Fair Value Measurement (Unaudited) Unobservable Inputs (Details) (USD $) In Millions, unless otherwise specified							3 Months Ended					3 Months Ended		3 Months Ended		3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 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]		Mar. 31, 2014 Plains Offshore Warrants [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]		Mar. 31, 2014 Crude Oil Options [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]		Mar. 31, 2014 Crude Oil Options [Member] Minimum [Member]	Mar. 31, 2014 Crude Oil Options [Member] Minimum [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]	Mar. 31, 2014 Crude Oil Options [Member] Maximum [Member]	Mar. 31, 2014 Crude Oil Options [Member] Maximum [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]	Mar. 31, 2014 Crude Oil Options [Member] Weighted Average [Member]	Mar. 31, 2014 Crude Oil Options [Member] Weighted Average [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]	Mar. 31, 2014 Sales [Member] Crude Oil Options [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring [Member]	Mar. 31, 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												16.00%		38.00%		21.00%
Deferred Premium Price											5.15		7.22		6.40
Derivative Liability	$ (401)	$ (320)	$ (289)	[1]	$ (311)	[1]	$ (2)		$ (309)
Net realized losses							0		(1)	[2]
Net unrealized (losses) gains included in earnings related to assets and liabilities still held at the end of the period							1	[3]	(36)	[4]							35	1
Settlement payments							0		58
Derivative Liability	$ (401)	$ (320)	$ (289)	[1]	$ (311)	[1]	$ (1)		$ (288)

[1] Recorded at fair value.

[2] Recorded in revenues.

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

[4] Included net unrealized losses of $35 million recorded in revenues and $1 million of interest expense associated with the deferred premiums.