Accounting Policies - Narrative (Details) shares in Millions, $ in Millions		12 Months Ended
	Apr. 28, 2023 USD ($) shares	Apr. 30, 2023 USD ($) Facility Contract	Apr. 30, 2022 USD ($)	Apr. 30, 2021 USD ($)	Apr. 30, 2020 USD ($)
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		$ 655.8	$ 169.9	$ 334.3	$ 391.1
Advertising expense		160.3	176.5	224.4
Reserve for credit loss		2.3	2.3
Unrealized pre-tax gains included in accumulated other comprehensive income (loss) on available-for-sale securities		1.8	2.4
Accumulated other comprehensive income (loss)		$ (239.2)	(237.4)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for share-based payments		3 years
Compensation cost related to nonvested share-based awards not yet recognized		$ 36.4
Weighted-average period of recognition		1 year 10 months 24 days
Excess tax benefit from share-based compensation		$ 1.4	1.1
Excess tax deficiency from share-based compensation				0.1
Accounting Policies (Additional Textual) [Abstract]
Charges for defined contribution plans		41.0	40.9	41.2
Property, Plant and Equipment [Line Items]
Operating Lease, Expense		113.3	111.0	108.7
Schedule of Investments [Line Items]
Investment in equity securities		$ 487.8	0.0
Concentration Risk [Line Items]
Facilities covered by union contracts | Facility		7
Number of union contracts expiring in 2024 | Contract		1
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Condensed Financial Statements, Captions [Line Items]
Accumulated other comprehensive income (loss)		$ (34.3)	(21.1)	(9.0)	$ (50.5)
Selling, Distribution And Administrative Expense
Condensed Financial Statements, Captions [Line Items]
Distribution costs		304.5	294.1	281.8
Research and development costs		$ 47.3	48.8	$ 57.7
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for share-based payments		1 year
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period for share-based payments		3 years
Machinery and equipment [Member] | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of assets		3 years
Machinery and equipment [Member] | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of assets		20 years
Capitalized software costs [Member] | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of assets		1 year
Capitalized software costs [Member] | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of assets		7 years
Buildings, fixtures, and improvements [Member] | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life of assets		5 years
Buildings, fixtures, and improvements [Member] | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life of assets		40 years
Post Holdings Inc.
Schedule of Investments [Line Items]
Investment in equity securities, current, ownership percentage		8.00%
Unrealized Gain (Loss) on Investments		$ (3.8)
Post Holdings Inc. | Pet Food Brands
Schedule of Investments [Line Items]
Proceeds from Divestiture of Business, Equity | shares	5.4
Investment in equity securities	$ 491.6	$ 487.8
Mountain Country Foods [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest acquired		20.00%
Numi, Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of equity interest acquired		42.00%
Unionized Employees [Member] | Number of Employees, Total [Member]
Concentration Risk [Line Items]
Percentage of concentration risk		22.00%
Unionized Employees Subject to Union Contracts Expiring within One Year | Number of Employees, Total [Member]
Concentration Risk [Line Items]
Percentage of concentration risk		1.00%
Cash Equivalents [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents		$ 614.0	116.3
Work In Process Inventory
Condensed Financial Statements, Captions [Line Items]
Work-in-process inventory		82.5	65.8
Other Noncurrent Assets
Condensed Financial Statements, Captions [Line Items]
Marketable securities and other investments		24.0	26.6
Accounts Payable [Member]
Condensed Financial Statements, Captions [Line Items]
Supplier Financing, Outstanding Payment Obligations		$ 414.2	$ 314.3