5 19.8 57.0 43.0 Active Nutrition 44.0 26.1 79.2 45.9 Private Brands — 14.2 — 31.1 Total segment profit 224.7 209.8 446.0 402.6 General corporate expenses and other 37.3 45.5 85.7 73.8 Gain on sale of business (2.6 ) — (127.3 ) — Interest expense, net 85.5 98.8 144.9 189.3 Loss on extinguishment of debt, net — 0.3 6.1 37.6 Expense (income) on swaps, net 63.0 (50.5 ) 114.7 (53.2 ) Earnings before income taxes and equity method loss $ 41.5 $ 115.7 $ 221.9 $ 155.1 Depreciation and amortization Post Consumer Brands $ 29.9 $ 30.9 $ 59.4 $ 61.8 Weetabix 8.8 12.7 17.5 19.8 Foodservice 27.7 26.0 54.7 49.9 Refrigerated Retail 19.7 15.3 37.7 22.8 Active Nutrition 6.3 6.4 12.7 12.9 Private Brands — 11.7 — 25.1 Total segment depreciation and amortization 92.4 103.0 182.0 192.3 Corporate and accelerated depreciation 5.4 1.6 9.4 2.8 Total $ 97.8 $ 104.6 $ 191.4 $ 195.1 Assets March 31, September 30, Post Consumer Brands $ 3,375.0 $ 3,391.7 Weetabix 1,856.7 1,853.3 Foodservice and Refrigerated Retail 5,105.1 5,132.4 Active Nutrition 600.8 559.3 Private Brands — 1,055.3 Corporate 345.2 1,065.5 Total $ 11,282.8 $ 13,057.5

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Mar. 31, 2019
Revenue from Contracts with Customers [Abstract]
Impact of Adopting ASC 606	Three Months Ended March 31, 2019 As Reported Under Topic 606 As Reported Under Prior Guidance Impact of Adoption Net Sales $ 1,387.8 $ 1,395.1 $ (7.3 ) Cost of goods sold 936.5 936.5 — Gross Profit 451.3 458.6 (7.3 ) Selling, general and administrative expenses 225.8 233.4 (7.6 ) Amortization of intangible assets 40.4 40.4 — Gain on sale of business (2.6 ) (2.6 ) — Other operating expenses, net 1.4 1.4 — Operating Profit $ 186.3 $ 186.0 $ 0.3 Six Months Ended March 31, 2019 As Reported Under Topic 606 As Reported Under Prior Guidance Impact of Adoption Net Sales $ 2,799.1 $ 2,810.7 $ (11.6 ) Cost of goods sold 1,921.3 1,921.3 — Gross Profit 877.8 889.4 (11.6 ) Selling, general and administrative expenses 442.9 455.2 (12.3 ) Amortization of intangible assets 80.7 80.7 — Gain on sale of business (127.3 ) (127.3 ) — Other operating expenses, net 1.3 1.3 — Operating Profit $ 480.2 $ 479.5 $ 0.7
Disaggregation of Revenues	Three Months Ended Six Months Ended 2019 2018 2019 2018 Cereal and granola $ 563.2 $ 595.1 $ 1,119.4 $ 1,150.8 Egg and egg products 381.1 380.2 775.8 761.3 Side dishes 123.4 111.9 269.1 168.1 Cheese and dairy 53.7 59.6 124.0 131.3 Sausage 36.7 28.7 80.3 28.7 Protein-based products and supplements 216.5 205.2 402.3 391.2 Nut butters and dried fruit and nut — 118.3 — 232.6 Pasta — 68.8 — 136.4 Other 13.7 19.6 29.1 21.2 Eliminations (0.5 ) (1.3 ) (0.9 ) (2.4 ) Net Sales $ 1,387.8 $ 1,586.1 $ 2,799.1 $ 3,019.2

Business Combinations (Tables)

Business Combinations (Tables)	6 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Bob Evans Opening Balance Sheet with Measurement Period Adjustments	Acquisition Date Amounts Recognized as of September 30, 2018 (a) Adjustments During Fiscal 2019 Acquisition Date Amounts Recognized (as Adjusted) Cash and cash equivalents $ 15.6 $ — $ 15.6 Receivables 58.5 — 58.5 Inventories 27.1 — 27.1 Prepaid expenses and other current assets 34.3 — 34.3 Property 184.3 — 184.3 Goodwill 898.3 (0.7 ) 897.6 Other intangible assets 782.0 — 782.0 Other assets 0.4 — 0.4 Accounts payable (18.2 ) — (18.2 ) Other current liabilities (58.5 ) — (58.5 ) Deferred tax liability - long-term (194.9 ) 0.7 (194.2 ) Other liabilities (5.3 ) — (5.3 ) Total acquisition cost $ 1,723.6 $ — $ 1,723.6
Pro Forma Information	Three Months Ended Six Months Ended 2019 2018 2019 2018 Pro forma net sales $ 1,387.8 $ 1,392.0 $ 2,799.1 $ 2,771.4 Pro forma net earnings available to common shareholders $ 42.0 $ 96.8 $ 84.3 $ 373.9 Pro forma basic earnings per common share $ 0.59 $ 1.45 $ 1.23 $ 5.63 Pro forma diluted earnings per common share $ 0.57 $ 1.31 $ 1.16 $ 4.96

Restructuring (Tables)

Restructuring (Tables)	6 Months Ended
	Mar. 31, 2019
Restructuring [Abstract]
Restructuring charges and related liabilities	Employee-Related Costs Accelerated Depreciation Total Balance at September 30, 2017 $ — $ — $ — Charge to expense 1.5 0.3 1.8 Cash payments — — — Non-cash charges — (0.3 ) (0.3 ) Balance at March 31, 2018 $ 1.5 $ — $ 1.5 Balance, September 30, 2018 $ 2.7 $ — $ 2.7 Charge to expense 1.5 4.3 5.8 Cash payments (0.1 ) — (0.1 ) Non-cash charges — (4.3 ) (4.3 ) Balance, March 31, 2019 $ 4.1 $ — $ 4.1 Total expected restructuring charge $ 5.2 $ 10.5 $ 15.7 Cumulative restructuring charges incurred to date 4.2 6.8 11.0 Remaining expected restructuring charge $ 1.0 $ 3.7 $ 4.7

Assets and Liabilities Held f_2

Assets and Liabilities Held for Sale (Tables)	6 Months Ended
	Mar. 31, 2019
Assets and Liabilities Held for Sale [Abstract]
Assets and Liabilities Held for Sale	September 30, 2018 Current assets held for sale Restricted cash $ 0.7 Receivables, net 79.8 Inventories 111.6 Prepaid expenses and other current assets 1.5 Property, net (a) 1.4 $ 195.0 Other assets held for sale Property, net (a) $ 165.1 Goodwill 417.1 Other intangible assets, net 270.4 Other assets 4.0 $ 856.6 Current liabilities held for sale Accounts payable $ 37.4 Other current liabilities 28.2 $ 65.6 Other liabilities held for sale Long-term debt $ 614.6 Deferred income taxes 79.9 Other liabilities 0.6 $ 695.1 (a) In accordance with ASC Topic 360, “Property, Plant, and Equipment,” the building classified as held for sale related to the closure of the Company’s Post Consumer Brands cereal warehouse in Clinton, Massachusetts and the 8th Avenue properties held for sale are classified as current and noncurrent, respectively, on the Condensed Consolidated Balance Sheet.

