Equity Option - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified		1 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended
Nov. 30, 2010 Year	Nov. 30, 2010 Capped call (equity options)	Jul. 02, 2011 Capped call (equity options)	May 31, 2011 Capped call (equity options) Series - I	Jul. 02, 2011 Capped call (equity options) Series - I	May 31, 2011 Series - I Month
Over the counter capped call purchased, maturity period	5					3
Number of common shares purchased under call option		8,433,123	8,433,123	2,448,588	2,448,588
Call option, aggregate premium		$ 50.3	$ 50.3	$ 19.6	$ 19.6
Call option, average price		$ 5.97		$ 8.00
Aggregate fair value of call options			$ 66.8		$ 10.7

The maximum number of shares that could be issued to net share settle a contract, if applicable. If a contract does not have a fixed or determinable maximum number of shares that may be required to be issued, disclose the fact that a potentially infinite number of shares could be issued to settle the contract.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 00-19
-Paragraph 50
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 40
-Section 50
-Paragraph 5
-Subparagraph (b)(2),(c)
-URI http://asc.fasb.org/extlink&oid=6445032&loc=d3e90205-114008

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration