Financing Arrangements - Additional Information (Details) € in Millions	3 Months Ended	6 Months Ended
	Aug. 31, 2019 USD ($)	Nov. 30, 2019 USD ($)	Aug. 31, 2019 EUR (€)	May 31, 2019 USD ($)
Line Of Credit Facility [Line Items]
Financial Covenant Terms Ratio		350.00%
Financial Covenant Compliance Ratio		260.00%
Commercial paper outstanding		$ 150,000,000
Letters Of Credit Outstanding		53,000,000
Long Term Debt, Including Current Maturities and Exclusive of finance Leases Carrying Value		18,600,000,000		$ 17,500,000,000
Long Term Debt, Including Current Maturities and Exclusive of finance Leases Fair Value		$ 19,600,000,000		$ 17,800,000,000
Long-term debt weighted-average interest rate		3.50%
Maximum [Member]
Line Of Credit Facility [Line Items]
Commercial paper outstanding		$ 150,000,000
Five-Year Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Term		5 years
Line Of Credit Facility Maximum Borrowing Capacity		$ 2,000,000,000.0
Line of Credit Facility, Expiration Date		2024-03
Letter of Credit Maximum Sublimit Amount		$ 250,000,000
364-Day Credit Agreement [Member]
Line Of Credit Facility [Line Items]
Line of Credit Facility, Term		364 days
Line Of Credit Facility Maximum Borrowing Capacity		$ 1,500,000,000
Line of Credit Facility, Expiration Date		2020-03
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Line of credit facility outstanding for future borrowings		$ 3,297,000,000
Senior Unsecured Debt [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount	$ 2,100,000,000
3.10% Fixed-rate Notes Due in August 2029 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount	$ 1,000,000,000.0
Fixed interest rate	3.10%		3.10%
Debt instrument, maturity date	2029-08
0.45% Fixed-rate Notes Due in August 2025 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount | €			€ 500
Fixed interest rate	0.45%		0.45%
Debt instrument, maturity date	2025-08
1.30% Fixed-rate Notes Due in August 2031 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount | €			€ 500
Fixed interest rate	1.30%		1.30%
Debt instrument, maturity date	2031-08
2.30% Fixed-rate Notes Due in February1 2020 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount	$ 400,000,000
Fixed interest rate	2.30%		2.30%
Debt instrument, maturity date	Feb. 01, 2020
0.50% Notes Due April 09, 2020 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount | €			€ 500
Fixed interest rate	0.50%		0.50%
Debt instrument, maturity date	Apr. 09, 2020