Long-term Debt and Other Financing Arrangements - Additional Information (Details) € in Millions	1 Months Ended		12 Months Ended
	Jan. 31, 2019 USD ($)	Oct. 31, 2018 USD ($)	May 31, 2019 USD ($)	Jan. 31, 2019 EUR (€)	May 31, 2018 USD ($)
Line Of Credit Facility [Line Items]
Long-term debt weighted-average interest rate			3.50%
Long term debt, including current maturities and exclusive of capital leases fair value			$ 17,800,000,000		$ 16,600,000,000
Letter of Credit Maximum Sublimit Amount			$ 250,000,000
Financial Covenant Terms Ratio			350.00%
Financial Covenant Compliance Ratio			225.00%
Letters Of Credit Outstanding			$ 53,000,000
Commercial paper outstanding			0
Letter of Credit Outstanding Sublimit Unused Amount			$ 197,000,000
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
Line of Credit Facility, Expiration Date			Mar. 22, 2024
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			Mar. 20, 2020
Senior Unsecured Debt [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount	$ 1,200,000,000	$ 1,250,000,000
0.7% Fixed-rate Notes Due in May 2022 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount | €				€ 640
Fixed interest rate	0.70%			0.70%
Debt instrument, maturity date	May 13, 2022
3.4% Fixed-rate Notes Due in January 2022 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount	$ 500,000,000
Fixed interest rate	3.40%			3.40%
Debt instrument, maturity date	Jan. 14, 2022
Floating Rate Notes Due April 11, 2019 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount | €				€ 500
Debt instrument, maturity date	Apr. 11, 2019
4.20% Fixed-rate Notes Due in October 2028 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount		$ 400,000,000
Fixed interest rate		4.20%
Debt instrument, maturity date		Oct. 17, 2028
4.95% Fixed-rate Notes Due in October 2048 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount		$ 850,000,000
Fixed interest rate		4.95%
Debt instrument, maturity date		Oct. 17, 2048
8.000% Notes Due January 15, 2019 [Member]
Line Of Credit Facility [Line Items]
Debt instrument, face amount		$ 750,000,000
Fixed interest rate		8.00%
Debt instrument, maturity date		Jan. 15, 2019