Additional Financial Information - Components of Other, Net Included in Statements of Operations (Parenthetical) (Detail) (CME Group, Inc [Member], USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
Apr. 30, 2013	Jun. 30, 2013
CME Group, Inc [Member]
Components of Other Income (Expense) [Line Items]
Sale of investment in joint venture	10.00%
Gain on sale of investment		$ 12

This item represents the gain (loss) realized during the period from the sale of investments accounted for under the cost method of accounting and any losses recognized thereon for impairments of other than a temporary nature.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 9

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.7(c),9(a))

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph c, d

-Article 5

Name:	us-gaap_CostMethodInvestmentsRealizedGainLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration