Fair Value Measurement (Unaudited) Unobservable Inputs (Details) (USD $) In Millions, unless otherwise specified							6 Months Ended					6 Months Ended		6 Months Ended		6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]		Dec. 31, 2013 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]		Jun. 30, 2014 Plains Offshore Warrants [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]		Jun. 30, 2014 Crude Oil Options [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]		Jun. 30, 2014 Crude Oil Options [Member] Minimum [Member]	Jun. 30, 2014 Crude Oil Options [Member] Minimum [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]	Jun. 30, 2014 Crude Oil Options [Member] Maximum [Member]	Jun. 30, 2014 Crude Oil Options [Member] Maximum [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]	Jun. 30, 2014 Crude Oil Options [Member] Weighted Average [Member]	Jun. 30, 2014 Crude Oil Options [Member] Weighted Average [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]	Jun. 30, 2014 Sales [Member] Crude Oil Options [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]	Jun. 30, 2014 Interest Expense [Member] Crude Oil Options [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Assumptions, Implied Volatilities												14.00%		55.00%		21.00%
Deferred Premium Price											5.15		7.22		6.49
Derivative Liability	$ (317)	$ (320)	$ (298)	[1],[2]	$ (311)	[1]	$ (2)		$ (309)
Net realized losses							0		(6)	[3]
Net unrealized (losses) gains included in earnings related to assets and liabilities still held at the end of the period							2	[4]	(100)	[5]							(98)	(2)
Settlement payments							0		117
Derivative Liability	$ (317)	$ (320)	$ (298)	[1],[2]	$ (311)	[1]	$ 0		$ (298)

[1] Recorded at fair value.

[2] Refer to Note 7 for further discussion and balance sheet classifications. Crude oil options are net of $329 million at June 30, 2014, and $444 million at December 31, 2013, for deferred premiums and accrued interest.

[3] Recorded in revenues.

[4] Recorded in other (expense) income, net.

[5] Included net unrealized losses of $98 million recorded in revenues and $2 million of interest expense associated with the deferred premiums.