Post (POST) 10-K 16 Nov 18 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Sep. 30, 2018	Nov. 12, 2018	Mar. 31, 2018
Document Information
Entity Registrant Name	Post Holdings, Inc.
Entity Central Index Key	1,530,950
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		66,573,470
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 4,367,483,164

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Net Sales	$ 6,257.2	$ 5,225.8	$ 5,026.8
Cost of goods sold	4,390.4	3,651.7	3,479.4
Gross Profit	1,866.8	1,574.1	1,547.4
Selling, general and administrative expenses	975.2	867.4	839.7
Amortization of intangible assets	177.4	159.1	152.6
Impairment of goodwill and other intangible assets	124.9	26.5	0
Other operating expenses, net	1.8	0.8	9.4
Operating Profit	587.5	520.3	545.7
Interest expense, net	387.3	314.8	306.5
Loss on extinguishment of debt, net	31.1	222.9	86.4
(Income) expense on swaps, net	(95.6)	(91.8)	182.9
Earnings (Loss) before Income Taxes and Equity Method Loss	264.7	74.4	(30.1)
Income tax (benefit) expense	(204)	26.1	(26.8)
Equity method loss, net of tax	0.3	0	0
Net Earnings (Loss) Including Noncontrolling Interest	468.4	48.3	(3.3)
Less: Net earnings attributable to noncontrolling interest	1.1	0	0
Net Earnings (Loss)	467.3	48.3	(3.3)
Preferred stock dividends	(10)	(13.5)	(25.1)
Net Earnings (Loss) Available to Common Shareholders	$ 457.3	$ 34.8	$ (28.4)
Earnings (Loss) per share:
Basic earnings (loss) per common share	$ 6.87	$ 0.51	$ (0.41)
Diluted (loss) earnings per common share	$ 6.16	$ 0.50	$ (0.41)
Weighted-Average Common Shares Outstanding:
Weighted-average shares for basic earnings (loss) per share	66.6	67.8	68.8
Weighted-average shares for diluted earnings (loss) per share	75.9	69.9	68.8

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net earnings (loss) including noncontrolling interest	$ 468.4	$ 48.3	$ (3.3)
Pension and postretirement benefits adjustments:
Unrealized pension and postretirement benefit obligations	5	47.8	6.2
Reclassifications to net earnings (loss)	(3.2)	(2.3)	(0.8)
Unrealized gain on plan amendment (see Note 18)	0	0	35.6
Hedging adjustments:
Unrealized net gain (loss) on derivatives	72.2	(18.8)	0
Reclassifications to net earnings (loss)	(3.6)	0.7	0
Other reclassifications	(0.5)	0	0
Foreign currency translation adjustments:
Unrealized foreign currency translation adjustments	(51.3)	(5.7)	5.5
Reclassifications to net earnings (loss) (see Note 4)	0	0	(1.3)
Tax benefit (expense) on other comprehensive income:
Pension and postretirement benefits	1	(8.3)	(16.5)
Hedging	(19.6)	7	0
Total Other Comprehensive Income	0	20.4	28.7
Less: Comprehensive income attributable to noncontrolling interest	1.7	0	0
Total Comprehensive Income	$ 466.7	$ 68.7	$ 25.4

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017
Current Assets
Cash and cash equivalents	$ 989.7	$ 1,525.9
Restricted cash	4.8	4.2
Receivables, net	462.3	480.6
Inventories	484.2	573.5
Current assets held for sale	195	0
Prepaid expenses and other current assets	64.3	31.7
Total Current Assets	2,200.3	2,615.9
Property, net	1,709.7	1,690.7
Goodwill	4,499.6	4,032
Other intangible assets, net	3,539.3	3,353.9
Other assets held for sale	856.6	0
Other assets	252	184.3
Total Assets	13,057.5	11,876.8
Current Liabilities
Current portion of long-term debt	22.1	22.1
Accounts payable	365.1	336
Current liabilities held for sale	65.6	0
Other current liabilities	339.3	346.3
Total Current Liabilities	792.1	704.4
Long-term debt	7,232.1	7,149.1
Deferred income taxes	778.4	905.8
Other liabilities held for sale	695.1	0
Other liabilities	499.3	327.8
Total Liabilities	9,997	9,087.1
Commitments and Contingencies
Shareholders’ Equity
Preferred Stock, Value, Issued	0	0
Common stock, $0.01 par value, 300.0 shares authorized, 66.7 and 66.1 shares outstanding, respectively	0.8	0.7
Additional paid-in capital	3,590.9	3,566.5
Retained earnings (accumulated deficit)	88	(376)
Accumulated other comprehensive loss	(39.4)	(40)
Treasury stock, at cost, 8.6 and 5.8 shares, respectively	(589.9)	(371.2)
Total Shareholders’ Equity Excluding Noncontrolling Interest	3,050.4	2,780
Noncontrolling interest	10.1	9.7
Total Shareholders’ Equity	3,060.5	2,789.7
Total Liabilities and Shareholders’ Equity	$ 13,057.5	$ 11,876.8

Consolidated Balance Sheets Con

Consolidated Balance Sheets Consolidated Balance Sheet (Parentheticals) - $ / shares shares in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Par value of preferred stock	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	50	50
Common Stock, Shares Authorized	300	300
Common Stock, Shares, Issued	66.7	66.1
Par value of common stock	$ 0.01	$ 0.01
Treasury Stock, Shares	8.6	5.8
Series B Preferred Stock
Par value of preferred stock	$ 0.01
Preferred Stock, Dividend Rate, Percentage	3.75%	3.75%
Preferred stock issued	0	1.5
Preferred Stock, Shares Outstanding	0	1.5
Series C Preferred Stock
Par value of preferred stock	$ 0.01
Preferred Stock, Dividend Rate, Percentage	2.50%	2.50%
Preferred stock issued	3.2	3.2
Preferred Stock, Shares Outstanding	3.2	3.2

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Cash Flows from Operating Activities:
Net earnings (loss) including noncontrolling interest	$ 468.4	$ 48.3	$ (3.3)
Adjustments to reconcile of net (loss) earnings to net cash provided by operating activities:
Depreciation and amortization	398.4	323.1	302.8
Loss on extinguishment of debt, net	31.1	222.9	86.4
Loss (gain) on foreign currency	0.7	(30.8)	(0.2)
Impairment of goodwill and other intangible assets	124.9	26.5	0
Unrealized (gain) loss on interest rate swaps and cross-currency swaps, net	(96.7)	(93.6)	182.4
Non-cash stock-based compensation expense	30.9	23.6	17.2
Deferred income taxes	(256.5)	17.4	(74.6)
Other, net	8.8	6.7	12.9
Other changes in operating assets and liabilities, net of business acquisitions and held for sale assets and liabilities:
Increase in receivables	(6)	(45.9)	(4)
Decrease (increase) in inventories	3.6	(2.5)	(37.2)
Decrease (increase) in prepaid expenses and other current assets	7.9	3.7	(3.5)
Increase in other assets	(24)	(8.7)	(2.8)
Increase (decrease) in accounts payable and other current liabilities	29.4	(109)	18.8
(Decrease) increase in non-current liabilities	(1.6)	5	7.5
Net Cash Provided by Operating Activities	719.3	386.7	502.4
Cash Flows from Investing Activities
Business acquisitions, net of cash acquired	(1,454.4)	(1,915.2)	(94.4)
Additions to property	(225)	(190.4)	(121.5)
Restricted cash	(1.3)	4.2	10.4
Proceeds from sale of property and assets held for sale	0.2	10.6	2.1
Proceeds from sale of businesses	0	0	7.3
Other, net	3.6	0	0
Net Cash Used in Investing Activities	(1,676.9)	(2,090.8)	(196.1)
Cash Flows from Financing Activities
Proceeds from issuance of long-term debt	1,625	4,700	1,750
Repayments of long-term debt	(912.1)	(2,088.4)	(1,632.2)
Purchases of treasury stock	(218.7)	(317.8)	0
Payments of preferred stock dividends	(10.8)	(13.5)	(14.4)
Premium from issuance of long-term debt	0	41.2	0
Preferred stock conversion	0	0	(10.9)
Payments of debt issuance costs and deferred financing fees	(24.9)	(59)	(24.3)
Payments of debt extinguishment costs	(33.7)	(219.8)	(88)
Proceeds from exercise of stock awards	5.7	13.4	6.6
Net cash received from stock repurchase contracts	0	0	1.1
Distribution to noncontrolling interest	1.4	0	0
Other, net	(5.7)	(3)	7.6
Net Cash Provided by (Used in) Financing Activities	423.4	2,053.1	(4.5)
Effect of Exchange Rate Changes on Cash and Cash Equivalents	(2)	33.3	0.4
Net (Decrease) Increase in Cash and Cash Equivalents	(536.2)	382.3	302.2
Cash and Cash Equivalents, Beginning of Year	1,525.9	1,143.6	841.4
Cash and Cash Equivalents, End of Year	$ 989.7	$ 1,525.9	$ 1,143.6

Consolidated Statement of Share

Consolidated Statement of Shareholders' Equity - USD ($) shares in Millions, $ 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	Common Stock	Preferred Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred Stock, Shares		5.6
Common Stock, Shares			62.1
Balance at beginning of period at Sep. 30, 2015	$ 2,976	$ 0.1	$ 0.6	$ 3,538.8	$ (421)	$ (26.6)		$ (62.5)	$ (53.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings (loss)	(3.3)				(3.3)
Preferred stock dividends declared	(14.4)			(14.4)
Preferred stock conversion (shares)												(0.9)
Preferred stock conversion		(0.1)
Preferred Stock Conversion, Shares Issued			(2)								2
Preferred Stock Conversion, Value of Shares Issued			$ 0.1
Preferred stock conversion	(10.9)			(10.9)
Activity under stock and deferred compensation plans	14.2			14.2
Activity under stock and deferred compensation plans (shares)			0.6									0
Stock-based compensation expense	17.2			17.2
Net cash received from stock repurchase contracts	1.1			1.1
Tangible equity units conversion (shares)			0.2								0.2
Net earnings attributable to noncontrolling interest	0
Distribution to noncontrolling interest	0
Other comprehensive income (loss):
Net change in retirement benefits, net of tax	24.5					24.5
Foreign currency translation adjustments	4.2							4.2
Balance at the end of period at Sep. 30, 2016	3,008.6	$ 0	$ 0.7	3,546	(424.3)	(2.1)		(58.3)	(53.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred Stock, Shares		4.7
Common Stock, Shares			64.9
Net earnings (loss)	48.3				48.3
Preferred stock dividends declared	(13.5)			(13.5)
Preferred stock conversion	0
Activity under stock and deferred compensation plans	10.4			10.4
Activity under stock and deferred compensation plans (shares)		0	0.5
Stock-based compensation expense	23.6			23.6
Net cash received from stock repurchase contracts	0			0
Tangible equity units conversion (shares)		0	4.7								4.7
Purchases of treasury stock (shares)			(4)
Purchases of treasury stock	(317.8)		$ 317.8						(317.8)
Noncontrolling interest in acquisition	9.7									$ 9.7
Net earnings attributable to noncontrolling interest	0
Distribution to noncontrolling interest	0
Other comprehensive income (loss):
Net change in retirement benefits, net of tax	37.2					37.2
Net change in hedges, net of tax	(11.1)						$ (11.1)
Foreign currency translation adjustments	(5.7)							(5.7)
Balance at the end of period at Sep. 30, 2017	2,789.7	$ 0	$ 0.7	3,566.5	(376)	35.1	(11.1)	(64)	(371.2)	9.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred Stock, Shares		4.7
Common Stock, Shares			66.1
Net earnings (loss)	467.3				467.3
Adoption of accounting standards update 2018-02	1.4				1.4
Preferred stock dividends declared	(10.8)			(6.8)	(4)
Preferred stock conversion (shares)												(1.5)
Preferred stock conversion	(0.1)	$ 0
Preferred Stock Conversion, Shares Issued											3.1
Preferred Stock Conversion, Value of Shares Issued			$ 0.1
Preferred stock conversion	0			0
Activity under stock and deferred compensation plans	0.3			0.3
Activity under stock and deferred compensation plans (shares)			0.3									0
Stock-based compensation expense	30.9			30.9
Net cash received from stock repurchase contracts	0
Tangible equity units conversion (shares)			0									0
Purchases of treasury stock (shares)			(2.8)									0
Purchases of treasury stock	(218.7)		$ 218.7						(218.7)
Net earnings attributable to noncontrolling interest	1.1									1.1
Distribution to noncontrolling interest	(1.4)				(0.7)					(0.7)
Other comprehensive income (loss):
Net change in retirement benefits, net of tax	2.8					2.8
Net change in hedges, net of tax	48.5						48.5
Foreign currency translation adjustments	(50.7)							(50.7)
Balance at the end of period at Sep. 30, 2018	$ 3,060.5	$ 0	$ 0.8	$ 3,590.9	$ 88	$ 37.9	$ 37.4	$ (114.7)	$ (589.9)	$ 10.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Preferred Stock, Shares		3.2
Common Stock, Shares			66.7

Background

Background	12 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background	BACKGROUND Post Holdings, Inc. (“Post” or the “Company”) is a consumer packaged goods holding company operating in the center-of-the-store, refrigerated, foodservice, food ingredient, active nutrition and private brand food categories. The Company’s products are sold through a variety of channels such as grocery, club and drug stores, mass merchandisers, foodservice, food ingredient and e-commerce. As of September 30, 2018, Post operates in five reportable segments: Post Consumer Brands, Weetabix, Refrigerated Food, Active Nutrition and Private Brands. The Post Consumer Brands segment includes the North American ready-to-eat (“RTE”) cereal business; the Weetabix segment includes the RTE cereal and branded muesli business sold and distributed primarily outside of North America; the Refrigerated Food segment includes refrigerated foodservice, primarily egg and potato, and refrigerated retail, inclusive of side dishes, egg, cheese and sausage; the Active Nutrition segment includes protein shakes, bars and powders and nutritional supplements; and the Private Brands segment includes peanut and other nut butters, dried fruit and nut products, granola and pasta. Pursuant to the Transaction Agreement (the “Transaction Agreement”), dated as of August 2, 2018, among Post, 8th Avenue Food & Provisions, Inc. (“8th Avenue”), and THL Equity Fund VIII Investors (PB), LLC, an affiliate of Thomas H. Lee Partners, L.P., Post and affiliates of Thomas H. Lee Partners, L.P. (collectively, “THL”) separately capitalized 8th Avenue (the “8th Avenue Transactions”). Upon the closing of the 8th Avenue Transactions, 8th Avenue became the holding company for Post’s private brands business, reported herein as Post’s Private Brands segment, and Post received total proceeds of $875.0 , retaining shares of common stock equal to 60.5% of the common equity in 8th Avenue. Upon completion of the 8th Avenue Transactions, 8th Avenue is no longer consolidated in the Company's financial statements and the 60.5% retained interest in 8th Avenue is accounted for using the equity method. At September 30, 2018, the assets and liabilities of the Private Brands segment were classified as held for sale. For additional information, see Notes 4, 6 and 16. Unless otherwise stated or the context otherwise indicates, all references in these financial statements and notes to “Post,” “the Company,” “us,” “our” or “we” mean Post Holdings, Inc. and its consolidated and non-consolidated subsidiaries. Certain prior year amounts have been reclassified to conform with the 2018 presentation. These reclassifications had no impact on Net Earnings (Loss) or Shareholders’ Equity, as previously reported.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Summary of Signifcant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation — The consolidated financial statements include the operations of Post and its wholly-owned and majority-owned subsidiaries. All intercompany transactions have been eliminated. Use of Estimates and Allocations — The consolidated financial statements of the Company are prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”), which require certain elections as to accounting policy, estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent liabilities at the dates of the financial statements and the reported amount of net revenues and expenses during the reporting periods. Significant accounting policy elections, estimates and assumptions include, among others, pension and benefit plan assumptions, valuation assumptions of goodwill and other intangible assets, marketing programs, self-insurance reserves and income taxes. Actual results could differ from those estimates. Business Combinations — The Company uses the acquisition method in accounting for acquired businesses. Under the acquisition method, the Company’s financial statements reflect the operations of an acquired business starting from the completion of the acquisition. The assets acquired and liabilities assumed are recorded at their respective estimated fair values at the date of the acquisition. Any excess of the purchase price over the estimated fair values of the identifiable net assets acquired is recorded as goodwill. Cash Equivalents — Cash equivalents include all highly liquid investments with original maturities of less than three months. Restricted Cash — Restricted cash includes items such as cash deposits which serve as collateral for certain commodity hedging contracts as well as the Company's high deductible workers’ compensation insurance program. Receivables — Receivables are reported at net realizable value. This value includes appropriate allowances for doubtful accounts, cash discounts and other amounts which the Company does not ultimately expect to collect. The Company determines its allowance for doubtful accounts based on historical losses as well as the economic status of and its relationship with its customers, especially those identified as “at risk.” A receivable is considered past due if payments have not been received within the agreed upon invoice terms. Receivables are written off against the allowance when the customer files for bankruptcy protection or are otherwise deemed to be uncollectible based upon the Company’s evaluation of the customer’s solvency. The Weetabix segment sells certain receivables to third party institutions without recourse. Receivables sold during the year ended September 30, 2018 were $137.3 and receivables sold in fiscal 2017 subsequent to July 3, 2017, the date of the Weetabix Group acquisition (as defined in Note 4), were $37.3 . Inventories — Inventories, other than flocks, are generally valued at the lower of average cost (determined on a first-in, first-out basis) or net realizable value (“NRV”). Reported amounts have been reduced by an allowance for obsolete product and packaging materials based on a review of inventories on hand compared to estimated future usage and sales. Flock inventory represents the cost of purchasing and raising chicken flocks to egg laying maturity. The costs included in our flock inventory include the costs of the chicks, the feed fed to the birds and the labor and overhead costs incurred to operate the pullet facilities until the birds are transferred into the laying facilities, at which time their cost is amortized to operations, as cost of goods sold, over their expected useful lives of one to two years. Restructuring Expenses — Restructuring charges principally consist of severance, accelerated stock compensation and other employee separation costs and accelerated depreciation. The Company recognizes restructuring obligations and liabilities for exit and disposal activities at fair value in the period the liability is incurred. Employee severance costs are expensed when they become probable and reasonably estimable under established severance plans. Depreciation expense related to assets that will be disposed of or idled as a part of the restructuring activity is accelerated through the expected date of the asset shut down. See Note 5 for information about restructuring expenses. Held for Sale Assets and Liabilities — Assets and liabilities are classified as held for sale if the Company has committed to a plan for selling the assets and liabilities, is actively and reasonably marketing them and sale is reasonably expected within one year. The carrying value of assets held for sale is included in “Current assets held for sale” and “Other assets held for sale” on the Consolidated Balance Sheets. The carrying value of liabilities held for sale is included in “Current liabilities held for sale” and “Other liabilities held for sale” on the Consolidated Balance Sheets. See Note 6 for information about assets and liabilities held for sale. Property — Property is recorded at cost, and depreciation expense is generally provided on a straight-line basis over the estimated useful lives of the properties. Estimated useful lives range from 1 to 29 years for machinery and equipment; 1 to 40 years for buildings, building improvements and leasehold improvements; and 1 to 7 years for software. Total depreciation expense was $221.0 , $164.0 and $150.2 in fiscal 2018 , 2017 and 2016 , respectively. Any gains and losses incurred on the sale or disposal of assets are included in “Other operating expenses, net” in the Consolidated Statements of Operations. Repair and maintenance costs incurred in connection with on-going and planned major maintenance activities are accounted for under the direct expensing method. Property consisted of: September 30, 2018 2017 Land and land improvements $ 88.2 $ 90.9 Buildings and leasehold improvements 720.7 699.4 Machinery and equipment 1,507.4 1,439.3 Software 112.0 64.5 Construction in progress 114.7 100.0 2,543.0 2,394.1 Accumulated depreciation (833.3 ) (703.4 ) $ 1,709.7 $ 1,690.7 Other Intangible Assets — Other intangible assets consist primarily of customer relationships and trademarks/brands acquired in business combinations and include both indefinite and definite-lived assets. Amortization expense related to definite-lived intangible assets, which is provided on a straight-line basis over the estimated useful lives of the assets, was $177.4 , $159.1 and $152.6 in fiscal 2018 , 2017 and 2016 , respectively. For the definite-lived intangible assets recorded as of September 30, 2018 , amortization expense of $159.2 , $159.2 , $159.2 , $156.4 and $159.0 is expected for fiscal 2019 , 2020 , 2021 , 2022 and 2023 , respectively. Other intangible assets consisted of: September 30, 2018 September 30, 2017 Carrying Amount Accum. Amort. Net Amount Carrying Amount Accum. Amort. Net Amount Subject to amortization: Customer relationships $ 2,307.0 $ (444.4 ) $ 1,862.6 $ 2,249.3 $ (416.7 ) $ 1,832.6 Trademarks and brands 768.5 (188.2 ) 580.3 834.1 (162.9 ) 671.2 Other 3.1 (3.1 ) — 21.7 (9.8 ) 11.9 3,078.6 (635.7 ) 2,442.9 3,105.1 (589.4 ) 2,515.7 Not subject to amortization: Trademarks and brands 1,096.4 — 1,096.4 838.2 — 838.2 $ 4,175.0 $ (635.7 ) $ 3,539.3 $ 3,943.3 $ (589.4 ) $ 3,353.9 Recoverability of Assets — The Company continually evaluates whether events or circumstances have occurred which might impair the recoverability of the carrying value of its assets, including property, identifiable intangibles and goodwill. Trademarks with indefinite lives are reviewed for impairment during the fourth quarter of each fiscal year following the annual forecasting process, or more frequently if facts and circumstances indicate the trademark may be impaired. The trademark impairment tests require us to estimate the fair value of the trademark and compare it to its carrying value. The estimated fair value is determined using an income-based approach (the relief-from-royalty method), which requires significant assumptions for each brand, including estimates regarding future revenue growth, discount rates and appropriate royalty rates. Assumptions are determined after consideration of several factors for each brand, including profit levels, research of external royalty rates by third party experts and the relative importance of each brand to the Company. Revenue growth assumptions are based on historical trends and management’s expectations for future growth by brand. The discount rate is based on a weighted-average cost of capital utilizing industry market data of similar companies. In addition, definite-lived assets and indefinite-lived intangible assets are reassessed as needed when information becomes available that is believed to negatively impact the fair market value of an asset. In general, an asset is deemed impaired and written down to its fair value if estimated related future cash flows are less than its carrying amount. See Note 7 for information about goodwill impairments. At September 30, 2018, the Company recorded an impairment charge of $124.9 for the Weetabix trademark to adjust its carrying value to its estimated fair value of $261.8 . The impairment charge for the Weetabix trademark is a result of reduced branded cereal volumes related to Weetabix’s pricing reset and shifting consumer preferences to private label products. For the years ended September 30, 2017 and 2016, the Company conducted impairment reviews and concluded there was no impairment of other intangible assets as of September 30, 2017 or 2016. These fair value measurements fall within Level 3 of the fair value hierarchy as described in Note 15. The trademark impairment losses are reported in “Impairment of goodwill and other intangible assets” on the Consolidated Statements of Operations. Deferred Compensation Investments — The Company funds a portion of its deferred compensation liability by investing in certain mutual funds, or funds that employ a similar investment strategy, and are purchased in substantially the same amounts, as selected by the participating employees. Because management’s intent is to invest in a manner that matches the deferral options chosen by the participants and those participants can elect to transfer amounts in or out of each of the designated deferral options at any time, these investments have been classified as trading assets and are stated at fair value in “Prepaid expenses and other current assets” and “Other assets” on the Consolidated Balance Sheets (see Note 15). Both realized and unrealized gains and losses on these assets are included in “Selling, general and administrative expenses” in the Consolidated Statements of Operations and offset the related change in the deferred compensation liability. Derivative Financial Instruments — 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. The Company’s derivative programs include strategies that qualify and strategies that do not qualify for hedge accounting treatment. To qualify for hedge accounting, the hedging relationship, both at inception of the hedge and on an ongoing basis, is expected to be highly effective in achieving offsetting changes in the fair value of the hedged risk during the period that the hedge is designated. All derivatives are recognized on the balance sheet at fair value. For derivatives that qualify for hedge accounting, the derivative is designated as a hedge on the date in which the derivative contract is entered. A derivative could be designated as a hedge of a forecasted transaction or of the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge) or a hedge of a net investment in a foreign operation. Some derivatives may also be considered natural hedging instruments, where changes in fair value act as economic offsets to changes in fair value of the underlying hedged item and are not designated for hedge accounting. The Company does not have any derivatives currently designated as fair value hedges. The effective portion of gains and losses on cash flow hedges are recorded in other comprehensive income (“OCI”), until earnings are affected by the variability of cash flows. If the hedge is no longer effective, all changes in the fair value of the derivative are included in earnings for each period until the instrument matures. If a derivative is used as a hedge of a net investment in a foreign operation, its changes in fair value, to the extent effective as a hedge, are recorded in OCI. Any ineffective portion of designated hedges are recognized in earnings. Changes in the fair value of derivatives that are not designated for hedge accounting are recognized in earnings. Cash flows from derivatives that are accounted for as hedges and cash flows on derivatives utilized as economic hedges, are classified in the same category on the Statements of Cash Flows as the item being hedged or on a basis consistent with the nature of the instrument. Revenue — Revenue is recognized when title of goods and risk of loss is transferred to the customer, as specified by the shipping terms. Net sales reflect gross sales, including amounts billed to customers for shipping and handling, less sales discounts and trade allowances (including promotional price buy downs and new item promotional funding). Customer trade allowances are generally computed as a percentage of gross sales. Products are generally sold with no right of return, except in the case of goods which do not meet product specifications or are damaged, and related reserves are maintained based on return history. If additional rights of return are granted, revenue recognition is deferred. Estimated reductions to revenue for customer incentive offerings are based upon customer redemption history. Cost of Goods Sold — Cost of goods sold includes, among other things, inbound and outbound freight costs (including the Company-owned fleet) and depreciation expense related to assets used in production, while storage and other warehousing costs are included in “Selling, general and administrative expenses” in the Consolidated Statements of Operations. Storage and other warehousing costs totaled $ 169.4 , $ 142.9 and $ 124.1 in fiscal 2018 , 2017 and 2016 , respectively. Advertising — Advertising costs are expensed as incurred except for costs of producing media advertising such as television commercials or magazine advertisements, which are deferred until the first time the advertising takes place. The amounts reported as assets on the Consolidated Balance Sheets as “Prepaid expenses and other current assets” were $1.9 and $1.3 as of September 30, 2018 and 2017 , respectively. Stock-based Compensation — The Company recognizes the cost of employee services received in exchange for awards of equity instruments based on the grant-date fair value of equity awards and the fair market value at each quarterly reporting date for liability awards. That cost is recognized over the period during which an employee is required to provide service in exchange for the award — the requisite service period (usually the vesting period). See Note 19 for disclosures related to stock-based compensation. Income Tax (Benefit) Expense — Income tax (benefit) expense is estimated based on income taxes in each jurisdiction and includes the effects of both current tax exposures and the temporary differences resulting from differing treatment of items for tax and financial reporting purposes. These temporary differences result in deferred tax assets and liabilities. A valuation allowance is established against the related deferred tax assets to the extent that it is more likely than not that the future benefits will not be realized. Reserves are recorded for estimated exposures associated with the Company’s tax filing positions, which are subject to periodic audits by governmental taxing authorities. Interest incurred due to an underpayment of income taxes is classified as income taxes. While the Company considers the undistributed earnings of its foreign subsidiaries to be permanently reinvested, the Company recorded a one-time transition tax on such earnings during the year ended September 30, 2018 in accordance with the Tax Cuts and Jobs Act (the “Tax Act”). See Note 9 for disclosures related to income taxes.

Recently Issued and Adopted Acc

Recently Issued and Adopted Accounting Standards	12 Months Ended
	Sep. 30, 2018
Recently Issued Accounting Standards [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 results of operations, OCI, financial condition, cash flows or shareholders’ equity based on current information. Recently Issued In August 2018, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“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 standards update largely aligns the guidance on recognizing implementation costs incurred in a cloud computing arrangement that is a service contract with that for implementation costs incurred to develop or obtain internal-use software, including hosting arrangements that include an internal-use software license. This ASU is effective for annual periods beginning after December 15, 2019 and interim periods therein (i.e., Post’s financial statements for the year ending September 30, 2021), with early adoption permitted. The Company will early adopt this ASU on October 1, 2018 on a prospective basis, as permitted by the standard. This change is not expected to have a material impact on the Company’s financial statements. In August 2018, the FASB issued ASU 2018-14, “Compensation - Retirement Benefits - Defined Benefit Plans - General (Subtopic 715-20): Disclosure Framework - Changes to the Disclosure Requirements for Defined Benefit Plans.” This standards update removes, clarifies and adds certain disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. This ASU is effective for annual periods ending after December 15, 2020 and interim periods therein (i.e., Post’s financial statements for the year ending September 30, 2021), with early adoption permitted. The Company is currently evaluating the impact and timing of adopting this standard. In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement.” This standards update removes, modifies and adds certain disclosure requirements related to fair value measurements. This ASU is effective for annual periods beginning after December 15, 2019 and interim periods therein (i.e., Post’s financial statements for the year ending September 30, 2021), with early adoption permitted. The Company is currently evaluating the impact and timing of adopting this standard. In June 2018, the FASB issued ASU 2018-07, “Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting.” This standards update 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. 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). The Company will early adopt this ASU on October 1, 2018 on a prospective basis, as permitted by the standard. The Company had not issued any nonemployee share-based payment awards as of September 30, 2018, however, share-based payment awards granted to employees of 8th Avenue will be accounted for as nonemployee compensation beginning on October 1, 2018. 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 standards update 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. The amendments in this ASU also allow only the service cost component to be eligible for capitalization when applicable. The Company will adopt this standard on October 1, 2018 and will use the retrospective method of adoption, as required by the standard. The adoption of this ASU will result in a change in operating profit and a corresponding change to other (income) expense, net to reflect the exclusion of all components of net benefit cost, with the exception of service cost, from operating profit. The reclassification would have resulted in a decrease in operating profit of $14.0 and $3.6 for the years ended September 30, 2018 and 2017, respectively, and an increase in operating profit of $3.1 for the year ended September 30, 2016. This ASU also permits an entity to capitalize the service cost component as part of an asset, such as inventory, on a prospective basis. This change is not expected to have a material impact on the Company’s financial statements. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842).” This standards update requires a company to recognize right-of-use assets and lease liabilities with terms greater than one year 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 standard on October 1, 2019 and expects to use the modified retrospective method of adoption applied prospectively as of the adoption date. 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 expanded disclosures to present additional information related to its leasing arrangements. In November 2016, the FASB issued ASU 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash.” This standards update 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. This ASU is effective for annual periods beginning after December 15, 2017 and interim periods therein (i.e., Post’s financial statements for the year ending September 30, 2019), with early adoption permitted. The Company will adopt this standard on October 1, 2018 and will use the retrospective method of adoption. The Company currently classifies changes in restricted cash as an investing activity in the Consolidated Statements of Cash Flows, not as a component of cash and cash equivalents as required by this ASU. The change in restricted cash included in “Net Cash Used in Investing Activities” on the Consolidated Statements of Cash Flows was $(1.3) , $4.2 and $10.4 for the years ended September 30, 2018, 2017 and 2016, respectively. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” which will supersede all 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. The standard also calls for additional disclosures around the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. This ASU is effective for annual and interim periods beginning on or after December 15, 2017 (i.e., Post’s financial statements for the year ending September 30, 2019). The Company has completed its assessment of the impact this standard will have on its accounting policies, processes, system requirements, internal controls and disclosures. The Company will adopt this standard on October 1, 2018 and will use the modified retrospective transition method of adoption. The adoption will not have a material impact on its financial statements as the impact of this ASU will be limited to recognition timing and classification changes of immaterial amounts within the statement of operations and balance sheet. Recently Adopted In March 2018, the FASB issued ASU 2018-05, “Income Taxes (Topic 740): Amendments to the Securities and Exchange Commission (“SEC”) Paragraphs Pursuant to SEC Staff Accounting Bulletin No. 118,” which codifies the SEC’s interpretive guidance released on December 22, 2017, when the Tax Act was signed into law. See Note 9 for additional information regarding the adoption of this standard. In February 2018, the FASB issued ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” This standards update amends Accounting Standards Codification (“ASC”) Topic 220 “Income Statement—Reporting Comprehensive Income,” to allow a reclassification from accumulated OCI to retained earnings for stranded tax effects resulting from the Tax Act. In accordance with this standard, the Company early adopted this ASU during the second quarter of fiscal 2018, which resulted in an adjustment to “Retained earnings (accumulated deficit)” and “Accumulated other comprehensive loss” of $1.4 on the Consolidated Balance Sheet. In July 2015, the FASB issued ASU 2015-11, “Inventory (Topic 330): Simplifying the Measurement of Inventory.” This standards update requires most inventory to be measured at the lower of cost or NRV, thereby simplifying the previous guidance under which an entity must measure inventory at the lower of cost or market. Market is defined as replacement cost, NRV or NRV less a normal profit margin. This ASU does not apply to inventory that is measured using either the last-in, first-out method or the retail inventory method. The Company adopted this ASU during the first quarter of fiscal 2018. The adoption of this ASU did not have a material impact on the Company’s consolidated financial statements or related disclosures.

