PENSION AND POSTRETIREMENT BENEFITS - Schedule of Estimated Future Gross Benefit Payments (Details) $ in Millions	May 31, 2020 USD ($)
Pension Benefits
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
2021	$ 199.4
2022	202.7
2023	204.7
2024	206.2
2025	207.6
Succeeding 5 years	1,038.0
Health Care and Life Insurance Benefits
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
2021	10.1
2022	9.3
2023	8.5
2024	7.8
2025	7.1
Succeeding 5 years	$ 27.3

Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in fourth fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in third fiscal year following latest fiscal year.

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Amount of benefits for defined benefit plan expected to be paid in second fiscal year following latest fiscal year.

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