Income Taxes - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions			1 Months Ended	3 Months Ended			7 Months Ended	9 Months Ended		12 Months Ended
		May 31, 2018	Feb. 28, 2018	Feb. 28, 2019	Nov. 30, 2018	Feb. 28, 2018	Dec. 31, 2017	Feb. 28, 2019	Feb. 28, 2018	May 31, 2018	May 31, 2017
Income Taxes [Line Items]
Effective tax rate	[1]			20.60%		(137.30%)		21.80%	(15.00%)
Income tax benefit related to lower statutory Income tax rate on earnings				$ 60		$ 120		$ 230	$ 165
Income tax benefit from accelerated deductions to be claimed on 2018 tax return								60
Provisional benefit related to remeasurement of net U.S. deferred tax liability		$ (1,150)						(1,150)
Expense from the impact on deferred taxes attributable to a lower enacted tax rate				50
Provisional benefit related to foreign tax credits								36
Effective income tax rate reconciliation, change in deferred tax assets valuation allowance, amount								90
Recognition of benefit from TCJA										$ 225
Tax Cuts And Jobs Act Of 2017,Recognition of Benefit per diluted share										$ 0.94
Provisional benefit related to remeasurement of net U.S. deferred tax liability, income tax expense amount recognized				$ 4	$ 4
Effective income tax rate reconciliation, at federal statutory income tax rate, percent				21.00%			35.00%			29.20%	35.00%
U.S. Pension Plans [Member]
Income Taxes [Line Items]
Income tax benefit related to lower statutory Income tax rate on earnings			$ 204
Defined benefit plan contributions by employer			$ 1,500					$ 1,000	$ 2,500

[1] 2018 includes a blended U.S. statutory federal income tax rate of 29.2% while 2019 includes the fully phased-in rate of 21%.