Retirement Plans - Schedule of Tax Qualified Pension Plans Contributions (Details) - U.S. Pension Plans [Member] - USD ($) $ in Millions	6 Months Ended
	Nov. 30, 2018	Nov. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan contributions by employer	$ 500	$ 750
Defined Contribution Plan, Tax Status [Extensible List]	us-gaap:QualifiedPlanMember	us-gaap:QualifiedPlanMember
Required Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan contributions by employer		$ 268
Voluntary Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan contributions by employer	$ 500	$ 482