The amount of cash paid for the settlement of litigation or for other legal issues during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

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

Contingencies - Deepwater Horizon Events (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2011
Macondo Exploration Well [Member]
Loss Contingencies [Line Items]
Nonoperated interest			25.00%
Deepwater Horizon [Member] \| Judicial Ruling [Member] \| Clean Water Act [Member]
Loss Contingencies [Line Items]
CWA penalty		$ 159.5
Amount of penalty paid	$ 159.5