Business Combinations and Dives

Business Combinations and Divestitures	12 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Business Combinations and Divestitures	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. Fiscal 2018 Acquisitions 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. 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. The Company estimates additional payments of $342.4 will be made subsequent to the closing date, which includes payments to former holders of shares of Bob Evans common stock who had exercised appraisal rights, payments in connection with Bob Evans deferred compensation plans and payments to compensate Bob Evans employees due to the cancellation of their outstanding employee stock awards. At September 30, 2018 , the 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 is the number of shares of Bob Evans common stock for which former Bob Evans stockholders had demanded appraisal and 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% . The liability is reported in “Other liabilities” on the Consolidated Balance Sheet. Bob Evans is a producer of refrigerated potato and pasta side dishes, pork sausage and a variety of refrigerated and frozen convenience food items and is reported in the Company’s Refrigerated Food segment (see Note 22). Based upon the preliminary 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. Net sales and operating profit for Bob Evans included in the Consolidated Statements of Operations were $333.1 and $14.5 , respectively, for the year ended September 30, 2018 . Certain preliminary values of the Bob Evans acquisition, including property, goodwill, other intangible assets and deferred taxes, are not yet finalized pending the final purchase price allocation and are subject to change once additional information is obtained. The goodwill generated by the Company’s acquisition of Bob Evans will not be deductible for U.S. income tax purposes; however, $13.8 of goodwill generated by business combinations completed by Bob Evans in periods prior to its acquisition transferred to Post and is expected to be tax deductible. The following table provides the preliminary 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. Measurement period adjustments have been made to the allocation of purchase price since the date of the Bob Evans acquisition. Cash and cash equivalents $ 15.6 Receivables 58.5 Inventories 27.1 Prepaid expenses and other current assets 34.3 Property 184.3 Goodwill 898.3 Other intangible assets 782.0 Other assets 0.4 Accounts payable (18.2 ) Other current liabilities (58.5 ) Deferred tax liability - long-term (194.9 ) Other liabilities (5.3 ) Total acquisition cost $ 1,723.6 Transactions Subsequent to Period End On October 1, 2018, the Company completed the previously announced 8th Avenue Transactions pursuant to the Transaction Agreement, dated as of August 2, 2018, among Post, 8th Avenue and THL Equity Fund VIII Investors (PB), LLC in which Post and THL separately capitalized 8th Avenue. Upon the closing of the 8th Avenue Transactions, 8th Avenue became the holding company for Post’s private brands business, reported herein as Post’s Private Brands segment, and Post received total gross proceeds of $875.0 , 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 prior to the closing of the 8th Avenue Transactions. 8th Avenue refinanced the Bridge Loan promptly after the time of the closing of the 8th Avenue Transactions on October 1, 2018, with proceeds from permanent debt financings, which include two term loans and a revolving credit facility. Pursuant to the 8th Avenue Transactions, THL received 2.5 shares of 8th Avenue preferred stock with an 11% cumulative, quarterly compounding dividend and $100.00 per share liquidation value and 39.5% of the common equity in 8th Avenue. Effective October 1, 2018, 8th Avenue is 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. In determining the accounting treatment of the retained interest, management concluded that 8th Avenue is 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 but does retain significant influence and therefore the use of the equity method of accounting is required. At September 30, 2018, all of the Private Brands segment assets and liabilities, excluding cash, are classified as held for sale (see Note 6). Fiscal 2017 Acquisitions On July 3, 2017, the Company completed its acquisition of Latimer Newco 2 Limited (“Latimer”), and all of Latimer’s direct and indirect subsidiaries at the time of acquisition, including Weetabix Limited (collectively the “Weetabix Group”) for a purchase price of approximately £1,400.0 with a payment at closing of £1,454.1 , excluding £48.0 of cash acquired (approximately $1,887.2 , excluding $62.2 of cash acquired). The Weetabix Group is a packaged food company that primarily produces branded and private label RTE cereal and muesli products. The Weetabix Group is reported in two reportable segments. The results of the Weetabix operations outside of North America (“Weetabix”) are reported in the Weetabix segment, and the Weetabix North American operations (“Weetabix NA”) are reported in the Post Consumer Brands segment (see Note 22). Based on the purchase price allocation of Weetabix, the Company recorded $172.8 of customer relationships to be amortized over a weighted-average period of approximately 20 years, $29.5 to definite-lived trademarks and brands to be amortized over a weighted-average period of 16 years and $385.1 of indefinite-lived trademarks. Based on the purchase price allocation of Weetabix NA, the Company recorded $13.6 of customer relationships to be amortized over a weighted-average period of 21 years. The following table provides the allocation of the purchase price related to the fiscal 2017 acquisition of the Weetabix Group based upon the fair value of assets and liabilities assumed, including the provisional amounts recognized related to the acquisition as of September 30, 2017, as well as measurement period adjustments made during the year ended September 30, 2018. The final fair value of goodwill related to the acquisition of the Weetabix Group will not be deductible for U.S. income tax purposes. Acquisition Date Amounts Recognized as of September 30, 2017 (a) Adjustments During the Year Ended September 30, 2018 Acquisition Date Amounts Recognized (as Adjusted) Cash and cash equivalents $ 62.2 $ — $ 62.2 Receivables (c) 39.7 (1.9 ) 37.8 Inventories (b), (c) 63.4 (0.2 ) 63.2 Prepaid expenses and other current assets 1.2 — 1.2 Property (b) 283.9 (3.0 ) 280.9 Goodwill (d) 969.3 11.5 980.8 Other intangible assets (b) 608.4 (7.4 ) 601.0 Other assets 112.0 — 112.0 Accounts payable (66.3 ) — (66.3 ) Other current liabilities (c) (28.4 ) (0.1 ) (28.5 ) Deferred tax liability - long-term (c) (137.6 ) 1.1 (136.5 ) Other liabilities (10.9 ) — (10.9 ) Noncontrolling interest (9.7 ) — (9.7 ) Total acquisition cost $ 1,887.2 $ — $ 1,887.2 (a) As previously reported in Post’s 2017 Annual Report on Form 10-K filed with the SEC on November 17, 2017. (b) Adjustments reflect updated ASC 805 valuation of tangible and intangible assets. (c) Adjustments reflect other Weetabix Group purchase accounting adjustments. (d) Adjustment reflects the change in goodwill as a result of the adjustments described in (b) and (c). On October 3, 2016, the Company completed its acquisition of National Pasteurized Eggs, Inc. (“NPE”) for $93.5 , subject to working capital and other adjustments, resulting in a payment at closing of $97.0 . In February 2017, a final settlement of net working capital and other adjustments was reached, resulting in an amount back to the Company of $1.2 . NPE is a producer of pasteurized shell eggs, including cage-free eggs, and is reported in the Refrigerated Food segment (see Note 22). Based upon the purchase price allocation, the Company recorded $43.9 of customer relationships to be amortized over a weighted-average period of 16 years and $7.5 of trademarks and brands to be amortized over a weighted-average period of 20 years. The following table provides the allocation of the purchase price related to the fiscal 2017 acquisition of NPE based upon the fair value of assets and liabilities assumed. The final fair value of goodwill related to the acquisition of NPE will not be deductible for U.S. income tax purposes. NPE Cash and cash equivalents $ 5.6 Receivables 8.5 Inventories 2.1 Prepaid expenses and other current assets 0.4 Property 10.4 Goodwill 46.3 Other intangible assets 51.4 Current portion of long-term debt (0.1 ) Accounts payable (6.3 ) Other current liabilities (2.9 ) Long-term debt (0.2 ) Deferred tax liability - long-term (18.7 ) Total acquisition cost $ 96.5 Fiscal 2016 Acquisitions On October 3, 2015, the Company completed its acquisition of Willamette Egg Farms (“WEF”) for $90.0 , subject to working capital and other adjustments, resulting in a payment at closing of $109.0 . In December 2015, a final settlement of net working capital and other adjustments was reached, resulting in an additional amount paid by the Company of $4.6 . WEF is a producer, processor and wholesale distributor of eggs and egg products and is reported in the Refrigerated Food segment (see Note 22). Based upon the purchase price allocation, the Company recorded $12.7 of customer relationships to be amortized over a weighted-average period of 20 years and $2.5 to trademarks and brands to be amortized over a weighted-average period of 20 years. The following table provides the allocation of the purchase price related to the fiscal 2016 acquisition of WEF based upon the fair value of assets and liabilities assumed. The final fair value of goodwill related to the acquisition of WEF will be deductible for U.S. income tax purposes. WEF Cash and cash equivalents $ 19.2 Receivables 11.1 Inventories 10.3 Prepaid expenses and other current assets 0.5 Property 56.2 Goodwill 4.2 Other intangible assets 15.2 Other assets 0.1 Accounts payable (2.2 ) Other current liabilities (1.0 ) Total acquisition cost $ 113.6 Transaction-related expenses The Company incurs transaction-related expenses in conjunction 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. During the years ended September 30, 2018 , 2017 and 2016 , the Company incurred transaction-related expenses of $35.8 , $30.5 and $8.5 , respectively, recorded in “Selling, general and administrative expenses” in the Consolidated Statements of Operations. For the years ended September 30, 2018 and 2017, transaction-related expenses included costs attributable to the 8th Avenue Transactions of $12.4 and $0.6 , respectively. There were no transaction-related expenses related to the 8th Avenue Transactions incurred in the year ended September 30, 2016. In addition, during the year ended September 30, 2017, the Company recorded net foreign currency gains of $30.0 related to cash held in Pounds Sterling to fund the acquisition of the Weetabix Group, which were recorded in “Selling, general and administrative expenses” in the Consolidated Statement of Operations. Unaudited Pro Forma Information The following unaudited pro forma information presents a summary of the combined results of operations of the Company and the aggregate results of all businesses acquired in fiscal 2018 , 2017 and 2016 for the periods presented as if the fiscal 2018 acquisition had occurred on October 1, 2016, the fiscal 2017 acquisitions had occurred on October 1, 2015 and the fiscal 2016 acquisition had occurred on October 1, 2014, along with certain pro forma adjustments. Additionally, the divestiture of 8th Avenue is presented in the unaudited pro forma information as if it occurred on October 1, 2017. These pro forma adjustments give effect to the amortization of certain definite-lived intangible assets, adjusted depreciation based upon 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. 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 acquisitions occurred on the assumed dates, nor is it necessarily an indication of future operating results. 2018 2017 2016 Pro forma net sales $ 5,587.1 $ 5,258.3 $ 5,751.2 Pro forma net earnings available to common shareholders $ 432.1 $ 23.6 $ 2.0 Pro forma basic earnings per share $ 6.49 $ 0.35 $ 0.03 Pro forma diluted earnings per share $ 5.83 $ 0.34 $ 0.03

Restructuring

Restructuring	12 Months Ended
	Sep. 30, 2018
Restructuring and Related Activities [Abstract]
Restructuring	RESTRUCTURING In February 2018, the Company announced its plan to close its cereal manufacturing facility in Clinton, Massachusetts, which manufactures certain Weetabix Group 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. In September 2015, the Company announced its plan to close its Dymatize manufacturing facility located in Farmers Branch, Texas and permanently transfered production to third party facilities under co-manufacturing agreements. Plant production ceased in the fourth quarter of 2015 and the facility was sold in December 2016. No additional restructuring costs were incurred in fiscal 2018 or 2017. In May 2015, the Company announced its plan to consolidate its cereal business administrative offices into its Lakeville, Minnesota location. In connection with the consolidation, the Company closed its office located in Parsippany, New Jersey and relocated those functions as well as certain functions located in Battle Creek, Michigan to the Lakeville office. The Parsippany office closure was completed during fiscal 2016. No additional restructuring costs were incurred in fiscal 2018 or 2017. Amounts related to the restructuring events are shown in the following table. All costs are recognized in “Selling, general and administrative expenses” in the Condensed Consolidated Statements of Operations with the exception of accelerated depreciation expense incurred in the year ended September 30, 2018, which is included in “Cost of goods sold.” These expenses are not included in the measure of segment performance for any segment (see Note 22). Employee-Related Costs Accelerated Depreciation Total Balance, September 30, 2015 $ 10.5 $ — $ 10.5 Charge to expense 2.1 0.4 2.5 Cash payments (10.6 ) — (10.6 ) Non-cash charges (0.9 ) (0.4 ) (1.3 ) Balance, September 30, 2016 $ 1.1 $ — $ 1.1 Cash payments (1.1 ) — (1.1 ) Balance, September 30, 2017 $ — $ — $ — Charge to expense 2.7 2.5 5.2 Non-cash charges — (2.5 ) (2.5 ) Balance, September 30, 2018 $ 2.7 $ — $ 2.7 Total expected restructuring charge $ 17.7 $ 9.0 $ 26.7 Cumulative incurred to date 15.3 5.0 20.3 Remaining expected restructuring charge $ 2.4 $ 4.0 $ 6.4

Assets and Liabilities Held For

Assets and Liabilities Held For Sale	12 Months Ended
	Sep. 30, 2018
Assets and Liabilities Held for Sale [Abstract]
Assets 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 Consolidated Balance Sheet as of September 30, 2018 are shown in the following table. There were no assets or liabilities held for sale at September 30, 2017. 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 property held for sale are classified as current and noncurrent, respectively, on the Consolidated Balance Sheet. In connection with the 8th Avenue Transactions (see Note 4), the Company had assets and liabilities held for sale at September 30, 2018. The Company recorded earnings before income taxes related to 8th Avenue, reported herein as the Private Brands segment, of $60.8 , $58.1 and $71.4 in the years ended September 30, 2018, 2017 and 2016, respectively. Additionally, the Company had a building classified as assets held for sale at September 30, 2018, related to the planned closure of the Company’s Post Consumer Brands cereal warehouse in Clinton, Massachusetts (see Note 5). Held for sale net (gains) losses of $(0.2) and $9.3 were recorded in the years ended September 30, 2017 and 2016, respectively. There were no held for sale (gains) or losses recorded in the year ended September 30, 2018. The net gains and losses are reported as “Other operating expenses, net” on the Consolidated Statements of Operations. In the year ended September 30, 2018, the book values of the assets and liabilities for 8th Avenue and the Clinton, Massachusetts manufacturing facility were both lower than fair value, therefore, no fair value adjustment was recorded at the time the assets and liabilities were classified as held for sale. Any final adjustments to the fair values of 8th Avenue and the Clinton, Massachusetts manufacturing facility will be recognized upon the closing of the 8th Avenue Transactions and the sale of the facility, respectively. In the year ended September 30, 2017, the gain related to the September 2015 closure of the Company’s Dymatize manufacturing facility located in Farmers Branch, Texas. In the year ended September 30, 2016, of the total $9.3 held for sale loss, $4.5 related to the September 2015 closure of the Company’s Dymatize manufacturing facility located in Farmers Branch, Texas and $4.8 related to the April 2013 closure of the Company’s cereal plant located in Modesto, California. These expenses are not included in the measure of segment performance for any segment (see Note 22).

Goodwill

Goodwill	12 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	GOODWILL The changes in the carrying amount of goodwill by segment are noted in the following table. Post Consumer Brands Weetabix Refrigerated Food Active Nutrition Private Brands Total Balance, September 30, 2016 Goodwill (gross) $ 1,994.0 $ — $ 1,185.3 $ 180.7 $ 417.1 $ 3,777.1 Accumulated impairment losses (609.1 ) — — (88.3 ) — (697.4 ) Goodwill (net) $ 1,384.9 $ — $ 1,185.3 $ 92.4 $ 417.1 $ 3,079.7 Goodwill acquired 5.3 964.0 46.3 — — 1,015.6 Impairment loss — — — (26.5 ) — (26.5 ) Currency translation adjustment 0.3 (37.1 ) — — — (36.8 ) Balance, September 30, 2017 Goodwill (gross) $ 1,999.6 $ 926.9 $ 1,231.6 $ 180.7 $ 417.1 $ 4,755.9 Accumulated impairment losses (609.1 ) — — (114.8 ) — (723.9 ) Goodwill (net) $ 1,390.5 $ 926.9 $ 1,231.6 $ 65.9 $ 417.1 $ 4,032.0 Goodwill acquired — — 898.3 — — 898.3 Acquisition related adjustment 12.6 (1.1 ) — — — 11.5 Held for sale assets — — — — (417.1 ) (417.1 ) Currency translation adjustment (0.2 ) (24.9 ) — — — (25.1 ) Balance, September 30, 2018 Goodwill (gross) $ 2,012.0 $ 900.9 $ 2,129.9 $ 180.7 $ — $ 5,223.5 Accumulated impairment losses (609.1 ) — — (114.8 ) — (723.9 ) Goodwill (net) $ 1,402.9 $ 900.9 $ 2,129.9 $ 65.9 $ — $ 4,499.6 Goodwill represents the excess of the cost of acquired businesses over the fair market value of their identifiable net assets. The Company conducts a goodwill impairment qualitative assessment during the fourth quarter of each fiscal year following the annual forecasting process, or more frequently if facts and circumstances indicate that goodwill may be impaired. The goodwill impairment qualitative assessment requires an analysis to determine if it is more likely than not that the fair value of the business is less than its carrying amount. If adverse qualitative trends are identified that could negatively impact the fair value of the business, a quantitative goodwill impairment test is performed. In fiscal years 2018 , 2017 and 2016 , the Company elected not to perform a qualitative assessment and instead performed a quantitative impairment test for all reporting units. The estimated fair value is determined using a combined income and market approach with a greater weighting on the income approach. The income approach is based on discounted future cash flows and requires significant assumptions, including estimates regarding future revenue, profitability and capital requirements. The market approach is based on a market multiple (revenue and EBITDA which stands for earnings before interest, income taxes, depreciation and amortization) and requires an estimate of appropriate multiples based on market data. The Company did not record a goodwill impairment charge at September 30, 2018, as all reporting units passed the quantitative impairment test. For the year ended September 30, 2017, the Company recorded a charge of $26.5 for the impairment of goodwill. The impairment charge related to the Dymatize reporting unit which is included in the Active Nutrition segment. In fiscal 2017, consistent with the prior year, the specialty sports nutrition category, in which Dymatize sold the majority of its products, continued to experience weak sales, which resulted in management lowering its long-term expectations for the Dymatize reporting unit. After conducting step one of the impairment analysis, it was determined that the carrying value of the Dymatize reporting unit exceeded its fair value by $76.6 , and the Company recorded an impairment charge for goodwill down to the fair value. At the time of the analysis, the Dymatize reporting unit had $26.5 of remaining goodwill, and therefore an impairment charge for the entire goodwill balance of $26.5 was recorded. For the year ended September 30, 2016, the Company concluded there was no impairment of goodwill. With the exception of Dymatize, all reporting units passed step one of the impairment test. Dymatize failed step one and accordingly, step two of the analysis was performed as was required prior to the adoption of ASU 2017-04, “Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment” in fiscal 2017. Based on the results of step two, it was determined that the fair value of the goodwill allocated to the Dymatize reporting unit exceeded its carrying value by approximately $36.0 and was therefore not impaired as of September 30, 2016. These fair value measurements fell within Level 3 of the fair value hierarchy as described in Note 15. The goodwill impairment losses are aggregated with trademark impairment losses in “Impairment of goodwill and other intangible assets” in the Consolidated Statements of Operations.

Equity Interests

Equity Interests	12 Months Ended
	Sep. 30, 2018
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Interests	EQUITY INTERESTS In connection with its acquisition of the Weetabix Group in July 2017 (see Note 4), the Company acquired an equity interest in two legal entities, Alpen Food Company South Africa (Pty) Limited (“Alpen”) and Weetabix East Africa Limited (“Weetabix East Africa”). Results of both entities are reported in the Weetabix segment (see Note 22). Alpen is a South African based company that produces RTE cereal and muesli. The Company owns 50% of Alpen’s common stock with no other indicators of control and, accordingly, the Company accounts for its investment in Alpen using the equity method. The investment in Alpen was $5.2 and $4.5 at September 30, 2018 and 2017, respectively, and is included in “Other assets” on the Consolidated Balance Sheets. The Company had a note receivable balance with Alpen of $1.0 and $1.0 at September 30, 2018 and 2017, respectively, which is included in “Other assets” on the 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 consolidated financial statements. Weetabix East Africa had a long-term payable with Pioneer Food Group Limited, the owner of the remaining 49.9% of the business, of $0.5 at September 30, 2017, which is included in “Other liabilities” on the Consolidated Balance Sheet. No such payable existed at September 30, 2018.

Income Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income taxes	INCOME TAXES The (benefit) expense for income taxes consisted of the following: Year Ended September 30, 2018 2017 2016 Current: Federal $ 27.3 $ (5.8 ) $ 37.6 State 5.2 4.3 1.7 Foreign 20.0 10.2 8.5 52.5 8.7 47.8 Deferred: Federal (253.5 ) 19.7 (64.8 ) State 21.4 2.7 (7.5 ) Foreign (24.4 ) (5.0 ) (2.3 ) (256.5 ) 17.4 (74.6 ) Income tax (benefit) expense $ (204.0 ) $ 26.1 $ (26.8 ) The effective tax rate for fiscal 2018 was (77.1)% compared to 35.1% for fiscal 2017 and 89.0% for fiscal 2016 . A reconciliation of income tax (benefit) expense with amounts computed at the statutory federal rate follows: Year Ended September 30, 2018 2017 2016 Computed tax (a) $ 64.9 $ 26.1 $ (10.5 ) Enacted tax law and changes, including the Tax Act (a) (270.9 ) — 0.7 Non-deductible goodwill impairment loss — 7.2 — Non-deductible compensation 1.2 1.8 2.6 Non-deductible transaction costs 1.5 2.9 — Domestic production activities deduction (5.9 ) — (4.3 ) State income taxes, net of effect on federal tax 5.6 0.8 (6.2 ) Non-taxable interest income (2.4 ) (3.4 ) (2.6 ) Valuation allowances 4.1 4.8 3.8 Change in deferred tax rates 0.3 — (2.0 ) Uncertain tax positions 0.3 (0.5 ) (2.0 ) Sale and liquidation of Michael Foods Canadian egg business — — (3.6 ) Income tax credits (2.3 ) (1.4 ) (1.5 ) Rate differential on foreign income (5.3 ) (6.8 ) (1.8 ) Excess tax benefits for share-based payments (1.8 ) (6.2 ) — Other, net (none in excess of 5% of statutory tax) 6.7 0.8 0.6 Income tax (benefit) expense $ (204.0 ) $ 26.1 $ (26.8 ) (a) Fiscal 2018 federal corporate income tax was computed using a blended U.S. federal corporate income tax rate of 24.5% . The fiscal 2018 tax rate was impacted by the Tax Act, as discussed below. Fiscal 2017 and 2016 federal corporate income tax was computed at the federal statutory rate of 35% . Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Deferred tax non-current assets (liabilities) were as follows: September 30, 2018 September 30, 2017 Assets Liabilities Net Assets Liabilities Net Accrued vacation, incentive and severance $ 10.0 $ — $ 10.0 $ 16.2 $ — $ 16.2 Inventory 4.0 — 4.0 3.0 — 3.0 Accrued liabilities 24.3 — 24.3 16.6 — 16.6 Property — (161.7 ) (161.7 ) — (210.1 ) (210.1 ) Intangible assets — (688.3 ) (688.3 ) — (882.5 ) (882.5 ) Pension and other postretirement benefits — (15.3 ) (15.3 ) 5.3 — 5.3 Stock-based and deferred compensation 27.5 — 27.5 28.7 — 28.7 Derivative mark-to-market adjustments 18.1 — 18.1 91.9 — 91.9 Net operating loss carryforwards 27.2 — 27.2 38.7 — 38.7 Other items 4.7 (3.2 ) 1.5 6.5 (1.6 ) 4.9 Total gross deferred income taxes 115.8 (868.5 ) (752.7 ) 206.9 (1,094.2 ) (887.3 ) Valuation allowance (25.7 ) — (25.7 ) (18.5 ) — (18.5 ) Total deferred taxes $ 90.1 $ (868.5 ) $ (778.4 ) $ 188.4 $ (1,094.2 ) $ (905.8 ) As of September 30, 2018 , the Company had U.S. federal net operating loss (“NOL”) carryforwards totaling approximately $57.1 , which have expiration dates beginning in fiscal 2021 and extending through fiscal 2038 , as well as state NOL carryforwards totaling approximately $475.0 , which have expiration dates beginning in fiscal 2019 and extending through fiscal 2037 . As of September 30, 2018, Post had NOL carryforwards in foreign jurisdictions of $8.3 . As certain of these NOLs and carryforwards were acquired through acquisitions made during fiscal 2013, 2014, 2017 and 2018 as a result of ownership changes, the deductibility of the NOLs is subject to limitation under section 382 of the Internal Revenue Code (“IRC”) and similar limitations under state tax law. Giving consideration to IRC section 382 and state limitations, the Company believes it will generate sufficient taxable income to fully utilize the U.S. federal and certain state NOLs before they expire. Approximately $16.6 of the deferred tax asset related to the state NOLs has been offset by a valuation allowance based on management’s judgment that it is more likely than not that the benefits of those deferred tax assets will not be realized in the future. At September 30, 2018 , the Company had undistributed earnings of consolidated foreign subsidiaries of $6.2 , and the Company intends to indefinitely reinvest undistributed earnings of its foreign subsidiaries. In accordance with the Tax Act, the Company recorded a one-time transition tax on such earnings during the year ended September 30, 2018, as discussed below. For the years ended September 30, 2018 , 2017 and 2016 , foreign (loss) income before income taxes was $(24.3) , $24.7 and $29.6 , respectively. Tax Act In fiscal 2018, the effective tax rate was impacted by the Tax Act, which was enacted on December 22, 2017. The SEC issued interpretive guidance regarding the Tax Act, which was codified by ASU 2018-05 in March 2018. The Tax Act resulted in significant impacts to the Company’s accounting for income taxes with the most significant of these impacts relating to 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 enacts a new U.S. federal corporate income tax rate of 21% that will fully go into effect for the Company’s fiscal 2019 tax year and is prorated with the pre-December 22, 2017 U.S. federal corporate income tax rate of 35% for the Company’s current tax year. This proration resulted in a blended U.S. federal income tax rate of 24.5% for fiscal 2018. At the time these financial statements were issued, the Company had not completed the accounting for the tax effects related to the enactment of the Tax Act. However, provisional estimates were made in the following instances: (i) the Company remeasured its existing deferred tax assets and liabilities considering both the current fiscal year blended rate and the 21% rate for future periods and recorded a provisional tax benefit of $281.2 and (ii) the Company calculated the one-time transition tax and recorded provisional tax expense of $10.3 . Full expensing of certain depreciable assets will result in a temporary difference and will be analyzed as assets are placed in service. The changes included in the Tax Act are broad and complex, and as such, the final transition impacts of the Tax Act may differ from the above estimates, possibly materially, due to, among other things, changes in interpretations of the Tax Act, any legislative action to address questions that arise because of the Tax Act, any changes in current accounting standards for income taxes or related interpretations in response to the Tax Act or any updates or changes to estimates the Company has utilized to calculate the transition impacts, including impacts resulting from changes to current year earnings estimates and foreign exchange rates. ASU 2018-05 allows for a measurement period of up to one year after the enactment date of the Tax Act to finalize the recording of the related tax impacts. The Company currently anticipates finalizing and recording any resulting adjustments by December 31, 2018. Unrecognized Tax Benefits The Company recognizes the tax benefit from uncertain tax positions only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities. The tax benefits recognized from such positions are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. To the extent the Company’s assessment of such tax positions changes, the change in estimate will be recorded in the period in which the determination is made. Unrecognized tax benefits activity for the years ended September 30, 2018 and 2017 is presented in the following table: Unrecognized tax benefits, September 30, 2016 $ 9.3 Additions for tax positions taken in current year and acquisitions — Reductions for tax positions taken in prior years — Settlements with tax authorities/statute expirations (0.7 ) Unrecognized tax benefits, September 30, 2017 $ 8.6 Additions for tax positions taken in current year and acquisitions 2.0 Reductions for tax positions taken in prior years (0.1 ) Held for sale liabilities (0.6 ) Settlements with tax authorities/statute expirations — Unrecognized tax benefits, September 30, 2018 $ 9.9 The amount of the net unrecognized tax benefits that, if recognized, would directly affect the effective tax rate is $8.3 at September 30, 2018 . The Company believes that, due to expiring statutes of limitations and settlements with authorities, it is reasonably possible that the total unrecognized tax benefits may decrease up to approximately $7.0 within twelve months of the reporting date. The Company computes tax-related interest and penalties as the difference between the tax position recognized for financial reporting purposes and the amount previously taken on the Company’s tax returns and classifies these amounts as components of income tax expense. The Company recorded $0.8 , $0.3 and $(0.1) related to interest and penalties in the years ended September 30, 2018, 2017 and 2016. The Company had accrued interest and penalties of $3.5 and $2.7 at September 30, 2018 and 2017 , respectively. The accrued interest and penalties are not included in the table above. U.S. federal, U.S. state and foreign jurisdictions income tax returns for the tax years ended September 30, 2017 , 2016 and 2015 are subject to examination by the tax authorities in each respective jurisdiction. With respect to the Bob Evans acquisition, the Company assumed all income tax liabilities for those jurisdictions which remain subject to examination, primarily consisting of tax years ended April 2015 through the short tax year ended January 11, 2018, the date of acquisition. With respect to the fiscal 2017 acquisition of the Weetabix Group, the Company assumed substantially all income tax liabilities for those jurisdictions which remain subject to examination. The Company did not assume any pre-acquisition tax liabilities related to the fiscal 2016 acquisition of WEF. With respect to the NPE acquisition made in fiscal 2017 and acquisitions made in fiscal 2015, the seller generally retained responsibility for all income tax liabilities through the date of acquisition. With respect to the Michael Foods acquisition, the Company assumed all income tax liabilities for those certain jurisdictions which remain subject to examination, consisting primarily of the short tax year ended June 2, 2014, the date of acquisition.

Earnings (loss) per Share

Earnings (loss) per Share	12 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings (loss) per Share	EARNINGS (LOSS) PER SHARE Basic earnings (loss) per share is based on the average number of common shares outstanding during the period. Diluted earnings (loss) per share is based on the average number of shares used for the basic earnings (loss) per share calculation, adjusted for the dilutive effect of stock options, stock appreciation rights and restricted stock units using the “treasury stock” method. The impact of potentially dilutive convertible preferred stock is calculated using the “if-converted” method. For the periods outstanding, the Company’s tangible equity units (“TEUs”) (see Note 20) were assumed to be settled at the minimum settlement amount of 1.7114 shares per TEU for weighted-average shares for basic earnings per share. For diluted earnings (loss) per share, the TEUs, to the extent dilutive, were assumed to be settled at a conversion factor based on the daily volume-weighted-average price per share of the Company’s common stock not to exceed 2.0964 shares per TEU. All TEU purchase contracts were settled as of June 1, 2017. 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 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 (see Note 21). Year ended September 30, 2018 2017 2016 Net earnings (loss) for basic loss per share $ 457.3 $ 34.8 $ (28.4 ) Dilutive preferred stock dividends 10.0 — — Net earnings (loss) for diluted loss per share $ 467.3 $ 34.8 $ (28.4 ) Weighted-average shares outstanding 66.6 65.2 63.9 Effect of TEUs on weighted-average shares for basic earnings (loss) per share — 2.6 4.9 Weighted-average shares for basic earnings (loss) per share 66.6 67.8 68.8 Effect of dilutive securities: Stock options 1.8 1.8 — Stock appreciation rights 0.1 — — Restricted stock awards 0.4 0.3 — Preferred shares conversion to common 7.0 — — Total dilutive securities 9.3 2.1 — Weighted-average shares for diluted earnings (loss) per share 75.9 69.9 68.8 Basic earnings (loss) per common share $ 6.87 $ 0.51 $ (0.41 ) Diluted earnings (loss) per common share $ 6.16 $ 0.50 $ (0.41 ) The following table details the securities that have been excluded from the calculation of weighted-average shares for diluted earnings (loss) per share as they were anti-dilutive. Year ended September 30, 2018 2017 2016 Stock options 0.6 0.3 4.3 Stock appreciation rights — — 0.2 Restricted stock awards 0.1 — 0.5 Preferred shares conversion to common — 9.1 9.1

Supplemental Operations Stateme

Supplemental Operations Statement and Cash Flow Information	12 Months Ended
	Sep. 30, 2018
Supplemental Operations Statement and Cash Flow Information [Abstract]
Supplemental Operations Statement and Cash Flow Information	SUPPLEMENTAL OPERATIONS STATEMENT AND CASH FLOW INFORMATION Year Ended September 30, 2018 2017 2016 Advertising and promotion expenses $ 153.4 $ 159.7 $ 184.2 Repair and maintenance expenses 149.1 162.6 141.6 Research and development expenses 25.1 18.6 16.3 Rent expense 41.3 41.8 32.0 Interest income (7.4 ) (6.8 ) (2.7 ) Interest paid 373.9 333.6 309.6 Income taxes paid 23.0 29.6 73.4 Accrued additions to property 30.4 21.0 12.7

Supplemental Balance Sheet Info

Supplemental Balance Sheet Information	12 Months Ended
	Sep. 30, 2018
Supplemental Balance Sheet Information [Abstract]
Supplemental Balance Sheet Information	SUPPLEMENTAL BALANCE SHEET INFORMATION September 30, 2018 2017 Receivables, net Trade $ 412.8 $ 421.6 Income tax receivable 41.5 46.4 Other 10.3 14.2 464.6 482.2 Allowance for doubtful accounts (2.3 ) (1.6 ) $ 462.3 $ 480.6 Inventories Raw materials and supplies $ 107.8 $ 129.8 Work in process 17.8 16.9 Finished products 324.1 395.6 Flocks 34.5 31.2 $ 484.2 $ 573.5 Other Assets Pension asset $ 167.0 $ 154.6 Hedging assets - non-current 52.0 0.3 Other 33.0 29.4 $ 252.0 $ 184.3 Accounts Payable Trade $ 329.3 $ 306.5 Book cash overdrafts 26.7 17.8 Other 9.1 11.7 $ 365.1 $ 336.0 Other Current Liabilities Advertising and promotion $ 53.6 $ 74.5 Accrued interest 38.5 36.5 Accrued compensation 114.2 89.9 Hedging liabilities 27.7 54.6 Accrued legal settlements 23.9 8.6 Other 81.4 82.2 $ 339.3 $ 346.3 Other Liabilities Pension and other postretirement benefit obligations $ 53.3 $ 83.5 Hedging liabilities - non-current 113.7 188.9 Accrued compensation - non-current 30.4 29.2 Accrued appraisal rights and related interest 267.0 — Other 34.9 26.2 $ 499.3 $ 327.8

Allowance for Doubtful Accounts

Allowance for Doubtful Accounts	12 Months Ended
	Sep. 30, 2018
Allowance for Doubtful Accounts [Abstract]
Allowance for Doubtful Accounts	ALLOWANCE FOR DOUBTFUL ACCOUNTS September 30, 2018 2017 2016 Balance, beginning of year $ 1.6 $ 1.6 $ 2.0 Provision charged to expense 0.1 0.3 1.2 Write-offs, less recoveries (1.2 ) (0.3 ) (1.6 ) Held for sale assets (0.5 ) — — Other (a) 2.3 — — Balance, end of year $ 2.3 $ 1.6 $ 1.6 (a) Other items are primarily related to acquisitions.

