General (Details) - USD ($) $ in Millions	3 Months Ended
Aug. 31, 2015	Aug. 31, 2014	May. 31, 2015
Long Term Debt [Abstract]
Long Term Debt Exclusive of Capital Leases Carrying Value	$ 239		$ 239
Long Term Debt Exclusive Of Capital Leases Fair Value	320		$ 345
Stock Based Compensation Details [Abstract]
Stock-based compensation	$ 16	$ 16

Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

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-Section S99

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-Subparagraph (SX 210.5-02.22)

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Section S99

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-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-Name Regulation S-X (SX)

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-Name Regulation S-X (SX)

-Number 210

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Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant