Business Combinations (Details) $ / shares in Units, £ in Millions, $ in Millions					3 Months Ended			9 Months Ended
	Jan. 12, 2018 USD ($) $ / shares shares	Jul. 03, 2017 USD ($)	Jul. 03, 2017 GBP (£)	Oct. 03, 2016 USD ($)	Jun. 30, 2018 USD ($) shares	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Jun. 30, 2018 USD ($) shares	Jun. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)
Business Acquisition
Payments to Acquire Businesses, Net of Cash Acquired								$ 1,454.0	$ 90.2
Goodwill					$ 4,927.8			4,927.8		$ 4,032.0
Goodwill, Purchase Accounting Adjustments								11.5
Transaction-related expenses					$ 2.5	$ 3.3		$ 26.5	6.8
Bob Evans Farms
Business Acquisition
Business Acquisition, Share Price | $ / shares	$ 77.00
Payments to Acquire Businesses, Net of Cash Acquired	$ 1,381.2
Shares not yet paid | shares	4,350,000				3,300,000			3,300,000
Payments to be made subsequent to the closing of the acquisition	$ 342.4
Basis spread on amounts owed to appraisal rights holders					5.00%
Business Combination, Pro Forma Information, Net Sales of Acquiree since Acquisition Date, Actual					$ 112.0			$ 219.6
Business Combination, Pro Forma Information, Operating Profit of Acquiree since Acquisition Date, Actual					9.9			9.0
Cash and cash equivalents	15.6
Receivables	58.3
Inventories	27.1
Prepaid expenses and other current assets	34.3
Property	184.6
Goodwill	897.4
Other intangible assets	782.0
Other assets	0.4
Accounts payable	(18.2)
Other current liabilities	(58.8)
Deferred tax liability - long-term	(194.1)
Other liabilities	(5.0)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	1,723.6
Bob Evans Farms | Other Liabilities
Business Acquisition
Payments to be made subsequent to the closing of the acquisition					262.1			262.1
Bob Evans Farms | Trademarks
Business Acquisition
Indefinite-Lived Intangible Assets Acquired	400.0
Bob Evans Farms | Customer Relationships
Business Acquisition
Definite-lived Intangible Assets Acquired	$ 376.0
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	18 years
Bob Evans Farms | Trademarks
Business Acquisition
Definite-lived Intangible Assets Acquired	$ 6.0
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Weetabix Group
Business Acquisition
Business Combination, Consideration Transferred | £			£ 1,400.0
Cash Acquired from Acquisition | £			48.0
Cash and cash equivalents					62.2			62.2		62.2
Receivables					37.8			37.8		39.7
Inventories					63.2			63.2		63.4
Prepaid expenses and other current assets					1.2			1.2		1.2
Property					280.9			280.9		283.9
Goodwill					980.8			980.8		969.3
Other intangible assets					601.0			601.0		608.4
Other assets					112.0			112.0		112.0
Accounts payable					(66.3)			(66.3)		(66.3)
Other current liabilities					(28.5)			(28.5)		(28.4)
Deferred tax liability - long-term					(136.5)			(136.5)		(137.6)
Other liabilities					(10.9)			(10.9)		(10.9)
Noncontrolling interest					(9.7)			(9.7)		(9.7)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net					$ 1,887.2			1,887.2		$ 1,887.2
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory								(0.2)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property								(3.0)
Goodwill, Purchase Accounting Adjustments								11.5
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Other intangible assets								(7.4)
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred								0.0
Weetabix Group | Cash and Cash Equivalents
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets								0.0
Weetabix Group | Accounts Receivable
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets								(1.9)
Weetabix Group | Prepaid Expenses and Other Current Assets
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets								0.0
Weetabix Group | Other Assets
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Assets								0.0
Weetabix Group | Accounts Payable
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								0.0
Weetabix Group | Other Current Liabilities
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								(0.1)
Weetabix Group | Deferred tax liability - long term
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								1.1
Weetabix Group | Other Liabilities
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								0.0
Weetabix Group | Noncontrolling Interest
Business Acquisition
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Financial Liabilities								$ 0.0
Weetabix Group | United Kingdom, Pounds
Business Acquisition
Payments to Acquire Businesses, Net of Cash Acquired | £			£ 1,454.1
Weetabix Group | United States of America, Dollars
Business Acquisition
Payments to Acquire Businesses, Net of Cash Acquired		$ 1,887.2
Cash Acquired from Acquisition		62.2
Weetabix Group | Trademarks
Business Acquisition
Indefinite-Lived Intangible Assets Acquired		385.1
Weetabix Group | Customer Relationships
Business Acquisition
Definite-lived Intangible Assets Acquired		$ 172.8
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		20 years	20 years
Weetabix Group | Customer Relationships | North America
Business Acquisition
Definite-lived Intangible Assets Acquired		$ 13.6
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		21 years	21 years
Weetabix Group | Trademarks
Business Acquisition
Definite-lived Intangible Assets Acquired		$ 29.5
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		16 years	16 years
National Pasteurized Eggs
Business Acquisition
Payments to Acquire Businesses, Net of Cash Acquired				$ 97.0
Business Combination, Consideration Transferred				93.5
Business Combinations, Purchase Price Adjustment, Net Working Capital Settlement							$ 1.2
National Pasteurized Eggs | Customer Relationships
Business Acquisition
Definite-lived Intangible Assets Acquired				$ 43.9
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				16 years
National Pasteurized Eggs | Trademarks
Business Acquisition
Definite-lived Intangible Assets Acquired				$ 7.5
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				20 years
Selling, General and Administrative Expenses | Weetabix Group
Business Acquisition
Net foreign currency gains						$ 33.5			$ 33.5