Derivative Financial Instrument

Derivative Financial Instruments and Hedging	12 Months Ended
	Sep. 30, 2018
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 September 30, 2018 , 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 five lump sum settlements with the first settlement occurring in July 2019 and the last in July 2021 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 January 2021 and July 2022 that require quarterly cash settlements and are used as net investment hedges of the Company’s investment in the Weetabix Group, 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 (see Note 16). 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 Consolidated Statement of Operations for the year ended September 30, 2018 and $0.5 was reclassified to “Property, net” on the Consolidated Balance Sheet as of September 30, 2018. As of July 1, 2017, the Company changed the designation of its cross-currency swap contracts from a non-designated hedging instrument to a net investment hedge. Prior to its designation as a net investment hedge, the Company had reported non-cash mark-to-market adjustments related to the cross-currency swaps in “(Income) expense on swaps, net” in the Consolidated Statements of Operations. The following table shows the notional amounts of derivative instruments held. September 30, September 30, Not designated as hedging instruments under ASC Topic 815: Commodity contracts $ 64.3 $ 53.8 Energy contracts 20.8 25.6 Foreign exchange contracts - Forward contracts 9.3 3.8 Interest rate swap 74.6 76.1 Interest rate swaps - Rate-lock swaps 1,649.3 1,649.3 Designated as hedging instruments under ASC Topic 815: Foreign exchange contracts - Forward contracts — 20.9 Foreign exchange contracts - Cross-currency swaps 662.9 448.7 Interest rate swap 1,000.0 1,000.0 The following tables present the balance sheet location and fair value of the Company’s derivative instruments on a gross and net basis as of September 30, 2018 and 2017 , along with the portion designated as hedging instruments under ASC Topic 815. The Company does not offset derivative assets and liabilities within the Consolidated Balance Sheets. Fair Value Portion Designated as Hedging Instruments Balance Sheet Location September 30, September 30, September 30, September 30, Asset Derivatives: Commodity contracts Prepaid expenses and other current assets $ 1.9 $ 0.5 $ — $ — Energy contracts Prepaid expenses and other current assets 4.9 3.8 — — Commodity contracts Other assets 0.2 — — — Energy contracts Other assets 0.3 — — — Foreign exchange contracts Prepaid expenses and other current assets 1.2 1.3 1.1 1.1 Foreign exchange contracts Other assets 17.6 0.3 17.6 0.3 Interest rate swaps Prepaid expenses and other current assets 6.4 — 6.4 — Interest rate swaps Other assets 33.9 — 30.6 — $ 66.4 $ 5.9 $ 55.7 $ 1.4 Liability Derivatives: Commodity contracts Other current liabilities $ 2.2 $ 1.9 $ — $ — Energy contracts Other current liabilities 0.4 0.3 — — Foreign exchange contracts Other current liabilities 1.5 1.5 1.4 1.5 Foreign exchange contracts Other liabilities 19.4 23.6 19.4 23.6 Interest rate swaps Other current liabilities 23.6 50.9 — 0.7 Interest rate swaps Other liabilities 94.3 165.3 — 4.2 $ 141.4 $ 243.5 $ 20.8 $ 30.0 The following tables present the effects of the Company’s derivative instruments on the Company’s Consolidated Statements of Operations and Consolidated Statements of Comprehensive Income (Loss) for the years ended September 30, 2018 , 2017 and 2016 . Derivatives Not Designated as Hedging Instruments Statement of Operations Location Loss (Gain) Recognized in Statement of Operations 2018 2017 2016 Commodity contracts Cost of goods sold $ 4.0 $ (0.4 ) $ 7.5 Energy contracts Cost of goods sold (6.4 ) (1.3 ) 1.2 Foreign exchange contracts Selling, general and administrative expenses 1.5 0.8 — Foreign exchange contracts (Income) expense on swaps, net — 10.3 — Interest rate swaps (Income) expense on swaps, net (95.6 ) (102.1 ) 182.9 Derivatives Designated as Hedging Instruments (Gain) Loss Recognized in OCI (Gain) Loss Reclassified from Accumulated OCI into Earnings Statement of Operations Location 2018 2017 2016 2018 2017 2016 Foreign exchange contracts $ (0.2 ) $ (1.6 ) $ — $ (1.3 ) $ — $ — Selling, general and administrative expenses Interest rate swaps (44.2 ) 5.6 — (2.3 ) 0.7 — Interest expense, net Cross-currency swaps (27.8 ) 14.8 — — — — (Income) expense on swaps, net Accumulated OCI included a $50.0 net gain on hedging instruments before taxes ( $37.4 after taxes) at September 30, 2018 , compared to a $18.1 net loss before taxes ( $11.1 after taxes) at September 30, 2017 . Approximately $6.4 of the net cash flow hedge gains reported in accumulated OCI at September 30, 2018 is expected to be reclassified into earnings within the next 12 months. For gains or losses associated with interest rate swaps, the reclassification will occur over the term of the related debt. A reclassification of gains and losses reported in accumulated OCI related to the cross-currency swaps will only occur in the event all United Kingdom-based operations are liquidated. At September 30, 2018, accumulated OCI included settlements of cross-currency swaps of $4.8 . There were no settlements of cross-currency swaps included in accumulated OCI at September 30, 2017. At September 30, 2018 and September 30, 2017 , the Company had pledged collateral of $4.5 and $2.9 , respectively, related to its commodity and energy contracts. These amounts are classified as “Restricted cash” on the Consolidated Balance Sheets.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The following table presents the 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: September 30, 2018 September 30, 2017 Total Level 1 Level 2 Total Level 1 Level 2 Assets Deferred compensation investment $ 43.6 $ 43.6 $ — $ 15.4 $ 15.4 $ — Derivative assets 66.4 — 66.4 5.9 — 5.9 $ 110.0 $ 43.6 $ 66.4 $ 21.3 $ 15.4 $ 5.9 Liabilities Deferred compensation liabilities $ 52.2 $ — $ 52.2 $ 22.5 $ — $ 22.5 Derivative liabilities 141.4 — 141.4 243.5 — 243.5 $ 193.6 $ — $ 193.6 $ 266.0 $ — $ 266.0 The deferred compensation investment is primarily invested in mutual funds and its fair value is measured using the market approach. This investment is in the same funds, or funds that employ a similar investment strategy, and 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 expects to pay $24.1 related to the termination of Bob Evans’s deferred compensation plans within the next 12 months. 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 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 short-term and long-term debt at fair value on the Consolidated Balance Sheets. Based on current market rates, the fair value of the Company’s debt (Level 2), including amounts classified as held for sale, was $7,790.9 and $7,343.4 as of September 30, 2018 and 2017 , respectively. 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. In the year ended September 30, 2018, the Company recorded indefinite-lived intangible asset impairment charges of $124.9 . In the year ended September 30, 2017, the Company recorded goodwill impairment losses of $26.5 . There were no such charges recorded in the year ended September 30, 2016. These losses were recorded as “Impairment of goodwill and other intangible assets” in the Consolidated Statement of Operations. For additional information on other intangibles assets and goodwill, see Note 2 and Note 7, respectively. There were no other fair value measurement losses recognized during the years ended September 30, 2018, 2017 and 2016. As stated previously (see Note 6), the Company had assets and liabilities held for sale related to the 8th Avenue Transactions and a building related to the planned closure of the Company’s Post Consumer Brands cereal warehouse in Clinton, Massachusetts as of September 30, 2018, and assets held for sale related to the September 2015 closure of the Company’s Dymatize manufacturing facility located in Farmers Branch, Texas and the April 2013 closure of the Company’s cereal plant located in Modesto, California as of September 30, 2016. 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, 2016 $ 10.1 Gain on assets held for sale 0.2 Proceeds from the sale of assets held for sale (10.3 ) Balance, September 30, 2017 $ — Transfers of assets into held for sale 1,051.6 Transfers of liabilities into held for sale (760.7 ) Balance, September 30, 2018 $ 290.9

Long Term Debt

Long Term Debt	12 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Long-term Debt	LONG-TERM DEBT Long-term debt as of the dates indicated consists of the following: September 30, 2018 2017 5.625% Senior Notes maturing January 2028 $ 960.9 $ — 5.50% Senior Notes maturing March 2025 1,000.0 1,000.0 5.75% Senior Notes maturing March 2027 1,326.3 1,500.0 5.00% Senior Notes maturing August 2026 1,710.3 1,750.0 8.00% Senior Notes maturing July 2025 122.2 137.5 6.00% Senior Notes maturing December 2022 — 630.0 Term Loan 2,172.5 2,194.5 Bridge Loan (a) — — Capital leases 0.2 0.2 7,292.4 7,212.2 Less: Current Portion (22.1 ) (22.1 ) Debt issuance costs, net (a) (71.2 ) (81.8 ) Plus: Unamortized premium 33.0 40.8 Total long-term debt $ 7,232.1 $ 7,149.1 (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 June 2, 2014, the Company issued $630.0 principal value of 6.00% senior notes due in December 2022. The 6.00% senior notes were issued at par, and the Company received $619.0 after paying related fees of $11.0 , which were deferred and amortized to interest expense over the term of the notes. The principal balance of these notes was repaid during the year ended September 30, 2018. Interest payments on the 6.00% senior notes were due semi-annually each June 15 and December 15. On August 18, 2015, the Company issued $400.0 principal value of 8.00% senior notes due in July 2025. The 8.00% senior notes were issued at par, and the Company received $396.0 after paying related fees of $4.0 , which were deferred and amortized to interest expense over the term of the notes. Interest payments on the 8.00% senior notes are due semi-annually each January 15 and July 15. On August 3, 2016, the Company issued $1,750.0 principal value of 5.00% senior notes due in August 2026. The 5.00% senior notes were issued at par, and the Company received $1,725.7 after paying related fees of $24.3 , which were deferred and will be amortized to interest expense over the term of the notes. Interest payments on the 5.00% senior notes are due semi-annually each February 15 and August 15. On February 14, 2017, the Company issued $1,000.0 principal value of 5.50% senior notes due in March 2025 and $750.0 principal value of 5.75% senior notes due in March 2027. The 5.50% and 5.75% senior notes were issued at par, and the Company received $1,725.4 after paying related fees of $24.6 , which were deferred and will be amortized to interest expense over the term of the notes. On August 10, 2017, the Company issued an additional $750.0 principal value of 5.75% notes due in March 2027. The additional 5.75% senior notes were issued at 105.5% of par value, and the Company received $784.0 after paying investment banking and other fees of $7.2 . The premium related to the 5.75% senior notes was recorded as an unamortized premium, which is included in “Long-term debt” on the Consolidated Balance Sheets at September 30, 2018 and 2017 and will be amortized as a reduction to interest expense over the term of the notes. Interest payments on the 5.50% and 5.75% senior notes are due semi-annually each March 1 and September 1. On December 1, 2017, the Company issued $1,000.0 principal value of 5.625% senior notes due in January 2028. The 5.625% senior notes were issued at par, and the Company received $990.6 after paying investment banking and other fees of $9.4 , which are being deferred and amortized to interest expense over the term of the notes. Interest payments on the 5.625% senior notes are due semi-annually each January 15 and July 15. All of the Company’s senior notes are fully and unconditionally guaranteed, jointly and severally, on a senior unsecured basis by each of the Company’s existing and future domestic subsidiaries, other than immaterial subsidiaries, receivables finance subsidiaries and subsidiaries the Company designated as unrestricted subsidiaries (the “Guarantors”). The Company’s foreign subsidiaries do not guarantee the senior notes. These guarantees are subject to release in limited circumstances (only upon the occurrence of certain customary conditions). Credit Agreement On March 28, 2017, the Company entered into an amended and restated credit agreement, and further amended the credit agreement on April 28, 2017, March 8, 2018 and August 17, 2018 (as further amended and restated, 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 $18.5 , which reduced the available borrowing capacity to $781.5 at September 30, 2018 . The outstanding amounts under the Revolving Credit Facility must be repaid on or before March 28, 2022. The Company incurred $4.2 and $4.6 of issuance costs in connection with the Credit Agreement in the years ended September 30, 2018 and 2017, respectively, which are included in “Prepaid expenses and other current assets” and “Other assets” on the Consolidated Balance Sheets. 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 also permits the Company, subject to certain conditions, to incur incremental equivalent debt, in an aggregate maximum amount 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. Additionally, the Credit Agreement permits the Company to incur additional unsecured debt if, among other conditions, its consolidated interest coverage ratio (as defined in the Credit Agreement) would be greater than or equal to 2.00 to 1.00 after giving effect to such new debt. The Company entered into a third amendment to the Credit Agreement on August 17, 2018, which permits the Company, among other things, to designate certain of its subsidiaries as unrestricted subsidiaries and once so designated, permits the disposition of (and release of liens on) assets of and equity interests in the Company’s unrestricted subsidiaries and permits the release of such unrestricted subsidiaries as guarantors. 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 0.250% to 0.375% , also depending on the Company’s senior secured leverage ratio. The Credit Agreement contains affirmative and negative covenants customary for agreements of this type, including delivery of financial and other information, compliance with laws, maintenance of property, existence, insurance and books and records, inspection rights, obligation to provide collateral and guarantees by certain new subsidiaries, preparation of environmental reports, participation in an annual meeting with the agent and the lenders under the Credit Agreement, further assurances, limitations with respect to indebtedness, liens, fundamental changes, restrictive agreements, use of proceeds, amendments of organization documents, accounting changes, prepayments and amendments of certain indebtedness, dispositions of assets, acquisitions and other investments, sale leaseback transactions, conduct of business, transactions with affiliates, dividends and redemptions or repurchases of stock, and granting liens. 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 ERISA 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. The Company’s obligations under the Credit Agreement are unconditionally guaranteed by each of the Guarantors. The Company’s obligations under the Credit Agreement are secured by security interests on substantially all of the personal property assets of the Company and the Guarantors and are secured by the material domestic real property assets of the Company and the Guarantors. Term Loans On May 24, 2017, the Company entered into a Joinder Agreement No. 1 (“Joinder No. 1”). Joinder No.1 provided for an incremental term loan of $1,200.0 (the “ Joinder No. 1 Term Loan”) under the Credit Agreement. Pursuant to Joinder No. 1, the Company borrowed $1,200.0 . On June 29, 2017, the Company entered into a Joinder Agreement No. 2 (“Joinder No. 2”). Joinder No. 2 provided for an incremental term loan of $1,000.0 (the “ Joinder No. 2 Term Loan”) under the Credit Agreement. Pursuant to Joinder No. 2, the Company borrowed $1,000.0 and used the proceeds, together with cash on hand, to finance its fiscal 2017 acquisition of the Weetabix Group (see Note 4). The Joinder No. 2 Term Loan was combined with the outstanding amounts under the Joinder No.1 Term Loan (collectively the “Term Loan”). On March 8, 2018, the Company entered into a second amendment to the Credit Agreement (the “Second Amendment”). Under the Second Amendment, the interest rate margin for the Term Loan was reduced by 25 basis points such that a Term Loan that is a Eurodollar Rate Loan accrues interest at the Eurodollar Rate plus 2.00% per annum, and a Term Loan that is a Base Rate Loan accrues interest at the Base Rate plus 1.00% per annum (as such terms are defined in the Credit Agreement). The maturity date for the Term Loan remains May 24, 2024, and all other material provisions of the Credit Agreement remain unchanged. The Term Loan requires quarterly principal installments of $5.5 , which began on September 30, 2017. The interest rate on the Term Loan was 4.22% and 3.49% at September 30, 2018 and 2017, respectively. The Company incurred $23.7 of issuance costs in connection with the Term Loan in the year ended September 30, 2017. 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 (“Bridge Loan Facility”) and borrowed $625.0 under the Bridge Loan Facility (the Bridge Loan, as defined in Note 4). The Bridge Loan bore interest at a rate per annum equal to (i) with respect to the period commencing on September 24, 2018, and ending on October 1, 2018, the Eurodollar Rate (as such term is defined in the Bridge Loan Facility) plus 450 basis points , (ii) with respect to the period commencing on October 1, 2018 and ending on October 8, 2018, the Eurodollar Rate plus 500 basis points , (iii) with respect to the period between October 8, 2018 and November 30, 2018, 12.00% and (iv) with respect to the period on or after November 30, 2018 through the maturity date, 12.25% . Payments of interest on the Bridge Loan were due on October 1, 2018, October 8, 2018, December 31, 2018 and the last day of each quarter thereafter. The Bridge Loan Facility would mature on August 23, 2024. In connection with the Bridge Loan Facility, the Company incurred issuance costs of $10.4 , which are being deferred and amortized to interest expense over the term of the loan. Of the total amount of debt issuance costs incurred, $7.8 were reimbursed 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. Upon the assumption of the Bridge Loan by 8th Avenue, the Company was required under the Credit Agreement to use the net cash proceeds from the Bridge Loan and the cash proceeds received from THL under the Transaction Agreement to repay a portion of the Term Loan. Additionally, on October 1, 2018, 8th Avenue and its domestic subsidiaries (other than immaterial subsidiaries and other excluded subsidiaries) entered into (i) a First Lien Credit Agreement and (ii) a Second Lien Credit Agreement . The First Lien Credit Agreement provides for (i) a term loan in an aggregate principal amount of $525.0 (the “First Lien Term Loan Facility”) and (ii) a revolving credit facility in an aggregate amount of up to $150.0 (the “First Lien Revolving Credit Facility”). The Second Lien Credit Agreement provides for a term loan in an aggregate principal amount of $100.0 (the “Second Lien Term Loan Facility”). 8th Avenue used the proceeds of the First Lien Term Loan Facility, the Second Lien Term Loan Facility and a portion of the First Lien Revolving Credit Facility to repay the Bridge Loan under the Bridge Facility Agreement, to pay certain fees and expenses related to the 8th Avenue Transactions and for general corporate purposes. Repayments of Long-Term Debt The following table shows the Company’s repayments of long-term debt and associated gain or loss included in “Loss on extinguishment of debt” on the Consolidated Statements of Operations for the years ended September 30, 2018 , 2017 and 2016 . Repayments of Long-Term Debt Loss on Extinguishment of Debt, net Year Ended Issuance Principal Amount Repaid Debt Repurchased at a Discount Premium and Debt Extinguishment Costs Paid Write-offs of Debt Issuance Costs Write-off of Unamortized (Premium)/Discount 6.00% Senior Notes $ 630.0 $ — $ 30.8 $ 6.5 $ — 5.625% Senior Notes 39.1 (2.1 ) — 0.4 — 5.75% Senior Notes 173.7 (3.1 ) — 1.9 (4.6 ) 5.00% Senior Notes 39.7 (2.5 ) — 0.4 — 8.00% Senior Notes 15.3 — 2.0 0.1 — Term Loan (a) 22.0 — 0.9 0.4 — 2018 Total $ 919.8 $ (7.7 ) $ 33.7 $ 9.7 $ (4.6 ) 6.75% Senior Notes $ 875.0 $ — $ 63.0 $ 8.9 $ (13.4 ) 7.375% Senior Notes 133.0 — 4.9 1.2 (2.1 ) 7.75% Senior Notes 800.0 — 108.6 6.3 — 8.00% Senior Notes 262.5 — 43.3 2.2 — Term Loan 5.5 — — — — TEUs 11.0 — — — — 4.57% 2012 Series Bond 1.3 — — — — Capital lease 0.1 — — — — 2017 Total $ 2,088.4 $ — $ 219.8 $ 18.6 $ (15.5 ) 7.375% Senior Notes $ 1,242.0 $ — $ 88.0 $ 12.4 $ (21.8 ) Term Loan 374.4 — — 6.4 1.4 TEUs 14.1 — — — — 4.57% 2012 Series Bond 1.6 — — — — Capital lease 0.1 — — — — 2016 Total $ 1,632.2 $ — $ 88.0 $ 18.8 $ (20.4 ) (a) In connection with the Second Amendment discussed above, the Company recorded a write-off of debt issuance costs and other expenses during the year ended September 30, 2018. 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 September 30, 2018 , 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 September 30, 2018 , the pro forma consolidated interest coverage ratio exceeded this threshold.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Legal Proceedings Antitrust claims In late 2008 and early 2009, some 22 class action lawsuits were filed in various federal courts against Michael Foods, Inc. (“MFI”), a wholly-owned subsidiary of the Company, and some 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: (1) a nationwide class of direct purchasers of shell eggs (“direct purchaser class”); (2) 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 (3) indirect purchasers of shell eggs (“indirect purchaser plaintiffs”). Resolution of claims: (1) 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; (2) MFI settled all claims asserted against it by opt-out plaintiffs related to shell egg purchases on confidential terms in January 2017; and (3) 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 opt-out plaintiffs. The district court had granted summary judgment precluding any claims for egg products purchases by 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. At September 30, 2018, the Company had accrued $6.0 for this matter that was included in “Other current liabilities” on the Consolidated Balance Sheet. There was no accrual for these matters at September 30, 2017. 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 results of operations and cash flows could be materially affected. During the years ended September 30, 2018, 2017 and 2016, the Company expensed $8.3 , $74.5 and $28.5 related to these settlements, respectively, which was included in “Selling, general and administrative expenses” in the Consolidated Statements of Operations. 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 so long as such persons comply with applicable procedural requirements. By virtue of these lawsuits, approximately 3.3 shares of Bob Evans common stock (which were held by such former stockholders) are before the court for appraisal. 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 at the $77.00 per share merger consideration amount. The Company intends to vigorously defend the cases. At September 30, 2018, the Company had an accrual of $267.0 included in “Other liabilities” on the Consolidated Balance Sheet for these matters, which is the number of shares of Bob Evans common stock for which former Bob Evans stockholders have demanded appraisal and have not withdrawn their demands multiplied by the $77.00 per share merger consideration, plus statutory interest (see Note 4). There were no accruals for these matters at September 30, 2017. 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 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 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 consolidated 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 consolidated financial position, results of operations or cash flows of the Company. Leases Lease Commitments Future minimum rental payments under noncancelable operating leases in effect as of September 30, 2018 were $28.2 , $26.4 , $24.6 , $23.9 , $21.6 and $84.8 for fiscal 2019 , 2020 , 2021 , 2022 , 2023 and thereafter, respectively. Bob Evans Lease Guarantee 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 September 30, 2018, 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 September 30, 2018, 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 September 30, 2018.

Pension and Other Postretiremen

Pension and Other Postretirement Benefits	12 Months Ended
	Sep. 30, 2018
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 U.S., 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). The following disclosures reflect amounts related to the Company’s employees based on separate actuarial valuations, projections and certain allocations. 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. With respect to defined benefits for Canadian Post Consumer Brands employees, eligibility is frozen to new entrants and benefit accrual is frozen for salaried employees. During the year ended September 30, 2018, certain U.S. defined benefit plans for Weetabix NA employees were merged into the Company defined benefit plan for U.S. employees. With respect to defined benefits for U.S. Post Consumer Brands employees, eligibility is frozen to new employees and benefit accruals are frozen for all administrative employees and certain production employees. Benefit accrual is frozen for salaried Weetabix NA employees in the U.S. With respect to defined benefit plans for Weetabix employees in the United Kingdom, eligibility is frozen to new entrants, and benefit accrual is frozen with respect to participants in the executive scheme. Defined Benefit Pension Plans The following table provides a reconciliation of the changes in the pension plans’ benefit obligations and fair value of assets over the two year period ended September 30, 2018 , and a statement of the funded status and amounts recognized on the combined balance sheets as of September 30, 2018 and 2017 . North America Other International Year Ended Year Ended 2018 2017 2018 2017 Change in benefit obligation Benefit obligation at beginning of period $ 100.6 $ 71.2 $ 723.6 $ — Service cost 4.2 4.1 6.7 1.7 Interest cost 3.6 2.5 19.6 4.9 Plan participants’ contributions 0.6 0.6 2.4 0.6 Actuarial gain (4.3 ) (1.0 ) (14.0 ) (46.4 ) Business combinations — 25.5 — 746.0 Benefits paid (3.4 ) (3.0 ) (27.6 ) (6.2 ) Currency translation (0.4 ) 0.7 (19.5 ) 23.0 Benefit obligation at end of period $ 100.9 $ 100.6 $ 691.2 $ 723.6 Change in fair value of plan assets Fair value of plan assets at beginning of period $ 80.9 $ 54.3 $ 876.7 $ — Actual return on plan assets 3.9 5.4 9.6 0.3 Employer contributions 32.6 7.7 7.2 2.4 Business combinations — 15.2 — 852.2 Plan participants’ contributions 0.6 0.6 2.4 0.6 Benefits paid (3.4 ) (3.0 ) (27.6 ) (6.2 ) Currency translation (0.5 ) 0.7 (23.8 ) 27.4 Fair value of plan assets at end of period 114.1 80.9 844.5 876.7 Funded status $ 13.2 $ (19.7 ) $ 153.3 $ 153.1 Amounts recognized in assets or liabilities Other assets $ 13.7 $ 1.5 $ 153.3 $ 153.1 Other liabilities (0.5 ) (21.2 ) — — Net amount recognized $ 13.2 $ (19.7 ) $ 153.3 $ 153.1 Amounts recognized in accumulated other comprehensive loss Net actuarial loss (gain) $ 9.5 $ 14.3 $ (32.0 ) $ (40.2 ) Prior service cost 0.5 0.6 — — Total $ 10.0 $ 14.9 $ (32.0 ) $ (40.2 ) Weighted-average assumptions used to determine benefit obligation Discount rate — U.S. plans 4.30 % 3.86 % n/a n/a Discount rate — Canadian plans 3.53 % 3.63 % n/a n/a Discount rate — Other international plans n/a n/a 2.81 % 2.72 % Rate of compensation increase — U.S. plans 3.00 % 3.00 % n/a n/a Rate of compensation increase — Canadian plans 2.75 % 2.69 % n/a n/a Rate of compensation increase — Other international plans n/a n/a 2.75 % 2.70 % The fair value of plan assets for the North American pension plans exceeded the accumulated benefit obligation at September 30, 2018 , whereas the accumulated benefit obligation exceeded the fair value of plan assets for the North American pension plans at September 30, 2017 . The fair value of plan assets for the other international pension plans exceeded the accumulated benefit obligation at September 30, 2018 and September 30, 2017 . The aggregate accumulated benefit obligation for the North American pension plans was $98.9 and $98.3 at September 30, 2018 and 2017 , respectively. The aggregate accumulated benefit obligation for the other international pension plans was $677.6 and $690.4 at September 30, 2018 and 2017 , respectively. The following tables provide the components of net periodic benefit cost for the pension plans including amounts recognized in OCI. North America Year Ended September 30, 2018 2017 2016 Components of net periodic benefit cost Service cost $ 4.2 $ 4.1 $ 4.0 Interest cost 3.6 2.5 2.5 Expected return on plan assets (4.4 ) (3.2 ) (2.6 ) Recognized net actuarial loss 1.1 1.6 1.1 Recognized prior service cost 0.1 0.2 0.3 Net periodic benefit cost $ 4.6 $ 5.2 $ 5.3 Weighted-average assumptions used to determine net benefit cost Discount rate — U.S. plans 3.86 % 3.66 % 4.55 % Discount rate — Canadian plans 3.63 % 3.18 % 3.82 % Rate of compensation increase — U.S. plans 3.00 % 2.99 % 3.00 % Rate of compensation increase — Canadian plans 2.69 % 2.50 % 2.75 % Expected return on plan assets — U.S. plans 5.46 % 5.33 % 5.20 % Expected return on plan assets — Canadian plans 6.00 % 6.00 % 6.00 % Changes in benefit obligation recognized in Total Comprehensive Income Net (gain) loss $ (3.7 ) $ (3.1 ) $ 5.1 Recognized loss (1.1 ) (1.6 ) (1.1 ) Plan amendment (a) — — 0.5 Recognized prior service cost (0.1 ) (0.2 ) (0.3 ) Currency translation — (0.1 ) — Total recognized in other comprehensive income (before tax effects) $ (4.9 ) $ (5.0 ) $ 4.2 (a) In the second quarter of fiscal 2016, the Company finalized a new collective bargaining agreement that resulted in an amendment to its North American pension plans. Other International Year Ended September 30, 2018 2017 2016 Components of net periodic benefit cost Service cost $ 6.7 $ 1.7 $ — Interest cost 19.6 4.9 — Expected return on plan assets (31.7 ) (7.5 ) — Net periodic benefit cost $ (5.4 ) $ (0.9 ) $ — Weighted-average assumptions used to determine net benefit cost Discount rate 2.72 % 2.61 % — % Rate of compensation increase 2.70 % 2.75 % — % Expected return on plan assets 3.56 % 3.52 % — % Changes in plan assets and benefit obligation recognized in Total Comprehensive Income Net loss (gain) $ 8.2 $ (39.3 ) $ — Currency translation — (0.9 ) — Total recognized in other comprehensive income (before tax effects) $ 8.2 $ (40.2 ) $ — The estimated net actuarial loss and prior service cost expected to be reclassified from accumulated OCI into net periodic benefit cost during 2019 related to North American pension benefits are zero and $0.1 , respectively. There are no estimated net actuarial gain and prior service cost (credit) expected to be reclassified from accumulated OCI into net periodic benefit cost during 2019 related to other international pension benefits. The Company expects to make contributions of $0.5 and $5.0 to its defined benefit North American and other international pension plans, respectively, during fiscal 2019 . The expected return on North American pension plan assets was determined based on historical and expected future returns of the various asset classes, using the target allocation. The broad target allocations are 51.0% equity securities, 34.5% fixed income, 10.0% debt securities, 4.0% real assets and 0.5% cash. At September 30, 2018 , equity securities were 53.6% , fixed income was 33.2% , debt securities were 8.9% , real assets were 3.4% and cash was 0.9% of the fair value of total plan assets, 99.6% of which was invested in passive index funds. At September 30, 2017 , equity securities were 58.3% , fixed income was 17.6% , debt securities were 19.4% , real assets were 3.7% and cash was 1.0% of the fair value of total plan assets, 69.6% of which was invested in passive index funds. The allocation guidelines were established based on management’s determination of the appropriate risk posture and long-term objectives. The expected return on other international pension plan assets was determined based on historical and expected future returns of the various asset classes, using the target allocation. The broad target allocations are 52.6% debt securities, 20.8% liability driven instruments, 20.8% fixed income, 3.6% real assets, 0.2% other and 2.0% cash. At September 30, 2018 , debt securities were 57.3% , liability hedging instruments were 23.8% , fixed income was 18.5% , other was 0.2% and cash was 0.2% of the fair value of total plan assets, 31.8% of which was invested in passive index funds. At September 30, 2017 , debt securities were 52.7% , liability hedging instruments were 23.3% , fixed income was 23.2% , real assets were 0.4% , other was 0.1% and cash was 0.3% of the fair value of total plan assets, 25.6% of which was invested in passive index funds. The allocation guidelines were established based on management’s determination of the appropriate risk posture and long-term objectives. The following tables present the North American and other international pension plans’ assets measured at fair value on a recurring basis and the basis for that measurement. The fair value of mutual funds is based on quoted net asset values of the shares held by the plan at year end. North America September 30, 2018 September 30, 2017 Total Level 1 Level 2 Total Level 1 Level 2 Equities $ 9.5 $ — $ 9.5 $ 16.4 $ 7.8 $ 8.6 Bonds 10.1 0.1 10.0 11.3 11.3 — Fixed income 14.7 — 14.7 4.6 — 4.6 Real assets — — — 0.9 0.9 — Cash 1.1 1.1 — 0.8 0.8 — Fair value of plan assets in the fair value hierarchy 35.4 1.2 34.2 34.0 20.8 13.2 Equities 51.7 — — 30.7 — — Pooled assets — — — 4.5 — — Fixed income 23.2 — — 9.6 — — Real assets 3.8 — — 2.1 — — Investments measured at net asset value (a) 78.7 — — 46.9 — — Total plan assets $ 114.1 $ 1.2 $ 34.2 $ 80.9 $ 20.8 $ 13.2 Other International September 30, 2018 September 30, 2017 Total Level 1 Level 2 Total Level 1 Level 2 Bonds $ 439.5 $ 416.6 $ 22.9 $ 461.7 $ 441.1 $ 20.6 Liability driven instruments 201.4 201.4 — 204.2 204.2 — Fixed income 61.5 61.5 — 108.3 108.3 — Cash 1.6 1.6 — 2.7 2.7 — Fair value of plan assets in the fair value hierarchy 704.0 681.1 22.9 776.9 756.3 20.6 Bonds 44.4 — — — — — Fixed income 94.2 — — 95.0 — — Real assets — — — 3.9 — — Other 1.9 — — 0.9 — — Investments measured at net asset value (a) 140.5 — — 99.8 — — Total plan assets $ 844.5 $ 681.1 $ 22.9 $ 876.7 $ 756.3 $ 20.6 (a) In accordance with ASC Topic 820-10, certain investments were measured at net asset value per share (“NAV”). In cases where the fair value was measured at NAV using the practical expedient provided for in ASC Topic 820-10, the investments have not been classified in the fair value hierarchy. The fair value amounts presented in these tables are intended to permit reconciliation of the fair value hierarchy to the tables above. Other Postretirement Benefits The following table provides a reconciliation of the changes in the North American other postretirement benefit obligations over the two year period ended September 30, 2018 . Besides the North American plans, the Company does not maintain any other postretirement benefit plans. Year Ended 2018 2017 Change in benefit obligation Benefit obligation at beginning of period $ 65.0 $ 68.6 Service cost 0.5 0.6 Interest cost 2.1 2.0 Plan amendment — (0.1 ) Actuarial gain (9.9 ) (4.4 ) Benefits paid (2.3 ) (2.1 ) Currency translation (0.2 ) 0.4 Benefit obligation at end of period $ 55.2 $ 65.0 Change in fair value of plan assets Employer contributions 2.3 2.1 Benefits paid (2.3 ) (2.1 ) Fair value of plan assets at end of period — — Funded status $ (55.2 ) $ (65.0 ) Amounts recognized in assets or liabilities Other current liabilities (2.4 ) (2.7 ) Other liabilities (52.8 ) (62.3 ) Net amount recognized $ (55.2 ) $ (65.0 ) Amounts recognized in accumulated other comprehensive loss Net actuarial (gain) loss $ (1.2 ) $ 8.6 Prior service credit (24.1 ) (28.8 ) Total $ (25.3 ) $ (20.2 ) Weighted-average assumptions used to determine benefit obligation Discount rate — U.S. plans 4.27 % 3.77 % Discount rate — Canadian plans 3.54 % 3.69 % Rate of compensation increase — Canadian plans 2.75 % 2.75 % The following table provides the components of net periodic benefit cost for the other postretirement benefit plans including amounts recognized in OCI. Year Ended September 30, 2018 2017 2016 Components of net periodic benefit cost Service cost $ 0.5 $ 0.6 $ 1.0 Interest cost 2.1 2.0 4.0 Recognized net actuarial loss 0.3 0.7 1.6 Recognized prior service credit (4.7 ) (4.8 ) (3.8 ) Net periodic benefit cost $ (1.8 ) $ (1.5 ) $ 2.8 Weighted-average assumptions used to determine net benefit cost Discount rate — U.S. plans (Prior to plan amendment) (a) n/a n/a 4.60 % Discount rate — U.S. plans (Subsequent to plan amendment) (a) 3.77 % 3.54 % 4.22 % Discount rate — Canadian plans 3.69 % 3.23 % 3.91 % Rate of compensation increase — Canadian plans 2.75 % 2.75 % 2.75 % Changes in plan assets and benefit obligation recognized in Total Comprehensive Income Net gain $ (9.9 ) $ (4.4 ) $ (11.3 ) Recognized loss (0.3 ) (0.7 ) (1.6 ) Plan amendment (a) — (0.1 ) (36.1 ) Recognized prior service credit 4.7 4.8 3.8 Currency translation 0.4 0.1 (0.1 ) Total recognized in other comprehensive income (before tax effects) $ (5.1 ) $ (0.3 ) $ (45.3 ) (a) In the second quarter of fiscal 2016, the Company finalized a new collective bargaining agreement that resulted in an amendment to its other postretirement benefit plans. The plan was re-measured as of February 29, 2016. For fiscal 2016, the discount rate was 4.6% for the first five months of benefit cost and 4.22% for the last seven months of benefit cost. For September 30, 2018 measurement purposes, the assumed annual rate of increase in the future per capita cost of covered health care benefits related to domestic plans for 2019 was 6.5% for participants both under the age of 65 and over the age of 65, declining gradually to an ultimate rate of 5.0% for 2025 and beyond. For September 30, 2017 measurement purposes, the assumed annual rate of increase in the future per capita cost of covered health care benefits related to domestic plans for 2018 was 7.0% and 5.8% for participants under the age of 65 and over the age of 65, respectively, declining gradually to an ultimate rate of 5.0% for 2022 and beyond. For September 30, 2018 and 2017 measurement purposes, the assumed annual rate of increase in the future per capita cost of covered health care benefits related to Canadian plans for the following fiscal year was 6.0% and 6.5% , respectively, declining gradually to an ultimate rate of 4.5% for 2021 and beyond for the years ended September 30, 2018 and 2017 . A 1% change in assumed health care cost trend rates would result in the following changes in the accumulated postretirement benefit obligation and in the total service and interest cost components for fiscal 2018 : Increase Decrease Effect on postretirement benefit obligation $ 5.2 $ (4.3 ) Effect on total service and interest cost 0.3 (0.2 ) The estimated net actuarial gain and prior service credit expected to be reclassified from accumulated OCI into net periodic benefit cost during 2019 related to other postretirement benefits are $0.1 and $4.7 , respectively. Additional Information As of September 30, 2018 , expected future benefit payments and related federal subsidy receipts (Medicare Part D) in the next ten fiscal years were as follows: 2019 2020 2021 2022 2023 2024- 2028 Pension benefits $ 23.0 $ 23.9 $ 24.9 $ 26.0 $ 27.1 $ 155.5 Other benefits 2.4 2.8 2.8 3.0 3.1 16.5 Subsidy receipts — 0.1 0.1 0.1 0.1 1.1 In addition to the defined benefit plans described above, the Company sponsors a defined contribution 401(k) plan under which it makes matching contributions. The Company expensed $ 19.6 , $ 18.2 and $ 15.6 for the years ended September 30, 2018 , 2017 and 2016 , respectively.

Stock-Based Compensation Plans

Stock-Based Compensation Plans	12 Months Ended
	Sep. 30, 2018
Stock-Based Compensation [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION On February 3, 2012, the Company established the 2012 Long-Term Incentive Plan (the “2012 Plan”) which permitted the issuance of various stock-based compensation awards of up to 6.5 shares. On January 28, 2016, the Company established the 2016 Long-Term Incentive Plan (the “2016 Plan”) which permits issuance of stock-based compensation awards of up to 2.4 shares. Upon establishment of the 2016 Plan, all remaining shares available to be issued under the 2012 Plan were transferred to the 2016 Plan. Awards issued under the 2012 Plan and 2016 Plan have a maximum term of 10 years, provided, however, that the Corporate Governance and Compensation Committee of the Board of Directors may, in its discretion, grant awards with a longer term to participants who are located outside the United States. Total compensation cost for cash and non-cash stock-based compensation awards recognized in the years ended September 30, 2018 , 2017 and 2016 was $33.8 , $30.7 and $25.6 , respectively, and the related recognized deferred tax benefit for each of those periods was approximately $7.8 , $9.7 and $8.0 , respectively. As of September 30, 2018 , the total compensation cost related to non-vested awards not yet recognized was $55.5 , which is expected to be recognized over a weighted-average period of 2.1 years. In connection with employee retirement and reorganization initiatives during fiscal 2015, the Company accelerated the vesting of unvested equity awards for 25 employees in the year ended September 30, 2016. As a result of this acceleration, the Company recorded $2.2 of incremental cash and stock-based compensation expense in the year ended September 30, 2016. No such expense was recorded in the years ended September 30, 2018 and 2017. Stock Appreciation Rights (“SSAR”) Information about SSARs is summarized in the following table. Upon exercise of each SSAR, the holder will receive the number of shares of Post common stock equal in value to the difference between the exercise price and the fair market value at the date of exercise, less all applicable taxes. The total intrinsic value of SSARs exercised was $0.1 , $0.6 and $5.1 in the years ended September 30, 2018 , 2017 and 2016 , respectively. There were no SSARs granted during the years ended September 30, 2018 , 2017 and 2016 . Stock-Settled Stock Appreciation Rights Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term in Years Aggregate Intrinsic Value Outstanding at September 30, 2017 137,831 $ 41.63 Granted — — Exercised (1,800 ) 18.10 Forfeited — — Expired — — Outstanding at September 30, 2018 136,031 41.94 4.73 $ 7.6 Vested and expected to vest as of September 30, 2018 136,031 41.94 4.73 7.6 Exercisable at September 30, 2018 136,031 41.94 4.73 7.6 Cash Settled Stock Appreciation Rights (“SAR”) Information about SARs is summarized in the following table. There were no SARs granted during the years ended September 30, 2018 , 2017 and 2016 . Cash used by the Company to settle SARs was $5.0 and $0.7 for the years ended September 30, 2018 and 2016 , respectively. There were no cash settlements of SARs for the year ended September 30, 2017. Cash-Settled Stock Appreciation Rights Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term in Years Aggregate Intrinsic Value Outstanding at September 30, 2017 104,500 $ 46.43 Granted — — Exercised (102,000 ) 47.12 Forfeited — — Expired — — Outstanding at September 30, 2018 2,500 18.10 1.98 $ 0.2 Vested and expected to vest as of September 30, 2018 2,500 18.10 1.98 0.2 Exercisable at September 30, 2018 2,500 18.10 1.98 0.2 The fair value of each SAR was estimated for each reporting period using the Black-Scholes Model. The expected term is estimated based on the award’s vesting period and contractual term, along with historical exercise behavior on similar awards. Expected volatilities are based on historical volatility trends and other factors. The risk-free rate is the interpolated U.S. Treasury rate for a term equal to the expected term. The following table presents the assumptions used to remeasure the fair value of outstanding SARs at September 30, 2018 , 2017 and 2016 . 2018 2017 2016 Expected term 0 2.9 3.8 Expected stock price volatility 21.5% 31.7% 32.4% Risk-free interest rate 2.6% 1.6% 1.0% Expected dividends 0% 0% 0% Fair value (per right) $79.94 $54.18 $44.44 Stock Options Stock Options Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term in Years Aggregate Intrinsic Value Outstanding at September 30, 2017 4,198,500 $ 45.36 Granted 248,206 80.04 Exercised (128,999 ) 45.12 Forfeited (6,667 ) 71.32 Expired — — Outstanding at September 30, 2018 4,311,040 47.32 5.63 $ 218.6 Vested and expected to vest as of September 30, 2018 4,311,040 47.32 5.63 218.6 Exercisable at September 30, 2018 3,647,330 43.67 5.24 198.3 The fair value of each stock option was estimated on the date of grant using the Black-Scholes Model. The Company uses the simplified method for estimating a stock option term as it does not have sufficient historical share options exercise experience upon which to estimate an expected term. The expected term is estimated based on the award’s vesting period and contractual term. Expected volatilities are based on historical volatility trends and other factors. The risk-free rate is the interpolated U.S. Treasury rate for a term equal to the expected term. The weighted-average assumptions and fair values for stock options granted during the years ended September 30, 2018 , 2017 and 2016 are summarized in the table below. 2018 2017 2016 Expected term 6.5 6.5 6.5 Expected stock price volatility 30.7% 30.6% 29.1% Risk-free interest rate 2.2% 1.9% 1.9% Expected dividends 0% 0% 0% Fair value (per option) $28.52 $24.80 $20.22 The total intrinsic value of stock options exercised was $4.7 , $17.6 and $5.1 in the years ended September 30, 2018 , 2017 and 2016 , respectively. Restricted Stock Units Restricted Stock Units Weighted- Average Grant Date Fair Value Per Share Nonvested at September 30, 2017 730,040 $ 63.55 Granted 478,325 80.19 Vested (213,824 ) 60.99 Forfeited (52,673 ) 75.01 Nonvested at September 30, 2018 941,868 71.94 The grant date fair value of each restricted stock award was determined based upon the closing price of the Company’s stock on the date of grant. The total vest date fair value of restricted stock units that vested during fiscal 2018 , 2017 and 2016 was $17.4 , $10.5 and $32.0 , respectively. In fiscal 2018 , 2017 and 2016 , the Company granted 13,300 , 10,200 and 15,000 restricted stock units to its non-management members of the Board of Directors, respectively. Due to vesting provisions of these awards, the Company determined that 11,400 , 8,500 and 12,500 of these awards granted in fiscal 2018, 2017 and 2016, respectively, had subjective acceleration rights such that the Company expensed the grant date fair value upon issuance and recognized related expense of $0.9 in the year ended September 30, 2018 and $0.7 in each of the years ended September 30, 2017 and 2016 . Cash Settled Restricted Stock Units Cash-Settled Restricted Stock Units Weighted- Average Grant Date Fair Value Per Share Nonvested at September 30, 2017 100,119 $ 49.47 Granted — — Vested (38,537 ) 43.28 Forfeited (1,330 ) 62.90 Nonvested at September 30, 2018 60,252 53.13 Cash settled restricted stock awards are liability awards and as such, their fair value is based upon the closing price of the Company’s stock for each reporting period, with the exception of 49,000 cash settled restricted stock units that are valued at the greater of the closing stock price or the grant price of $51.43 . Cash used by the Company to settle restricted stock units was $3.2 , $4.1 and $5.9 for the years ended September 30, 2018 , 2017 and 2016 , respectively. Performance-Based Restricted Stock Units (“PRSU”) Performance-Based Restricted Stock Units Weighted- Average Grant Date Fair Value Per Share Nonvested at September 30, 2017 — $ — Granted 32,307 97.74 Vested — — Forfeited — — Nonvested at September 30, 2018 32,307 97.74 During the year ended September 30, 2018, the Company granted PRSUs to certain employees. These awards will be earned by comparing the Company’s total shareholder return (“TSR”) during a three year period to the respective TSRs of companies in a performance peer group. Based upon the Company’s ranking in its performance peer group when comparing TSRs, a recipient of the PRSU grant may earn a total award ranging from 0% to 200% of the target award. The fair value of each PRSU was estimated on the grant date using a Monte Carlo simulation. There were no PRSUs granted during the years ended September 30, 2017 and 2016. The assumptions for PRSUs granted during the year ended September 30, 2018 are summarized in the table below. 2018 Expected term 3.0 Expected stock price volatility 31.8% Risk-free interest rate 1.8% Expected dividend yield 0% Deferred Compensation Post provides deferred compensation plans for directors and key employees through which eligible participants may elect to defer payment of all or a portion of their compensation, or with respect to key employee participants, all or a portion of their eligible annual bonus until a later date based on the participant’s elections. Participant deferrals for employee participants may be notionally invested in Post common stock equivalents (Equity Option) or into a number of funds operated by The Vanguard Group Inc. with a variety of investment strategies and objectives (Vanguard Funds). In order to receive a 33.3% matching contribution, deferrals for director participants must be made into Post common stock equivalents. Deferrals into the Equity Option are generally distributed in Post stock for employees and cash for directors, while deferrals into the Vanguard Funds are distributed in cash. There are no significant costs related to the administration of the deferred compensation plans. Post funds its deferred compensation liability (potential cash distributions) by investing in the Vanguard Funds in the same amounts as selected by the participating employees. Both realized and unrealized gains and losses on these investments are included in “Selling, general and administrative expenses” in the Consolidated Statements of Operations and offset the related change in the deferred compensation liability. For additional information, refer to Note 15.

Tangible Equity Units

Tangible Equity Units	12 Months Ended
	Sep. 30, 2018
Tangible Equity Units [Abstract]
Tangible Equity Units	TANGIBLE EQUITY UNITS In May 2014, the Company completed a public offering of 2.875 TEUs, each with a stated value of $100.00 . Each TEU was comprised of a prepaid stock purchase contract and a senior amortizing note due June 1, 2017. The prepaid common stock purchase contracts were recorded as additional paid-in capital, net of issuance costs, and the senior notes were recorded as long-term debt. Issuance costs associated with the debt component were recorded as deferred financing costs within “Long-term debt” on the Consolidated Balance Sheets and were amortized using the effective interest rate method over the term of the instrument to June 1, 2017. At September 30, 2018 and 2017, there was no long-term debt related to TEUs recorded on the Consolidated Balance Sheets. Post allocated the proceeds from the issuance of the TEUs to equity and debt based on the relative fair values of the respective components of each TEU. The proceeds received in the offering were $278.6 , which were net of financing fees of $8.9 . The aggregate values assigned upon issuance of each component of the TEUs were as follows (amounts in millions except price per TEU): Equity Component Debt Component TEUs Total Price per TEU $ 85.48 $ 14.52 $ 100.00 Gross proceeds $ 245.7 $ 41.8 $ 287.5 Issuance costs (7.6 ) (1.3 ) (8.9 ) Net proceeds $ 238.1 $ 40.5 $ 278.6 Balance sheet impact (at issuance) Long-term debt (deferred financing fees) $ — $ 1.3 $ 1.3 Current portion of long-term debt — 13.3 13.3 Long-term debt — 28.5 28.5 Additional paid-in capital 238.1 — 238.1 The senior amortizing note component of each TEU’s initial principal amount of $14.5219 bore interest at 5.25% per annum and had a final installment payment date on June 1, 2017. The Company paid equal quarterly cash installments of $1.3125 per amortizing note on March 1, June 1, September 1 and December 1 of each year. Payments commenced on September 1, 2014 and ended on June 1, 2017. Each installment constituted a payment of interest and a partial repayment of principal. The senior amortizing note component of the TEUs was repaid as of June 1, 2017 and the Company delivered 1.7114 shares of its common stock per purchase contract. Holders of TEUs, or their separated purchase contract components, settled 2.8 and 0.1 purchase contracts during the years ended September 30, 2017 and 2016, respectively, for which the Company issued 4.7 and 0.2 shares of common stock during the years ended September 30, 2017 and 2016, respectively. All outstanding purchase contracts were settled as of September 30, 2017.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Sep. 30, 2018
Stockholders' Equity Attributable to Parent [Abstract]
Shareholders' Equity	SHAREHOLDERS’ EQUITY Preferred Stock During the years ended September 30, 2018 and 2017, the Company had two classes of preferred stock, the 2.5% Series C Cumulative Perpetual Convertible Preferred Stock (the “Series C Preferred”) and the 3.75% Series B Cumulative Perpetual Convertible Preferred Stock (the “Series B Preferred”). There are 50.0 preferred shares authorized. Series C Preferred The Series C Preferred has a $0.01 par value per share and a $100.00 liquidation value per share. There were 3.2 shares outstanding at both September 30, 2018 and 2017 . The Series C Preferred earns cumulative dividends at a rate of 2.5% per annum payable quarterly on February 15, May 15, August 15 and November 15. The Series C Preferred is non-voting and ranks senior to the Company’s outstanding common stock upon the Company’s dissolution or liquidation. The Series C Preferred has no maturity date; however, holders of the Series C Preferred may convert their stock at an initial conversion rate of 1.8477 shares of the Company’s common stock per share of convertible preferred stock, which is equivalent to a conversion price of $54.12 per share of common stock. On or after February 15, 2019, the Company may redeem all or some of the Series C Preferred at a redemption price equal to 100% of the liquidation preference per share, plus accrued and unpaid dividends to the redemption date if the closing sale price of our common stock has been at least 150% of the conversion price then in effect for at least 20 trading days during any 30 day trading day period ending on, and including, the trading day immediately preceding the date of the redemption notice. Series B Preferred The Series B Preferred had a $0.01 par value per share and a $100.00 liquidation value per share. There were zero and 1.5 shares outstanding at September 30, 2018 and 2017 , respectively. The Series B Preferred earned cumulative dividends at a rate of 3.75% per annum payable quarterly on February 15, May 15, August 15 and November 15. The Series B Preferred was non-voting and ranked senior to the Company’s outstanding common stock upon the Company’s dissolution or liquidation. In December 2015, the Company and a holder of the Company’s Series B Preferred entered into an exchange agreement pursuant to which the shareholder agreed to deliver 0.9 shares of the Series B Preferred to the Company in exchange for 2.0 shares of common stock and $10.9 of cash. The number of shares of common stock exchanged in the transaction was based upon the current conversion rate, under the Certificate of Designation, Rights and Preferences for the Series B Preferred, of 2.1192 shares of common stock per share of Series B Preferred. For the year ended September 30, 2016, the cash paid increased “Preferred stock dividends” on the Consolidated Statement of Operations. 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 redemption was announced, were converted into 3.1 shares of the Company’s common stock. The number of shares of common stock exchanged in the transaction was based upon the current conversion rate, under the Certificate of Designation, Rights and Preferences for the Series B Preferred, of 2.1192 shares of common stock per share of Series B Preferred. The remaining shares of Series B Preferred were redeemed. Common Stock During the year ended September 30, 2018, the Company repurchased 2.8 shares of its common stock at an average share price of $76.21 per share for a total cost of $218.7 , including brokers’ commissions. During the year ended September 30, 2017, the Company repurchased 4.0 shares of its common stock at an average share price of $79.53 per share for a total cost of $317.8 , including brokers’ commissions. These share repurchases were recorded as “Treasury stock, at cost” on the Consolidated Balance Sheet. In March 2016, the Company entered into a structured share repurchase arrangement which required cash payments totaling $28.3 , including transaction-related fees of $0.2 . At the May 2016 expiration of the agreement, the market price of Post’s common stock exceeded the pre-determined contract price, resulting in cash payments to the Company of $29.4 .

Segments

Segments	12 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Segments	SEGMENTS During the second quarter of fiscal 2018, the Company reorganized its operating segments, which resulted in reorganized reportable segments in accordance with ASC Topic 280, “Segment Reporting.” At September 30, 2018, the Company’s reportable segments were as follows: • Post Consumer Brands: North American RTE cereal business; • Weetabix: RTE cereal and the branded muesli business sold and distributed primarily outside of North America; • Refrigerated Food: refrigerated foodservice, primarily egg and potato, and refrigerated retail, inclusive of side dishes, egg, cheese and sausage; • Active Nutrition: protein shakes, bars and powders and nutritional supplements; and • Private Brands: peanut and other nut butters, dried fruit and nut products, granola and pasta. All historical segment results reported herein have been reclassified to conform with the September 30, 2018 presentation. Management evaluates each segment’s performance based on its segment profit, which is its operating profit before impairment of property, goodwill and other intangible assets, facility closure related costs, restructuring expenses, (gains)/losses on assets and liabilities held for sale, (gains)/losses on sale of facilities and other unallocated corporate income and expenses. Post’s external revenues were primarily generated by sales within the United States; foreign (primarily located in the United Kingdom and Canada) sales were approximately 13% of total fiscal 2018 net sales. Sales are attributed to individual countries based on the address to which the product is shipped. As of September 30, 2018 and 2017 , the majority of Post’s tangible long-lived assets were located in the United States; the remainder are located primarily in the United Kingdom and Canada which combined have a net carrying value of approximately $284.3 and $311.1 , respectively. Additionally, the Company had tangible long-lived assets located in Canada of $12.4 , which were classified as held for sale at September 30, 2018 . In the years ended September 30, 2018 , 2017 and 2016 , one customer accounted for $784.6 , $704.1 and $668.8 , respectively, or approximately 13% , of total net sales in each year. All segments, except Weetabix, sell products to this major customer. The following tables present information about the Company’s reportable segments. In addition, the tables present net sales by product. Note that “Additions to property and intangibles” excludes additions through business acquisitions (see Note 4). Year Ended September 30, 2018 2017 2016 Net Sales Post Consumer Brands $ 1,831.7 $ 1,742.5 $ 1,728.2 Weetabix 423.4 112.4 — Refrigerated Food 2,337.9 1,870.8 1,917.4 Active Nutrition 827.5 713.2 574.7 Private Brands 848.9 791.2 811.1 Eliminations (12.2 ) (4.3 ) (4.6 ) Total $ 6,257.2 $ 5,225.8 $ 5,026.8 Segment Profit Post Consumer Brands $ 329.2 $ 354.9 $ 290.4 Weetabix 87.2 14.5 — Refrigerated Food 247.6 110.6 245.7 Active Nutrition 124.4 96.4 44.7 Private Brands 60.8 58.1 71.4 Total segment profit 849.2 634.5 652.2 General corporate expenses and other 136.8 87.7 106.5 Impairment of goodwill and other intangibles 124.9 26.5 — Interest expense, net 387.3 314.8 306.5 Loss on extinguishment of debt, net 31.1 222.9 86.4 (Income) expense on swaps, net (95.6 ) (91.8 ) 182.9 Earnings (loss) before income taxes and equity method loss $ 264.7 $ 74.4 $ (30.1 ) Net sales by product Cereal and granola $ 2,351.2 $ 1,963.9 $ 1,838.5 Egg and egg products 1,542.8 1,419.1 1,417.0 Cheese and dairy 248.6 259.4 320.9 Side dishes 398.2 192.3 179.5 Sausage 96.0 — — Pasta 258.4 249.4 270.6 Protein-based products and supplements 827.5 713.2 574.7 Nut butters and dried fruit and nut 487.5 432.5 429.1 Other 53.0 — — Eliminations (6.0 ) (4.0 ) (3.5 ) Total $ 6,257.2 $ 5,225.8 $ 5,026.8 Additions to property and intangibles Post Consumer Brands $ 51.5 $ 57.8 $ 34.8 Weetabix 26.3 13.6 — Refrigerated Food 114.6 66.0 51.6 Active Nutrition 5.0 3.9 4.4 Private Brands 26.6 29.1 23.5 Corporate 1.0 20.0 7.2 Total $ 225.0 $ 190.4 $ 121.5 Depreciation and amortization Post Consumer Brands $ 122.0 $ 112.4 $ 105.5 Weetabix 38.1 7.7 — Refrigerated Food 163.3 125.4 119.9 Active Nutrition 25.9 25.3 25.0 Private Brands 40.9 48.6 46.4 Total segment depreciation and amortization 390.2 319.4 296.8 Corporate and accelerated depreciation 8.2 3.7 6.0 Total $ 398.4 $ 323.1 $ 302.8 September 30, 2018 2017 2016 Assets, end of year Post Consumer Brands $ 3,391.7 $ 3,440.5 $ 3,387.0 Weetabix 1,853.3 2,048.9 — Refrigerated Food 5,132.4 3,176.0 3,099.3 Active Nutrition 559.3 581.3 624.8 Private Brands 1,055.3 1,054.9 1,054.7 Corporate 1,065.5 1,575.2 1,194.8 Total $ 13,057.5 $ 11,876.8 $ 9,360.6

Quarterly Financial Information

Quarterly Financial Information	12 Months Ended
	Sep. 30, 2018
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	SUMMARY QUARTERLY FINANCIAL INFORMATION (UNAUDITED) First Second Third Fourth Quarter Quarter Quarter Quarter Fiscal 2018 Net sales $ 1,433.1 $ 1,586.1 $ 1,608.1 $ 1,629.9 Gross profit 451.7 475.7 461.4 478.0 Impairment of goodwill and other intangible assets — — — 124.9 Net earnings (loss) 294.9 91.5 96.5 (15.6 ) Net earnings (loss) available to common shareholders 291.5 88.9 94.5 (17.6 ) Basic earnings (loss) per share $ 4.42 $ 1.33 $ 1.41 $ (0.26 ) Diluted earnings (loss) per share $ 3.82 $ 1.20 $ 1.29 $ (0.26 ) Fiscal 2017 Net sales $ 1,249.8 $ 1,255.4 $ 1,272.1 $ 1,448.5 Gross profit 379.2 364.1 393.7 437.1 Impairment of goodwill and other intangible assets — — — 26.5 Net earnings (loss) 101.8 (2.1 ) (59.4 ) 8.0 Net earnings (loss) available to common shareholders 98.4 (5.5 ) (62.8 ) 4.7 Basic earnings (loss) per share $ 1.42 $ (0.08 ) $ (0.93 ) $ 0.07 Diluted earnings (loss) per share $ 1.27 $ (0.08 ) $ (0.93 ) $ 0.07

Summary of Significant Accoun_2

Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Principles of combination	Principles of Consolidation — The consolidated financial statements include the operations of Post and its wholly-owned and majority-owned subsidiaries. All intercompany transactions have been eliminated.
Use of estimates and allocations	Use of Estimates and Allocations — The consolidated financial statements of the Company are prepared in conformity with accounting principles generally accepted in the United States of America (“GAAP”), which require certain elections as to accounting policy, estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent liabilities at the dates of the financial statements and the reported amount of net revenues and expenses during the reporting periods. Significant accounting policy elections, estimates and assumptions include, among others, pension and benefit plan assumptions, valuation assumptions of goodwill and other intangible assets, marketing programs, self-insurance reserves and income taxes. Actual results could differ from those estimates.
Business combinations	Business Combinations — The Company uses the acquisition method in accounting for acquired businesses. Under the acquisition method, the Company’s financial statements reflect the operations of an acquired business starting from the completion of the acquisition. The assets acquired and liabilities assumed are recorded at their respective estimated fair values at the date of the acquisition. Any excess of the purchase price over the estimated fair values of the identifiable net assets acquired is recorded as goodwill.
Cash equivalents	Cash Equivalents — Cash equivalents include all highly liquid investments with original maturities of less than three months.
Restricted cash	Restricted Cash — Restricted cash includes items such as cash deposits which serve as collateral for certain commodity hedging contracts as well as the Company's high deductible workers’ compensation insurance program.
Receivables	Receivables — Receivables are reported at net realizable value. This value includes appropriate allowances for doubtful accounts, cash discounts and other amounts which the Company does not ultimately expect to collect. The Company determines its allowance for doubtful accounts based on historical losses as well as the economic status of and its relationship with its customers, especially those identified as “at risk.” A receivable is considered past due if payments have not been received within the agreed upon invoice terms. Receivables are written off against the allowance when the customer files for bankruptcy protection or are otherwise deemed to be uncollectible based upon the Company’s evaluation of the customer’s solvency.
Inventories	Inventories — Inventories, other than flocks, are generally valued at the lower of average cost (determined on a first-in, first-out basis) or net realizable value (“NRV”). Reported amounts have been reduced by an allowance for obsolete product and packaging materials based on a review of inventories on hand compared to estimated future usage and sales. Flock inventory represents the cost of purchasing and raising chicken flocks to egg laying maturity. The costs included in our flock inventory include the costs of the chicks, the feed fed to the birds and the labor and overhead costs incurred to operate the pullet facilities until the birds are transferred into the laying facilities, at which time their cost is amortized to operations, as cost of goods sold, over their expected useful lives of one to two years.
Restructuring Expenses	Restructuring Expenses — Restructuring charges principally consist of severance, accelerated stock compensation and other employee separation costs and accelerated depreciation. The Company recognizes restructuring obligations and liabilities for exit and disposal activities at fair value in the period the liability is incurred. Employee severance costs are expensed when they become probable and reasonably estimable under established severance plans. Depreciation expense related to assets that will be disposed of or idled as a part of the restructuring activity is accelerated through the expected date of the asset shut down. See Note 5 for information about restructuring expenses.
Assets and Liabilities Held For Sale	Held for Sale Assets and Liabilities — Assets and liabilities are classified as held for sale if the Company has committed to a plan for selling the assets and liabilities, is actively and reasonably marketing them and sale is reasonably expected within one year. The carrying value of assets held for sale is included in “Current assets held for sale” and “Other assets held for sale” on the Consolidated Balance Sheets. The carrying value of liabilities held for sale is included in “Current liabilities held for sale” and “Other liabilities held for sale” on the Consolidated Balance Sheets. See Note 6 for information about assets and liabilities held for sale.
Property	Property — Property is recorded at cost, and depreciation expense is generally provided on a straight-line basis over the estimated useful lives of the properties. Estimated useful lives range from 1 to 29 years for machinery and equipment; 1 to 40 years for buildings, building improvements and leasehold improvements; and 1 to 7 years for software. Total depreciation expense was $221.0 , $164.0 and $150.2 in fiscal 2018 , 2017 and 2016 , respectively. Any gains and losses incurred on the sale or disposal of assets are included in “Other operating expenses, net” in the Consolidated Statements of Operations. Repair and maintenance costs incurred in connection with on-going and planned major maintenance activities are accounted for under the direct expensing method.
Other intangible assets	Other Intangible Assets — Other intangible assets consist primarily of customer relationships and trademarks/brands acquired in business combinations and include both indefinite and definite-lived assets.
Recoverability of assets	Recoverability of Assets — The Company continually evaluates whether events or circumstances have occurred which might impair the recoverability of the carrying value of its assets, including property, identifiable intangibles and goodwill. Trademarks with indefinite lives are reviewed for impairment during the fourth quarter of each fiscal year following the annual forecasting process, or more frequently if facts and circumstances indicate the trademark may be impaired. The trademark impairment tests require us to estimate the fair value of the trademark and compare it to its carrying value. The estimated fair value is determined using an income-based approach (the relief-from-royalty method), which requires significant assumptions for each brand, including estimates regarding future revenue growth, discount rates and appropriate royalty rates. Assumptions are determined after consideration of several factors for each brand, including profit levels, research of external royalty rates by third party experts and the relative importance of each brand to the Company. Revenue growth assumptions are based on historical trends and management’s expectations for future growth by brand. The discount rate is based on a weighted-average cost of capital utilizing industry market data of similar companies. In addition, definite-lived assets and indefinite-lived intangible assets are reassessed as needed when information becomes available that is believed to negatively impact the fair market value of an asset. In general, an asset is deemed impaired and written down to its fair value if estimated related future cash flows are less than its carrying amount. See Note 7 for information about goodwill impairments.
Deferred compensation investments	Deferred Compensation Investments — The Company funds a portion of its deferred compensation liability by investing in certain mutual funds, or funds that employ a similar investment strategy, and are purchased in substantially the same amounts, as selected by the participating employees. Because management’s intent is to invest in a manner that matches the deferral options chosen by the participants and those participants can elect to transfer amounts in or out of each of the designated deferral options at any time, these investments have been classified as trading assets and are stated at fair value in “Prepaid expenses and other current assets” and “Other assets” on the Consolidated Balance Sheets (see Note 15). Both realized and unrealized gains and losses on these assets are included in “Selling, general and administrative expenses” in the Consolidated Statements of Operations and offset the related change in the deferred compensation liability.
Derivatives	Derivative Financial Instruments — 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. The Company’s derivative programs include strategies that qualify and strategies that do not qualify for hedge accounting treatment. To qualify for hedge accounting, the hedging relationship, both at inception of the hedge and on an ongoing basis, is expected to be highly effective in achieving offsetting changes in the fair value of the hedged risk during the period that the hedge is designated. All derivatives are recognized on the balance sheet at fair value. For derivatives that qualify for hedge accounting, the derivative is designated as a hedge on the date in which the derivative contract is entered. A derivative could be designated as a hedge of a forecasted transaction or of the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge) or a hedge of a net investment in a foreign operation. Some derivatives may also be considered natural hedging instruments, where changes in fair value act as economic offsets to changes in fair value of the underlying hedged item and are not designated for hedge accounting. The Company does not have any derivatives currently designated as fair value hedges. The effective portion of gains and losses on cash flow hedges are recorded in other comprehensive income (“OCI”), until earnings are affected by the variability of cash flows. If the hedge is no longer effective, all changes in the fair value of the derivative are included in earnings for each period until the instrument matures. If a derivative is used as a hedge of a net investment in a foreign operation, its changes in fair value, to the extent effective as a hedge, are recorded in OCI. Any ineffective portion of designated hedges are recognized in earnings. Changes in the fair value of derivatives that are not designated for hedge accounting are recognized in earnings. Cash flows from derivatives that are accounted for as hedges and cash flows on derivatives utilized as economic hedges, are classified in the same category on the Statements of Cash Flows as the item being hedged or on a basis consistent with the nature of the instrument.
Revenue	Revenue — Revenue is recognized when title of goods and risk of loss is transferred to the customer, as specified by the shipping terms. Net sales reflect gross sales, including amounts billed to customers for shipping and handling, less sales discounts and trade allowances (including promotional price buy downs and new item promotional funding). Customer trade allowances are generally computed as a percentage of gross sales. Products are generally sold with no right of return, except in the case of goods which do not meet product specifications or are damaged, and related reserves are maintained based on return history. If additional rights of return are granted, revenue recognition is deferred. Estimated reductions to revenue for customer incentive offerings are based upon customer redemption history.
Cost of good sold	Cost of Goods Sold — Cost of goods sold includes, among other things, inbound and outbound freight costs (including the Company-owned fleet) and depreciation expense related to assets used in production, while storage and other warehousing costs are included in “Selling, general and administrative expenses” in the Consolidated Statements of Operations.
Advertising	Advertising — Advertising costs are expensed as incurred except for costs of producing media advertising such as television commercials or magazine advertisements, which are deferred until the first time the advertising takes place.
Stock-based compensation	Stock-based Compensation — The Company recognizes the cost of employee services received in exchange for awards of equity instruments based on the grant-date fair value of equity awards and the fair market value at each quarterly reporting date for liability awards. That cost is recognized over the period during which an employee is required to provide service in exchange for the award — the requisite service period (usually the vesting period). See Note 19 for disclosures related to stock-based compensation.
Income tax (benefit) expense	Income Tax (Benefit) Expense — Income tax (benefit) expense is estimated based on income taxes in each jurisdiction and includes the effects of both current tax exposures and the temporary differences resulting from differing treatment of items for tax and financial reporting purposes. These temporary differences result in deferred tax assets and liabilities. A valuation allowance is established against the related deferred tax assets to the extent that it is more likely than not that the future benefits will not be realized. Reserves are recorded for estimated exposures associated with the Company’s tax filing positions, which are subject to periodic audits by governmental taxing authorities. Interest incurred due to an underpayment of income taxes is classified as income taxes. While the Company considers the undistributed earnings of its foreign subsidiaries to be permanently reinvested, the Company recorded a one-time transition tax on such earnings during the year ended September 30, 2018 in accordance with the Tax Cuts and Jobs Act (the “Tax Act”). See Note 9 for disclosures related to income taxes.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Property	Property consisted of: September 30, 2018 2017 Land and land improvements $ 88.2 $ 90.9 Buildings and leasehold improvements 720.7 699.4 Machinery and equipment 1,507.4 1,439.3 Software 112.0 64.5 Construction in progress 114.7 100.0 2,543.0 2,394.1 Accumulated depreciation (833.3 ) (703.4 ) $ 1,709.7 $ 1,690.7
Other intangible assets	Other intangible assets consisted of: September 30, 2018 September 30, 2017 Carrying Amount Accum. Amort. Net Amount Carrying Amount Accum. Amort. Net Amount Subject to amortization: Customer relationships $ 2,307.0 $ (444.4 ) $ 1,862.6 $ 2,249.3 $ (416.7 ) $ 1,832.6 Trademarks and brands 768.5 (188.2 ) 580.3 834.1 (162.9 ) 671.2 Other 3.1 (3.1 ) — 21.7 (9.8 ) 11.9 3,078.6 (635.7 ) 2,442.9 3,105.1 (589.4 ) 2,515.7 Not subject to amortization: Trademarks and brands 1,096.4 — 1,096.4 838.2 — 838.2 $ 4,175.0 $ (635.7 ) $ 3,539.3 $ 3,943.3 $ (589.4 ) $ 3,353.9

