Contingencies and Commitments (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Feb. 28, 2017	Mar. 31, 2017	Dec. 31, 2016
Contingencies and Commitments (Textual) [Abstract]
Total environmental accrual included in balance sheet		$ 260	$ 247
Expected years to incur the majority of expenditures		30 years
Letters of credit that secure performance obligations		$ 266
Burlington Resources, Inc [Member] | ECUADOR | Oil and Gas Properties [Member] | Confiscated Crude Oil Production [Member]
Loss Contingencies [Line Items]
Loss Contingency, Name of Plaintiff		Burlington Resources, Inc
Loss Contingency, Name of Defendant		The Republic of Ecuador
Litigation Settlement Amount	$ 380
Litigation Settlement Amount, Seperate Seetlement to Defendent, Environemental and Infrastructure Impacts	$ 42