Debt and Financing Arrangements (Details) - USD ($)		Jan. 31, 2021	Apr. 30, 2020	May 14, 2018
Long-term debt
Debt instrument face amount		$ 4,700,000,000.0	$ 5,400,000,000.0
Total long-term debt	[1]	4,670,700,000	5,373,300,000
Current portion of long-term debt	[1]	755,400,000	0
Long-term debt, less current portion	[1]	$ 3,915,300,000	$ 5,373,300,000
3.50% Senior Notes due October 15, 2021
Long-term debt
Interest rate on notes		3.50%	3.50%
Debt instrument face amount		$ 750,000,000.0	$ 750,000,000.0
Senior Notes	[1]	$ 755,400,000	$ 761,100,000
3.00% Senior Notes due March 15, 2022
Long-term debt
Interest rate on notes		3.00%	3.00%
Debt instrument face amount		$ 400,000,000.0	$ 400,000,000.0
Senior Notes	[1]	$ 399,200,000	$ 398,700,000
3.50% Senior Notes due March 15, 2025
Long-term debt
Interest rate on notes		3.50%	3.50%
Debt instrument face amount		$ 1,000,000,000.0	$ 1,000,000,000.0
Senior Notes	[1]	$ 996,600,000	$ 996,000,000.0
3.38% Senior Notes due December 15, 2027
Long-term debt
Interest rate on notes		3.38%	3.38%
Debt instrument face amount		$ 500,000,000.0	$ 500,000,000.0
Senior Notes	[1]	$ 497,000,000.0	$ 496,700,000
2.38 % Senior Notes due March 15, 2030
Long-term debt
Interest rate on notes		2.38%	2.38%
Debt instrument face amount		$ 500,000,000.0	$ 500,000,000.0
Senior Notes	[1]	$ 495,600,000	$ 495,200,000
4.25% Senior Notes due March 15, 2035
Long-term debt
Interest rate on notes		4.25%	4.25%
Debt instrument face amount		$ 650,000,000.0	$ 650,000,000.0
Senior Notes	[1]	$ 644,200,000	$ 643,900,000
4.38% Senior Notes due March 15, 2045
Long-term debt
Interest rate on notes		4.38%	4.38%
Debt instrument face amount		$ 600,000,000.0	$ 600,000,000.0
Senior Notes	[1]	$ 586,900,000	$ 586,500,000
3.55% Senior Notes due March 15, 2050
Long-term debt
Interest rate on notes		3.55%	3.55%
Debt instrument face amount		$ 300,000,000.0	$ 300,000,000.0
Senior Notes	[1]	295,800,000	295,700,000
Term Loan Credit Agreement due May 14, 2021
Long-term debt
Debt instrument face amount		0	700,000,000.0	$ 1,500,000,000
Term loan credit agreement carrying value	[1]	0	699,500,000
Current portion of long term debt
Long-term debt
Debt instrument face amount		750,000,000.0	0
Total long term debt, less current portion
Long-term debt
Debt instrument face amount		$ 3,950,000,000.0	$ 5,400,000,000.0

[1] Represents the carrying amount included in the Condensed Consolidated Balance Sheets, which includes the impact of capitalized debt issuance costs, offering discounts, and terminated interest rate contracts.