Commitments and Contingencies (Details)	1 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2014 USD ($) number_of_paymentinstallments	Sep. 30, 2015 USD ($) Class_Actions	Sep. 30, 2015 USD ($) Class_Actions	Sep. 30, 2014 USD ($) number_of_paymentinstallments	Dec. 31, 2014 USD ($)	Apr. 22, 2010 USD ($) Fatalities
Loss Contingencies [Line Items]
Loss contingency related to Macondo well incident (non-current)		$ 72,000,000	$ 72,000,000		$ 439,000,000
Loss Contingency, Estimated Recovery from Third Party		118,000,000	118,000,000
Loss contingency related to Macondo well (current)		400,000,000	400,000,000		$ 367,000,000
Loss Contingency, Information about Litigation Matters [Abstract]
Loss Contingency, Settlement Agreement, Terms	$ 1,100,000,000	333,000,000	(333,000,000)	$ 0
Number of Payment Installments | number_of_paymentinstallments	3			3
Installment Payment for Legal Fees | number_of_paymentinstallments	1			1
BP Fault Apportionment in Macondo Ruling	67.00%			67.00%
Transocean Fault Apportionment In Macondo Ruling	30.00%			30.00%
Halliburton Fault Apportionment In Macondo Ruling	3.00%			3.00%
Number Of Years	2 years
Indemnification and insurance [Abstract]
Insurance coverage not reimbursed		200,000,000	200,000,000
Macondo well incident
Loss Contingencies [Line Items]
Loss contingency related to Macondo well (total)		472,000,000	472,000,000
Number of fatalities | Fatalities						11
Maximum per day fine for violating federal regulations related to INCs		35,000
Indemnification and insurance [Abstract]
Total amount of general liability insurance program						$ 600,000,000
Legal Fees			1,500,000,000
Legal fees and related expenses covered by insurance		$ 403,000,000	$ 403,000,000
Securities and related litigation
Loss Contingency, Information about Litigation Matters [Abstract]
Number of similar class action lawsuits that were later consolidated into one suit | Class_Actions		20	20