Debt and Financing Arrangements (Details) - USD ($)		Oct. 31, 2018	May 14, 2018	Apr. 30, 2018
Long-term debt
Debt instrument face amount		$ 5,900,000,000		$ 4,700,000,000
Long-term debt	[1]	$ 5,885,100,000		$ 4,688,000,000
2.20% Senior Notes due December 6, 2019
Long-term debt
Interest rate on notes		2.20%		2.20%
Debt instrument face amount		$ 300,000,000		$ 300,000,000
Notes Payable, Noncurrent	[1]	$ 299,100,000		$ 298,600,000
2.50% Senior Notes due March 15, 2020
Long-term debt
Interest rate on notes		2.50%		2.50%
Debt instrument face amount		$ 500,000,000		$ 500,000,000
Notes Payable, Noncurrent	[1]	$ 498,400,000		$ 497,800,000
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		$ 750,000,000
Notes Payable, Noncurrent	[1]	$ 772,000,000		$ 775,600,000
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		$ 400,000,000
Notes Payable, Noncurrent	[1]	$ 397,700,000		$ 397,300,000
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		$ 1,000,000,000
Notes Payable, Noncurrent	[1]	$ 994,800,000		$ 994,400,000
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		$ 500,000,000
Notes Payable, Noncurrent	[1]	$ 496,000,000		$ 495,800,000
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		$ 650,000,000
Notes Payable, Noncurrent	[1]	$ 643,300,000		$ 643,100,000
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		$ 600,000,000
Notes Payable, Noncurrent	[1]	585,700,000		585,400,000
Term Loan Credit Agreement due May 14, 2021
Long-term debt
Debt instrument face amount		1,200,000,000	$ 1,500,000,000.0	0
Term loan credit agreement carrying value	[1]	$ 1,198,100,000		$ 0

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