Business Combinations and Div_2

Business Combinations and Divestitures (Tables)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Business Acquisition
Weetabix Group Opening Balance Sheet with Measurement Period Adjustments	The following table provides the allocation of the purchase price related to the fiscal 2017 acquisition of the Weetabix Group based upon the fair value of assets and liabilities assumed, including the provisional amounts recognized related to the acquisition as of September 30, 2017, as well as measurement period adjustments made during the year ended September 30, 2018. The final fair value of goodwill related to the acquisition of the Weetabix Group will not be deductible for U.S. income tax purposes. Acquisition Date Amounts Recognized as of September 30, 2017 (a) Adjustments During the Year Ended September 30, 2018 Acquisition Date Amounts Recognized (as Adjusted) Cash and cash equivalents $ 62.2 $ — $ 62.2 Receivables (c) 39.7 (1.9 ) 37.8 Inventories (b), (c) 63.4 (0.2 ) 63.2 Prepaid expenses and other current assets 1.2 — 1.2 Property (b) 283.9 (3.0 ) 280.9 Goodwill (d) 969.3 11.5 980.8 Other intangible assets (b) 608.4 (7.4 ) 601.0 Other assets 112.0 — 112.0 Accounts payable (66.3 ) — (66.3 ) Other current liabilities (c) (28.4 ) (0.1 ) (28.5 ) Deferred tax liability - long-term (c) (137.6 ) 1.1 (136.5 ) Other liabilities (10.9 ) — (10.9 ) Noncontrolling interest (9.7 ) — (9.7 ) Total acquisition cost $ 1,887.2 $ — $ 1,887.2
Pro Forma Information	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 acquisitions occurred on the assumed dates, nor is it necessarily an indication of future operating results. 2018 2017 2016 Pro forma net sales $ 5,587.1 $ 5,258.3 $ 5,751.2 Pro forma net earnings available to common shareholders $ 432.1 $ 23.6 $ 2.0 Pro forma basic earnings per share $ 6.49 $ 0.35 $ 0.03 Pro forma diluted earnings per share $ 5.83 $ 0.34 $ 0.03
Bob Evans Farms
Business Acquisition
Opening Balance Sheet	The following table provides the preliminary 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. Measurement period adjustments have been made to the allocation of purchase price since the date of the Bob Evans acquisition. Cash and cash equivalents $ 15.6 Receivables 58.5 Inventories 27.1 Prepaid expenses and other current assets 34.3 Property 184.3 Goodwill 898.3 Other intangible assets 782.0 Other assets 0.4 Accounts payable (18.2 ) Other current liabilities (58.5 ) Deferred tax liability - long-term (194.9 ) Other liabilities (5.3 ) Total acquisition cost $ 1,723.6
National Pasteurized Eggs
Business Acquisition
Opening Balance Sheet		The following table provides the allocation of the purchase price related to the fiscal 2017 acquisition of NPE based upon the fair value of assets and liabilities assumed. The final fair value of goodwill related to the acquisition of NPE will not be deductible for U.S. income tax purposes. NPE Cash and cash equivalents $ 5.6 Receivables 8.5 Inventories 2.1 Prepaid expenses and other current assets 0.4 Property 10.4 Goodwill 46.3 Other intangible assets 51.4 Current portion of long-term debt (0.1 ) Accounts payable (6.3 ) Other current liabilities (2.9 ) Long-term debt (0.2 ) Deferred tax liability - long-term (18.7 ) Total acquisition cost $ 96.5
Willamette Egg
Business Acquisition
Opening Balance Sheet			The following table provides the allocation of the purchase price related to the fiscal 2016 acquisition of WEF based upon the fair value of assets and liabilities assumed. The final fair value of goodwill related to the acquisition of WEF will be deductible for U.S. income tax purposes. WEF Cash and cash equivalents $ 19.2 Receivables 11.1 Inventories 10.3 Prepaid expenses and other current assets 0.5 Property 56.2 Goodwill 4.2 Other intangible assets 15.2 Other assets 0.1 Accounts payable (2.2 ) Other current liabilities (1.0 ) Total acquisition cost $ 113.6

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Sep. 30, 2018
Restructuring and Related Activities [Abstract]
Schedule of Restructuring and Related Costs	Amounts related to the restructuring events are shown in the following table. All costs are recognized in “Selling, general and administrative expenses” in the Condensed Consolidated Statements of Operations with the exception of accelerated depreciation expense incurred in the year ended September 30, 2018, which is included in “Cost of goods sold.” These expenses are not included in the measure of segment performance for any segment (see Note 22). Employee-Related Costs Accelerated Depreciation Total Balance, September 30, 2015 $ 10.5 $ — $ 10.5 Charge to expense 2.1 0.4 2.5 Cash payments (10.6 ) — (10.6 ) Non-cash charges (0.9 ) (0.4 ) (1.3 ) Balance, September 30, 2016 $ 1.1 $ — $ 1.1 Cash payments (1.1 ) — (1.1 ) Balance, September 30, 2017 $ — $ — $ — Charge to expense 2.7 2.5 5.2 Non-cash charges — (2.5 ) (2.5 ) Balance, September 30, 2018 $ 2.7 $ — $ 2.7 Total expected restructuring charge $ 17.7 $ 9.0 $ 26.7 Cumulative incurred to date 15.3 5.0 20.3 Remaining expected restructuring charge $ 2.4 $ 4.0 $ 6.4

Assets and Liabilities Held F_2

Assets and Liabilities Held For Sale (Tables)	12 Months Ended
	Sep. 30, 2018
Assets and Liabilities Held for Sale [Abstract]
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 Consolidated Balance Sheet as of September 30, 2018 are shown in the following table. There were no assets or liabilities held for sale at September 30, 2017. 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

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Changes in carrying amount of goodwill	The changes in the carrying amount of goodwill by segment are noted in the following table. Post Consumer Brands Weetabix Refrigerated Food Active Nutrition Private Brands Total Balance, September 30, 2016 Goodwill (gross) $ 1,994.0 $ — $ 1,185.3 $ 180.7 $ 417.1 $ 3,777.1 Accumulated impairment losses (609.1 ) — — (88.3 ) — (697.4 ) Goodwill (net) $ 1,384.9 $ — $ 1,185.3 $ 92.4 $ 417.1 $ 3,079.7 Goodwill acquired 5.3 964.0 46.3 — — 1,015.6 Impairment loss — — — (26.5 ) — (26.5 ) Currency translation adjustment 0.3 (37.1 ) — — — (36.8 ) Balance, September 30, 2017 Goodwill (gross) $ 1,999.6 $ 926.9 $ 1,231.6 $ 180.7 $ 417.1 $ 4,755.9 Accumulated impairment losses (609.1 ) — — (114.8 ) — (723.9 ) Goodwill (net) $ 1,390.5 $ 926.9 $ 1,231.6 $ 65.9 $ 417.1 $ 4,032.0 Goodwill acquired — — 898.3 — — 898.3 Acquisition related adjustment 12.6 (1.1 ) — — — 11.5 Held for sale assets — — — — (417.1 ) (417.1 ) Currency translation adjustment (0.2 ) (24.9 ) — — — (25.1 ) Balance, September 30, 2018 Goodwill (gross) $ 2,012.0 $ 900.9 $ 2,129.9 $ 180.7 $ — $ 5,223.5 Accumulated impairment losses (609.1 ) — — (114.8 ) — (723.9 ) Goodwill (net) $ 1,402.9 $ 900.9 $ 2,129.9 $ 65.9 $ — $ 4,499.6

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Reconciliation of provision (benefit) for income taxes	The (benefit) expense for income taxes consisted of the following: Year Ended September 30, 2018 2017 2016 Current: Federal $ 27.3 $ (5.8 ) $ 37.6 State 5.2 4.3 1.7 Foreign 20.0 10.2 8.5 52.5 8.7 47.8 Deferred: Federal (253.5 ) 19.7 (64.8 ) State 21.4 2.7 (7.5 ) Foreign (24.4 ) (5.0 ) (2.3 ) (256.5 ) 17.4 (74.6 ) Income tax (benefit) expense $ (204.0 ) $ 26.1 $ (26.8 )
Reconciliation of income tax (benefit) provision	A reconciliation of income tax (benefit) expense with amounts computed at the statutory federal rate follows: Year Ended September 30, 2018 2017 2016 Computed tax (a) $ 64.9 $ 26.1 $ (10.5 ) Enacted tax law and changes, including the Tax Act (a) (270.9 ) — 0.7 Non-deductible goodwill impairment loss — 7.2 — Non-deductible compensation 1.2 1.8 2.6 Non-deductible transaction costs 1.5 2.9 — Domestic production activities deduction (5.9 ) — (4.3 ) State income taxes, net of effect on federal tax 5.6 0.8 (6.2 ) Non-taxable interest income (2.4 ) (3.4 ) (2.6 ) Valuation allowances 4.1 4.8 3.8 Change in deferred tax rates 0.3 — (2.0 ) Uncertain tax positions 0.3 (0.5 ) (2.0 ) Sale and liquidation of Michael Foods Canadian egg business — — (3.6 ) Income tax credits (2.3 ) (1.4 ) (1.5 ) Rate differential on foreign income (5.3 ) (6.8 ) (1.8 ) Excess tax benefits for share-based payments (1.8 ) (6.2 ) — Other, net (none in excess of 5% of statutory tax) 6.7 0.8 0.6 Income tax (benefit) expense $ (204.0 ) $ 26.1 $ (26.8 )
Deferred tax assets (liabilities)	Deferred tax non-current assets (liabilities) were as follows: September 30, 2018 September 30, 2017 Assets Liabilities Net Assets Liabilities Net Accrued vacation, incentive and severance $ 10.0 $ — $ 10.0 $ 16.2 $ — $ 16.2 Inventory 4.0 — 4.0 3.0 — 3.0 Accrued liabilities 24.3 — 24.3 16.6 — 16.6 Property — (161.7 ) (161.7 ) — (210.1 ) (210.1 ) Intangible assets — (688.3 ) (688.3 ) — (882.5 ) (882.5 ) Pension and other postretirement benefits — (15.3 ) (15.3 ) 5.3 — 5.3 Stock-based and deferred compensation 27.5 — 27.5 28.7 — 28.7 Derivative mark-to-market adjustments 18.1 — 18.1 91.9 — 91.9 Net operating loss carryforwards 27.2 — 27.2 38.7 — 38.7 Other items 4.7 (3.2 ) 1.5 6.5 (1.6 ) 4.9 Total gross deferred income taxes 115.8 (868.5 ) (752.7 ) 206.9 (1,094.2 ) (887.3 ) Valuation allowance (25.7 ) — (25.7 ) (18.5 ) — (18.5 ) Total deferred taxes $ 90.1 $ (868.5 ) $ (778.4 ) $ 188.4 $ (1,094.2 ) $ (905.8 )
Income Tax Contingency [Line Items]
Summary of Income Tax Contingencies [Table Text Block]	Unrecognized tax benefits, September 30, 2016 $ 9.3 Additions for tax positions taken in current year and acquisitions — Reductions for tax positions taken in prior years — Settlements with tax authorities/statute expirations (0.7 ) Unrecognized tax benefits, September 30, 2017 $ 8.6 Additions for tax positions taken in current year and acquisitions 2.0 Reductions for tax positions taken in prior years (0.1 ) Held for sale liabilities (0.6 ) Settlements with tax authorities/statute expirations — Unrecognized tax benefits, September 30, 2018 $ 9.9

Earnings (loss) per Share (Tabl

Earnings (loss) per Share (Tables)	12 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	Year ended September 30, 2018 2017 2016 Net earnings (loss) for basic loss per share $ 457.3 $ 34.8 $ (28.4 ) Dilutive preferred stock dividends 10.0 — — Net earnings (loss) for diluted loss per share $ 467.3 $ 34.8 $ (28.4 ) Weighted-average shares outstanding 66.6 65.2 63.9 Effect of TEUs on weighted-average shares for basic earnings (loss) per share — 2.6 4.9 Weighted-average shares for basic earnings (loss) per share 66.6 67.8 68.8 Effect of dilutive securities: Stock options 1.8 1.8 — Stock appreciation rights 0.1 — — Restricted stock awards 0.4 0.3 — Preferred shares conversion to common 7.0 — — Total dilutive securities 9.3 2.1 — Weighted-average shares for diluted earnings (loss) per share 75.9 69.9 68.8 Basic earnings (loss) per common share $ 6.87 $ 0.51 $ (0.41 ) Diluted earnings (loss) per common share $ 6.16 $ 0.50 $ (0.41 )
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following table details the securities that have been excluded from the calculation of weighted-average shares for diluted earnings (loss) per share as they were anti-dilutive. Year ended September 30, 2018 2017 2016 Stock options 0.6 0.3 4.3 Stock appreciation rights — — 0.2 Restricted stock awards 0.1 — 0.5 Preferred shares conversion to common — 9.1 9.1

Supplemental Operations State_2

Supplemental Operations Statement and Cash Flow Information (Tables)	12 Months Ended
	Sep. 30, 2018
Supplemental Operations Statement and Cash Flow Information [Abstract]
Supplemental Operations Statement and Cash Flow Information	Year Ended September 30, 2018 2017 2016 Advertising and promotion expenses $ 153.4 $ 159.7 $ 184.2 Repair and maintenance expenses 149.1 162.6 141.6 Research and development expenses 25.1 18.6 16.3 Rent expense 41.3 41.8 32.0 Interest income (7.4 ) (6.8 ) (2.7 ) Interest paid 373.9 333.6 309.6 Income taxes paid 23.0 29.6 73.4 Accrued additions to property 30.4 21.0 12.7

Supplemental Balance Sheet In_2

Supplemental Balance Sheet Information (Tables)	12 Months Ended
	Sep. 30, 2018
Supplemental Balance Sheet Information [Abstract]
Supplemental Balance Sheet Information	September 30, 2018 2017 Receivables, net Trade $ 412.8 $ 421.6 Income tax receivable 41.5 46.4 Other 10.3 14.2 464.6 482.2 Allowance for doubtful accounts (2.3 ) (1.6 ) $ 462.3 $ 480.6 Inventories Raw materials and supplies $ 107.8 $ 129.8 Work in process 17.8 16.9 Finished products 324.1 395.6 Flocks 34.5 31.2 $ 484.2 $ 573.5 Other Assets Pension asset $ 167.0 $ 154.6 Hedging assets - non-current 52.0 0.3 Other 33.0 29.4 $ 252.0 $ 184.3 Accounts Payable Trade $ 329.3 $ 306.5 Book cash overdrafts 26.7 17.8 Other 9.1 11.7 $ 365.1 $ 336.0 Other Current Liabilities Advertising and promotion $ 53.6 $ 74.5 Accrued interest 38.5 36.5 Accrued compensation 114.2 89.9 Hedging liabilities 27.7 54.6 Accrued legal settlements 23.9 8.6 Other 81.4 82.2 $ 339.3 $ 346.3 Other Liabilities Pension and other postretirement benefit obligations $ 53.3 $ 83.5 Hedging liabilities - non-current 113.7 188.9 Accrued compensation - non-current 30.4 29.2 Accrued appraisal rights and related interest 267.0 — Other 34.9 26.2 $ 499.3 $ 327.8

Allowance for Doubtful Accoun_2

Allowance for Doubtful Accounts (Tables)	12 Months Ended
	Sep. 30, 2018
Allowance for Doubtful Accounts [Abstract]
Allowance for Doubtful Accounts	September 30, 2018 2017 2016 Balance, beginning of year $ 1.6 $ 1.6 $ 2.0 Provision charged to expense 0.1 0.3 1.2 Write-offs, less recoveries (1.2 ) (0.3 ) (1.6 ) Held for sale assets (0.5 ) — — Other (a) 2.3 — — Balance, end of year $ 2.3 $ 1.6 $ 1.6

Derivative Financial Instrume_2

Derivative Financial Instruments and Hedging (Tables)	12 Months Ended
	Sep. 30, 2018
Derivative [Line Items]
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	September 30, September 30, Not designated as hedging instruments under ASC Topic 815: Commodity contracts $ 64.3 $ 53.8 Energy contracts 20.8 25.6 Foreign exchange contracts - Forward contracts 9.3 3.8 Interest rate swap 74.6 76.1 Interest rate swaps - Rate-lock swaps 1,649.3 1,649.3 Designated as hedging instruments under ASC Topic 815: Foreign exchange contracts - Forward contracts — 20.9 Foreign exchange contracts - Cross-currency swaps 662.9 448.7 Interest rate swap 1,000.0 1,000.0
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following tables present the balance sheet location and fair value of the Company’s derivative instruments on a gross and net basis as of September 30, 2018 and 2017 , along with the portion designated as hedging instruments under ASC Topic 815. The Company does not offset derivative assets and liabilities within the Consolidated Balance Sheets. Fair Value Portion Designated as Hedging Instruments Balance Sheet Location September 30, September 30, September 30, September 30, Asset Derivatives: Commodity contracts Prepaid expenses and other current assets $ 1.9 $ 0.5 $ — $ — Energy contracts Prepaid expenses and other current assets 4.9 3.8 — — Commodity contracts Other assets 0.2 — — — Energy contracts Other assets 0.3 — — — Foreign exchange contracts Prepaid expenses and other current assets 1.2 1.3 1.1 1.1 Foreign exchange contracts Other assets 17.6 0.3 17.6 0.3 Interest rate swaps Prepaid expenses and other current assets 6.4 — 6.4 — Interest rate swaps Other assets 33.9 — 30.6 — $ 66.4 $ 5.9 $ 55.7 $ 1.4 Liability Derivatives: Commodity contracts Other current liabilities $ 2.2 $ 1.9 $ — $ — Energy contracts Other current liabilities 0.4 0.3 — — Foreign exchange contracts Other current liabilities 1.5 1.5 1.4 1.5 Foreign exchange contracts Other liabilities 19.4 23.6 19.4 23.6 Interest rate swaps Other current liabilities 23.6 50.9 — 0.7 Interest rate swaps Other liabilities 94.3 165.3 — 4.2 $ 141.4 $ 243.5 $ 20.8 $ 30.0
Schedule of Derivative Instruments, Gain (Loss) in Statement of Financial Performance	The following tables present the effects of the Company’s derivative instruments on the Company’s Consolidated Statements of Operations and Consolidated Statements of Comprehensive Income (Loss) for the years ended September 30, 2018 , 2017 and 2016 . Derivatives Not Designated as Hedging Instruments Statement of Operations Location Loss (Gain) Recognized in Statement of Operations 2018 2017 2016 Commodity contracts Cost of goods sold $ 4.0 $ (0.4 ) $ 7.5 Energy contracts Cost of goods sold (6.4 ) (1.3 ) 1.2 Foreign exchange contracts Selling, general and administrative expenses 1.5 0.8 — Foreign exchange contracts (Income) expense on swaps, net — 10.3 — Interest rate swaps (Income) expense on swaps, net (95.6 ) (102.1 ) 182.9 Derivatives Designated as Hedging Instruments (Gain) Loss Recognized in OCI (Gain) Loss Reclassified from Accumulated OCI into Earnings Statement of Operations Location 2018 2017 2016 2018 2017 2016 Foreign exchange contracts $ (0.2 ) $ (1.6 ) $ — $ (1.3 ) $ — $ — Selling, general and administrative expenses Interest rate swaps (44.2 ) 5.6 — (2.3 ) 0.7 — Interest expense, net Cross-currency swaps (27.8 ) 14.8 — — — — (Income) expense on swaps, net

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Assets and liabilities measured at fair value	The following table presents the 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: September 30, 2018 September 30, 2017 Total Level 1 Level 2 Total Level 1 Level 2 Assets Deferred compensation investment $ 43.6 $ 43.6 $ — $ 15.4 $ 15.4 $ — Derivative assets 66.4 — 66.4 5.9 — 5.9 $ 110.0 $ 43.6 $ 66.4 $ 21.3 $ 15.4 $ 5.9 Liabilities Deferred compensation liabilities $ 52.2 $ — $ 52.2 $ 22.5 $ — $ 22.5 Derivative liabilities 141.4 — 141.4 243.5 — 243.5 $ 193.6 $ — $ 193.6 $ 266.0 $ — $ 266.0
Fair Value Measurements, Nonrecurring	The following table summarizes the Level 3 activity. Balance, September 30, 2016 $ 10.1 Gain on assets held for sale 0.2 Proceeds from the sale of assets held for sale (10.3 ) Balance, September 30, 2017 $ — Transfers of assets into held for sale 1,051.6 Transfers of liabilities into held for sale (760.7 ) Balance, September 30, 2018 $ 290.9

Long Term Debt (Tables)

Long Term Debt (Tables)	12 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Long-term debt as of the dates indicated consists of the following: September 30, 2018 2017 5.625% Senior Notes maturing January 2028 $ 960.9 $ — 5.50% Senior Notes maturing March 2025 1,000.0 1,000.0 5.75% Senior Notes maturing March 2027 1,326.3 1,500.0 5.00% Senior Notes maturing August 2026 1,710.3 1,750.0 8.00% Senior Notes maturing July 2025 122.2 137.5 6.00% Senior Notes maturing December 2022 — 630.0 Term Loan 2,172.5 2,194.5 Bridge Loan (a) — — Capital leases 0.2 0.2 7,292.4 7,212.2 Less: Current Portion (22.1 ) (22.1 ) Debt issuance costs, net (a) (71.2 ) (81.8 ) Plus: Unamortized premium 33.0 40.8 Total long-term debt $ 7,232.1 $ 7,149.1
Schedule of Extinguishment of Debt	The following table shows the Company’s repayments of long-term debt and associated gain or loss included in “Loss on extinguishment of debt” on the Consolidated Statements of Operations for the years ended September 30, 2018 , 2017 and 2016 . Repayments of Long-Term Debt Loss on Extinguishment of Debt, net Year Ended Issuance Principal Amount Repaid Debt Repurchased at a Discount Premium and Debt Extinguishment Costs Paid Write-offs of Debt Issuance Costs Write-off of Unamortized (Premium)/Discount 6.00% Senior Notes $ 630.0 $ — $ 30.8 $ 6.5 $ — 5.625% Senior Notes 39.1 (2.1 ) — 0.4 — 5.75% Senior Notes 173.7 (3.1 ) — 1.9 (4.6 ) 5.00% Senior Notes 39.7 (2.5 ) — 0.4 — 8.00% Senior Notes 15.3 — 2.0 0.1 — Term Loan (a) 22.0 — 0.9 0.4 — 2018 Total $ 919.8 $ (7.7 ) $ 33.7 $ 9.7 $ (4.6 ) 6.75% Senior Notes $ 875.0 $ — $ 63.0 $ 8.9 $ (13.4 ) 7.375% Senior Notes 133.0 — 4.9 1.2 (2.1 ) 7.75% Senior Notes 800.0 — 108.6 6.3 — 8.00% Senior Notes 262.5 — 43.3 2.2 — Term Loan 5.5 — — — — TEUs 11.0 — — — — 4.57% 2012 Series Bond 1.3 — — — — Capital lease 0.1 — — — — 2017 Total $ 2,088.4 $ — $ 219.8 $ 18.6 $ (15.5 ) 7.375% Senior Notes $ 1,242.0 $ — $ 88.0 $ 12.4 $ (21.8 ) Term Loan 374.4 — — 6.4 1.4 TEUs 14.1 — — — — 4.57% 2012 Series Bond 1.6 — — — — Capital lease 0.1 — — — — 2016 Total $ 1,632.2 $ — $ 88.0 $ 18.8 $ (20.4 )

Pension and Other Postretirem_2

Pension and Other Postretirement Benefits (Tables)	12 Months Ended
	Sep. 30, 2018
Defined Benefit Plan Disclosure
Expected future benefit payments and related federal subsidy receipts	of September 30, 2018 , expected future benefit payments and related federal subsidy receipts (Medicare Part D) in the next ten fiscal years were as follows: 2019 2020 2021 2022 2023 2024- 2028 Pension benefits $ 23.0 $ 23.9 $ 24.9 $ 26.0 $ 27.1 $ 155.5 Other benefits 2.4 2.8 2.8 3.0 3.1 16.5 Subsidy receipts — 0.1 0.1 0.1 0.1 1.1 In
Change in accumulated postretirement benefit obligation from a 1% change in assumed health care cost trend	% change in assumed health care cost trend rates would result in the following changes in the accumulated postretirement benefit obligation and in the total service and interest cost components for fiscal 2018 : Increase Decrease Effect on postretirement benefit obligation $ 5.2 $ (4.3 ) Effect on total service and interest cost 0.3 (0.2 )
Pension plan's assets measured at fair value on a recurring basis	The following tables present the North American and other international pension plans’ assets measured at fair value on a recurring basis and the basis for that measurement. The fair value of mutual funds is based on quoted net asset values of the shares held by the plan at year end. North America September 30, 2018 September 30, 2017 Total Level 1 Level 2 Total Level 1 Level 2 Equities $ 9.5 $ — $ 9.5 $ 16.4 $ 7.8 $ 8.6 Bonds 10.1 0.1 10.0 11.3 11.3 — Fixed income 14.7 — 14.7 4.6 — 4.6 Real assets — — — 0.9 0.9 — Cash 1.1 1.1 — 0.8 0.8 — Fair value of plan assets in the fair value hierarchy 35.4 1.2 34.2 34.0 20.8 13.2 Equities 51.7 — — 30.7 — — Pooled assets — — — 4.5 — — Fixed income 23.2 — — 9.6 — — Real assets 3.8 — — 2.1 — — Investments measured at net asset value (a) 78.7 — — 46.9 — — Total plan assets $ 114.1 $ 1.2 $ 34.2 $ 80.9 $ 20.8 $ 13.2 Other International September 30, 2018 September 30, 2017 Total Level 1 Level 2 Total Level 1 Level 2 Bonds $ 439.5 $ 416.6 $ 22.9 $ 461.7 $ 441.1 $ 20.6 Liability driven instruments 201.4 201.4 — 204.2 204.2 — Fixed income 61.5 61.5 — 108.3 108.3 — Cash 1.6 1.6 — 2.7 2.7 — Fair value of plan assets in the fair value hierarchy 704.0 681.1 22.9 776.9 756.3 20.6 Bonds 44.4 — — — — — Fixed income 94.2 — — 95.0 — — Real assets — — — 3.9 — — Other 1.9 — — 0.9 — — Investments measured at net asset value (a) 140.5 — — 99.8 — — Total plan assets $ 844.5 $ 681.1 $ 22.9 $ 876.7 $ 756.3 $ 20.6
Schedule of net benefit costs and assumptions used in calculation	The following tables provide the components of net periodic benefit cost for the pension plans including amounts recognized in OCI. North America Year Ended September 30, 2018 2017 2016 Components of net periodic benefit cost Service cost $ 4.2 $ 4.1 $ 4.0 Interest cost 3.6 2.5 2.5 Expected return on plan assets (4.4 ) (3.2 ) (2.6 ) Recognized net actuarial loss 1.1 1.6 1.1 Recognized prior service cost 0.1 0.2 0.3 Net periodic benefit cost $ 4.6 $ 5.2 $ 5.3 Weighted-average assumptions used to determine net benefit cost Discount rate — U.S. plans 3.86 % 3.66 % 4.55 % Discount rate — Canadian plans 3.63 % 3.18 % 3.82 % Rate of compensation increase — U.S. plans 3.00 % 2.99 % 3.00 % Rate of compensation increase — Canadian plans 2.69 % 2.50 % 2.75 % Expected return on plan assets — U.S. plans 5.46 % 5.33 % 5.20 % Expected return on plan assets — Canadian plans 6.00 % 6.00 % 6.00 % Changes in benefit obligation recognized in Total Comprehensive Income Net (gain) loss $ (3.7 ) $ (3.1 ) $ 5.1 Recognized loss (1.1 ) (1.6 ) (1.1 ) Plan amendment (a) — — 0.5 Recognized prior service cost (0.1 ) (0.2 ) (0.3 ) Currency translation — (0.1 ) — Total recognized in other comprehensive income (before tax effects) $ (4.9 ) $ (5.0 ) $ 4.2 (a) In the second quarter of fiscal 2016, the Company finalized a new collective bargaining agreement that resulted in an amendment to its North American pension plans. Other International Year Ended September 30, 2018 2017 2016 Components of net periodic benefit cost Service cost $ 6.7 $ 1.7 $ — Interest cost 19.6 4.9 — Expected return on plan assets (31.7 ) (7.5 ) — Net periodic benefit cost $ (5.4 ) $ (0.9 ) $ — Weighted-average assumptions used to determine net benefit cost Discount rate 2.72 % 2.61 % — % Rate of compensation increase 2.70 % 2.75 % — % Expected return on plan assets 3.56 % 3.52 % — % Changes in plan assets and benefit obligation recognized in Total Comprehensive Income Net loss (gain) $ 8.2 $ (39.3 ) $ — Currency translation — (0.9 ) — Total recognized in other comprehensive income (before tax effects) $ 8.2 $ (40.2 ) $ —
Schedule of change in projected benefit obligation, change in fair value of plan assets, and net funded status	The following table provides a reconciliation of the changes in the pension plans’ benefit obligations and fair value of assets over the two year period ended September 30, 2018 , and a statement of the funded status and amounts recognized on the combined balance sheets as of September 30, 2018 and 2017 . North America Other International Year Ended Year Ended 2018 2017 2018 2017 Change in benefit obligation Benefit obligation at beginning of period $ 100.6 $ 71.2 $ 723.6 $ — Service cost 4.2 4.1 6.7 1.7 Interest cost 3.6 2.5 19.6 4.9 Plan participants’ contributions 0.6 0.6 2.4 0.6 Actuarial gain (4.3 ) (1.0 ) (14.0 ) (46.4 ) Business combinations — 25.5 — 746.0 Benefits paid (3.4 ) (3.0 ) (27.6 ) (6.2 ) Currency translation (0.4 ) 0.7 (19.5 ) 23.0 Benefit obligation at end of period $ 100.9 $ 100.6 $ 691.2 $ 723.6 Change in fair value of plan assets Fair value of plan assets at beginning of period $ 80.9 $ 54.3 $ 876.7 $ — Actual return on plan assets 3.9 5.4 9.6 0.3 Employer contributions 32.6 7.7 7.2 2.4 Business combinations — 15.2 — 852.2 Plan participants’ contributions 0.6 0.6 2.4 0.6 Benefits paid (3.4 ) (3.0 ) (27.6 ) (6.2 ) Currency translation (0.5 ) 0.7 (23.8 ) 27.4 Fair value of plan assets at end of period 114.1 80.9 844.5 876.7 Funded status $ 13.2 $ (19.7 ) $ 153.3 $ 153.1 Amounts recognized in assets or liabilities Other assets $ 13.7 $ 1.5 $ 153.3 $ 153.1 Other liabilities (0.5 ) (21.2 ) — — Net amount recognized $ 13.2 $ (19.7 ) $ 153.3 $ 153.1 Amounts recognized in accumulated other comprehensive loss Net actuarial loss (gain) $ 9.5 $ 14.3 $ (32.0 ) $ (40.2 ) Prior service cost 0.5 0.6 — — Total $ 10.0 $ 14.9 $ (32.0 ) $ (40.2 ) Weighted-average assumptions used to determine benefit obligation Discount rate — U.S. plans 4.30 % 3.86 % n/a n/a Discount rate — Canadian plans 3.53 % 3.63 % n/a n/a Discount rate — Other international plans n/a n/a 2.81 % 2.72 % Rate of compensation increase — U.S. plans 3.00 % 3.00 % n/a n/a Rate of compensation increase — Canadian plans 2.75 % 2.69 % n/a n/a Rate of compensation increase — Other international plans n/a n/a 2.75 % 2.70 % he following table provides a reconciliation of the changes in the North American other postretirement benefit obligations over the two year period ended September 30, 2018 . Besides the North American plans, the Company does not maintain any other postretirement benefit plans. Year Ended 2018 2017 Change in benefit obligation Benefit obligation at beginning of period $ 65.0 $ 68.6 Service cost 0.5 0.6 Interest cost 2.1 2.0 Plan amendment — (0.1 ) Actuarial gain (9.9 ) (4.4 ) Benefits paid (2.3 ) (2.1 ) Currency translation (0.2 ) 0.4 Benefit obligation at end of period $ 55.2 $ 65.0 Change in fair value of plan assets Employer contributions 2.3 2.1 Benefits paid (2.3 ) (2.1 ) Fair value of plan assets at end of period — — Funded status $ (55.2 ) $ (65.0 ) Amounts recognized in assets or liabilities Other current liabilities (2.4 ) (2.7 ) Other liabilities (52.8 ) (62.3 ) Net amount recognized $ (55.2 ) $ (65.0 ) Amounts recognized in accumulated other comprehensive loss Net actuarial (gain) loss $ (1.2 ) $ 8.6 Prior service credit (24.1 ) (28.8 ) Total $ (25.3 ) $ (20.2 ) Weighted-average assumptions used to determine benefit obligation Discount rate — U.S. plans 4.27 % 3.77 % Discount rate — Canadian plans 3.54 % 3.69 % Rate of compensation increase — Canadian plans 2.75 % 2.75 %
Other Benefits
Defined Benefit Plan Disclosure
Schedule of net benefit costs and assumptions used in calculation	The following table provides the components of net periodic benefit cost for the other postretirement benefit plans including amounts recognized in OCI. Year Ended September 30, 2018 2017 2016 Components of net periodic benefit cost Service cost $ 0.5 $ 0.6 $ 1.0 Interest cost 2.1 2.0 4.0 Recognized net actuarial loss 0.3 0.7 1.6 Recognized prior service credit (4.7 ) (4.8 ) (3.8 ) Net periodic benefit cost $ (1.8 ) $ (1.5 ) $ 2.8 Weighted-average assumptions used to determine net benefit cost Discount rate — U.S. plans (Prior to plan amendment) (a) n/a n/a 4.60 % Discount rate — U.S. plans (Subsequent to plan amendment) (a) 3.77 % 3.54 % 4.22 % Discount rate — Canadian plans 3.69 % 3.23 % 3.91 % Rate of compensation increase — Canadian plans 2.75 % 2.75 % 2.75 % Changes in plan assets and benefit obligation recognized in Total Comprehensive Income Net gain $ (9.9 ) $ (4.4 ) $ (11.3 ) Recognized loss (0.3 ) (0.7 ) (1.6 ) Plan amendment (a) — (0.1 ) (36.1 ) Recognized prior service credit 4.7 4.8 3.8 Currency translation 0.4 0.1 (0.1 ) Total recognized in other comprehensive income (before tax effects) $ (5.1 ) $ (0.3 ) $ (45.3 )

