Acquisition (Details Textual) - USD ($)		3 Months Ended		6 Months Ended
	May 14, 2018	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2018	Oct. 31, 2017	Apr. 30, 2018
Acquisition [Line Items]
Goodwill		$ 6,474,700,000		$ 6,474,700,000		$ 5,942,200,000
Debt instrument face amount		5,900,000,000		5,900,000,000		4,700,000,000
Net sales		2,021,500,000	$ 1,923,600,000	3,924,000,000	$ 3,672,500,000
Operating Income (Loss)		330,500,000	332,100,000	557,400,000	567,300,000
Ainsworth [Member]
Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 1,900,000,000
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Inventory				10,900,000
Goodwill	680,900,000
Commercial Paper	400,000,000
Net sales		184,200,000		347,000,000
Operating Income (Loss)		4,500,000		400,000
Term Loan Credit Agreement due May 14, 2021
Acquisition [Line Items]
Debt instrument face amount	1,500,000,000.0	1,200,000,000		1,200,000,000		$ 0
Term Loan Credit Agreement due May 14, 2021 | Ainsworth [Member]
Acquisition [Line Items]
Debt instrument face amount	$ 1,500,000,000
U.S. Retail Pet Foods [Member]
Acquisition [Line Items]
Net sales		728,100,000	$ 551,100,000	1,399,300,000	$ 1,071,800,000
U.S. Retail Pet Foods [Member] | Ainsworth [Member]
Acquisition [Line Items]
Goodwill		$ 680,900,000		$ 680,900,000