Commitments and Contingencies (Details) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2011	Jun. 30, 2011	Dec. 31, 2010
The Gulf of Mexico/Macondo well incident
Federal government estimate of oil discharged from the well (in barrels)		4.9
Number of fatalities		11
Number of parties-of-interest in the Marine Board Investigation		16
Maximum per day assessment for negligent discharges under the CWA		$ 50,000
Maximum per day assessment for knowing discharges under the CWA		100,000
Maximum per day assessment for knowing endangerment under the CWA		2,000,000
Maximum per day civil penalty for strict liability under the CWA		1,100
Maximum per day civil penalty for gross negligence under the CWA		4,300
Liability cap under the OPA in addition to the full cost of removal of the discharged oil		75,000,000
Maximum fine per bird killed under the MBTA		15,000
Maximum imprisonment under the MBTA (in months)		6M
Maximum civil penalty per violation under the ESA		25,000
Maximum criminal penalty per violation under the ESA		50,000
DOJ minimum estimate of removal costs and damages to the United States due to discharges of oil into the Gulf of Mexico		75,000,000
Number of days of advance notice to DOJ of any event that may involve substantial transfers of cash or other corporate assets outside the ordinary course of business		30D
Number of key findings related to possible causes of Macondo well incident (number of findings)		8
Number of things that could have contained hydrocarbon pressures		3
Number of centralizers used by BP		6
Number of general root causes of the Macondo well incident identified by the Investigation Report		2
Litigation
Minimum number of environmental class-action complaints related to the Macondo incident (number of complaints)		400
Minimum number of wrongful death and personal injury multiple plaintiff lawsuits related to the Macondo incident (in lawsuits)		40
Number of decedents in personal injury lawsuits		7
Number of allegedly injured persons in personal injury lawsuits		59
Minimum number of lawsuits relating to the Macondo well incident naming the company		6
Number of Louisiana lawsuits not consolidated		1
Number of Texas federal court lawsuits not consolidated		2
Number of Texas state court lawsuits not consolidated		2
Number of Delaware lawsuits not yet consolidated		9
Number of Mexican states included in pollution complaint		3
Number Of Proceedings Treated As Associated Cases		2
Interest of MOEX in Macondo well (in hundreths)		10.00%
Indemnification and insurance
Total amount of general liability insurance program		600,000,000
Pre-tax charge recognized by BP as a result of the Macondo well incident	400,000,000		40,900,000,000
Barracuda-Caratinga arbitration
Upper level of range of KBR cost estimates for Barracuda Creating solutions		148,000,000
Petrobras arbitration claim against KBR		220,000,000
Securities and related litigation
Number of similar class action lawsuits in connecton with the change in accounintg for revenue on long-term construction projects and related disclosures that were later consolidated into one suit		20
Shareholder derivative cases
Number of shareholder derivative lawsuits involving us and KBR were filed in Harris County		2
Environmental
Accrued liabilities for environmental matters		46,000,000	47,000,000
Number of Superfund sites (in sites)		10
Accrued Liabilities for superfund sites		7,000,000
Total Company Guarantee Obligations [Member]
Guarantee arrangements
Guarantee arrangements outstanding		1,500,000,000
Venezuela surety bonds [Member]
Guarantee arrangements
Guarantee arrangements outstanding		$ 240,000,000