Stock-Based Compensation Plans

Stock-Based Compensation Plans Stock-Based Compensation Plans (Tables)	12 Months Ended
	Sep. 30, 2018
Share-based Payment Award [Line Items]
Stock Options, Activity [Table Text Block]	Stock Options Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term in Years Aggregate Intrinsic Value Outstanding at September 30, 2017 4,198,500 $ 45.36 Granted 248,206 80.04 Exercised (128,999 ) 45.12 Forfeited (6,667 ) 71.32 Expired — — Outstanding at September 30, 2018 4,311,040 47.32 5.63 $ 218.6 Vested and expected to vest as of September 30, 2018 4,311,040 47.32 5.63 218.6 Exercisable at September 30, 2018 3,647,330 43.67 5.24 198.3
Stock Options, Valuation Assumptions [Table Text Block]	2018 2017 2016 Expected term 6.5 6.5 6.5 Expected stock price volatility 30.7% 30.6% 29.1% Risk-free interest rate 2.2% 1.9% 1.9% Expected dividends 0% 0% 0% Fair value (per option) $28.52 $24.80 $20.22
Stock Settled
Share-based Payment Award [Line Items]
Stock Appreciation Rights, Activity [Table Text Block]	Stock-Settled Stock Appreciation Rights Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term in Years Aggregate Intrinsic Value Outstanding at September 30, 2017 137,831 $ 41.63 Granted — — Exercised (1,800 ) 18.10 Forfeited — — Expired — — Outstanding at September 30, 2018 136,031 41.94 4.73 $ 7.6 Vested and expected to vest as of September 30, 2018 136,031 41.94 4.73 7.6 Exercisable at September 30, 2018 136,031 41.94 4.73 7.6
Non-Stock Options, Valuation Assumptions [Table Text Block]
Restricted Stock Units, Activity [Table Text Block]	Restricted Stock Units Weighted- Average Grant Date Fair Value Per Share Nonvested at September 30, 2017 730,040 $ 63.55 Granted 478,325 80.19 Vested (213,824 ) 60.99 Forfeited (52,673 ) 75.01 Nonvested at September 30, 2018 941,868 71.94
Cash Settled
Share-based Payment Award [Line Items]
Stock Appreciation Rights, Activity [Table Text Block]	Cash-Settled Stock Appreciation Rights Weighted- Average Exercise Price Per Share Weighted- Average Remaining Contractual Term in Years Aggregate Intrinsic Value Outstanding at September 30, 2017 104,500 $ 46.43 Granted — — Exercised (102,000 ) 47.12 Forfeited — — Expired — — Outstanding at September 30, 2018 2,500 18.10 1.98 $ 0.2 Vested and expected to vest as of September 30, 2018 2,500 18.10 1.98 0.2 Exercisable at September 30, 2018 2,500 18.10 1.98 0.2
Non-Stock Options, Valuation Assumptions [Table Text Block]	2018 2017 2016 Expected term 0 2.9 3.8 Expected stock price volatility 21.5% 31.7% 32.4% Risk-free interest rate 2.6% 1.6% 1.0% Expected dividends 0% 0% 0% Fair value (per right) $79.94 $54.18 $44.44
Restricted Stock Units, Activity [Table Text Block]	Cash-Settled Restricted Stock Units Weighted- Average Grant Date Fair Value Per Share Nonvested at September 30, 2017 100,119 $ 49.47 Granted — — Vested (38,537 ) 43.28 Forfeited (1,330 ) 62.90 Nonvested at September 30, 2018 60,252 53.13
Performance-Based Restricted Stock Units
Share-based Payment Award [Line Items]
Share-based Compensation Arrangements by Share-based Payment Award, Performance-Based Units, Vested and Expected to Vest [Table Text Block]	Performance-Based Restricted Stock Units Weighted- Average Grant Date Fair Value Per Share Nonvested at September 30, 2017 — $ — Granted 32,307 97.74 Vested — — Forfeited — — Nonvested at September 30, 2018 32,307 97.74
Non-Stock Options, Valuation Assumptions [Table Text Block]	2018 Expected term 3.0 Expected stock price volatility 31.8% Risk-free interest rate 1.8% Expected dividend yield 0%

Tangible Equity Units (Tables)

Tangible Equity Units (Tables)	12 Months Ended
	Sep. 30, 2018
Tangible Equity Units [Abstract]
Tangible Equity Units Table	The aggregate values assigned upon issuance of each component of the TEUs were as follows (amounts in millions except price per TEU): Equity Component Debt Component TEUs Total Price per TEU $ 85.48 $ 14.52 $ 100.00 Gross proceeds $ 245.7 $ 41.8 $ 287.5 Issuance costs (7.6 ) (1.3 ) (8.9 ) Net proceeds $ 238.1 $ 40.5 $ 278.6 Balance sheet impact (at issuance) Long-term debt (deferred financing fees) $ — $ 1.3 $ 1.3 Current portion of long-term debt — 13.3 13.3 Long-term debt — 28.5 28.5 Additional paid-in capital 238.1 — 238.1

Segments (Tables)

Segments (Tables)	12 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information, by Segment	The following tables present information about the Company’s reportable segments. In addition, the tables present net sales by product. Note that “Additions to property and intangibles” excludes additions through business acquisitions (see Note 4). Year Ended September 30, 2018 2017 2016 Net Sales Post Consumer Brands $ 1,831.7 $ 1,742.5 $ 1,728.2 Weetabix 423.4 112.4 — Refrigerated Food 2,337.9 1,870.8 1,917.4 Active Nutrition 827.5 713.2 574.7 Private Brands 848.9 791.2 811.1 Eliminations (12.2 ) (4.3 ) (4.6 ) Total $ 6,257.2 $ 5,225.8 $ 5,026.8 Segment Profit Post Consumer Brands $ 329.2 $ 354.9 $ 290.4 Weetabix 87.2 14.5 — Refrigerated Food 247.6 110.6 245.7 Active Nutrition 124.4 96.4 44.7 Private Brands 60.8 58.1 71.4 Total segment profit 849.2 634.5 652.2 General corporate expenses and other 136.8 87.7 106.5 Impairment of goodwill and other intangibles 124.9 26.5 — Interest expense, net 387.3 314.8 306.5 Loss on extinguishment of debt, net 31.1 222.9 86.4 (Income) expense on swaps, net (95.6 ) (91.8 ) 182.9 Earnings (loss) before income taxes and equity method loss $ 264.7 $ 74.4 $ (30.1 ) Net sales by product Cereal and granola $ 2,351.2 $ 1,963.9 $ 1,838.5 Egg and egg products 1,542.8 1,419.1 1,417.0 Cheese and dairy 248.6 259.4 320.9 Side dishes 398.2 192.3 179.5 Sausage 96.0 — — Pasta 258.4 249.4 270.6 Protein-based products and supplements 827.5 713.2 574.7 Nut butters and dried fruit and nut 487.5 432.5 429.1 Other 53.0 — — Eliminations (6.0 ) (4.0 ) (3.5 ) Total $ 6,257.2 $ 5,225.8 $ 5,026.8 Additions to property and intangibles Post Consumer Brands $ 51.5 $ 57.8 $ 34.8 Weetabix 26.3 13.6 — Refrigerated Food 114.6 66.0 51.6 Active Nutrition 5.0 3.9 4.4 Private Brands 26.6 29.1 23.5 Corporate 1.0 20.0 7.2 Total $ 225.0 $ 190.4 $ 121.5 Depreciation and amortization Post Consumer Brands $ 122.0 $ 112.4 $ 105.5 Weetabix 38.1 7.7 — Refrigerated Food 163.3 125.4 119.9 Active Nutrition 25.9 25.3 25.0 Private Brands 40.9 48.6 46.4 Total segment depreciation and amortization 390.2 319.4 296.8 Corporate and accelerated depreciation 8.2 3.7 6.0 Total $ 398.4 $ 323.1 $ 302.8 September 30, 2018 2017 2016 Assets, end of year Post Consumer Brands $ 3,391.7 $ 3,440.5 $ 3,387.0 Weetabix 1,853.3 2,048.9 — Refrigerated Food 5,132.4 3,176.0 3,099.3 Active Nutrition 559.3 581.3 624.8 Private Brands 1,055.3 1,054.9 1,054.7 Corporate 1,065.5 1,575.2 1,194.8 Total $ 13,057.5 $ 11,876.8 $ 9,360.6

Summary Quarterly Financial Inf

Summary Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Sep. 30, 2018
Quarterly Financial Information [Abstract]
Schedule of Quarterly Financial Information	First Second Third Fourth Quarter Quarter Quarter Quarter Fiscal 2018 Net sales $ 1,433.1 $ 1,586.1 $ 1,608.1 $ 1,629.9 Gross profit 451.7 475.7 461.4 478.0 Impairment of goodwill and other intangible assets — — — 124.9 Net earnings (loss) 294.9 91.5 96.5 (15.6 ) Net earnings (loss) available to common shareholders 291.5 88.9 94.5 (17.6 ) Basic earnings (loss) per share $ 4.42 $ 1.33 $ 1.41 $ (0.26 ) Diluted earnings (loss) per share $ 3.82 $ 1.20 $ 1.29 $ (0.26 ) Fiscal 2017 Net sales $ 1,249.8 $ 1,255.4 $ 1,272.1 $ 1,448.5 Gross profit 379.2 364.1 393.7 437.1 Impairment of goodwill and other intangible assets — — — 26.5 Net earnings (loss) 101.8 (2.1 ) (59.4 ) 8.0 Net earnings (loss) available to common shareholders 98.4 (5.5 ) (62.8 ) 4.7 Basic earnings (loss) per share $ 1.42 $ (0.08 ) $ (0.93 ) $ 0.07 Diluted earnings (loss) per share $ 1.27 $ (0.08 ) $ (0.93 ) $ 0.07

Background Background (Details)

Background Background (Details) - 8th Avenue $ in Millions	Aug. 02, 2018USD ($)
Schedule of Equity Method Investments [Line Items]
Proceeds from independent capitalization of a subsidiary	$ 875
Equity Method Investment, Ownership Percentage	60.50%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2018
Weetabix Segment | Operating Segments
Business Acquisition
Receivables Sold	$ 37.3	$ 137.3

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Property (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment, gross	$ 2,543	$ 2,394.1
Accumulated depreciation	(833.3)	(703.4)
Property, net	1,709.7	1,690.7
Depreciation	221	164	$ 150.2
Land
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment, gross	88.2	90.9
Building and leasehold improvements
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment, gross	$ 720.7	699.4
Building and leasehold improvements | Minimum
Property, Plant and Equipment, Net [Abstract]
Useful life	1 year
Building and leasehold improvements | Maximum
Property, Plant and Equipment, Net [Abstract]
Useful life	40 years
Machinery and equipment
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment, gross	$ 1,507.4	1,439.3
Machinery and equipment | Minimum
Property, Plant and Equipment, Net [Abstract]
Useful life	1 year
Machinery and equipment | Maximum
Property, Plant and Equipment, Net [Abstract]
Useful life	29 years
Software
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment, gross	$ 112	64.5
Software | Minimum
Property, Plant and Equipment, Net [Abstract]
Useful life	1 year
Software | Maximum
Property, Plant and Equipment, Net [Abstract]
Useful life	7 years
Construction in Progress
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment, gross	$ 114.7	$ 100

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Finite-Lived and Indefinite-Lived, Intangible Assets
Amortization of intangible assets	$ 177.4	$ 159.1	$ 152.6
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2,019	159.2
2,020	159.2
2,021	159.2
2,022	156.4
2,023	159
Finite-Lived Intangible Assets [Abstract]
Finite-Lived Intangible Assets, Gross	3,078.6	3,105.1
Finite-Lived Intangible Assets, Accumulated Amortization	(635.7)	(589.4)
Finite-Lived Intangible Assets, Net	2,442.9	2,515.7
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Carrying amount, total	4,175	3,943.3
Other intangible assets, net	3,539.3	3,353.9
Customer Relationships
Finite-Lived Intangible Assets [Abstract]
Finite-Lived Intangible Assets, Gross	2,307	2,249.3
Finite-Lived Intangible Assets, Accumulated Amortization	(444.4)	(416.7)
Finite-Lived Intangible Assets, Net	1,862.6	1,832.6
Trademarks
Finite-Lived Intangible Assets [Abstract]
Finite-Lived Intangible Assets, Gross	768.5	834.1
Finite-Lived Intangible Assets, Accumulated Amortization	(188.2)	(162.9)
Finite-Lived Intangible Assets, Net	580.3	671.2
Other Intangible Assets
Finite-Lived Intangible Assets [Abstract]
Finite-Lived Intangible Assets, Gross	3.1	21.7
Finite-Lived Intangible Assets, Accumulated Amortization	(3.1)	(9.8)
Finite-Lived Intangible Assets, Net	0	11.9
Trademarks
Indefinite-lived Intangible Assets (Excluding Goodwill) [Abstract]
Indefinite-lived Intangible Assets (Excluding Goodwill)	$ 1,096.4	$ 838.2

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Recoverability of Assets (Details) - Trademarks - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Indefinite-lived Intangible Assets (Excluding Goodwill)	$ 1,096.4	$ 838.2
Weetabix Brand
Finite-Lived Intangible Assets [Line Items]
Impairment of Weetabix Trademark	124.9
Indefinite-lived Intangible Assets (Excluding Goodwill)	$ 261.8

Summary of Significant Accoun_8

Summary of Significant Accounting Policies - Cost of Products Sold (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Accounting Policies [Abstract]
Cost Of Goods Sold, Storage And Warehouse Costs	$ 169.4	$ 142.9	$ 124.1

Summary of Significant Accoun_9

Summary of Significant Accounting Policies Advertising (Details) - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017
Accounting Policies [Abstract]
Prepaid Advertising	$ 1.9	$ 1.3

Recently Issued and Adopted A_2

Recently Issued and Adopted Accounting Standards Recently Issued and Adopted Accounting Standards (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2018
New Accounting Pronouncement, Early Adoption [Line Items]
(Increase) decrease in Restricted Cash	$ (1.3)	$ 4.2	$ 10.4
Retained earnings (accumulated deficit)	88	(376)
Accumulated other comprehensive loss	(39.4)	(40)
Accounting Standards Update 2017-07
New Accounting Pronouncement, Early Adoption [Line Items]
(Decrease) increase in Operating Profit	(14)	(3.6)	3.1
Accounting Standards Update 2016-18
New Accounting Pronouncement, Early Adoption [Line Items]
(Increase) decrease in Restricted Cash	$ (1.3)	$ 4.2	$ 10.4
Accounting Standards Update 2018-02
New Accounting Pronouncement, Early Adoption [Line Items]
Retained earnings (accumulated deficit)				$ 1.4
Accumulated other comprehensive loss				$ 1.4

Business Combinations and Div_3

Business Combinations and Divestitures (Details) $ / shares in Units, £ in Millions, shares in Millions	Jan. 12, 2018USD ($)$ / sharesshares	Jul. 03, 2017USD ($)	Jul. 03, 2017GBP (£)	Oct. 03, 2016USD ($)	Oct. 04, 2015USD ($)	Feb. 28, 2017USD ($)	Sep. 30, 2018USD ($)shares	Sep. 30, 2018USD ($)$ / sharesshares	Sep. 30, 2017USD ($)$ / shares	Sep. 30, 2016USD ($)$ / shares	Oct. 01, 2018USD ($)shares	Aug. 02, 2018USD ($)	Sep. 30, 2017GBP (£)	Oct. 03, 2015USD ($)
Business Acquisition
Payments to Acquire Businesses, Net of Cash Acquired								$ 1,454,400,000	$ 1,915,200,000	$ 94,400,000
Accrued appraisal rights and related interest							$ 267,000,000	267,000,000	0
Business Combination, Acquisition Related Costs								35,800,000	30,500,000	8,500,000
Goodwill							$ 4,499,600,000	4,499,600,000	4,032,000,000
Goodwill, Purchase Accounting Adjustments								11,500,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred								0
Pro forma net sales								5,587,100,000	5,258,300,000	5,751,200,000
Pro forma net earnings available to common stockholders								$ 432,100,000	$ 23,600,000	$ 2,000,000
Pro forma basic earnings per share | $ / shares								$ 6.49	$ 0.35	$ 0.03
Pro forma diluted earnings per share | $ / shares								$ 5.83	$ 0.34	$ 0.03
8th Avenue
Business Acquisition
Equity Method Investment, Ownership Percentage												60.50%
Proceeds from independent capitalization of a subsidiary												$ 875,000,000
Post | 8th Avenue
Business Acquisition
Equity Method Investment, Ownership Percentage											60.50%
Proceeds from issuance of Preferred Stock											$ 250,000,000
Proceeds from independent capitalization of a subsidiary											$ 875,000,000
THL | 8th Avenue
Business Acquisition
Preferred stock issued | shares											2.5
Preferred Stock, Dividend Rate, Agreed upon Percentage											11.00%
Preferred Stock, Per Share Liquidation Value											$ 100
Equity Method Investment, Percentage, Ownership of Controlling Owners											39.50%
Bob Evans Farms
Business Acquisition
Business Acquisition, Share Price | $ / shares	$ 77
Payments to Acquire Businesses, Net of Cash Acquired	$ 1,381,200,000
Shares not yet paid | shares	4.4						3.3	3.3
Payments to be made subsequent to the closing of the acquisition	$ 342,400,000
Accrued appraisal rights and related interest							$ 267,000,000	$ 267,000,000
Basis Spread on Accrued Appraisal Rights								5.00%
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual								$ 333,100,000
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual								14,500,000
Business Acquisition, Goodwill, Expected Tax Deductible Amount	13,800,000
Cash and cash equivalents	15,600,000
Receivables	58,500,000
Inventories	27,100,000
Prepaid expenses and other current assets	34,300,000
Property	184,300,000
Goodwill	898,300,000
Other intangible assets	782,000,000
Other assets	400,000
Accounts payable	(18,200,000)
Other current liabilities	(58,500,000)
Deferred tax liability, long-term	(194,900,000)
Other Liabilities	(5,300,000)
Total acquisition cost	1,723,600,000
Bob Evans Farms | Customer Relationships
Business Acquisition
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 376,000,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	18 years
Bob Evans Farms | Trademarks
Business Acquisition
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 6,000,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Bob Evans Farms | Trademarks
Business Acquisition
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets	$ 400,000,000
National Pasteurized Eggs
Business Acquisition
Payments to Acquire Businesses, Net of Cash Acquired				$ 97,000,000
Consideration Transferred				93,500,000
Cash and cash equivalents				5,600,000
Receivables				8,500,000
Inventories				2,100,000
Prepaid expenses and other current assets				400,000
Property				10,400,000
Goodwill				46,300,000
Other intangible assets				51,400,000
Current portion of long-term debt				(100,000)
Accounts payable				(6,300,000)
Other current liabilities				(2,900,000)
Long-term debt				(200,000)
Deferred tax liability, long-term				(18,700,000)
Total acquisition cost				$ 96,500,000
Business Combinations, Purchase Price Adjustment, Net Working Capital Settlement						$ 1,200,000
National Pasteurized Eggs | Customer Relationships
Business Acquisition
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				16 years
Other intangible assets				$ 43,900,000
National Pasteurized Eggs | Trademarks
Business Acquisition
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				20 years
Other intangible assets				$ 7,500,000
Weetabix Group
Business Acquisition
Payments to Acquire Businesses, Net of Cash Acquired | £			£ 1,454.1
Cash and cash equivalents							62,200,000	62,200,000	$ 62,200,000
Receivables							37,800,000	37,800,000	39,700,000
Inventories							63,200,000	63,200,000	63,400,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory								(200,000)
Prepaid expenses and other current assets							1,200,000	1,200,000	1,200,000
Property							280,900,000	280,900,000	283,900,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment								(3,000,000)
Goodwill							980,800,000	980,800,000	969,300,000
Goodwill, Purchase Accounting Adjustments								11,500,000
Other intangible assets							601,000,000	601,000,000	608,400,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles								(7,400,000)
Other assets							112,000,000	112,000,000	112,000,000
Accounts payable							(66,300,000)	(66,300,000)	(66,300,000)
Other current liabilities							(28,500,000)	(28,500,000)	(28,400,000)
Deferred tax liability, long-term							(136,500,000)	(136,500,000)	(137,600,000)
Other Liabilities							(10,900,000)	(10,900,000)	(10,900,000)
Noncontrolling interest							(9,700,000)	(9,700,000)	(9,700,000)
Total acquisition cost							1,887,200,000	1,887,200,000	1,887,200,000				£ 1,400
Cash Acquired from Acquisition		$ 62,200,000	£ 48
Weetabix Group | Customer Relationships
Business Acquisition
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		20 years	20 years
Other intangible assets		$ 172,800,000
Weetabix Group | Trademarks
Business Acquisition
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		16 years	16 years
Other intangible assets		$ 29,500,000
Weetabix Group | Selling, general and administrative expenses
Business Acquisition
Gain (Loss) on Foreign Currency Derivatives Recorded in Earnings, Net								30,000,000
Weetabix Group | Trademarks
Business Acquisition
Other intangible assets		$ 385,100,000
Weetabix Group | North America | Customer Relationships
Business Acquisition
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		21 years	21 years
Other intangible assets		$ 13,600,000
Willamette Egg
Business Acquisition
Payments to Acquire Businesses, Gross					$ 90,000,000
Consideration Transferred					109,000,000
Cash and cash equivalents														$ 19,200,000
Receivables														11,100,000
Inventories														10,300,000
Prepaid expenses and other current assets														500,000
Property														56,200,000
Goodwill														4,200,000
Other intangible assets														15,200,000
Other assets														100,000
Accounts payable														(2,200,000)
Other current liabilities														(1,000,000)
Total acquisition cost														$ 113,600,000
Business Combinations, Purchase Price Adjustment, Net Working Capital Settlement								4,600,000
Willamette Egg | Customer Relationships
Business Acquisition
Finite-lived Intangible Assets Acquired					$ 12,700,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life					20 years
Willamette Egg | Trademarks
Business Acquisition
Finite-lived Intangible Assets Acquired					$ 2,500,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life					20 years
Cash and Cash Equivalents | Weetabix Group
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets								0
Accounts Receivable | Weetabix Group
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets								(1,900,000)
Prepaid expenses and other current assets | Weetabix Group
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets								0
Other Assets | Weetabix Group
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets								0
Accounts Payable | Weetabix Group
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								0
Other current liabilities | Weetabix Group
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								(100,000)
Deferred tax liability - long-term | Weetabix Group
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								1,100,000
Other liabilities | Weetabix Group
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								0
Noncontrolling Interest | Weetabix Group
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								0
8th Avenue
Business Acquisition
Business Combination, Acquisition Related Costs								$ 12,400,000	$ 600,000
8th Avenue | Bridge Loan
Business Acquisition
Proceeds from Bridge Loan							$ 625,000,000

Restructuring (Details)

Restructuring (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Restructuring Reserve [Roll Forward]
Balance	$ 0	$ 1.1	$ 10.5
Charge to expense	5.2		2.5
Cash payments		(1.1)	(10.6)
Non-cash charges	(2.5)		(1.3)
Balance	2.7	0	1.1
Total expected restructuring charge	26.7
Cumulative incurred to date	20.3
Remaining expected restructuring charge	6.4
Employee Severance
Restructuring Reserve [Roll Forward]
Balance	0	1.1	10.5
Charge to expense	2.7		2.1
Cash payments		(1.1)	(10.6)
Non-cash charges	0		(0.9)
Balance	2.7	0	1.1
Total expected restructuring charge	17.7
Cumulative incurred to date	15.3
Remaining expected restructuring charge	2.4
Accelerated depreciation
Restructuring Reserve [Roll Forward]
Balance	0	0	0
Charge to expense	2.5		0.4
Cash payments		0	0
Non-cash charges	(2.5)		(0.4)
Balance	0	$ 0	$ 0
Total expected restructuring charge	9
Cumulative incurred to date	5
Remaining expected restructuring charge	$ 4

Assets and Liabilities Held F_3

Assets and Liabilities Held For Sale (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
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	195	$ 0
Other assets held for sale
Property, net	165.1
Other intangible assets, net	270.4
Goodwill	417.1
Other assets	4
Other assets held for sale	856.6	0
Current liabilities held for sale
Accounts payable	37.4
Other current liabilities	28.2
Current liabilities held for sale	65.6	0
Other liabilities held for sale
Long-term debt	614.6
Deferred income taxes	79.9
Other liabilities	0.6
Other liabilities held for sale	695.1	0
Earnings before income taxes	587.5	520.3	$ 545.7
(Gains) Losses on assets held for sale		(0.2)	9.3
Farmers Branch, Texas Facility | Facility Closing
Other liabilities held for sale
(Gains) Losses on assets held for sale			4.5
Modesto, California Facility | Facility Closing
Other liabilities held for sale
(Gains) Losses on assets held for sale			4.8
Operating Segments
Other liabilities held for sale
Earnings before income taxes	849.2	634.5	652.2
Private Brands segment | Operating Segments
Other liabilities held for sale
Earnings before income taxes	$ 60.8	$ 58.1	$ 71.4

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Goodwill [Line Items]
Goodwill	$ 4,499.6	$ 4,032
Impairment Loss		26.5	$ 0
Goodwill, Purchase Accounting Adjustments	11.5
Held for sale assets	(417.1)
Post Consumer Brands Segment
Goodwill [Line Items]
Goodwill, Purchase Accounting Adjustments	12.6
Held for sale assets	0
Weetabix Segment
Goodwill [Line Items]
Impairment Loss		0
Goodwill, Purchase Accounting Adjustments	(1.1)
Held for sale assets	0
Refrigerated Food Segment
Goodwill [Line Items]
Goodwill, Purchase Accounting Adjustments	0
Held for sale assets	0
Active Nutrition segment
Goodwill [Line Items]
Goodwill, Purchase Accounting Adjustments	0
Held for sale assets	0
Private Brands segment
Goodwill [Line Items]
Impairment Loss		0
Goodwill, Purchase Accounting Adjustments	0
Held for sale assets	(417.1)
Operating Segments
Goodwill [Line Items]
Goodwill (gross)	5,223.5	4,755.9	3,777.1
Accumulated impairment losses	(723.9)	(723.9)	(697.4)
Goodwill	4,499.6	4,032	3,079.7
Goodwill acquired	898.3	1,015.6
Currency translation adjustment	(25.1)	(36.8)
Operating Segments | Post Consumer Brands Segment
Goodwill [Line Items]
Goodwill (gross)	2,012	1,999.6	1,994
Accumulated impairment losses	(609.1)	(609.1)	(609.1)
Goodwill	1,402.9	1,390.5	1,384.9
Goodwill acquired	0	5.3
Currency translation adjustment	(0.2)	0.3
Operating Segments | Weetabix Segment
Goodwill [Line Items]
Goodwill (gross)	900.9	926.9	0
Accumulated impairment losses	0	0	0
Goodwill	900.9	926.9	0
Goodwill acquired	0	964
Currency translation adjustment	(24.9)	(37.1)
Operating Segments | Refrigerated Food Segment
Goodwill [Line Items]
Goodwill (gross)	2,129.9	1,231.6	1,185.3
Accumulated impairment losses	0	0	0
Goodwill	2,129.9	1,231.6	1,185.3
Goodwill acquired	898.3	46.3
Currency translation adjustment	0	0
Operating Segments | Active Nutrition segment
Goodwill [Line Items]
Goodwill (gross)	180.7	180.7	180.7
Accumulated impairment losses	(114.8)	(114.8)	(88.3)
Goodwill	65.9	65.9	92.4
Goodwill acquired	0	0
Impairment Loss		(26.5)
Reporting Unit, Amount of Carrying Value in Excess of Fair Value		76.6
Currency translation adjustment	0	0
Operating Segments | Private Brands segment
Goodwill [Line Items]
Goodwill (gross)	0	417.1	417.1
Accumulated impairment losses	0	0	0
Goodwill	0	417.1	417.1
Goodwill acquired	0	0
Currency translation adjustment	$ 0	$ 0
Operating Segments | Dymatize
Goodwill [Line Items]
Reporting Unit, Amount of Fair Value in Excess of Carrying Amount			$ 36

Equity Interests (Details)

Equity Interests (Details) $ in Millions	Jul. 03, 2017joint_venture	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)
Alpen Food Company South Africa (Proprietary) Limited
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		50.00%
Weetabix East Africa Limited
Schedule of Equity Method Investments [Line Items]
Ownership Percentage by Parent		50.10%
Weetabix Group
Schedule of Equity Method Investments [Line Items]
Number of Joint Ventures Acquired | joint_venture	2
Other Assets | Alpen Food Company South Africa (Proprietary) Limited
Schedule of Equity Method Investments [Line Items]
Investment in subsidiaries		$ 5.2	$ 4.5
Other Liabilities | Weetabix East Africa Limited
Schedule of Equity Method Investments [Line Items]
Accounts Payable, Related Parties		0	0.5
Melck Street Management Proprietary Limited | Other Assets | Alpen Food Company South Africa (Proprietary) Limited
Schedule of Equity Method Investments [Line Items]
Accounts Receivable, Related Parties		$ 1	$ 1
Pioneer Food Group Limited | Weetabix East Africa Limited
Schedule of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		49.90%

Income Taxes - Income tax (bene

Income Taxes - Income tax (benefit) provision (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Current
Federal	$ 27.3	$ (5.8)	$ 37.6
State	5.2	4.3	1.7
Foreign	20	10.2	8.5
Current	52.5	8.7	47.8
Deferred
Federal	(253.5)	19.7	(64.8)
State	21.4	2.7	(7.5)
Foreign	(24.4)	(5)	(2.3)
Deferred	(256.5)	17.4	(74.6)
Income tax (benefit) expense	$ (204)	$ 26.1	$ (26.8)

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Computed tax (a)	$ 64.9	$ 26.1	$ (10.5)
Enacted tax law changes, including the Tax Act	(270.9)	0	0.7
Non-deductible goodwill impairment loss	0	7.2	0
Non-deductible compensation	1.2	1.8	2.6
Non-deductible transaction costs	1.5	2.9	0
Domestic production activities deduction	(5.9)	0	(4.3)
State income taxes, net of effect on federal tax	5.6	0.8	(6.2)
Non-taxable interest income	(2.4)	(3.4)	(2.6)
Valuation allowances	4.1	4.8	3.8
Change in deferred tax rates	0.3	0	(2)
Uncertain tax positions	0.3	(0.5)	(2)
Sale and liquidation of Michael Foods Canadian egg business	0	0	(3.6)
Income tax credits	(2.3)	(1.4)	(1.5)
Rate differential on foreign income	(5.3)	(6.8)	(1.8)
Excess tax benefits for share-based payments	(1.8)	(6.2)	0
Other, net (none in excess of 5% of statutory tax)	6.7	0.8	0.6
Income tax (benefit) expense	$ (204)	$ 26.1	$ (26.8)
Fiscal 2018 Blended Tax Rate	24.50%
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Pre-December 22, 2017 Federal statutory rate	35.00%	35.00%	35.00%
None in excess of 5% of computed tax	5.00%	5.00%	5.00%

Income Taxes - Deferred Taxes (

Income Taxes - Deferred Taxes (Details) - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017
Components of Deferred Tax Liabilities [Abstract]
Noncurrent deferred tax liabilities	$ (778.4)	$ (905.8)
Assets
Components of Deferred Tax Assets [Abstract]
Total gross deferred income taxes, current	90.1	188.4
Assets | Noncurrent
Components of Deferred Tax Assets [Abstract]
Accrued vacation, incentive and severance	10	16.2
Inventory	4	3
Accrued liabilities	24.3	16.6
Deferred Tax Assets, Pension and other postretirement benefits	0	5.3
Stock-based and deferred compensation	27.5	28.7
Derivative mark-to-market adjustments	18.1	91.9
Net operating loss carryforwards	27.2	38.7
Other items, non-current assets	4.7	6.5
Valuation allowance	(25.7)	(18.5)
Total gross deferred income taxes	115.8	206.9
Liability
Components of Deferred Tax Liabilities [Abstract]
Total deferred tax liabilities, gross	(868.5)	(1,094.2)
Liability | Noncurrent
Components of Deferred Tax Assets [Abstract]
Property	(161.7)	(210.1)
Intangible assets	(688.3)	(882.5)
Components of Deferred Tax Liabilities [Abstract]
Deferred Tax Liabilities, Pension and Other Postreitrement Benefits	(15.3)
Other items, current liabilities	(3.2)	(1.6)
Noncurrent deferred tax liabilities	(868.5)	(1,094.2)
Net Assets
Deferred Tax Assets (Liabilities), Net [Abstract]
Total deferred tax assets (liabilities), net	778.4	905.8
Net Assets | Noncurrent
Components of Deferred Tax Assets [Abstract]
Accrued vacation, incentive and severance	10	16.2
Inventory	4	3
Accrued liabilities	24.3	16.6
Property	(161.7)	(210.1)
Intangible assets	(688.3)	(882.5)
Deferred Tax Assets, Pension and other postretirement benefits		5.3
Stock-based and deferred compensation	27.5	28.7
Derivative mark-to-market adjustments	18.1	91.9
Net operating loss carryforwards	27.2	38.7
Valuation allowance	(25.7)	(18.5)
Components of Deferred Tax Liabilities [Abstract]
Deferred Tax Liabilities, Pension and Other Postreitrement Benefits	(15.3)
Noncurrent deferred tax liabilities	(752.7)	(887.3)
Deferred Tax Assets (Liabilities), Net [Abstract]
Other items, net	$ 1.5	$ 4.9

Income Taxes - Income Taxes Nar

Income Taxes - Income Taxes Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosures
Effective tax rate	(77.10%)	35.10%	89.00%
Operating Loss Carryforwards, Limitations on Usage	$ 16.6
Undistributed Earnings of Foreign Subsidiaries	6.2
Foreign income (loss) before income taxes	$ (24.3)	$ 24.7	$ 29.6
Newly Enacted Tax Rate	21.00%
Tax Benefit Due to Newly Enacted Tax Rate	$ 281.2
Pre-December 22, 2017 Federal statutory rate	35.00%	35.00%	35.00%
Fiscal 2018 Blended Tax Rate	24.50%
Tax Expense due to repatriation of foreign earnings	$ 10.3
Domestic Tax Authority
Income Tax Disclosures
Operating Loss Carryforwards	57.1
State and Local Jurisdiction
Income Tax Disclosures
Operating Loss Carryforwards	475
Foreign Tax Authority
Income Tax Disclosures
Operating Loss Carryforwards	$ 8.3
Minimum
Income Tax Disclosures
Tax Credit Carryforward, Expiration Date	Jan. 1, 2021
Minimum | State and Local Jurisdiction
Income Tax Disclosures
Tax Credit Carryforward, Expiration Date	Jan. 1, 2019
Maximum
Income Tax Disclosures
Tax Credit Carryforward, Expiration Date	Jan. 1, 2038
Maximum | State and Local Jurisdiction
Income Tax Disclosures
Tax Credit Carryforward, Expiration Date	Jan. 1, 2037

