Other Financial Instruments and Fair Value Measurements (Details 1) - Fair value measurements recurring [Member] - USD ($) $ in Millions		Jul. 31, 2022	Apr. 30, 2022
Financial assets (liabilities) measured at fair value on a recurring basis
Total long-term debt	[1]	$ (3,986.3)	$ (3,977.7)
Total financial instruments measured at fair value		(3,955.7)	(3,926.3)
Equity mutual funds
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	5.2	5.7
Municipal obligations
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	18.5	19.9
Money market funds
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	2.1	1.0
Commodity contracts - net
Financial assets (liabilities) measured at fair value on a recurring basis
Derivative financial instruments	[3]	4.1	23.1
Foreign currency exchange contracts - net
Financial assets (liabilities) measured at fair value on a recurring basis
Derivative financial instruments	[3]	0.7	1.7
Fair Value, Inputs, Level 1 [Member]
Financial assets (liabilities) measured at fair value on a recurring basis
Total long-term debt	[1]	(3,986.3)	(3,977.7)
Total financial instruments measured at fair value		(3,974.7)	(3,947.4)
Fair Value, Inputs, Level 1 [Member] | Equity mutual funds
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	5.2	5.7
Fair Value, Inputs, Level 1 [Member] | Municipal obligations
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	0.0	0.0
Fair Value, Inputs, Level 1 [Member] | Money market funds
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	2.1	1.0
Fair Value, Inputs, Level 1 [Member] | Commodity contracts - net
Financial assets (liabilities) measured at fair value on a recurring basis
Derivative financial instruments	[3]	4.1	23.4
Fair Value, Inputs, Level 1 [Member] | Foreign currency exchange contracts - net
Financial assets (liabilities) measured at fair value on a recurring basis
Derivative financial instruments	[3]	0.2	0.2
Fair Value, Inputs, Level 2 [Member]
Financial assets (liabilities) measured at fair value on a recurring basis
Total long-term debt	[1]	0.0	0.0
Total financial instruments measured at fair value		19.0	21.1
Fair Value, Inputs, Level 2 [Member] | Equity mutual funds
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	0.0	0.0
Fair Value, Inputs, Level 2 [Member] | Municipal obligations
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	18.5	19.9
Fair Value, Inputs, Level 2 [Member] | Money market funds
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	0.0	0.0
Fair Value, Inputs, Level 2 [Member] | Commodity contracts - net
Financial assets (liabilities) measured at fair value on a recurring basis
Derivative financial instruments	[3]	0.0	(0.3)
Fair Value, Inputs, Level 2 [Member] | Foreign currency exchange contracts - net
Financial assets (liabilities) measured at fair value on a recurring basis
Derivative financial instruments	[3]	0.5	1.5
Fair Value, Inputs, Level 3 [Member]
Financial assets (liabilities) measured at fair value on a recurring basis
Total long-term debt	[1]	0.0	0.0
Total financial instruments measured at fair value		0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Equity mutual funds
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Municipal obligations
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Money market funds
Financial assets (liabilities) measured at fair value on a recurring basis
Marketable securities and other investments	[2]	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Commodity contracts - net
Financial assets (liabilities) measured at fair value on a recurring basis
Derivative financial instruments	[3]	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Foreign currency exchange contracts - net
Financial assets (liabilities) measured at fair value on a recurring basis
Derivative financial instruments	[3]	$ 0.0	$ 0.0

[1] Long-term debt is composed of public Senior Notes, which are traded in an active secondary market and valued using quoted prices. For additional information, see Note 7: Debt and Financing Arrangements.

[2] Marketable securities and other investments consists of funds maintained for the payment of benefits associated with nonqualified retirement plans. The funds include equity securities listed in active markets, municipal obligations valued by a third party using valuation techniques that utilize inputs that are derived principally from or corroborated by observable market data, and money market funds with maturities of three months or less. Based on the short-term nature of these money market funds, carrying value approximates fair value. As of July 31, 2022, our municipal obligations are scheduled to mature as follows: $0.2 in 2023, $1.7 in 2024, $1.8 in 2025, $0.8 in 2026, $4.4 in 2027, and the remaining $9.6 in 2028 and beyond.

[3] Level 1 commodity and foreign currency exchange derivatives are valued using quoted market prices for identical instruments in active markets. Level 2 commodity and foreign currency exchange derivatives are valued using quoted prices for similar assets or liabilities in active markets. For additional information, see Note 9: Derivative Financial Instruments.