Gain on Disposal of Assets, net - Additional Information (Detail) $ in Millions	3 Months Ended
Sep. 30, 2013 USD ($)
Property Plant And Equipment Useful Life And Values [Abstract]
Sale of the Noble Lewis Dugger	$ 61
Gain on sale of assets	$ 36

Amount of gain (loss) on sale or disposal of proven and unproven oil and gas properties.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

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