Unrecognized tax benefits (Deta

Unrecognized tax benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits	$ 9.9	$ 8.6	$ 9.3
Unrecognized Tax Benefits, Increases Resulting from Current Period Tax Positions	2	0
Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions	(0.1)	0
Unrecognized Tax Benefits, Held for Sale Liabilities	(0.6)
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	0	(0.7)
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	8.3
Decrease in Unrecognized Tax Benefits is Reasonably Possible	7
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	3.5	2.7
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ (0.8)	$ (0.3)	$ (0.1)

Earnings (loss) per Share (Deta

Earnings (loss) per Share (Details) - USD ($) $ / shares in Units, $ in Millions	May 31, 2014	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share, Diluted
Net Earnings (Loss) Available to Common Shareholders		$ (17.6)	$ 94.5	$ 88.9	$ 291.5	$ 4.7	$ (62.8)	$ (5.5)	$ 98.4	$ 457.3	$ 34.8	$ (28.4)
Dilutive preferred stock dividends										10	0	0
Net Income (Loss) Available to Common Stockholders, Diluted										$ 467.3	$ 34.8	$ (28.4)
Weighted-average shares outstanding										66,600,000	65,200,000	63,900,000
Dilutive Securities, Effect on Weighted Average Basic Shares Outstanding										0	2,600,000	4,900,000
Weighted-average shares for basic earnings (loss) per share										66,600,000	67,800,000	68,800,000
Effect of dilutive securities										9,300,000	2,100,000	0
Weighted-average shares for diluted earnings (loss) per share										75,900,000	69,900,000	68,800,000
Basic earnings (loss) per common share		$ (0.26)	$ 1.41	$ 1.33	$ 4.42	$ 0.07	$ (0.93)	$ (0.08)	$ 1.42	$ 6.87	$ 0.51	$ (0.41)
Diluted (loss) earnings per common share		$ (0.26)	$ 1.29	$ 1.20	$ 3.82	$ 0.07	$ (0.93)	$ (0.08)	$ 1.27	$ 6.16	$ 0.50	$ (0.41)
Stock Options
Earnings Per Share, Diluted
Effect of dilutive securities										1,800,000	1,800,000	0
Stock Appreciation Rights
Earnings Per Share, Diluted
Effect of dilutive securities										100,000	0	0
Restricted Stock
Earnings Per Share, Diluted
Effect of dilutive securities										400,000	300,000	0
Preferred Stock
Earnings Per Share, Diluted
Effect of dilutive securities										7,000,000	0	0
Series B Preferred Stock
Earnings Per Share, Diluted
Preferred Stock, Dividend Rate, Percentage										3.75%	3.75%
Conversion of Stock, Shares Converted										1,500,000		900,000
Common Stock
Earnings Per Share, Diluted
Preferred Stock Conversion, Shares Issued										3,100,000		2,000,000
Minimum
Earnings Per Share, Diluted
Tangible Equity Unit, Equity Component, Settlement Rate per Unit	1.7114										1.7114
Maximum
Earnings Per Share, Diluted
Tangible Equity Unit, Equity Component, Settlement Rate per Unit											2.0964

Earnings (loss) per Share Antid

Earnings (loss) per Share Antidilutive shares excluded from earnings per share (Details) - shares shares in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.6	0.3	4.3
Stock Appreciation Rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0	0.2
Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.1	0	0.5
Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	9.1	9.1

Supplemental Operations State_3

Supplemental Operations Statement and Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Supplemental Operations Statement and Cash Flow Information [Abstract]
Advertising and promotion expenses	$ 153.4	$ 159.7	$ 184.2
Repair and maintenance expenses	149.1	162.6	141.6
Research and development expenses	25.1	18.6	16.3
Rent expense	41.3	41.8	32
Interest income	(7.4)	(6.8)	(2.7)
Interest paid	373.9	333.6	309.6
Income taxes paid	23	29.6	73.4
Accrued additions to property	$ 30.4	$ 21	$ 12.7

Supplemental Balance Sheet In_3

Supplemental Balance Sheet Information (Details) - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017
Receivables, net
Trade	$ 412.8	$ 421.6
Income tax receivable	41.5	46.4
Other	10.3	14.2
Gross receivables	464.6	482.2
Allowance for doubtful accounts	(2.3)	(1.6)
Receivables, net	462.3	480.6
Inventories
Raw materials and supplies	107.8	129.8
Work in process	17.8	16.9
Finished products	324.1	395.6
Flocks	34.5	31.2
Inventories	484.2	573.5
Other Assets
Pension asset	167	154.6
Hedging Assets, Noncurrent	52	0.3
Other	33	29.4
Other Assets	252	184.3
Accounts Payable
Trade	329.3	306.5
Book cash overdrafts	26.7	17.8
Other	9.1	11.7
Accounts payable	365.1	336
Current Liabilities
Advertising and promotion	53.6	74.5
Accrued interest	38.5	36.5
Accrued compensation	114.2	89.9
Hedging liabilities	27.7	54.6
Accrued legal settlements	23.9	8.6
Other	81.4	82.2
Other current liabilities	339.3	346.3
Other Liabilities
Pension and other postretirement benefit obligations	53.3	83.5
Hedging liabilities - non-current	113.7	188.9
Accrued compensation - non-current	30.4	29.2
Accrued appraisal rights and related interest	267	0
Other	34.9	26.2
Other Liabilities	$ 499.3	$ 327.8

Allowance for Doubtful Accoun_3

Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Allowance For Doubtful Accounts Receivable [Roll Forward]
Balance, beginning of year	$ 1.6	$ 1.6	$ 2
Provision charged to expense	0.1	0.3	1.2
Write-offs, less recoveries	(1.2)	(0.3)	(1.6)
Held for sale assets	(0.5)	0	0
Other, Primarily relates to Acquisitions	2.3	0	0
Balance, end of year	$ 2.3	$ 1.6	$ 1.6

Derivative Financial Instrume_3

Derivative Financial Instruments and Hedging Derivative Financial Instruments and Hedging Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Derivative [Line Items]
Reclassification of gains (losses) previously recorded in AOCI	$ 1.8
Reclassifications to net earnings (loss)	1.3	$ 3.6	$ (0.7)	$ 0
Other reclassifications	$ 0.5	$ 0.5	$ 0	$ 0

Derivative Financial Instrume_4

Derivative Financial Instruments and Hedging (Details) - USD ($) $ in Millions	Sep. 30, 2018	Sep. 30, 2017
Derivatives, Fair Value
Derivative Liability	$ 141.4	$ 243.5
Derivative Asset	66.4	5.9
Level 2
Derivatives, Fair Value
Asset Derivatives:		5.9
Liability Derivatives:		243.5
Derivative Liability	141.4	243.5
Derivative Asset	66.4	5.9
Portion Designated as Hedging Instruments | Level 2
Derivatives, Fair Value
Asset Derivatives:	55.7	1.4
Liability Derivatives:	20.8	30
Commodity contracts | Level 2 | Prepaid expenses and other current assets
Derivatives, Fair Value
Asset Derivatives:	1.9	0.5
Commodity contracts | Level 2 | Other Assets
Derivatives, Fair Value
Asset Derivatives:	0.2	0
Commodity contracts | Level 2 | Other current liabilities
Derivatives, Fair Value
Liability Derivatives:	2.2	1.9
Commodity contracts | Not Designated as Hedging Instrument
Derivatives, Fair Value
Derivative, Notional Amount	64.3	53.8
Commodity contracts | Portion Designated as Hedging Instruments | Level 2 | Prepaid expenses and other current assets
Derivatives, Fair Value
Asset Derivatives:	0	0
Commodity contracts | Portion Designated as Hedging Instruments | Level 2 | Other Assets
Derivatives, Fair Value
Asset Derivatives:	0	0
Commodity contracts | Portion Designated as Hedging Instruments | Level 2 | Other current liabilities
Derivatives, Fair Value
Liability Derivatives:	0	0
Energy contracts | Level 2 | Prepaid expenses and other current assets
Derivatives, Fair Value
Asset Derivatives:	4.9	3.8
Energy contracts | Level 2 | Other Assets
Derivatives, Fair Value
Asset Derivatives:	0.3	0
Energy contracts | Level 2 | Other current liabilities
Derivatives, Fair Value
Liability Derivatives:	0.4	0.3
Energy contracts | Not Designated as Hedging Instrument
Derivatives, Fair Value
Derivative, Notional Amount	20.8	25.6
Energy contracts | Portion Designated as Hedging Instruments | Level 2 | Prepaid expenses and other current assets
Derivatives, Fair Value
Asset Derivatives:	0	0
Energy contracts | Portion Designated as Hedging Instruments | Level 2 | Other Assets
Derivatives, Fair Value
Asset Derivatives:	0	0
Energy contracts | Portion Designated as Hedging Instruments | Level 2 | Other current liabilities
Derivatives, Fair Value
Liability Derivatives:	0	0
Foreign exchange contracts | Level 2 | Prepaid expenses and other current assets
Derivatives, Fair Value
Asset Derivatives:	1.2	1.3
Foreign exchange contracts | Level 2 | Other Assets
Derivatives, Fair Value
Asset Derivatives:	17.6	0.3
Foreign exchange contracts | Level 2 | Other current liabilities
Derivatives, Fair Value
Liability Derivatives:	1.5	1.5
Foreign exchange contracts | Level 2 | Other liabilities
Derivatives, Fair Value
Liability Derivatives:	19.4	23.6
Foreign exchange contracts | Not Designated as Hedging Instrument
Derivatives, Fair Value
Derivative, Notional Amount	9.3	3.8
Foreign exchange contracts | Portion Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount	0	20.9
Foreign exchange contracts | Portion Designated as Hedging Instruments | Level 2 | Prepaid expenses and other current assets
Derivatives, Fair Value
Asset Derivatives:	1.1	1.1
Foreign exchange contracts | Portion Designated as Hedging Instruments | Level 2 | Other Assets
Derivatives, Fair Value
Asset Derivatives:	17.6	0.3
Foreign exchange contracts | Portion Designated as Hedging Instruments | Level 2 | Other current liabilities
Derivatives, Fair Value
Liability Derivatives:	1.4	1.5
Foreign exchange contracts | Portion Designated as Hedging Instruments | Level 2 | Other liabilities
Derivatives, Fair Value
Liability Derivatives:	19.4	23.6
Currency Swap | Portion Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount	662.9	448.7
Interest rate swaps | Level 2 | Prepaid expenses and other current assets
Derivatives, Fair Value
Liability Derivatives:	6.4	0
Interest rate swaps | Level 2 | Other Assets
Derivatives, Fair Value
Liability Derivatives:	33.9	0
Interest rate swaps | Level 2 | Other current liabilities
Derivatives, Fair Value
Liability Derivatives:	23.6	50.9
Interest rate swaps | Level 2 | Other liabilities
Derivatives, Fair Value
Liability Derivatives:	94.3	165.3
Interest rate swaps | Not Designated as Hedging Instrument
Derivatives, Fair Value
Derivative, Notional Amount	74.6	76.1
Interest rate swaps | Portion Designated as Hedging Instruments
Derivatives, Fair Value
Derivative, Notional Amount	1,000	1,000
Interest rate swaps | Portion Designated as Hedging Instruments | Level 2 | Prepaid expenses and other current assets
Derivatives, Fair Value
Liability Derivatives:	6.4	0
Interest rate swaps | Portion Designated as Hedging Instruments | Level 2 | Other Assets
Derivatives, Fair Value
Liability Derivatives:	30.6	0
Interest rate swaps | Portion Designated as Hedging Instruments | Level 2 | Other current liabilities
Derivatives, Fair Value
Liability Derivatives:	0	0.7
Interest rate swaps | Portion Designated as Hedging Instruments | Level 2 | Other liabilities
Derivatives, Fair Value
Liability Derivatives:	0	4.2
Interest rate swap, rate lock swaps | Not Designated as Hedging Instrument
Derivatives, Fair Value
Derivative, Notional Amount	$ 1,649.3	$ 1,649.3

Derivative Financial Instrume_5

Derivative Financial Instruments and Hedging Gain (Loss) recognized in earnings from derivative instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Commodity contracts | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
Loss (Gain) Recognized in Statement of Operations	$ 4	$ (0.4)	$ 7.5
Energy contracts | Cost of goods sold
Derivative Instruments, Gain (Loss) [Line Items]
Loss (Gain) Recognized in Statement of Operations	(6.4)	(1.3)	1.2
Foreign exchange contracts | Selling, general and administrative expenses
Derivative Instruments, Gain (Loss) [Line Items]
Loss (Gain) Recognized in Statement of Operations	1.5	0.8	0
Currency Swap | (Income) expense on swaps, net
Derivative Instruments, Gain (Loss) [Line Items]
Loss (Gain) Recognized in Statement of Operations	0	10.3	0
Interest rate swaps | (Income) expense on swaps, net
Derivative Instruments, Gain (Loss) [Line Items]
Loss (Gain) Recognized in Statement of Operations	$ (95.6)	$ (102.1)	$ 182.9

Derivative Financial Instrume_6

Derivative Financial Instruments and Hedging Derivative and Financial Instruments designated as hedges and Pledged Collateral (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Derivative [Line Items]
(Gain) Loss Recognized in OCI	$ 72.2	$ (18.8)	$ 0
Accumulated Other Comprehensive Income, Cumulative Changes in Net Loss from Hedges, Before Tax	50	18.1
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Hedges, Effect Net of Tax	37.4	11.1
Hedging Gains to be Reclassified During Next 12 Months	(6.4)
Cross Currency Swap Settlements Recognized in AOCI	4.8
Collateral Already Posted	4.5	2.9
Selling, general and administrative expenses | Portion Designated as Hedging Instruments | Foreign exchange contracts
Derivative [Line Items]
(Gain) Loss Recognized in OCI	(0.2)	(1.6)	0
(Gain) Loss Reclassified from Accumulated OCI into Earnings	(1.3)	0	0
Interest expense, net | Portion Designated as Hedging Instruments | Interest rate swaps
Derivative [Line Items]
(Gain) Loss Recognized in OCI	(44.2)	5.6	0
(Gain) Loss Reclassified from Accumulated OCI into Earnings	(2.3)	0.7	0
(Income) expense on swaps, net | Portion Designated as Hedging Instruments | Currency Swap
Derivative [Line Items]
(Gain) Loss Recognized in OCI	(27.8)	14.8	0
(Gain) Loss Reclassified from Accumulated OCI into Earnings	$ 0	$ 0	$ 0

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended					12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Impairment of goodwill and other intangible assets	$ 124.9	$ 26.5	$ 0	$ 0	$ 0	$ 124.9	$ 26.5	$ 0
Deferred compensation investment	43.6	15.4				43.6	15.4
Derivative Asset	66.4	5.9				66.4	5.9
Assets, Fair Value Disclosure	110	21.3				110	21.3
Deferred compensation liabilities	52.2	22.5				52.2	22.5
Derivative Liability	141.4	243.5				141.4	243.5
Liabilities, Fair Value Disclosure	193.6	266				193.6	266
Gain on assets held for sale							(0.2)	9.3
Goodwill, Impairment Loss							26.5	0
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred compensation investment	43.6	15.4				43.6	15.4
Derivative Asset	0	0				0	0
Assets, Fair Value Disclosure	43.6	15.4				43.6	15.4
Deferred compensation liabilities	0	0				0	0
Derivative Liability	0	0				0	0
Liabilities, Fair Value Disclosure	0	0				0	0
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt, Fair Value Disclosure	7,790.9	7,343.4				7,790.9	7,343.4
Deferred compensation investment	0	0				0	0
Derivative Asset	66.4	5.9				66.4	5.9
Assets, Fair Value Disclosure	66.4	5.9				66.4	5.9
Deferred compensation liabilities	52.2	22.5				52.2	22.5
Derivative Liability	141.4	243.5				141.4	243.5
Liabilities, Fair Value Disclosure	193.6	266				193.6	266
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of assets held-for-sale	290.9	$ 0				290.9	0	$ 10.1
Gain on assets held for sale							0.2
Proceeds from Sale of Property Held-for-sale							$ (10.3)
Assets | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Increase (Decrease) in Assets Held-for-sale						1,051.6
Liabilities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Increase (Decrease) in Assets Held-for-sale						(760.7)
Bob Evans Farms
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Deferred Compensation Liability, Current	$ 24.1					$ 24.1

Long Term Debt (Details)

Long Term Debt (Details)	Oct. 08, 2018	Oct. 01, 2018USD ($)	Sep. 30, 2018USD ($)	Dec. 31, 2018	Nov. 30, 2018	Sep. 30, 2018USD ($)	Jun. 30, 2018	Dec. 31, 2017USD ($)	Sep. 30, 2017USD ($)	Jun. 30, 2017USD ($)	Mar. 31, 2017USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2014USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)
Debt Instrument
Repayments of Long-term Debt															$ 912,100,000	$ 2,088,400,000	$ 1,632,200,000
Gross Repayments of Long-term debt															919,800,000
Capital leases			$ 200,000			$ 200,000			$ 200,000						200,000	200,000
Long-term Debt and Capital Lease Obligations, Including Current Maturities			7,292,400,000			7,292,400,000			7,212,200,000						7,292,400,000	7,212,200,000
Current portion of long-term debt			(22,100,000)			(22,100,000)			(22,100,000)						(22,100,000)	(22,100,000)
Unamortized Debt Issuance Expense			71,200,000			71,200,000			81,800,000						71,200,000	81,800,000
Plus: Unamortized premium			33,000,000			33,000,000			40,800,000						33,000,000	40,800,000
Total long-term debt			7,232,100,000			7,232,100,000			7,149,100,000						7,232,100,000	7,149,100,000
Debt Covenant, Leverage Ratio			$ 4.25			$ 4.25									$ 4.25
Debt Covenant, Percentage of Revolving Credit Commitments			30.00%			30.00%									30.00%
Debt covenant, interest coverage ratio															$ 2
Loss on extinguishment of debt, net															31,100,000	222,900,000	86,400,000
Premium and Debt Extinguishment Costs Paid															33,700,000	219,800,000	88,000,000
Payments of Debt Issuance Costs															$ 24,900,000	59,000,000	24,300,000
Debt Instruments, Covenant Compliance, Percentage of Revolving Credit Commitments			30.00%			30.00%									30.00%
Revolving Credit Facility
Debt Instrument
Debt Covenant, Maximum Undischarged Judgments											$ 75,000,000
Line of Credit Facility, Current Borrowing Capacity											800,000,000
Line of Credit Facility, Capacity Available for Specific Purpose Other than for Trade Purchases			$ 700,000,000			$ 700,000,000									$ 700,000,000
Debt Covenant, Proforma Consolidated Leverage Ratio			6.50			6.50									6.50
Debt Covenant, Proforma Senior Secured Leverage Ratio			3			3									3
Letters of Credit Outstanding, Amount			18,500,000			18,500,000									18,500,000
Line of Credit Facility, Remaining Borrowing Capacity			781,500,000			781,500,000									781,500,000
Payments of Debt Issuance Costs															4,200,000	4,600,000
Debt Covenant, Quarterly Interest Ratio			2			2									$ 2
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%
Line of Credit
Debt Instrument
Line of Credit Facility, Current Borrowing Capacity											50,000,000
Senior Notes | 5.625% Senior Notes Maturing January 2028
Debt Instrument
Repayments of Long-term Debt															$ 39,100,000
Long-term Debt			$ 960,900,000			$ 960,900,000			0						$ 960,900,000	0
Senior Notes								$ 1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage			5.625%			5.625%									5.625%
Debt Instrument, Increase, Additional Borrowings								990,600,000
Payments of Debt Issuance Costs								$ 9,400,000
Senior Notes | 5.50% Senior Notes maturing March 2025
Debt Instrument
Long-term Debt			$ 1,000,000,000			$ 1,000,000,000			1,000,000,000						$ 1,000,000,000	1,000,000,000
Senior Notes											1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage			5.50%			5.50%									5.50%
Senior Notes | 5.75% Senior Notes maturing March 2027
Debt Instrument
Repayments of Long-term Debt															$ 173,700,000
Long-term Debt			$ 1,326,300,000			$ 1,326,300,000			1,500,000,000						$ 1,326,300,000	1,500,000,000
Senior Notes											$ 750,000,000
Debt Instrument, Interest Rate, Stated Percentage			5.75%			5.75%					5.75%				5.75%
Senior Notes | 5.50% and 5.75% Senior Notes
Debt Instrument
Debt Instrument, Increase, Additional Borrowings											$ 1,725,400,000
Payments of Debt Issuance Costs											$ 24,600,000
Senior Notes | Additional Issuance of 5.75% Senior Notes Maturing in March 2027
Debt Instrument
Senior Notes									750,000,000							$ 750,000,000
Debt Instrument, Interest Rate, Stated Percentage			5.75%			5.75%									5.75%
Debt Instrument, Issuance Price, Percentage of Par Value																105.50%
Debt Instrument, Increase, Additional Borrowings									784,000,000
Payments of Debt Issuance Costs									7,200,000
Senior Notes | 5.00% Senior Notes maturing August 2026
Debt Instrument
Repayments of Long-term Debt															$ 39,700,000
Long-term Debt			$ 1,710,300,000			$ 1,710,300,000			1,750,000,000						$ 1,710,300,000	$ 1,750,000,000
Senior Notes												$ 1,750,000,000					1,750,000,000
Debt Instrument, Interest Rate, Stated Percentage			5.00%			5.00%									5.00%
Debt Instrument, Increase, Additional Borrowings												1,725,700,000
Payments of Debt Issuance Costs												$ 24,300,000
Senior Notes | 7.75% Senior Notes maturing March 2024
Debt Instrument
Repayments of Long-term Debt																800,000,000
Senior Notes | 8.00% Senior Notes maturing July 2025
Debt Instrument
Repayments of Long-term Debt															$ 15,300,000	262,500,000
Long-term Debt			$ 122,200,000			$ 122,200,000			137,500,000						$ 122,200,000	137,500,000
Senior Notes													$ 400,000,000
Debt Instrument, Interest Rate, Stated Percentage			8.00%			8.00%									8.00%
Debt Instrument, Increase, Additional Borrowings													396,000,000
Payments of Debt Issuance Costs													$ 4,000,000
Senior Notes | TEUs
Debt Instrument
Repayments of Long-term Debt																11,000,000	14,100,000
Senior Notes | 6.00% Senior Notes maturing December 2022
Debt Instrument
Repayments of Long-term Debt															$ 630,000,000
Long-term Debt			$ 0			$ 0			630,000,000						$ 0	630,000,000
Senior Notes														$ 630,000,000
Debt Instrument, Interest Rate, Stated Percentage			6.00%			6.00%									6.00%
Debt Instrument, Increase, Additional Borrowings														619,000,000
Payments of Debt Issuance Costs														$ 11,000,000
Senior Notes | 6.75% Senior Notes maturing December 2021
Debt Instrument
Repayments of Long-term Debt																875,000,000
Senior Notes | 7.375% Senior Notes maturing February 2022
Debt Instrument
Repayments of Long-term Debt																133,000,000	1,242,000,000
Term Loan
Debt Instrument
Repayments of Long-term Debt															$ 22,000,000	5,500,000	374,400,000
Long-term Debt			$ 2,172,500,000			$ 2,172,500,000			$ 2,194,500,000						$ 2,172,500,000	$ 2,194,500,000
Interest Rate Margin Decrease							0.25
Debt Instrument, Interest Rate, Effective Percentage			4.22%			4.22%			3.49%						4.22%	3.49%
Debt Instrument, Periodic Payment, Principal															$ 5,500,000
Payments of Debt Issuance Costs																$ 23,700,000
Term Loan | Joinder No. 1 Term Loan
Debt Instrument
Loans Payable to Bank										$ 1,200,000,000
Proceeds from Term Loan or Bridge Loan										1,200,000,000
Term Loan | Joinder No. 2 Term Loan
Debt Instrument
Loans Payable to Bank										$ 1,000,000,000
Proceeds from Term Loan or Bridge Loan									$ 1,000,000,000
Bridge Loan
Debt Instrument
Long-term Debt			$ 0			$ 0			$ 0						0	0
Loans Payable to Bank			$ 625,000,000			625,000,000									$ 625,000,000
Debt Instrument, Basis Spread on Variable Rate Debt	5		4.50
Debt Instrument, Interest Rate During Period				12.25%	12.00%
Secured Debt | 4.57% 2012 Series Bond maturing September 2017
Debt Instrument
Repayments of Long-term Debt																1,300,000	1,600,000
Capital Lease Obligations
Debt Instrument
Repayments of Long-term Debt																100,000	100,000
Base Rate | Revolving Credit Facility | Minimum
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate															0.75%
Base Rate | Revolving Credit Facility | Maximum
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate															1.25%
Base Rate | Term Loan
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate							1.00%
Eurodollar | Revolving Credit Facility | Minimum
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate															1.75%
Eurodollar | Revolving Credit Facility | Maximum
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate															2.25%
Eurodollar | Term Loan
Debt Instrument
Debt Instrument, Basis Spread on Variable Rate							2.00%
Long-term debt held for sale | Bridge Loan
Debt Instrument
Proceeds from Term Loan or Bridge Loan						625,000,000
Payments of Debt Issuance Costs															$ 10,400,000
Unamortized Debt Issuance Expense to be Reimbursed			$ 7,800,000			$ 7,800,000									7,800,000
8th Avenue | First Lien Revolving Credit Facility
Debt Instrument
Revolving Credit Facility		$ 150,000,000
8th Avenue | Term Loan | Second Lien Term Loan
Debt Instrument
Proceeds from Term Loan or Bridge Loan		525,000,000
8th Avenue | Term Loan | First Lien Term Loan
Debt Instrument
Proceeds from Term Loan or Bridge Loan		$ 100,000,000
Loss on extinguishment of debt, net
Debt Instrument
Debt Repurchased at a Discount															(7,700,000)	0	0
Premium and Debt Extinguishment Costs Paid															33,700,000	219,800,000	88,000,000
Write off of Deferred Debt Issuance Cost															9,700,000	18,600,000	18,800,000
Write-off of Unamortized Debt Discount/(Premium)															(4,600,000)	(15,500,000)	(20,400,000)
Loss on extinguishment of debt, net | Senior Notes | 5.625% Senior Notes Maturing January 2028
Debt Instrument
Debt Repurchased at a Discount															(2,100,000)
Premium and Debt Extinguishment Costs Paid															0
Write off of Deferred Debt Issuance Cost															400,000
Write-off of Unamortized Debt Discount/(Premium)															0
Loss on extinguishment of debt, net | Senior Notes | 5.75% Senior Notes maturing March 2027
Debt Instrument
Debt Repurchased at a Discount															(3,100,000)
Premium and Debt Extinguishment Costs Paid															0
Write off of Deferred Debt Issuance Cost															1,900,000
Write-off of Unamortized Debt Discount/(Premium)															(4,600,000)
Loss on extinguishment of debt, net | Senior Notes | 5.00% Senior Notes maturing August 2026
Debt Instrument
Debt Repurchased at a Discount															(2,500,000)
Premium and Debt Extinguishment Costs Paid															0
Write off of Deferred Debt Issuance Cost															400,000
Write-off of Unamortized Debt Discount/(Premium)															0
Loss on extinguishment of debt, net | Senior Notes | 7.75% Senior Notes maturing March 2024
Debt Instrument
Debt Repurchased at a Discount																0
Premium and Debt Extinguishment Costs Paid																108,600,000
Write off of Deferred Debt Issuance Cost																6,300,000
Write-off of Unamortized Debt Discount/(Premium)																0
Loss on extinguishment of debt, net | Senior Notes | 8.00% Senior Notes maturing July 2025
Debt Instrument
Debt Repurchased at a Discount															0	0
Premium and Debt Extinguishment Costs Paid															2,000,000	43,300,000
Write off of Deferred Debt Issuance Cost															100,000	2,200,000
Write-off of Unamortized Debt Discount/(Premium)															0	0
Loss on extinguishment of debt, net | Senior Notes | TEUs
Debt Instrument
Debt Repurchased at a Discount																0	0
Premium and Debt Extinguishment Costs Paid																0	0
Write off of Deferred Debt Issuance Cost																0	0
Write-off of Unamortized Debt Discount/(Premium)																0	0
Loss on extinguishment of debt, net | Senior Notes | 6.00% Senior Notes maturing December 2022
Debt Instrument
Debt Repurchased at a Discount															0
Premium and Debt Extinguishment Costs Paid															30,800,000
Write off of Deferred Debt Issuance Cost															6,500,000
Write-off of Unamortized Debt Discount/(Premium)															0
Loss on extinguishment of debt, net | Senior Notes | 6.75% Senior Notes maturing December 2021
Debt Instrument
Debt Repurchased at a Discount																0
Premium and Debt Extinguishment Costs Paid																63,000,000
Write off of Deferred Debt Issuance Cost																8,900,000
Write-off of Unamortized Debt Discount/(Premium)																(13,400,000)
Loss on extinguishment of debt, net | Senior Notes | 7.375% Senior Notes maturing February 2022
Debt Instrument
Debt Repurchased at a Discount																0	0
Premium and Debt Extinguishment Costs Paid																4,900,000	88,000,000
Write off of Deferred Debt Issuance Cost																1,200,000	12,400,000
Write-off of Unamortized Debt Discount/(Premium)																(2,100,000)	(21,800,000)
Loss on extinguishment of debt, net | Term Loan
Debt Instrument
Debt Repurchased at a Discount															0	0	0
Premium and Debt Extinguishment Costs Paid															900,000	0	0
Write off of Deferred Debt Issuance Cost															400,000	0	6,400,000
Write-off of Unamortized Debt Discount/(Premium)															$ 0	0	1,400,000
Loss on extinguishment of debt, net | Secured Debt | 4.57% 2012 Series Bond maturing September 2017
Debt Instrument
Debt Repurchased at a Discount																0	0
Premium and Debt Extinguishment Costs Paid																0	0
Write off of Deferred Debt Issuance Cost																0	0
Write-off of Unamortized Debt Discount/(Premium)																0	0
Loss on extinguishment of debt, net | Capital Lease Obligations
Debt Instrument
Debt Repurchased at a Discount																0	0
Premium and Debt Extinguishment Costs Paid																0	0
Write off of Deferred Debt Issuance Cost																0	0
Write-off of Unamortized Debt Discount/(Premium)																$ 0	$ 0

Commitments and Contingencies (

Commitments and Contingencies (Details) $ / shares in Units, shares in Millions	Dec. 08, 2016USD ($)	Sep. 30, 2018USD ($)plaintiff_groupdefendantshares	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Jan. 12, 2018$ / sharesshares
Loss Contingencies [Line Items]
Accrued legal settlements		$ 23,900,000	$ 8,600,000
Accrued appraisal rights and related interest		267,000,000	0
Future Minimum Payments Due and Rent Expense
2,019		28,200,000
2,020		26,400,000
2,021		24,600,000
2,022		23,900,000
2,023		21,600,000
Thereafter		$ 84,800,000
Bob Evans Farms
Loss Contingencies [Line Items]
Shares not yet paid | shares		3.3			4.4
Business Acquisition, Share Price | $ / shares					$ 77
Accrued appraisal rights and related interest		$ 267,000,000
Future Minimum Payments Due and Rent Expense
Lease Guarantee, Number of Properties		143
Current annual rent of guaranteed leases		$ 13,500,000
Lease Guarantee, Interest rate increase		1.50%
Lease Guarantee, Remaining Lease Term		17 years
Michael Foods
Loss Contingencies [Line Items]
Loss Contingency, Pending Claims, Number		22
Loss Contingency, Pending Claims, Other Defendants | defendant		20
Loss Contingency, Pending Claims, Number of Plaintiff Groups | plaintiff_group		3
Litigation Settlement	$ 75,000,000
Accrued legal settlements		$ 6,000,000
Litigation Settlement, Expense		$ 8,300,000	$ 74,500,000	$ 28,500,000

