Acquisition (Details Textual) - USD ($)		12 Months Ended
	May 14, 2018	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2018
Acquisition [Line Items]
Cash payments for acquisitions		$ 0	$ 1,903,000,000.0	$ 0
Debt instrument face amount		5,400,000,000.0	5,500,000,000.0
Goodwill		6,304,500,000	6,310,900,000	5,942,200,000
Ainsworth [Member]
Acquisition [Line Items]
Cash payments for acquisitions	$ 1,900,000,000
Commercial paper	400,000,000.0
Total intangible assets	1,300,000,000
Goodwill deductible for tax purposes	446,000,000.0	385,800,000
Term Loan Credit Agreement due May 14, 2021
Acquisition [Line Items]
Debt instrument face amount		700,000,000.0	800,000,000.0
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]
Goodwill		$ 2,442,300,000	$ 2,442,300,000	$ 1,824,500,000
U.S. Retail Pet Foods [Member] | Ainsworth [Member]
Acquisition [Line Items]
Goodwill	$ 617,800,000