Goodwill (Tables)

Goodwill (Tables)	6 Months Ended
	Mar. 31, 2019
Goodwill
Carrying Amount of Goodwill	Post Consumer Brands Weetabix Foodservice Refrigerated Retail Active Nutrition Total Balance, September 30, 2018 Goodwill (gross) $ 2,012.0 $ 900.9 $ 1,336.1 $ 793.8 $ 180.7 $ 5,223.5 Accumulated impairment losses (609.1 ) — — — (114.8 ) (723.9 ) Goodwill (net) $ 1,402.9 $ 900.9 $ 1,336.1 $ 793.8 $ 65.9 $ 4,499.6 Acquisition related adjustment — — (0.5 ) (0.2 ) — (0.7 ) Currency translation adjustment (0.2 ) 0.2 — — — — Balance, March 31, 2019 Goodwill (gross) $ 2,011.8 $ 901.1 $ 1,335.6 $ 793.6 $ 180.7 $ 5,222.8 Accumulated impairment losses (609.1 ) — — — (114.8 ) (723.9 ) Goodwill (net) $ 1,402.7 $ 901.1 $ 1,335.6 $ 793.6 $ 65.9 $ 4,498.9

Intangible Assets, net (Tables)

Intangible Assets, net (Tables)	6 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Total Intangible Assets	March 31, 2019 September 30, 2018 Carrying Accumulated Amortization Net Carrying Accumulated Amortization Net Subject to amortization: Customer relationships $ 2,307.0 $ (503.9 ) $ 1,803.1 $ 2,307.0 $ (444.4 ) $ 1,862.6 Trademarks and brands 815.2 (209.4 ) 605.8 768.5 (188.2 ) 580.3 Other intangible assets 3.1 (3.1 ) — 3.1 (3.1 ) — 3,125.3 (716.4 ) 2,408.9 3,078.6 (635.7 ) 2,442.9 Not subject to amortization: Trademarks and brands 1,049.7 — 1,049.7 1,096.4 — 1,096.4 $ 4,175.0 $ (716.4 ) $ 3,458.6 $ 4,175.0 $ (635.7 ) $ 3,539.3

Equity Interests and Related _2

Equity Interests and Related Party Transactions (Tables)	6 Months Ended
	Mar. 31, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity method loss attributable to 8th Avenue	Three Months Ended Six Months Ended 8th Avenue’s net loss available to 8th Avenue’s common shareholders $ (11.3 ) $ (22.8 ) 60.5 % 60.5 % Equity method loss available to Post $ (6.8 ) $ (13.8 ) Less: Amortization of basis difference, net of tax (a) 1.8 5.4 Equity method loss, net of tax $ (8.6 ) $ (19.2 ) (a) The Company adjusted the historical basis of 8th Avenue’s assets and liabilities to fair value and recognized a total basis difference of $70.3 , which represents Post’s retained portion of the gain on sale. The basis difference related to inventory of $2.0 , net of tax, was included in equity method loss in the six months ended March 31, 2019. 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 March 31, 2019, the remaining basis difference to be amortized was $64.9 .
8th Avenue Summarized Financial Information	Three Months Ended Six Months Ended Net sales $ 213.7 $ 427.8 Gross profit $ 35.5 $ 69.2 Net loss $ (4.2 ) $ (8.7 ) Less: Preferred stock dividend 7.1 14.1 Net Loss Available to 8th Avenue Common Shareholders $ (11.3 ) $ (22.8 )

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Computation of basic and diluted earnings per share	Three Months Ended Six Months Ended 2019 2018 2019 2018 Net earnings for basic earnings per share $ 43.0 $ 88.9 $ 166.6 $ 380.4 Dilutive preferred stock dividends 1.0 2.6 3.0 6.0 Net earnings for diluted earnings per share $ 44.0 $ 91.5 $ 169.6 $ 386.4 Weighted-average shares for basic earnings per share 70.6 66.8 68.6 66.4 Effect of dilutive securities: Stock options 1.7 1.7 1.9 1.7 Stock appreciation rights 0.1 0.1 0.1 0.1 Restricted stock awards 0.4 0.2 0.4 0.3 Preferred shares conversion to common 2.5 7.2 4.2 8.1 Total dilutive securities 4.7 9.2 6.6 10.2 Weighted-average shares for diluted earnings per share 75.3 76.0 75.2 76.6 Basic earnings per common share $ 0.61 $ 1.33 $ 2.43 $ 5.73 Diluted earnings per common share $ 0.58 $ 1.20 $ 2.26 $ 5.04
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share	Three Months Ended Six Months Ended 2019 2018 2019 2018 Stock options 0.1 0.6 0.4 0.6

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Mar. 31, 2019
Inventory [Abstract]
Inventories	March 31, September 30, Raw materials and supplies $ 97.6 $ 107.8 Work in process 17.0 17.8 Finished products 406.3 324.1 Flocks 34.2 34.5 $ 555.1 $ 484.2

Property, net (Tables)

Property, net (Tables)	6 Months Ended
	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Property, net	March 31, September 30, Property, at cost $ 2,647.4 $ 2,543.0 Accumulated depreciation (928.7 ) (833.3 ) $ 1,718.7 $ 1,709.7

Derivative Financial Instrume_2

Derivative Financial Instruments and Hedging (Tables)	6 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Notional amounts of derivatives held	March 31, September 30, Not designated as hedging instruments under ASC Topic 815: Commodity contracts $ 33.0 $ 64.3 Energy contracts 49.3 20.8 Foreign exchange contracts - Forward contracts 4.0 9.3 Interest rate swap 73.9 74.6 Interest rate swaps - Rate-lock swaps 1,649.3 1,649.3 Designated as hedging instruments under ASC Topic 815: Foreign exchange contracts - Cross-currency swaps 448.7 662.9 Interest rate swap 200.0 1,000.0
Derivative Instruments in Condensed Consolidated Balance Sheets	Fair Value Portion Designated as Hedging Instruments Balance Sheet Location March 31, September 30, March 31, September 30, Asset Derivatives: Commodity contracts Prepaid expenses and other current assets $ 1.1 $ 1.9 $ — $ — Energy contracts Prepaid expenses and other current assets 4.7 4.9 — — Commodity contracts Other assets 1.5 0.2 — — Energy contracts Other assets — 0.3 — — Foreign exchange contracts Prepaid expenses and other current assets — 1.2 — 1.1 Foreign exchange contracts Other assets — 17.6 — 17.6 Interest rate swaps Prepaid expenses and other current assets — 6.4 — 6.4 Interest rate swaps Other assets — 33.9 — 30.6 $ 7.3 $ 66.4 $ — $ 55.7 Liability Derivatives: Commodity contracts Other current liabilities $ 0.9 $ 2.2 $ — $ — Energy contracts Other current liabilities 0.9 0.4 — — Foreign exchange contracts Other current liabilities 0.9 1.5 0.9 1.4 Foreign exchange contracts Other liabilities 11.2 19.4 11.2 19.4 Interest rate swaps Other current liabilities 53.4 23.6 0.1 — Interest rate swaps Other liabilities 176.2 94.3 0.5 — $ 243.5 $ 141.4 $ 12.7 $ 20.8
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 March 31, 2019 and 2018. Derivatives Not Designated as Hedging Instruments Statement of Operations Location Loss (Gain) Recognized in Statement of Operations 2019 2018 Commodity contracts Cost of goods sold $ 3.2 $ (5.1 ) Energy contracts Cost of goods sold (8.3 ) (0.7 ) Interest rate swaps Expense (income) on swaps, net 63.0 (50.5 ) Derivatives Designated as Hedging Instruments Loss (Gain) Recognized in OCI Gain Reclassified from Accumulated OCI into Earnings Statement of Operations Location 2019 2018 2019 2018 Foreign exchange contracts $ — $ — $ — $ (1.3 ) Selling, general and administrative expenses Interest rate swaps 2.5 (20.6 ) (0.4 ) (0.5 ) Interest expense, net Cross-currency swaps 9.4 15.2 — — Expense (income) on swaps, net 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 six months ended March 31, 2019 and 2018. Derivatives Not Designated as Hedging Instruments Statement of Operations Location Loss (Gain) Recognized in Statement of Operations 2019 2018 Commodity contracts Cost of goods sold $ 3.0 $ (4.7 ) Energy contracts Cost of goods sold — (2.9 ) Foreign exchange contracts Selling, general and administrative expenses — 0.2 Interest rate swaps Expense (income) on swaps, net 114.7 (53.2 ) Derivatives Designated as Hedging Instruments Loss (Gain) Recognized in OCI Gain Reclassified from Accumulated OCI into Earnings Statement of Operations Location 2019 2018 2019 2018 Foreign exchange contracts $ — $ (0.2 ) $ — $ (1.3 ) Selling, general and administrative expenses Interest rate swaps 7.1 (29.6 ) (30.5 ) (0.2 ) Interest expense, net Cross-currency swaps (19.6 ) 25.9 — — Expense (income) on swaps, net

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Mar. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Assets and liabilities measured at fair value on a recurring basis	March 31, 2019 September 30, 2018 Total Level 1 Level 2 Total Level 1 Level 2 Assets: Deferred compensation investments $ 10.6 $ 10.6 $ — $ 43.6 $ 43.6 $ — Derivative assets 7.3 — 7.3 66.4 — 66.4 $ 17.9 $ 10.6 $ 7.3 $ 110.0 $ 43.6 $ 66.4 Liabilities: Deferred compensation liabilities $ 30.4 $ — $ 30.4 $ 52.2 $ — $ 52.2 Derivative liabilities 243.5 — 243.5 141.4 — 141.4 $ 273.9 $ — $ 273.9 $ 193.6 $ — $ 193.6
Assets and liabilities held for sale, measured at fair value on a nonrecurring basis	The following table summarizes the Level 3 activity. Balance, September 30, 2018 $ 290.9 Gains related to assets and liabilities held for sale 125.3 Proceeds from the sale of assets and liabilities held for sale (276.6 ) Investment in 8th Avenue, working capital and other adjustments (139.6 ) Balance, March 31, 2019 $ —

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Long-term Debt	March 31, September 30, 2018 5.625% Senior Notes maturing January 2028 $ 940.9 $ 960.9 5.50% Senior Notes maturing March 2025 1,000.0 1,000.0 5.75% Senior Notes maturing March 2027 1,299.3 1,326.3 5.00% Senior Notes maturing August 2026 1,697.3 1,710.3 8.00% Senior Notes maturing July 2025 122.2 122.2 Term Loan 1,309.5 2,172.5 Bridge Loan (a) — — Capital lease 0.1 0.2 $ 6,369.3 $ 7,292.4 Less: Current portion of long-term debt (6.7 ) (22.1 ) Debt issuance costs, net (67.1 ) (71.2 ) Plus: Unamortized premium 30.7 33.0 Total long-term debt $ 6,326.2 $ 7,232.1 (a) In connection with the 8th Avenue Transactions, the Company classified its Bridge Loan and associated debt issuance costs as held for sale at September 30, 2018. See below for more information about the Bridge Loan. See Note 6 for information about assets and liabilities held for sale.
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 Premium and Debt Extinguishment Costs Paid Write-off of Debt Issuance Costs Write-off of Unamortized (Premium)/Discount Capital lease $ 0.1 $ — $ — $ — $ — 2019 Total $ 0.1 $ — $ — $ — $ — 5.75% Senior Notes $ 98.0 $ (1.3 ) $ — $ 1.1 $ (2.7 ) 8.00% Senior Notes 14.0 — 1.8 0.1 — Term Loan (a) 5.5 — 0.9 0.4 — 2018 Total $ 117.5 $ (1.3 ) $ 2.7 $ 1.6 $ (2.7 ) (a) In connection with an amendment to the Credit Agreement entered into on March 8, 2018, the Company paid debt extinguishment costs and recorded a write-off of debt issuance costs. Repayments of Long-Term Debt Loss on Extinguishment of Debt, net Six Months Ended Issuance or Borrowing Principal Amount Repaid Debt Repurchased at a Discount Premium and Debt Extinguishment Costs Paid Write-off of Debt Issuance Costs Write-off of Unamortized (Premium)/Discount 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 — Capital lease 0.1 — — — — Bridge Loan (a) — — — 2.6 — 2019 Total $ 923.1 $ (4.0 ) $ — $ 10.8 $ (0.7 ) 6.00% Senior Notes $ 630.0 $ — $ 30.8 $ 6.5 $ — 5.75% Senior Notes 98.0 (1.3 ) — 1.1 (2.7 ) 8.00% Senior Notes 14.0 — 1.8 0.1 — Term Loan (b) 11.0 — 0.9 0.4 — 2018 Total $ 753.0 $ (1.3 ) $ 33.5 $ 8.1 $ (2.7 ) (a) In connection with the assumption of the Bridge Loan by 8th Avenue discussed above, the Company recorded a write-off of debt issuance costs during the six months ended March 31, 2019 for costs that were not refunded at closing of the 8th Avenue Transactions. (b) In connection with an amendment to the Credit Agreement entered into on March 8, 2018, the Company paid debt extinguishment costs and recorded a write-off of debt issuance costs.

Pension and Other Postretirem_2

Pension and Other Postretirement Benefits (Tables)	6 Months Ended
	Mar. 31, 2019
Pension and Other Postretirement Benefits Cost (Reversal of Cost) [Abstract]
Components of net periodic benefit cost (gain)	North America Three Months Ended Six Months Ended 2019 2018 2019 2018 Service cost $ 0.9 $ 1.0 $ 1.9 $ 2.1 Interest cost 1.0 0.9 2.0 1.8 Expected return on plan assets (1.6 ) (1.1 ) (3.2 ) (2.2 ) Recognized net actuarial loss — 0.3 — 0.6 Recognized prior service cost 0.1 — 0.1 — Net periodic benefit cost $ 0.4 $ 1.1 $ 0.8 $ 2.3 Other International Three Months Ended Six Months Ended 2019 2018 2019 2018 Service cost $ 1.5 $ 1.7 $ 2.9 $ 3.4 Interest cost 4.8 5.1 9.6 9.9 Expected return on plan assets (7.3 ) (8.2 ) (14.6 ) (16.0 ) Net periodic benefit gain $ (1.0 ) $ (1.4 ) $ (2.1 ) $ (2.7 ) The following table provides the components of net periodic benefit gain for the North American other postretirement benefit plans. Three Months Ended Six Months Ended 2019 2018 2019 2018 Service cost $ 0.1 $ 0.1 $ 0.2 $ 0.3 Interest cost 0.5 0.5 1.1 1.0 Recognized net actuarial loss — — — 0.1 Recognized prior service credit (1.2 ) (1.1 ) (2.4 ) (2.3 ) Net periodic benefit gain $ (0.6 ) $ (0.5 ) $ (1.1 ) $ (0.9 )

Segments (Tables)

Segments (Tables)	6 Months Ended
	Mar. 31, 2019
Segment Reporting [Abstract]
Segment Reporting Information, by Segment	Three Months Ended Six Months Ended 2019 2018 2019 2018 Net Sales Post Consumer Brands $ 459.1 $ 462.3 $ 914.4 $ 894.3 Weetabix 104.1 109.0 205.0 208.7 Foodservice 389.1 380.2 797.2 749.1 Refrigerated Retail 219.5 219.8 481.1 361.5 Active Nutrition 216.5 205.2 402.3 391.2 Private Brands — 212.6 — 419.0 Eliminations (0.5 ) (3.0 ) (0.9 ) (4.6 ) Total $ 1,387.8 $ 1,586.1 $ 2,799.1 $ 3,019.2 Segment Profit Post Consumer Brands $ 83.2 $ 91.1 $ 167.2 $ 161.3 Weetabix 23.6 15.7 42.5 32.5 Foodservice 47.4 42.9 100.1 88.8 Refrigerated Retail 26.5 19.8 57.0 43.0 Active Nutrition 44.0 26.1 79.2 45.9 Private Brands — 14.2 — 31.1 Total segment profit 224.7 209.8 446.0 402.6 General corporate expenses and other 37.3 45.5 85.7 73.8 Gain on sale of business (2.6 ) — (127.3 ) — Interest expense, net 85.5 98.8 144.9 189.3 Loss on extinguishment of debt, net — 0.3 6.1 37.6 Expense (income) on swaps, net 63.0 (50.5 ) 114.7 (53.2 ) Earnings before income taxes and equity method loss $ 41.5 $ 115.7 $ 221.9 $ 155.1 Depreciation and amortization Post Consumer Brands $ 29.9 $ 30.9 $ 59.4 $ 61.8 Weetabix 8.8 12.7 17.5 19.8 Foodservice 27.7 26.0 54.7 49.9 Refrigerated Retail 19.7 15.3 37.7 22.8 Active Nutrition 6.3 6.4 12.7 12.9 Private Brands — 11.7 — 25.1 Total segment depreciation and amortization 92.4 103.0 182.0 192.3 Corporate and accelerated depreciation 5.4 1.6 9.4 2.8 Total $ 97.8 $ 104.6 $ 191.4 $ 195.1 Assets March 31, September 30, Post Consumer Brands $ 3,375.0 $ 3,391.7 Weetabix 1,856.7 1,853.3 Foodservice and Refrigerated Retail 5,105.1 5,132.4 Active Nutrition 600.8 559.3 Private Brands — 1,055.3 Corporate 345.2 1,065.5 Total $ 11,282.8 $ 13,057.5

Basis of Presentation (Details)

Basis of Presentation (Details) - 8th Avenue - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2019	Oct. 01, 2018
Business Divestiture, Purchase Price Adjustment, Net Working Capital Settlement	$ 16.8
Equity Method Investment, Ownership Percentage	60.50%	60.50%
Post Holdings, Inc.
Proceeds from independent capitalization of a subsidiary		$ 875
Equity Method Investment, Ownership Percentage		60.50%

