Amount classified as liabilities attributable to disposal group held for sale or disposed of.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=51719941&loc=d3e2941-110230

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=51716988&loc=d3e1107-107759

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721533-107759

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721673-107760

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

Assets Held for Sale (Detail) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
Assets Held for Sale (Detail) - USD ($) $ in Millions	Apr. 30, 2016	Mar. 31, 2016	Mar. 31, 2015
Property, Plant, and Equipment [Line Items]
Sales price, subject to closing adjustments		$ 35	$ 22
Held for Sale [Member]
Property, Plant, and Equipment [Line Items]
Assets associated with assets held for sale were not material
Liabilities associated with assets held for sale were not material
Oil and Gas Exploration and Production Reporting Segment [Member] \| Asset Disposed of by Sale [Member] \| Certain U.S. Onshore East Texas Assets [Member] \| Subsequent Event [Member]
Property, Plant, and Equipment [Line Items]
Sales price, subject to closing adjustments	$ 107