Pension and Other Postretirem_3

Pension and Other Postretirement Benefits - Change in Projected Benefit Obligation, Fair Value of Plan Assets, and Net Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Amounts recognized in assets or liabilities [Abstract]
Other liabilities	$ (53.3)	$ (83.5)
Other Benefits
Change in benefit obligation [roll forward]
Service cost	0.5	0.6	$ 1
Interest cost	2.1	2	4
North America | Pension Benefits
Change in benefit obligation [roll forward]
Benefit obligation at beginning of period	100.6	71.2
Service cost	4.2	4.1	4
Interest cost	3.6	2.5	2.5
Plan participants' contributions	0.6	0.6
Actuarial (gain) loss	(4.3)	(1)
Business combinations	0	25.5
Benefits Paid	(3.4)	(3)
Currency translation	(0.4)	0.7
Benefit obligation at end of period	100.9	100.6	71.2
Change in fair value of plan assets [roll forward]
Fair value of plan assets at beginning of period	80.9	54.3
Actual return on plan assets	3.9	5.4
Employer contributions	32.6	7.7
Business combinations	0	15.2
Benefits Paid	(3.4)	(3)
Currency translation	(0.5)	0.7
Fair value of plan assets at end of period	114.1	80.9	54.3
Defined benefit plan, funded status of plan [Abstract]
Funded status	13.2	(19.7)
Amounts recognized in assets or liabilities [Abstract]
Other assets	13.7	1.5
Other liabilities	(0.5)	(21.2)
Net amount recognized	13.2	(19.7)
Amounts recognized in accumulated other comprehensive income or loss [Abstract]
Net actuarial (gain) loss	9.5	14.3
Prior service cost (credit)	0.5	0.6
Total	10	14.9
Weighted-average assumptions used to determine benefit obligation [Abstract]
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	98.9	98.3
North America | Other Benefits
Change in benefit obligation [roll forward]
Benefit obligation at beginning of period	65	68.6
Service cost	0.5	0.6
Interest cost	2.1	2
Plan Amendment	0	(0.1)
Actuarial (gain) loss	(9.9)	(4.4)
Benefits Paid	(2.3)	(2.1)
Currency translation	(0.2)	0.4
Benefit obligation at end of period	55.2	65	68.6
Change in fair value of plan assets [roll forward]
Fair value of plan assets at beginning of period	0
Employer contributions	2.3	2.1
Benefits Paid	(2.3)	(2.1)
Fair value of plan assets at end of period	0	0
Defined benefit plan, funded status of plan [Abstract]
Funded status	(55.2)	(65)
Amounts recognized in assets or liabilities [Abstract]
Other current liabilities	(2.4)	(2.7)
Other liabilities	(52.8)	(62.3)
Net amount recognized	(55.2)	(65)
Amounts recognized in accumulated other comprehensive income or loss [Abstract]
Net actuarial (gain) loss	(1.2)	8.6
Prior service cost (credit)	(24.1)	(28.8)
Total	$ (25.3)	$ (20.2)
U.S. Plans, Pension Benefits | UNITED STATES
Weighted-average assumptions used to determine benefit obligation [Abstract]
Discount rate	4.27%	3.77%
U.S. Plans, Pension Benefits | UNITED STATES | Pension Benefits
Weighted-average assumptions used to determine benefit obligation [Abstract]
Discount rate	4.30%	3.86%
Rate of compensation increase	3.00%	3.00%
International Pension Plans | Other International
Weighted-average assumptions used to determine benefit obligation [Abstract]
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	$ 677.6	$ 690.4
International Pension Plans | Other International | Pension Benefits
Change in benefit obligation [roll forward]
Benefit obligation at beginning of period	723.6	0
Service cost	6.7	1.7	0
Interest cost	19.6	4.9	0
Plan participants' contributions	2.4	0.6
Actuarial (gain) loss	(14)	(46.4)
Business combinations	0	746
Benefits Paid	(27.6)	(6.2)
Currency translation	(19.5)	23
Benefit obligation at end of period	691.2	723.6	0
Change in fair value of plan assets [roll forward]
Fair value of plan assets at beginning of period	876.7	0
Actual return on plan assets	9.6	0.3
Employer contributions	7.2	2.4
Business combinations	0	852.2
Benefits Paid	(27.6)	(6.2)
Currency translation	(23.8)	27.4
Fair value of plan assets at end of period	844.5	876.7	$ 0
Defined benefit plan, funded status of plan [Abstract]
Funded status	153.3	153.1
Amounts recognized in assets or liabilities [Abstract]
Other assets	153.3	153.1
Other liabilities	0	0
Net amount recognized	153.3	153.1
Amounts recognized in accumulated other comprehensive income or loss [Abstract]
Net actuarial (gain) loss	(32)	(40.2)
Prior service cost (credit)	0	0
Total	$ (32)	$ (40.2)
Weighted-average assumptions used to determine benefit obligation [Abstract]
Discount rate	2.81%	2.72%
Rate of compensation increase	2.75%	2.70%
International Pension Plans | CANADA
Weighted-average assumptions used to determine benefit obligation [Abstract]
Discount rate	3.54%	3.69%
Rate of compensation increase	2.75%	2.75%
International Pension Plans | CANADA | Pension Benefits
Weighted-average assumptions used to determine benefit obligation [Abstract]
Discount rate	3.53%	3.63%
Rate of compensation increase	2.75%	2.69%

Pension and Other Postretirem_4

Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	5 Months Ended		7 Months Ended	12 Months Ended
	Feb. 29, 2016	Feb. 28, 2016	Sep. 30, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Changes in plan assets and benefit obligation recognized in other comprehensive income or loss [Abstract]
Net (gain) loss				$ (5)	$ (47.8)	$ (6.2)
Estimated net actuarial loss to be reclassified from accumulated other comprehensive income into net periodic benefit cost				0.1
Prior service cost expected to be reclassified from accumulated other comprehensive income into net periodic benefit cost				(4.7)
Other Benefits
Components of net periodic benefit cost [Abstract]
Service cost				0.5	0.6	1
Interest cost				2.1	2	4
Recognized net actuarial loss				0.3	0.7	1.6
Recognized prior service cost				(4.7)	(4.8)	(3.8)
Net periodic benefit cost				(1.8)	(1.5)	2.8
Weighted-average assumptions used to determine net benefit cost [Abstract]
Discount rate		4.60%	4.22%
Changes in plan assets and benefit obligation recognized in other comprehensive income or loss [Abstract]
Net (gain) loss				(9.9)	(4.4)	(11.3)
Recognized loss				(0.3)	(0.7)	(1.6)
Plan Amendment				0	(0.1)	(36.1)
Recognized prior service cost				4.7	4.8	3.8
Currency translation				0.4	0.1	(0.1)
Total recognized in other comprehensive income or loss (before tax effects)				(5.1)	(0.3)	(45.3)
North America | Pension Benefits
Components of net periodic benefit cost [Abstract]
Service cost				4.2	4.1	4
Interest cost				3.6	2.5	2.5
Expected return on plan assets				(4.4)	(3.2)	(2.6)
Recognized net actuarial loss				1.1	1.6	1.1
Recognized prior service cost				0.1	0.2	0.3
Net periodic benefit cost				4.6	5.2	5.3
Changes in plan assets and benefit obligation recognized in other comprehensive income or loss [Abstract]
Net (gain) loss				(3.7)	(3.1)	5.1
Recognized loss				(1.1)	(1.6)	(1.1)
Plan Amendment				0	0	0.5
Recognized prior service cost				(0.1)	(0.2)	(0.3)
Currency translation				0	(0.1)	0
Total recognized in other comprehensive income or loss (before tax effects)				(4.9)	(5)	$ 4.2
Estimated net actuarial loss to be reclassified from accumulated other comprehensive income into net periodic benefit cost				0
Prior service cost expected to be reclassified from accumulated other comprehensive income into net periodic benefit cost				0.1
North America | Other Benefits
Components of net periodic benefit cost [Abstract]
Service cost				0.5	0.6
Interest cost				$ 2.1	$ 2
U.S. Plans, Pension Benefits | North America | Pension Benefits
Weighted-average assumptions used to determine net benefit cost [Abstract]
Discount rate				3.86%	3.66%	4.55%
Rate of compensation increase				3.00%	2.99%	3.00%
Expected return on plan assets				5.46%	5.33%	5.20%
U.S. Plans, Pension Benefits | UNITED STATES | Other Benefits
Weighted-average assumptions used to determine net benefit cost [Abstract]
Discount rate	4.60%		4.22%	3.77%	3.54%
International Pension Plans | North America | Pension Benefits
Weighted-average assumptions used to determine net benefit cost [Abstract]
Discount rate				3.63%	3.18%	3.82%
Rate of compensation increase				2.69%	2.50%	2.75%
Expected return on plan assets				6.00%	6.00%	6.00%
International Pension Plans | CANADA | Other Benefits
Weighted-average assumptions used to determine net benefit cost [Abstract]
Discount rate				3.69%	3.23%	3.91%
Rate of compensation increase				2.75%	2.75%	2.75%
International Pension Plans | Other International | Pension Benefits
Components of net periodic benefit cost [Abstract]
Service cost				$ 6.7	$ 1.7	$ 0
Interest cost				19.6	4.9	0
Expected return on plan assets				(31.7)	(7.5)	0
Net periodic benefit cost				$ (5.4)	$ (0.9)	$ 0
Weighted-average assumptions used to determine net benefit cost [Abstract]
Discount rate				2.72%	2.61%	0.00%
Rate of compensation increase				2.70%	2.75%	0.00%
Expected return on plan assets				3.56%	3.52%	0.00%
Changes in plan assets and benefit obligation recognized in other comprehensive income or loss [Abstract]
Net (gain) loss				$ 8.2	$ (39.3)	$ 0
Currency translation				0	(0.9)	0
Total recognized in other comprehensive income or loss (before tax effects)				$ 8.2	$ (40.2)	$ 0

Pension and Other Postretirem_5

Pension and Other Postretirement Benefits - Pension Plan Assets Measured at Fair Value on a Recurring Basis (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
North America
Defined Benefit Plan Disclosure
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	$ 0.5
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Actual allocations, index funds	99.60%	69.60%
Pension plan's assets at fair value	$ 114.1	$ 80.9	$ 54.3
Defined Benefit Plan, Fair Value of Plan Assets not Measured at NAV	35.4	34
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	78.7	46.9
North America | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	1.2	20.8
Defined Benefit Plan, Fair Value of Plan Assets not Measured at NAV	1.2	20.8
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
North America | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	34.2	13.2
Defined Benefit Plan, Fair Value of Plan Assets not Measured at NAV	34.2	13.2
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	$ 0	$ 0
North America | Equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	51.00%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	53.60%	58.30%
Pension plan's assets at fair value	$ 9.5	$ 16.4
North America | Equities | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	0	7.8
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
North America | Equities | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	9.5	8.6
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
North America | Equities | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	$ 51.7	$ 30.7
North America | Fixed income
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	34.50%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	33.20%	17.60%
Pension plan's assets at fair value	$ 14.7	$ 4.6
North America | Fixed income | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	0	0
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
North America | Fixed income | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	14.7	4.6
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
North America | Fixed income | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	$ 23.2	$ 9.6
North America | Debt Securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	10.00%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	8.90%	19.40%
North America | Bonds
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	$ 10.1	$ 11.3
North America | Bonds | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	0.1	11.3
North America | Bonds | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	10	0
North America | Pooled Assets | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
North America | Pooled Assets | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
North America | Pooled Assets | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	$ 0	$ 4.5
North America | Real assets
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	4.00%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	3.40%	3.70%
Pension plan's assets at fair value	$ 0	$ 0.9
North America | Real assets | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	0	0.9
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
North America | Real assets | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	0	0
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
North America | Real assets | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	$ 3.8	$ 2.1
North America | Cash and Cash Equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.50%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	0.90%	1.00%
Pension plan's assets at fair value	$ 1.1	$ 0.8
North America | Cash and Cash Equivalents | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	1.1	0.8
North America | Cash and Cash Equivalents | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	0	$ 0
Other International
Defined Benefit Plan Disclosure
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	$ 5
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Actual allocations, index funds	31.80%	25.60%
Defined Benefit Plan, Fair Value of Plan Assets not Measured at NAV	$ 704	$ 776.9
Other International | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets not Measured at NAV	681.1	756.3
Other International | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets not Measured at NAV	$ 22.9	$ 20.6
Other International | Fixed income
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	20.80%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	18.50%	23.20%
Other International | Debt Securities
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	57.30%	52.70%
Other International | Liability Hedging Instruments
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	20.80%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	23.80%	23.30%
Other International | Real assets
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	3.60%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		0.40%
Other International | Other
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	0.20%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	0.20%	0.10%
Other International | Cash and Cash Equivalents
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	2.00%
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage	0.20%	0.30%
Other International | Corporate Debt Securities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	52.60%
International Pension Plans | Other International
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	$ 844.5	$ 876.7	$ 0
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	140.5	99.8
International Pension Plans | Other International | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	681.1	756.3
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	22.9	20.6
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Fixed income
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	61.5	108.3
International Pension Plans | Other International | Fixed income | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	62	108
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Fixed income | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	0	0
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Fixed income | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	94.2	95
International Pension Plans | Other International | Bonds
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	439.5	461.7
International Pension Plans | Other International | Bonds | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	417	441
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Bonds | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	22.9	20.6
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Bonds | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	44.4	0
International Pension Plans | Other International | Liability Hedging Instruments
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	201.4	204.2
International Pension Plans | Other International | Liability Hedging Instruments | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	201	204
International Pension Plans | Other International | Liability Hedging Instruments | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	0	0
International Pension Plans | Other International | Real assets | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Real assets | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Real assets | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	3.9
International Pension Plans | Other International | Cash and Cash Equivalents
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	1.6	2.7
International Pension Plans | Other International | Cash and Cash Equivalents | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	1.6	2.7
International Pension Plans | Other International | Cash and Cash Equivalents | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Pension plan's assets at fair value	0	0
International Pension Plans | Other International | Other | Level 1
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Other | Level 2
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	0	0
International Pension Plans | Other International | Other | Fair Value Measured at Net Asset Value Per Share [Member]
Defined Benefit Plan, Actual Plan Asset Allocation [Abstract]
Defined Benefit Plan, Plan Assets, Amount Measured at Net Asset Value	$ 1.9	$ 0.9

Pension and Other Postretirem_6

Pension and Other Postretirement Benefits - Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rate [Abstract]
Effect on postretirement benefit obligation, increase	$ 5.2
Effect on postretirement benefit obligation, decrease	(4.3)
Effect on total service and interest cost, increase	0.3
Effect on total service and interest cost, decrease	(0.2)
Estimated net actuarial loss to be reclassified from accumulated other comprehensive income into net periodic benefit cost	0.1
Prior service credit expected to be reclassified from accumulated other comprehensive income into net periodic benefit cost	$ 4.7
U.S. Plans, Pension Benefits | Other Benefits
Defined Benefit Plan Disclosure
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	5.00%	5.00%
U.S. Plans, Pension Benefits | Participants Over and Under 65 | Other Benefits
Defined Benefit Plan Disclosure
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	6.50%
U.S. Plans, Pension Benefits | Participants Under 65 | Other Benefits
Defined Benefit Plan Disclosure
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year		7.00%
U.S. Plans, Pension Benefits | Participants Over 65 | Other Benefits
Defined Benefit Plan Disclosure
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year		5.80%
International Pension Plans | CANADA | Other Benefits
Defined Benefit Plan Disclosure
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate	4.50%
International Pension Plans | CANADA | Participants Under 65 | Other Benefits
Defined Benefit Plan Disclosure
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	6.00%
International Pension Plans | CANADA | Participants Over 65 | Other Benefits
Defined Benefit Plan Disclosure
Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year	6.50%

Pension and Other Postretirem_7

Pension and Other Postretirement Benefits - Expected Future Benefit Payments and Related Federal Subsidy Receipts (Details) $ in Millions	Sep. 30, 2018USD ($)
Pension benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Year 1	$ 23
Year 2	23.9
Year 3	24.9
Year 4	26
Year 5	27.1
Year 6 and thereafter	155.5
Other benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
Year 1	2.4
Year 2	2.8
Year 3	2.8
Year 4	3
Year 5	3.1
Year 6 and thereafter	16.5
Disclosure of Expected Gross Prescription Drug Subsidy Receipts [Abstract]
Year 1	0
Year 2	0.1
Year 3	0.1
Year 4	0.1
Year 5	0.1
Years 6-10	$ 1.1

Pension and Other Postretirem_8

Pension and Other Postretirement Benefits - Defined contribution plan expense (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Retirement Benefits [Abstract]
401K Matching Contributions	$ 19.6	$ 18.2	$ 15.6

Stock-Based Compensation Plan_2

Stock-Based Compensation Plans - Stock-Based Compensation Plans Narrative (Details) $ in Millions	12 Months Ended
	Sep. 30, 2018USD ($)shares	Sep. 30, 2017USD ($)	Sep. 30, 2016USD ($)
Share-based Payment Award [Line Items]
Share-based Compensation Arrangement , Maximum Award Vesting Period	10 years
Matching contribution on Director Deferred Compensation	33.30%
Stock Based Compensation Awards [Abstract]
Stock-based Compensation Expense	$ 33.8	$ 30.7	$ 25.6
Recognized deferred tax beneft	7.8	9.7	$ 8
Compensation cost related to nonvested awards not yet recognized	$ 55.5
Awards not yet recognized. weighted average period to be recognized	2 years 1 month
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Number of Employees Affected			25
Share-based Compensation Arrangement by Share-based Payment Award, Plan Modification, Incremental Compensation Cost			$ 2.2
Stock Settled
Stock Based Compensation Awards [Abstract]
Exercised, Total Intrinsic Value	$ 0.1	$ 0.6	$ 5.1
Restricted Stock Awards [Abstract]
Granted | shares	0
2012 Long-Term Incentive Plan
Restricted Stock Awards [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | shares	6,500,000
2016 Long-Term Incentive Plan
Restricted Stock Awards [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized | shares	2,400,000

Stock-Based Compensation Plan_3

Stock-Based Compensation Plans - Stock Appreciation Rights Award Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Stock Appreciation Rights
Forfeited, Weighted Average Exercise Price	$ 71.32
Expired, Weighted Average Exercise Price	$ 0
Stock-based Compensation Expense	$ 33.8	$ 30.7	$ 25.6
Cash Settled
Stock Appreciation Rights
Total Share-based Liabilities Paid	$ 5	$ 0.7
Outstanding	2,500	104,500
Granted	0
Exercised	(102,000)
Forfeited	0
Expired	0
Vested And Expected To Vest	2,500
Exercisable	2,500
Outstanding, Weighted Average Exercise Price	$ 18.10	$ 46.43
Granted, Weighted Average Exercise Price	0
Exercised, Weighted Average Exercise Price	47.12
Forfeited, Weighted Average Exercise Price	0
Expired, Weighted Average Exercise Price	0
Vested And Expected To Vest, Weighted Average Exercise Price	18.10
Exercisable, Weighted Average Exercise Price	$ 18.10
Outstanding, Weighted Average Remaining Contractual Term	1 year 11 months 24 days
Vested And Expected To Vest, Outstanding, Weighted Average Remaining Contractual Term	1 year 11 months 24 days
Exercisable, Weighted Average Remaining Contractual Term	1 year 11 months 24 days
Outstanding, Intrinsic Value	$ 0.2
Vested And Expected To Vest, Outstanding, Aggregate Intrinsic Value	0.2
Exercisable, Aggregate Intrinsic Value	$ 0.2
Expected Term	0 years	2 years 11 months 10 days	3 years 9 months 14 days
Expected Volatility Rate	21.47%	31.66%	32.39%
Risk Free Interest Rate	2.58%	1.60%	0.99%
Expected Dividend Rate	0.00%	0.00%	0.00%
Fair Value Of Awards, Per Share	$ 79.94	$ 54.18	$ 44.44
Stock Settled
Stock Appreciation Rights
Outstanding	136,031	137,831
Granted	0
Exercised	(1,800)
Forfeited	0
Expired	0
Vested And Expected To Vest	136,031
Exercisable	136,031
Outstanding, Weighted Average Exercise Price	$ 41.94	$ 41.63
Granted, Weighted Average Exercise Price	0
Exercised, Weighted Average Exercise Price	18.10
Forfeited, Weighted Average Exercise Price	0
Expired, Weighted Average Exercise Price	0
Vested And Expected To Vest, Weighted Average Exercise Price	41.94
Exercisable, Weighted Average Exercise Price	$ 41.94
Outstanding, Weighted Average Remaining Contractual Term	4 years 8 months 23 days
Vested And Expected To Vest, Outstanding, Weighted Average Remaining Contractual Term	4 years 8 months 23 days
Exercisable, Weighted Average Remaining Contractual Term	4 years 8 months 23 days
Outstanding, Intrinsic Value	$ 7.6
Vested And Expected To Vest, Outstanding, Aggregate Intrinsic Value	7.6
Exercisable, Aggregate Intrinsic Value	7.6
Exercised, Total Intrinsic Value	$ 0.1	$ 0.6	$ 5.1

Stock-Based Compensation Plan_4

Stock-Based Compensation Plans - Stock Option award activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Share-based Payment Award [Line Items]
Outstanding	4,311,040	4,198,500
Granted	248,206
Exercised	(128,999)
Forfeited	(6,667)
Expired	0
Vested and Expected to Vest	4,311,040
Exercisable	3,647,330
Outstanding, Weighted Average Exercise Price	$ 47.32	$ 45.36
Granted, Weighted Average Exercise Price	80.04
Exercised, Weighted Average Exercise Price	45.12
Forfeited, Weighted Average Exercise Price	71.32
Expired, Weighted Average Exercise Price	0
Vested and Expected to Vest, Weighted Average Exercise Price	47.32
Exercisable, Weighted Average Exercise Price	$ 43.67
Outstanding, Weighted Average Remaining Contractual Term	5 years 7 months 16 days
Vested and Expected to Vest, Weighted Average Remaining Contractual Term	5 years 7 months 16 days
Exercisable, Weighted Average Remaining Contractual Term	5 years 2 months 25 days
Outstanding, Intrinsic Value	$ 218.6
Vested and Expected to Vest, Aggregate Intrinsic Value	218.6
Exercisable, Intrinsic Value	198.3
Stock Options
Share-based Payment Award [Line Items]
Exercised, Total Intrinsic Value	$ 4.7	$ 17.6	$ 5.1
Expected Term	6 years 6 months	6 years 6 months	6 years 6 months 15 days
Expected Volatility Rate	30.719%	30.61%	29.05%
Risk Free Interest Rate	2.2381%	1.91%	1.92%
Expected Dividend Rate	0.00%	0.00%	0.00%
Fair value per option	$ 28.52	$ 24.80	$ 20.22

Stock-Based Compensation Plan_5

Stock-Based Compensation Plans - Restricted Stock Units (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Stock Settled
Share-based Payment Award [Line Items]
Nonvestsed restricted stock awards	941,868	730,040
Granted	478,325
Vested	(213,824)
Forfeited	(52,673)
Grant date value per share	$ 71.94	$ 63.55
Granted, Weighted Average Exercise Price	80.19
Vested, Weighted Average Exercise Price	60.99
Forfeited, Weighted Average Exercise Price	$ 75.01
Fair value of restricted stock awards vested	$ 17.4	$ 10.5	$ 32
Share-based Compensation Arrangement by Share-based Payment Award, Accelerated Vesting, Number	11,400	8,500	12,500
Non-employee director share-based compensation	$ 0.9	$ 0.7	$ 0.7
Cash Settled
Share-based Payment Award [Line Items]
Restricted Stock Units valued at greater of current stock price or grant price	49,000
Grant date price of restricted stock units valued at greater of current stock price or grant price	$ 51.43
Nonvestsed restricted stock awards	60,252	100,119
Granted	0
Vested	(38,537)
Forfeited	(1,330)
Grant date value per share	$ 53.13	$ 49.47
Granted, Weighted Average Exercise Price	0
Vested, Weighted Average Exercise Price	43.28
Forfeited, Weighted Average Exercise Price	$ 62.90
Total Share-based Liabilities Paid	$ 3.2	$ 4.1	$ 5.9
2016 Long-Term Incentive Plan | Stock Settled
Share-based Payment Award [Line Items]
Granted	13,300	10,200	15,000

Stock-Based Compensation Plan_6

Stock-Based Compensation Plans Performance Restricted Stock Units (Details) - $ / shares	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Stock Settled
Share-based Payment Award [Line Items]
Nonvestsed restricted stock awards	32,307	0
Granted	32,307
Granted, Weighted Average Exercise Price	$ 97.74
Vested	0
Vested, Weighted Average Exercise Price	$ 0
Forfeited, Weighted Average Exercise Price	$ 0
Forfeited	0
Grant date value per share	$ 97.74	$ 0
Minimum
Share-based Payment Award [Line Items]
Total Award Range	0.00%
Maximum
Share-based Payment Award [Line Items]
Total Award Range	200.00%
Performance-Based Restricted Stock Units
Share-based Payment Award [Line Items]
Expected Term	3 years
Expected Volatility Rate	31.80%
Risk Free Interest Rate	1.80%
Expected Dividend Rate	0.00%

Tangible Equity Units (Details)

Tangible Equity Units (Details) - USD ($)	May 31, 2014	Sep. 30, 2017	Sep. 30, 2016
Tangible Equity Units [Line Items]
Tangible Equity Units, Number of Units Issued	2,875,000
Tangible Equity Units, Issuance Costs	$ (8,900,000)
Proceeds From Issuance of Tangible Equity Units Net	$ 278,600,000
Tangible Equity Units Unit Price	$ 100
Tangible Equity Units, Exchanged		2,800,000	100,000
Tangible Equity Units Equity Component
Tangible Equity Units [Line Items]
Tangible Equity Units, Carrying Amount	$ 85.48
Proceeds from Issuance of Tangible Equity Units, Gross	245,700,000
Tangible Equity Units, Issuance Costs	(7,600,000)
Proceeds From Issuance of Tangible Equity Units Net	238,100,000
Tangible Equity Units Debt Component
Tangible Equity Units [Line Items]
Tangible Equity Units, Carrying Amount	14.5219
Proceeds from Issuance of Tangible Equity Units, Gross	41,800,000
Tangible Equity Units, Issuance Costs	(1,300,000)
Proceeds From Issuance of Tangible Equity Units Net	$ 40,500,000
Debt Instrument, Interest Rate, Stated Percentage	5.25%
Tangible Equity Unit, Equity Component, Settlement Rate per Unit	$ 1.3125
Tangible Equity Units
Tangible Equity Units [Line Items]
Proceeds from Issuance of Tangible Equity Units, Gross	$ 287,500,000
Maximum
Tangible Equity Units [Line Items]
Tangible Equity Unit, Equity Component, Settlement Rate per Unit		2.0964
Minimum
Tangible Equity Units [Line Items]
Tangible Equity Unit, Equity Component, Settlement Rate per Unit	1.7114	1.7114
Long Term Debt, Current Maturities | Tangible Equity Units Equity Component
Tangible Equity Units [Line Items]
Proceeds from Issuance of Tangible Equity Units, Gross	$ 0
Long Term Debt, Current Maturities | Tangible Equity Units Debt Component
Tangible Equity Units [Line Items]
Proceeds from Issuance of Tangible Equity Units, Gross	13,300,000
Long Term Debt, Current Maturities | Tangible Equity Units
Tangible Equity Units [Line Items]
Proceeds from Issuance of Tangible Equity Units, Gross	13,300,000
Long-term Debt | Tangible Equity Units Equity Component
Tangible Equity Units [Line Items]
Proceeds from Issuance of Tangible Equity Units, Gross	0
Tangible Equity Units, Issuance Costs	0
Long-term Debt | Tangible Equity Units Debt Component
Tangible Equity Units [Line Items]
Proceeds from Issuance of Tangible Equity Units, Gross	28,500,000
Tangible Equity Units, Issuance Costs	1,300,000
Long-term Debt | Tangible Equity Units
Tangible Equity Units [Line Items]
Proceeds from Issuance of Tangible Equity Units, Gross	28,500,000
Tangible Equity Units, Issuance Costs	1,300,000
Additional Paid-in Capital | Tangible Equity Units Equity Component
Tangible Equity Units [Line Items]
Proceeds From Issuance of Tangible Equity Units Net	238,100,000
Additional Paid-in Capital | Tangible Equity Units Debt Component
Tangible Equity Units [Line Items]
Proceeds From Issuance of Tangible Equity Units Net	0
Additional Paid-in Capital | Tangible Equity Units
Tangible Equity Units [Line Items]
Proceeds From Issuance of Tangible Equity Units Net	$ 238,100,000
Common Stock
Tangible Equity Units [Line Items]
Tangible equity units conversion (shares)		4,700,000	200,000

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Class of Stock [Line Items]
Preferred Stock, Shares Authorized	50,000,000	50,000,000
Par value of preferred stock	$ 0.01	$ 0.01
Preferred stock conversion	$ 0	$ 0	$ 10.9
Purchases of treasury stock	$ (218.7)	$ (317.8)
Upfront payment for share repurchases			28.3
Transaction costs paid in connection with stock repurchase contracts			0.2
Aggregate cash received under share repurchase agreement			$ 29.4
Common Stock, Shares, Issued	66,700,000	66,100,000
Series B Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage	3.75%	3.75%
Par value of preferred stock	$ 0.01
Preferred Stock, Liquidation Preference Per Share	$ 100
Preferred Stock, Shares	0	1,500,000
Conversion of Stock, Shares Converted	1,500,000		900,000
Convertible Preferred Stock, Shares Issued upon Conversion	2.1192
Preferred stock conversion			$ 10.9
Series C Preferred Stock
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage	2.50%	2.50%
Par value of preferred stock	$ 0.01
Preferred Stock, Liquidation Preference Per Share	$ 100
Preferred Stock, Shares	3,200,000	3,200,000
Convertible Preferred Stock, Shares Issued upon Conversion	1.8477
Conversion price of convertible preferred stock	$ 54.12
Redemption Price as a Percentage of Liquidation Value	100.00%
Percentage of conversion price, closing sale price of common stock, minimum	150.00%
Conversion price in effect, days	20 days
Redemption notice, trading day period	30 days
Preferred Stock
Class of Stock [Line Items]
Conversion of Stock, Shares Converted	1,500,000		900,000
Treasury Stock, Shares, Acquired	0
Common Stock
Class of Stock [Line Items]
Preferred Stock Conversion, Shares Issued	3,100,000		2,000,000
Common Stock
Class of Stock [Line Items]
Preferred Stock Conversion, Shares Issued			(2,000,000)
Treasury Stock, Shares, Acquired	2,800,000	4,000,000
Treasury Stock Acquired, Average Cost Per Share	$ 76.21	$ 79.53
Purchases of treasury stock	$ 218.7	$ 317.8

Segments (Details)

Segments (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Net Sales	$ 1,629.9	$ 1,608.1	$ 1,586.1	$ 1,433.1	$ 1,448.5	$ 1,272.1	$ 1,255.4	$ 1,249.8	$ 6,257.2	$ 5,225.8	$ 5,026.8
Entity-Wide Revenue, Major Customer, Percentage									13.00%	13.00%	13.00%
Operating Income (Loss)									$ 587.5	$ 520.3	$ 545.7
Impairment of goodwill and other intangible assets	124.9				26.5	$ 0	$ 0	$ 0	124.9	26.5	0
Interest expense, net									387.3	314.8	306.5
Loss on extinguishment of debt, net									31.1	222.9	86.4
(Income) expense on swaps, net									(95.6)	(91.8)	182.9
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									264.7	74.4	(30.1)
Property, Plant and Equipment, Additions									225	190.4	121.5
Depreciation and amortization									398.4	323.1	302.8
Assets	13,057.5				11,876.8				13,057.5	11,876.8	9,360.6
Major customer sales, value
Segment Reporting Information [Line Items]
Net Sales									$ 784.6	704.1	668.8
Non-US
Segment Reporting Information [Line Items]
Sales to Foreign Countries as a Percentage of Total Net Sales									13.00%
Disclosure on Geographic Areas, Long-Lived Assets in Foreign Countries	284.3				311.1				$ 284.3	311.1
Operating Segments
Segment Reporting Information [Line Items]
Net Sales									6,257.2	5,225.8	5,026.8
Operating Income (Loss)									849.2	634.5	652.2
Depreciation and amortization									390.2	319.4	296.8
Operating Segments | Post Consumer Brands Segment
Segment Reporting Information [Line Items]
Net Sales									1,831.7	1,742.5	1,728.2
Operating Income (Loss)									329.2	354.9	290.4
Property, Plant and Equipment, Additions									51.5	57.8	34.8
Depreciation and amortization									122	112.4	105.5
Assets	3,391.7				3,440.5				3,391.7	3,440.5	3,387
Operating Segments | Weetabix Segment
Segment Reporting Information [Line Items]
Net Sales									423.4	112.4	0
Operating Income (Loss)									87.2	14.5	0
Property, Plant and Equipment, Additions									26.3	13.6	0
Depreciation and amortization									38.1	7.7	0
Assets	1,853.3				2,048.9				1,853.3	2,048.9	0
Operating Segments | Refrigerated Food Segment
Segment Reporting Information [Line Items]
Net Sales									2,337.9	1,870.8	1,917.4
Operating Income (Loss)									247.6	110.6	245.7
Property, Plant and Equipment, Additions									114.6	66	51.6
Depreciation and amortization									163.3	125.4	119.9
Assets	5,132.4				3,176				5,132.4	3,176	3,099.3
Operating Segments | Active Nutrition segment
Segment Reporting Information [Line Items]
Net Sales									827.5	713.2	574.7
Operating Income (Loss)									124.4	96.4	44.7
Property, Plant and Equipment, Additions									5	3.9	4.4
Depreciation and amortization									25.9	25.3	25
Assets	559.3				581.3				559.3	581.3	624.8
Operating Segments | Private Brands segment
Segment Reporting Information [Line Items]
Net Sales									848.9	791.2	811.1
Operating Income (Loss)									60.8	58.1	71.4
Property, Plant and Equipment, Additions									26.6	29.1	23.5
Depreciation and amortization									40.9	48.6	46.4
Assets	1,055.3				1,054.9				1,055.3	1,054.9	1,054.7
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Other Expenses									136.8	87.7	106.5
Property, Plant and Equipment, Additions									1	20	7.2
Depreciation and amortization									8.2	3.7	6
Assets	1,065.5				$ 1,575.2				1,065.5	1,575.2	1,194.8
Intersegment Eliminations
Segment Reporting Information [Line Items]
Net Sales									(12.2)	(4.3)	(4.6)
Cereal and granola | Operating Segments
Segment Reporting Information [Line Items]
Net Sales									2,351.2	1,963.9	1,838.5
Egg and egg products | Operating Segments
Segment Reporting Information [Line Items]
Net Sales									1,542.8	1,419.1	1,417
Cheese and dairy | Operating Segments
Segment Reporting Information [Line Items]
Net Sales									248.6	259.4	320.9
Side Dishes | Operating Segments
Segment Reporting Information [Line Items]
Net Sales									398.2	192.3	179.5
Sausage | Operating Segments
Segment Reporting Information [Line Items]
Net Sales									96	0	0
Pasta | Operating Segments
Segment Reporting Information [Line Items]
Net Sales									258.4	249.4	270.6
Protein-based products and supplements | Operating Segments
Segment Reporting Information [Line Items]
Net Sales									827.5	713.2	574.7
Nut butters and dried fruit and nut | Operating Segments
Segment Reporting Information [Line Items]
Net Sales									487.5	432.5	429.1
Other | Operating Segments
Segment Reporting Information [Line Items]
Net Sales									53	0	0
Product Eliminations
Segment Reporting Information [Line Items]
Net Sales									(6)	$ (4)	$ (3.5)
Assets Held For Sale | Non-US
Segment Reporting Information [Line Items]
Disclosure on Geographic Areas, Long-Lived Assets in Foreign Countries	$ 12.4								$ 12.4

Summary Quarterly Financial I_2

Summary Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Quarterly Financial Information [Abstract]
Net Sales	$ 1,629.9	$ 1,608.1	$ 1,586.1	$ 1,433.1	$ 1,448.5	$ 1,272.1	$ 1,255.4	$ 1,249.8	$ 6,257.2	$ 5,225.8	$ 5,026.8
Gross Profit	478	461.4	475.7	451.7	437.1	393.7	364.1	379.2	1,866.8	1,574.1	1,547.4
Impairment of goodwill and other intangible assets	124.9				26.5	0	0	0	124.9	26.5	0
Net earnings (loss)	(15.6)	96.5	91.5	294.9	8	(59.4)	(2.1)	101.8	467.3	48.3	(3.3)
Net Earnings (Loss) Available to Common Stockholders	$ (17.6)	$ 94.5	$ 88.9	$ 291.5	$ 4.7	$ (62.8)	$ (5.5)	$ 98.4	$ 457.3	$ 34.8	$ (28.4)
Basic earnings (loss) per common share	$ (0.26)	$ 1.41	$ 1.33	$ 4.42	$ 0.07	$ (0.93)	$ (0.08)	$ 1.42	$ 6.87	$ 0.51	$ (0.41)
Diluted (loss) earnings per common share	$ (0.26)	$ 1.29	$ 1.20	$ 3.82	$ 0.07	$ (0.93)	$ (0.08)	$ 1.27	$ 6.16	$ 0.50	$ (0.41)