Recently Issued and Adopted A_2

Recently Issued and Adopted Accounting Standards (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2018	Mar. 31, 2018
Cost of Goods Sold | Accounting Standards Update 2017-07
New Accounting Pronouncement, Early Adoption
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 3.3	$ 6.5
Selling, General and Administrative Expenses | Accounting Standards Update 2017-07
New Accounting Pronouncement, Early Adoption
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	0.3	0.6
Other income, net | Accounting Standards Update 2017-07
New Accounting Pronouncement, Early Adoption
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 3.6	7.1
Net Cash Used in Investing Activities | Accounting Standards Update 2016-18
New Accounting Pronouncement, Early Adoption
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ 1.9

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net Sales	$ 1,387.8	$ 1,586.1	$ 2,799.1	$ 3,019.2
Cost of goods sold	936.5	1,113.7	1,921.3	2,098.3
Gross Profit	451.3	472.4	877.8	920.9
Selling, general and administrative expenses	225.8	264.6	442.9	510.6
Amortization of intangible assets	40.4	46.4	80.7	87.9
Gain on sale of business	(2.6)	0	(127.3)	0
Other operating expenses, net	1.4	0.7	1.3	0.7
Operating Profit	186.3	$ 160.7	480.2	$ 321.7
Calculated under Revenue Guidance in Effect before Topic 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net Sales	1,395.1		2,810.7
Cost of goods sold	936.5		1,921.3
Gross Profit	458.6		889.4
Selling, general and administrative expenses	233.4		455.2
Amortization of intangible assets	40.4		80.7
Gain on sale of business	(2.6)		(127.3)
Other operating expenses, net	1.4		1.3
Operating Profit	186		479.5
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Recognition of Deferred Revenue	0.3		0.7
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net Sales	(7.3)		(11.6)
Cost of goods sold	0		0
Gross Profit	(7.3)		(11.6)
Selling, general and administrative expenses	7.6		12.3
Amortization of intangible assets	0		0
Gain on sale of business	0		0
Other operating expenses, net	0		0
Operating Profit	0.3		0.7
Retained Earnings
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	0.9		0.9
Deferred Income Taxes [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	0.3		0.3
Other Current Liabilities
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 1.2		$ 1.2

Revenue from Contracts with C_4

Revenue from Contracts with Customers Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue
Net Sales	$ 1,387.8	$ 1,586.1	$ 2,799.1	$ 3,019.2
Cereal and Granola
Disaggregation of Revenue
Net Sales	563.2	595.1	1,119.4	1,150.8
Egg and Egg Products
Disaggregation of Revenue
Net Sales	381.1	380.2	775.8	761.3
Side Dishes
Disaggregation of Revenue
Net Sales	123.4	111.9	269.1	168.1
Cheese and Dairy
Disaggregation of Revenue
Net Sales	53.7	59.6	124	131.3
Sausage
Disaggregation of Revenue
Net Sales	36.7	28.7	80.3	28.7
Protein-based Products and Supplements
Disaggregation of Revenue
Net Sales	216.5	205.2	402.3	391.2
Nut Butters and Dried Nut and Fruit
Disaggregation of Revenue
Net Sales	0	118.3	0	232.6
Pasta
Disaggregation of Revenue
Net Sales	0	68.8	0	136.4
Other
Disaggregation of Revenue
Net Sales	13.7	19.6	29.1	21.2
Eliminations
Disaggregation of Revenue
Net Sales	$ (0.5)	$ (1.3)	$ (0.9)	$ (2.4)

Business Combinations (Details)

Business Combinations (Details) - USD ($)	Jan. 12, 2018	Mar. 31, 2019	Sep. 30, 2018	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Oct. 01, 2018
Business Acquisition
Gain on sale of business related to 8th Avenue Transactions		$ 2,600,000		$ 0	$ 127,300,000	$ 0
Foreign currency losses reclassified from accumulated OCI		0		0	42,100,000	0
Payments to Acquire Businesses, Net of Cash Acquired					0	1,454,000,000
Goodwill		4,498,900,000	$ 4,499,600,000		4,498,900,000
Goodwill, Purchase Accounting Adjustments					(700,000)
Selling, General and Administrative Expenses
Business Acquisition
Transaction-related expenses		$ 3,800,000		20,900,000	$ 14,500,000	24,000,000
Bob Evans Farms
Business Acquisition
Business Acquisition, Share Price	$ 77
Payments to Acquire Businesses, Net of Cash Acquired	$ 1,381,200,000
Shares not yet paid	4,350,000		3,300,000
Basis spread on amounts owed to appraisal rights holders					5.00%
Shares for which merger consideration has been paid		2,500,000			2,500,000
Business Acquisition, Goodwill, Expected Tax Deductible Amount	$ 13,800,000
Cash and cash equivalents		$ 15,600,000	$ 15,600,000		$ 15,600,000
Receivables		58,500,000	58,500,000		58,500,000
Inventories		27,100,000	27,100,000		27,100,000
Prepaid expenses and other current assets		34,300,000	34,300,000		34,300,000
Property		184,300,000	184,300,000		184,300,000
Goodwill		897,600,000	898,300,000		897,600,000
Other intangible assets		782,000,000	782,000,000		782,000,000
Other assets		400,000	400,000		400,000
Accounts payable		(18,200,000)	(18,200,000)		(18,200,000)
Other current liabilities		(58,500,000)	(58,500,000)		(58,500,000)
Deferred tax liability - long-term		(194,200,000)	(194,900,000)		(194,200,000)
Other liabilities		(5,300,000)	(5,300,000)		(5,300,000)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net		1,723,600,000	1,723,600,000		1,723,600,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory					0
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property					0
Goodwill, Purchase Accounting Adjustments					(700,000)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other intangible assets					0
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred					0
Bob Evans Farms | Cash and Cash Equivalents
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets					0
Bob Evans Farms | Accounts Receivable
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets					0
Bob Evans Farms | Prepaid Expenses and Other Current Assets
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets					0
Bob Evans Farms | Other Assets
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets					0
Bob Evans Farms | Accounts Payable
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities					0
Bob Evans Farms | Other Current Liabilities
Business Acquisition
Payments to be made subsequent to the closing of the acquisition		$ 14,000,000			14,000,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities					0
Bob Evans Farms | Deferred tax liability - long term
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities					700,000
Bob Evans Farms | Other Liabilities
Business Acquisition
Payments to appraisal rights holders, including interest					257,600,000
Payments to be made subsequent to the closing of the acquisition			267,000,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities					$ 0
Bob Evans Farms | Trademarks
Business Acquisition
Indefinite-Lived Intangible Assets Acquired	400,000,000
Bob Evans Farms | Customer Relationships
Business Acquisition
Definite-lived Intangible Assets Acquired	$ 376,000,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	18 years
Bob Evans Farms | Trademarks
Business Acquisition
Definite-lived Intangible Assets Acquired	$ 6,000,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
8th Avenue
Business Acquisition
Equity Method Investment, Ownership Percentage		60.50%			60.50%		60.50%
Business Divestiture, Purchase Price Adjustment, Net Working Capital Settlement					$ 16,800,000
Transaction-related expenses		$ 800,000		$ 1,300,000	$ 9,900,000	$ 2,000,000
8th Avenue | Bridge Loan
Business Acquisition
Proceeds from Issuance of Unsecured Debt			625,000,000
8th Avenue | Post Holdings, Inc.
Business Acquisition
Proceeds from independent capitalization of a subsidiary							$ 875,000,000
Equity Method Investment, Ownership Percentage							60.50%
Proceeds from Issuance of Preferred Stock							$ 250,000,000
8th Avenue | Post Holdings, Inc. | Bridge Loan
Business Acquisition
Proceeds from Issuance of Unsecured Debt			$ 625,000,000
8th Avenue | THL
Business Acquisition
Equity Method Investment, Ownership Percentage							39.50%
Preferred Stock, Shares Issued							2,500,000
Preferred Stock, Dividend Rate, Agreed upon Percentage							11.00%
Preferred Stock, Liquidation Preference, Value							$ 100

