Commitments and Contingencies (Details) (USD $)	1 Months Ended	3 Months Ended				3 Months Ended	12 Months Ended		1 Months Ended
	Feb. 28, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Apr. 22, 2010 Fatalities	Mar. 31, 2014 Macondo well incident	Dec. 31, 2013 Macondo well incident Complaints Decendents Personal_Injury_Lawsuits Allegedly_Injured_Persons Phases	Dec. 15, 2010 Macondo well incident	Nov. 30, 2012 Macondo well incident BP Exploration Criminal_Charge	Jan. 31, 2013 Macondo well incident Transocean	Dec. 31, 2013 Securities and related litigation Class_Actions
Loss Contingencies [Line Items]
Site Contigency Penalty	$ 2,000,000
Number of fatalities					11
Loss Contingency, Accrual Carrying Value, Current			278,000,000	0			278,000,000
Loss Contingency, Accrual, Noncurrent			1,022,000,000	300,000,000			1,000,000,000
Maximum per barrel civil penalty for strict liability under the CWA						1,100
Maximum per barrel 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 civil penalty per violation under the ESA						25,000
Anadarko interest in Macondo well								25.00%
DOJ minimum estimate of removal costs and damages to the United Sates due to discharges of oil into the Gulf of Mexico						75,000,000
Criminal Fines, DOJ Macondo Settlement		200,000
Number of Days to Pay Criminal Fine		5 days
Number of criminal charges									0
Number of criminal charges from negligent misinterpretation of negative- pressure test									0
Amount agreed to pay related to legal matter									4,000,000,000	1,000,000,000
Criminal fines									1,300,000,000	400,000,000
Probation term		3 years							5 years	5 years
Number of monitors									2
Monitor term									4 years
Number of misdemeanor violations										1
Maximum per day fine for violating federal regulations related to INCs						35,000
Number of days to appeal INCs issued by the BSEE (in days)						60 days
Litigation [Abstract]
Minimum number of environmental class-action complaints							1,800
Minimum number of wrongful death and personal injury multiple plaintiff lawsuits							8
Number of decedents in personal injury lawsuits							4
Number of allegedly injured persons in personal injury lawsuits							10
Minimum number of lawsuits naming the company							6
Number of phases involved in limitation action trial							2
Number of similar class action lawsuits that were later consolidated into one suit											20
Loss Contingency Accrual							1,300,000,000
Accrual for Environmental Loss Contingencies			66,000,000	72,000,000
Indemnification and insurance [Abstract]
Total amount of general liability insurance program							600,000,000
Legal fees							264,000,000
Legal fees and related expenses covered by insurance							235,000,000
Pre-tax charge recognized by BP as a result of the Macondo well incident						$ 40,000,000,000