A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.4)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

Other Financial Data (Details) - Other Financial Data - Balance Sheet - USD ($) $ in Millions	May 31, 2018	May 31, 2017	May 31, 2016	May 31, 2015
Other Financial Data - Balance Sheet [Abstract]
Allowance for royalty advances	$ 97.0	$ 93.8
Allowance for doubtful accounts	12.4	13.7
Reserve For Return [Member]
Other Financial Data - Balance Sheet [Abstract]
Accounts receivable reserve for returns	$ 30.0	$ 36.3	$ 32.1	$ 27.9