Business combinations pro forma

Business combinations pro forma financial information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Business Combinations [Abstract]
Pro forma net sales	$ 1,387.8	$ 1,392	$ 2,799.1	$ 2,771.4
Pro forma net earnings available to common shareholders	$ 42	$ 96.8	$ 84.3	$ 373.9
Pro forma basic earnings per common share	$ 0.59	$ 1.45	$ 1.23	$ 5.63
Pro forma diluted earnings per common share	$ 0.57	$ 1.31	$ 1.16	$ 4.96

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Restructuring Reserve
Balance, Beginning of Period			$ 2.7	$ 0
Charge to expense	$ 3.3	$ 1.8	5.8	1.8
Cash payments			(0.1)	0
Non-cash charges			(4.3)	(0.3)
Balance, End of Period	4.1	1.5	4.1	1.5
Total expected restructuring charge	15.7		15.7
Cumulative restructuring charges incurred to date	11		11
Remaining expected restructuring charge	4.7		4.7
Employee Severance
Restructuring Reserve
Balance, Beginning of Period			2.7	0
Charge to expense			1.5	1.5
Cash payments			(0.1)	0
Non-cash charges			0	0
Balance, End of Period	4.1	1.5	4.1	1.5
Total expected restructuring charge	5.2		5.2
Cumulative restructuring charges incurred to date	4.2		4.2
Remaining expected restructuring charge	1		1
Accelerated depreciation
Restructuring Reserve
Balance, Beginning of Period			0	0
Charge to expense			4.3	0.3
Cash payments			0	0
Non-cash charges			(4.3)	(0.3)
Balance, End of Period	0	$ 0	0	$ 0
Total expected restructuring charge	10.5		10.5
Cumulative restructuring charges incurred to date	6.8		6.8
Remaining expected restructuring charge	$ 3.7		$ 3.7

Assets and Liabilities Held f_3

Assets and Liabilities Held for Sale (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Current assets held for sale
Restricted cash					$ 0.7
Receivables, net					79.8
Inventories					111.6
Prepaid expenses and other current assets					1.5
Property, net					1.4
Current assets held for sale	$ 0		$ 0		195
Other assets held for sale
Property, net					165.1
Goodwill					417.1
Other intangible assets, net					270.4
Other assets					4
Other assets held for sale	0		0		856.6
Current liabilities held for sale
Accounts payable					37.4
Other current liabilities					28.2
Current liabilities held for sale	0		0		65.6
Other liabilities held for sale
Long-term debt					614.6
Deferred income taxes					79.9
Other liabilities					0.6
Other liabilities held for sale	0		0		$ 695.1
Gain on sale of business related to 8th Avenue Transactions	$ 2.6	$ 0	127.3	$ 0
Gain on assets held for sale			125.3
8th Avenue | Sale of Business | Loss on extinguishment of debt, net
Other liabilities held for sale
Gain on assets held for sale			2.6
Post Consumer Brands | Cereal warehouse in Clinton, Massachusetts | Facility Closing
Other liabilities held for sale
Gain on assets held for sale			$ (0.6)

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2019	Sep. 30, 2018
Goodwill
Goodwill (gross)	$ 5,222.8	$ 5,223.5
Accumulated impairment losses	(723.9)	(723.9)
Goodwill	4,498.9	4,499.6
Acquisition related adjustment	(0.7)
Currency translation adjustment	0
Post Consumer Brands
Goodwill
Goodwill (gross)	2,011.8	2,012
Accumulated impairment losses	609.1	(609.1)
Goodwill	1,402.7	1,402.9
Acquisition related adjustment	0
Currency translation adjustment	(0.2)
Weetabix
Goodwill
Goodwill (gross)	901.1	900.9
Accumulated impairment losses	0	0
Goodwill	901.1	900.9
Acquisition related adjustment	0
Currency translation adjustment	0.2
Foodservice
Goodwill
Goodwill (gross)	1,335.6	1,336.1
Accumulated impairment losses	0	0
Goodwill	1,335.6	1,336.1
Acquisition related adjustment	(0.5)
Currency translation adjustment	0
Refrigerated Retail
Goodwill
Goodwill (gross)	793.6	793.8
Accumulated impairment losses	0	0
Goodwill	793.6	793.8
Acquisition related adjustment	(0.2)
Currency translation adjustment	0
Active Nutrition
Goodwill
Goodwill (gross)	180.7	180.7
Accumulated impairment losses	(114.8)	(114.8)
Goodwill	65.9	$ 65.9
Acquisition related adjustment	0
Currency translation adjustment	$ 0

Intangible Assets, net (Details

Intangible Assets, net (Details) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets, Gross	$ 3,125.3	$ 3,078.6
Finite-Lived Intangible Assets, Accumulated Amortization	(716.4)	(635.7)
Finite-Lived Intangible Assets, Net	2,408.9	2,442.9
Intangible Assets, Net (Excluding Goodwill)
Carrying amount, total	4,175	4,175
Other intangible assets, net	3,458.6	3,539.3
Trademarks and brands
Indefinite-Lived Intangible Assets (Excluding Goodwill)
Carrying amount	1,049.7	1,096.4
Customer Relationships
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets, Gross	2,307	2,307
Finite-Lived Intangible Assets, Accumulated Amortization	(503.9)	(444.4)
Finite-Lived Intangible Assets, Net	1,803.1	1,862.6
Trademarks and brands
Finite-Lived Intangible Assets
Finite-Lived Intangible Assets, Gross	815.2	768.5
Finite-Lived Intangible Assets, Accumulated Amortization	(209.4)	(188.2)
Finite-Lived Intangible Assets, Net	605.8	580.3
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

Equity Interests and Related _3

Equity Interests and Related Party Transactions (Details) $ in Millions	Jul. 03, 2017	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Oct. 01, 2018USD ($)	Sep. 30, 2018USD ($)
Schedule of Equity Method Investments
Equity method loss, net of tax		$ (8.8)	$ 0	$ (19.5)	$ 0
Equity method investments		$ 163.1		$ 163.1			$ 5.2
Number of Joint Ventures Acquired	2
8th Avenue
Schedule of Equity Method Investments
Equity Method Investment, Ownership Percentage		60.50%		60.50%		60.50%
Net Loss Available to 8th Avenue Common Shareholders		$ (11.3)		$ (22.8)
Equity method loss available to Common Shareholders		(6.8)		(13.8)
Less: Amortization of basis difference, net of tax (a)		1.8		5.4
Equity method loss, net of tax		(8.6)		(19.2)
Total Basis Difference Recognized						$ 70.3
Remaining Basis Difference to be Amortized		64.9		64.9
Net sales		213.7		427.8
Gross profit		35.5		69.2
Net loss		(4.2)		(8.7)
Less: Preferred stock dividend		7.1		14.1
Revenue from Related Parties		0.9		2
Purchases from and Royalties paid to Related Party		$ 2.8		$ 5.1
Alpen Food Company South Africa (Proprietary) Limited
Schedule of Equity Method Investments
Equity Method Investment, Ownership Percentage		50.00%		50.00%
Weetabix East Africa Limited
Schedule of Equity Method Investments
Noncontrolling Interest, Ownership Percentage by Parent		50.10%		50.10%
Inventory | 8th Avenue
Schedule of Equity Method Investments
Less: Amortization of basis difference, net of tax (a)				$ 2
Equity Method Investments | 8th Avenue
Schedule of Equity Method Investments
Equity method investments		$ 158.3		158.3
Equity Method Investments | Alpen Food Company South Africa (Proprietary) Limited
Schedule of Equity Method Investments
Equity method investments		4.8		4.8			5.2
Accounts Receivable | 8th Avenue
Schedule of Equity Method Investments
Accounts Receivable, Related Parties		3		3
Accounts Payable | 8th Avenue
Schedule of Equity Method Investments
Accounts Payable, Related Parties		0.7		0.7
Melck Street Management Proprietary Limited [Member] | Other Assets | Alpen Food Company South Africa (Proprietary) Limited
Schedule of Equity Method Investments
Notes Receivable, Related Parties, Noncurrent		1		1			$ 1
Selling, General and Administrative Expenses
Schedule of Equity Method Investments
MSA and Advisory Income		$ 1.1		$ 2.1
Post Holdings, Inc. | 8th Avenue
Schedule of Equity Method Investments
Equity Method Investment, Ownership Percentage						60.50%

Income Taxes (Details)

Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Income Tax Disclosure
Effective Income Tax Rate	(28.00%)	20.70%	14.50%	(149.50%)
Effective Income Tax Rate Reconciliation, Discrete Items, Amount	$ 21,200,000
Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount	17,600,000
Income tax (benefit) expense	$ (11,600,000)	$ 23,900,000	$ 32,200,000	$ (231,900,000)
Tax Benefit Due to Newly Enacted Tax Rate		$ 1,700,000		272,400,000	$ 281,200,000
Tax Expense due to Repatriation of Foreign Earnings				$ 7,100,000	$ 10,300,000
United States
Income Tax Disclosure
Federal Statutory Income Tax Rate			21.00%
Pre-December 22, 2017 Federal Income Tax Rate				35.00%
Fiscal 2018 Blended Tax Rate				24.50%

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Net Earnings Available to Common Shareholders	$ 43	$ 88.9	$ 166.6	$ 380.4
Dilutive preferred stock dividends	1	2.6	3	6
Net earnings for diluted earnings per share	$ 44	$ 91.5	$ 169.6	$ 386.4
Weighted-average shares for basic earnings per share	70.6	66.8	68.6	66.4
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	4.7	9.2	6.6	10.2
Weighted-average shares for diluted earnings per share	75.3	76	75.2	76.6
Basic earnings per share (in usd per share)	$ 0.61	$ 1.33	$ 2.43	$ 5.73
Diluted earnings per share (in usd per share)	$ 0.58	$ 1.20	$ 2.26	$ 5.04
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	1.7	1.7	1.9	1.7
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	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	0.4	0.2	0.4	0.3
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	2.5	7.2	4.2	8.1
Series B Preferred Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Series B, Dividend Rate, Percentage		3.75%
Conversion of Stock, Shares Converted		1.5
Common Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Conversion of Stock, Shares Issued	5.9	3.1
Series C Preferred Stock [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method
Series B, Dividend Rate, Percentage	2.50%
Conversion of Stock, Shares Converted	3.2

Earnings Per Share Antidilutive

Earnings Per Share Antidilutive shares excluded from earnings per share (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 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	0.6	0.4	0.6
Restricted Stock Awards
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0	0	0
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	0	0	0

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Inventory [Abstract]
Raw materials and supplies	$ 97.6	$ 107.8
Work in process	17	17.8
Finished products	406.3	324.1
Flocks	34.2	34.5
Inventories	$ 555.1	$ 484.2

Property, net (Details)

Property, net (Details) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018
Property, Plant and Equipment [Abstract]
Property, at cost	$ 2,647.4	$ 2,543
Accumulated depreciation	(928.7)	(833.3)
Property, net	$ 1,718.7	$ 1,709.7

Derivative Financial Instrume_3

Derivative Financial Instruments and Hedging (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Derivatives, Fair Value
Reclassifications to net earnings		$ (1.8)
Derivative Asset	$ 7.3		$ 7.3		$ 66.4
Derivative Liability	243.5		243.5		141.4
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax	0.4	1.8	30.5	$ 1.5
Level 2
Derivatives, Fair Value
Derivative Asset	7.3		7.3		66.4
Derivative Liability	243.5		243.5		141.4
Assets, Total
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset					66.4
Derivative Asset	7.3		7.3
Liabilities, Total
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability					141.4
Derivative Liability	243.5		243.5
Selling, General and Administrative Expenses
Derivatives, Fair Value
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax		$ 1.3
Portion Designated as Hedging Instruments | Assets, Total
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		55.7
Portion Designated as Hedging Instruments | Liabilities, Total
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	12.7		12.7		20.8
Commodity contracts | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	1.1		1.1		1.9
Commodity contracts | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	1.5		1.5		0.2
Commodity contracts | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0.9		0.9		2.2
Commodity contracts | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount	33		33		64.3
Commodity contracts | Portion Designated as Hedging Instruments | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		0
Commodity contracts | Portion Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		0
Commodity contracts | Portion Designated as Hedging Instruments | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0		0		0
Energy Contracts | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	4.7		4.7		4.9
Energy Contracts | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		0.3
Energy Contracts | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0.9		0.9		0.4
Energy Contracts | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount	49.3		49.3		20.8
Energy Contracts | Portion Designated as Hedging Instruments | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		0
Energy Contracts | Portion Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		0
Energy Contracts | Portion Designated as Hedging Instruments | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0		0		0
Foreign Exchange Contract - Forward Contracts | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		1.2
Foreign Exchange Contract - Forward Contracts | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		17.6
Foreign Exchange Contract - Forward Contracts | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount	4		4		9.3
Foreign Exchange Contract - Forward Contracts | Portion Designated as Hedging Instruments | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		1.1
Foreign Exchange Contract - Forward Contracts | Portion Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		17.6
Interest Rate Swap | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		6.4
Interest Rate Swap | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		33.9
Interest Rate Swap | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	53.4		53.4		23.6
Interest Rate Swap | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	176.2		176.2		94.3
Interest Rate Swap | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount	73.9		73.9		74.6
Interest Rate Swap | Portion Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount of Terminated Contracts			800
Derivative, Notional Amount	200		200		1,000
Interest Rate Swap | Portion Designated as Hedging Instruments | Other Current Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		6.4
Interest Rate Swap | Portion Designated as Hedging Instruments | Other Assets
Derivatives, Fair Value
Derivative Asset, Fair Value, Gross Asset	0		0		30.6
Interest Rate Swap | Portion Designated as Hedging Instruments | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0.1		0.1		0
Interest Rate Swap | Portion Designated as Hedging Instruments | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0.5		0.5		0
Interest Rate Swap | Portion Designated as Hedging Instruments | Interest expense, net
Derivatives, Fair Value
Proceeds from Hedge, Investing Activities			29.8
Interest rate swap, rate lock swaps | Derivatives Not Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount	1,649.3		1,649.3		1,649.3
Currency Swap | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0.9		0.9		1.5
Currency Swap | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	11.2		11.2		19.4
Currency Swap | Portion Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount of Terminated Contracts			214.2
Derivative, Notional Amount	448.7		448.7		662.9
Currency Swap | Portion Designated as Hedging Instruments | Accumulated Other Comprehensive Income
Derivatives, Fair Value
Derivative, Notional Amount of Terminated Contracts			26.2
Currency Swap | Portion Designated as Hedging Instruments | Other Current Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	0.9		0.9		1.4
Currency Swap | Portion Designated as Hedging Instruments | Other Liabilities
Derivatives, Fair Value
Derivative Liability, Fair Value, Gross Liability	$ 11.2		$ 11.2		$ 19.4

Derivative Financial Instrume_4

Derivative Financial Instruments and Hedging (Gain) Loss recognized in Statement of Operations from derivative instruments (Details) - Derivatives Not Designated as Hedging Instruments - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Commodity contracts | Cost of Goods Sold
Derivative Instruments, (Gain) Loss
(Gain) Loss Recognized in Statement of Operations	$ 3.2	$ (5.1)	$ 3	$ (4.7)
Energy Contracts | Cost of Goods Sold
Derivative Instruments, (Gain) Loss
(Gain) Loss Recognized in Statement of Operations	(8.3)	(0.7)	0	(2.9)
Foreign Exchange Contract - Forward Contracts | Selling, General and Administrative Expenses
Derivative Instruments, (Gain) Loss
(Gain) Loss Recognized in Statement of Operations			0	0.2
Interest rate swaps | Expense (income) on swaps, net
Derivative Instruments, (Gain) Loss
(Gain) Loss Recognized in Statement of Operations	$ 63	$ (50.5)	$ 114.7	$ (53.2)

Derivative Financial Instrume_5

Derivative Financial Instruments and Hedging Derivatives designated as hedges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Derivative Instruments, (Gain) Loss
Loss (Gain) Recognized in OCI	$ (11.9)	$ 5.4	$ 12.5	$ 3.9
Cross Currency Swap Settlements Included in AOCI	34.4		34.4		$ 4.8
Cross Currency Swap Settlements Recognized in AOCI	1.3	0.7	29.6	1.5
Collateral Already Posted	1.9		1.9		4.5
Hedging Instruments
Derivative Instruments, (Gain) Loss
Accumulated Other Comprehensive Income, Cumulative Changes in Net (Gain) Loss from Hedges, Before Tax	32		32		50
Accumulated Other Comprehensive Income, Cumulative Changes in Net (Gain) Loss from Hedges, Effect Net of Tax	32		32		$ 37.4
Foreign Exchange Contract - Forward Contracts | Hedging Instruments
Derivative Instruments, (Gain) Loss
Loss (Gain) Recognized in OCI	0	0	0	(0.2)
Foreign Exchange Contract - Forward Contracts | Selling, General and Administrative Expenses | Hedging Instruments
Derivative Instruments, (Gain) Loss
(Gain) Loss Reclassified from Accumulated OCI into Earnings	0	(1.3)	0	(1.3)
Interest Rate Swap | Hedging Instruments
Derivative Instruments, (Gain) Loss
Loss (Gain) Recognized in OCI	2.5	(20.6)	7.1	(29.6)
Interest Rate Swap Losses to be Reclassified During Next 12 Months	0.1		0.1
Interest Rate Swap | Interest expense, net | Hedging Instruments
Derivative Instruments, (Gain) Loss
(Gain) Loss Reclassified from Accumulated OCI into Earnings	(0.4)	(0.5)	(30.5)	(0.2)
Currency Swap | Hedging Instruments
Derivative Instruments, (Gain) Loss
Loss (Gain) Recognized in OCI	9.4	15.2	(19.6)	25.9
Currency Swap | Expense (income) on swaps, net | Hedging Instruments
Derivative Instruments, (Gain) Loss
(Gain) Loss Reclassified from Accumulated OCI into Earnings	$ 0	$ 0	$ 0	$ 0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2019	Oct. 01, 2018	Sep. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred Compensation Investment	$ 10.6		$ 43.6
Derivative Asset	7.3		66.4
Assets, Fair Value Disclosure	17.9		110
Deferred Compensation Liabilities	30.4		52.2
Derivative Liability	243.5		141.4
Other Liabilities, Fair Value Disclosure	273.9		193.6
Gains related to assets and liabilities held for sale	125.3
Proceeds from Sale of Assets and Liabilities Held for Sale	(276.6)
Fair market value investment in 8th Avenue	(139.6)
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred Compensation Investment	10.6		43.6
Derivative Asset	0		0
Assets, Fair Value Disclosure	10.6		43.6
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	7.3		66.4
Assets, Fair Value Disclosure	7.3		66.4
Deferred Compensation Liabilities	30.4		52.2
Derivative Liability	243.5		141.4
Other Liabilities, Fair Value Disclosure	273.9		193.6
Debt, Fair Value	6,320		7,790.9
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Balance, September 30, 2018	290.9
Balance, March 31, 2019	$ 0
Bob Evans Farms
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred Compensation Asset, Current			24.3
Deferred Compensation Liability, Current			$ 24.1
8th Avenue
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Equity Method Investment, Ownership Percentage	60.50%	60.50%

Commitments and Contingencies_2

Commitments and Contingencies (Details)	Dec. 31, 2016USD ($)	Mar. 31, 2019USD ($)defendantfacilitiesshares	Mar. 31, 2018USD ($)	Mar. 31, 2019USD ($)defendantfacilitiesshares	Mar. 31, 2018USD ($)	Sep. 30, 2018USD ($)shares	Jan. 12, 2018$ / sharesshares
Loss Contingencies
Litigation Settlement, Expense			$ 2,000,000		$ 2,000,000
Bob Evans Farms
Loss Contingencies
Business Acquisition, Share Price | $ / shares							$ 77
Basis spread on amounts owed to appraisal rights holders				5.00%
Shares for which merger consideration has been paid | shares		2,500,000		2,500,000
Shares not yet paid | shares						3,300,000	4,350,000
Lease Guarantee, Number of Properties | facilities		143		143
Current annual rent of guaranteed leases		$ 13,500,000
Lease Guarantee, Interest rate increase		1.50%
Lease Guarantee, Remaining Lease Term				17 years
Bob Evans Farms | Other Liabilities
Loss Contingencies
Payments to appraisal rights holders, including interest				$ 257,600,000
Payments to be made subsequent to the closing of the acquisition						$ 267,000,000
Bob Evans Farms | Other Current Liabilities
Loss Contingencies
Payments to be made subsequent to the closing of the acquisition		$ 14,000,000		$ 14,000,000
Michael Foods
Loss Contingencies
Claims filed, number		22		22
Loss Contingency, Number of Defendants | defendant		20		20
Loss Contingency, Pending Claims, Number of Plaintiff Groups		3		3
Litigation Settlement, Amount Awarded to Other Party	$ 75,000,000
Estimated Litigation Liability, Current		$ 6,000,000		$ 6,000,000		$ 6,000,000

Long-Term Debt (Details)

Long-Term Debt (Details)	Dec. 31, 2019USD ($)	Mar. 31, 2019USD ($)	Sep. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)	Sep. 30, 2018USD ($)
Debt Instrument
Capital Lease Obligations		$ 100,000	$ 200,000		$ 100,000		$ 200,000
Long-term Debt and Capital Lease Obligations, Including Current Maturities		6,369,300,000	7,292,400,000		6,369,300,000		7,292,400,000
Current portion of long-term debt		(6,700,000)	(22,100,000)		(6,700,000)		(22,100,000)
Unamortized Debt Issuance Expense		(67,100,000)	(71,200,000)		(67,100,000)		(71,200,000)
Plus: Unamortized premium		30,700,000	33,000,000		30,700,000		33,000,000
Long-term Debt and Capital Lease Obligations		$ 6,326,200,000	7,232,100,000		6,326,200,000		7,232,100,000
Payments of Debt Issuance Costs					8,700,000	$ 10,500,000
Payments of premiums and debt extinguishment costs					$ 0	33,500,000
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					$ 7,800,000	0
Gross Repayments of Long-term debt		$ 100,000		$ 117,500,000	$ 923,100,000	753,000,000
Debt Instruments, Covenant Compliance, Percentage of Revolving Credit Commitments		30.00%			30.00%
Capital lease
Debt Instrument
Gross Repayments of Long-term debt		$ 100,000			$ 100,000
Term Loan
Debt Instrument
Long-term Debt		$ 1,309,500,000	$ 2,172,500,000		$ 1,309,500,000		2,172,500,000
Debt Instrument, Periodic Payment, Principal	$ 3,300,000						$ 5,500,000
Debt Instrument, Interest Rate, Effective Percentage		4.49%	4.22%		4.49%		4.22%
Gross Repayments of Long-term debt				5,500,000	$ 863,000,000	11,000,000
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%
Bridge Loan
Debt Instrument
Long-term Debt		$ 0	$ 0		$ 0		$ 0
Payments of Debt Issuance Costs							10,400,000
Refund of debt issuance costs					7,800,000
Revolving Credit Facility
Debt Instrument
Line of Credit Facility, Current Borrowing Capacity		800,000,000			800,000,000
Letters of Credit Outstanding, Amount		22,800,000			22,800,000
Line of Credit Facility, Remaining Borrowing Capacity		777,200,000			777,200,000
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%
Line of Credit
Debt Instrument
Line of Credit Facility, Current Borrowing Capacity		50,000,000			$ 50,000,000
5.625% Senior Notes Maturing January 2028 | Senior Notes
Debt Instrument
Long-term Debt		940,900,000	960,900,000		940,900,000		960,900,000
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		1,000,000,000
5.75% Senior Notes Maturing March 2027 | Senior Notes
Debt Instrument
Long-term Debt		$ 1,299,300,000	1,326,300,000		1,299,300,000		1,326,300,000
Gross Repayments of Long-term debt				98,000,000	$ 27,000,000	98,000,000
5.00% Senior Notes Maturing in August 2026 | Senior Notes
Debt Instrument
Debt Instrument, Interest Rate, Stated Percentage		5.00%			5.00%
Long-term Debt		$ 1,697,300,000	1,710,300,000		$ 1,697,300,000		1,710,300,000
Payment of debt issuance costs in connection with debt consents		8,400,000
Gross Repayments of Long-term debt					13,000,000
8.00% Senior Notes Maturing in July 2025 | Senior Notes
Debt Instrument
Long-term Debt		122,200,000	122,200,000		122,200,000		122,200,000
Gross Repayments of Long-term debt				14,000,000		14,000,000
6.00% Senior Notes Maturing in December 2022 | Senior Notes
Debt Instrument
Gross Repayments of Long-term debt						630,000,000
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
Selling, General and Administrative Expenses | 5.00% Senior Notes Maturing in August 2026 | Senior Notes
Debt Instrument
Expense incurred in connection with debt consents		1,300,000			1,300,000
Loss on extinguishment of debt, net
Debt Instrument
Payments of premiums and debt extinguishment costs		0		2,700,000	0	33,500,000
Write off of Debt Issuance Costs and Other Expenses		0		1,600,000	10,800,000	8,100,000
Gain on Debt Repurchased at a Discount		0		(1,300,000)	(4,000,000)	(1,300,000)
Write-off of Unamortized Debt Discount/(Premium)		0		(2,700,000)	(700,000)	(2,700,000)
Loss on extinguishment of debt, net | Capital lease
Debt Instrument
Payments of premiums and debt extinguishment costs		0			0
Write off of Debt Issuance Costs and Other Expenses		0			0
Gain on Debt Repurchased at a Discount		0			0
Write-off of Unamortized Debt Discount/(Premium)		$ 0			0
Loss on extinguishment of debt, net | Term Loan
Debt Instrument
Payments of premiums and debt extinguishment costs				900,000	0	900,000
Write off of Debt Issuance Costs and Other Expenses				400,000	7,600,000	400,000
Gain on Debt Repurchased at a Discount				0	0	0
Write-off of Unamortized Debt Discount/(Premium)				0	0	0
Loss on extinguishment of debt, net | 5.625% Senior Notes Maturing January 2028 | Senior Notes
Debt Instrument
Payments of premiums and debt extinguishment costs					0
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
Loss on extinguishment of debt, net | 5.75% Senior Notes Maturing March 2027 | Senior Notes
Debt Instrument
Payments of premiums and debt extinguishment costs				0	0	0
Write off of Debt Issuance Costs and Other Expenses				1,100,000	300,000	1,100,000
Gain on Debt Repurchased at a Discount				(1,300,000)	(1,500,000)	(1,300,000)
Write-off of Unamortized Debt Discount/(Premium)				(2,700,000)	(700,000)	(2,700,000)
Loss on extinguishment of debt, net | 5.00% Senior Notes Maturing in August 2026 | Senior Notes
Debt Instrument
Payments of premiums and debt extinguishment costs					0
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
Loss on extinguishment of debt, net | 8.00% Senior Notes Maturing in July 2025 | Senior Notes
Debt Instrument
Payments of premiums and debt extinguishment costs				1,800,000		1,800,000
Write off of Debt Issuance Costs and Other Expenses				100,000		100,000
Gain on Debt Repurchased at a Discount				0		0
Write-off of Unamortized Debt Discount/(Premium)				$ 0		0
Loss on extinguishment of debt, net | 6.00% Senior Notes Maturing in December 2022 | Senior Notes
Debt Instrument
Payments of premiums and debt extinguishment costs						30,800,000
Write off of Debt Issuance Costs and Other Expenses						6,500,000
Gain on Debt Repurchased at a Discount						0
Write-off of Unamortized Debt Discount/(Premium)						$ 0
8th Avenue | Bridge Loan
Debt Instrument
Loans Payable to Bank			625,000,000				$ 625,000,000
Proceeds from Issuance of Unsecured Debt			625,000,000
Gross Repayments of Long-term debt					0
8th Avenue | Loss on extinguishment of debt, net | Bridge Loan
Debt Instrument
Payments of premiums and debt extinguishment costs					0
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
Post Holdings, Inc. | 8th Avenue | Bridge Loan
Debt Instrument
Proceeds from Issuance of Unsecured Debt			$ 625,000,000

Pension and Other Postretirem_3

Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Gain) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
North America | Pension Benefits
Components of net periodic benefit cost (gain)
Service cost	$ 0.9	$ 1	$ 1.9	$ 2.1
Interest cost	1	0.9	2	1.8
Expected return on plan assets	(1.6)	(1.1)	(3.2)	(2.2)
Recognized net actuarial loss	0	0.3	0	0.6
Recognized prior service cost (credit)	0.1	0	0.1	0
Net periodic benefit cost (gain)	0.4	1.1	0.8	2.3
North America | Other Postretirement Benefit Plan
Components of net periodic benefit cost (gain)
Service cost	0.1	0.1	0.2	0.3
Interest cost	0.5	0.5	1.1	1
Recognized net actuarial loss	0	0	0	0.1
Recognized prior service cost (credit)	(1.2)	(1.1)	(2.4)	(2.3)
Net periodic benefit cost (gain)	(0.6)	(0.5)	(1.1)	(0.9)
International Pension Plans | Non-North America | Pension Benefits
Components of net periodic benefit cost (gain)
Service cost	1.5	1.7	2.9	3.4
Interest cost	4.8	5.1	9.6	9.9
Expected return on plan assets	(7.3)	(8.2)	(14.6)	(16)
Net periodic benefit cost (gain)	$ (1)	$ (1.4)	$ (2.1)	$ (2.7)

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Class of Stock [Line Items]
Purchases of treasury stock			$ (65.8)	$ (138.8)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	1.3
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 32.71
Proceeds from exercises of stock awards	$ 41.5		$ 41.5	$ 4
Common Stock
Class of Stock [Line Items]
Purchases of treasury stock, shares	0.4	1.1	0.7	1.8
Treasury Stock Acquired, Average Cost Per Share (in USD per share)	$ 97.68	$ 74.03	$ 93.77	$ 75.59
Purchases of treasury stock	$ 40.5	$ 82.8	$ 65.8	$ 138.8
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Conversion of Stock, Shares Converted	3.2
Series B Preferred Stock
Class of Stock [Line Items]
Conversion of Stock, Shares Converted		1.5
Common Stock
Class of Stock [Line Items]
Conversion of Stock, Shares Issued	5.9	3.1

Segments (Details)

Segments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Oct. 01, 2018	Sep. 30, 2018
Segment Reporting Information
Investment, Ownership Percentage, Parent					60.50%
Net Sales	$ 1,387.8	$ 1,586.1	$ 2,799.1	$ 3,019.2
Gain on sale of business	(2.6)	0	(127.3)	0
Interest expense, net	85.5	98.8	144.9	189.3
Loss on extinguishment of debt, net	0	0.3	6.1	37.6
Expense (income) on swaps, net	63	(50.5)	114.7	(53.2)
Earnings before income taxes and equity method loss	41.5	115.7	221.9	155.1
Depreciation and amortization	97.8	104.6	191.4	195.1
Assets	11,282.8		11,282.8			$ 13,057.5
Corporate
Segment Reporting Information
General corporate expenses and other	37.3	45.5	85.7	73.8
Depreciation and amortization	5.4	1.6	9.4	2.8
Assets	345.2		345.2			1,065.5
Operating Segments
Segment Reporting Information
Net Sales	1,387.8	1,586.1	2,799.1	3,019.2
Segment Profit	224.7	209.8	446	402.6
Depreciation and amortization	92.4	103	182	192.3
Operating Segments | Post Consumer Brands
Segment Reporting Information
Net Sales	459.1	462.3	914.4	894.3
Segment Profit	83.2	91.1	167.2	161.3
Depreciation and amortization	29.9	30.9	59.4	61.8
Assets	3,375		3,375			3,391.7
Operating Segments | Weetabix
Segment Reporting Information
Net Sales	104.1	109	205	208.7
Segment Profit	23.6	15.7	42.5	32.5
Depreciation and amortization	8.8	12.7	17.5	19.8
Assets	1,856.7		1,856.7			1,853.3
Operating Segments | Foodservice
Segment Reporting Information
Net Sales	389.1	380.2	797.2	749.1
Segment Profit	47.4	42.9	100.1	88.8
Depreciation and amortization	27.7	26	54.7	49.9
Operating Segments | Refrigerated Retail
Segment Reporting Information
Net Sales	219.5	219.8	481.1	361.5
Segment Profit	26.5	19.8	57	43
Depreciation and amortization	19.7	15.3	37.7	22.8
Operating Segments | Foodservice and Refrigerated Retail
Segment Reporting Information
Assets	5,105.1		5,105.1			5,132.4
Operating Segments | Active Nutrition
Segment Reporting Information
Net Sales	216.5	205.2	402.3	391.2
Segment Profit	44	26.1	79.2	45.9
Depreciation and amortization	6.3	6.4	12.7	12.9
Assets	600.8		600.8			559.3
Operating Segments | Private Brands
Segment Reporting Information
Net Sales	0	212.6	0	419
Segment Profit	0	14.2	0	31.1
Depreciation and amortization	0	11.7	0	25.1
Assets	0		0			$ 1,055.3
Eliminations | Eliminations
Segment Reporting Information
Net Sales	$ (0.5)	$ (3)	$ (0.9)	$ (4.6)