Consolidated Statements of Shareholders' Equity (USD $) In Millions	Common Stock [Member]	Additional Paid in Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock at Cost [Member]	Retained Earnings [Member]	Total
Balance at Dec. 31, 2008	$ 641	$ 2,193	$ (110)	$ (614)	$ 4,199	$ 6,309
Net Income (Loss)	0	0	0	0	(131)	(131)
Stock-based Compensation Expense	0	49	0	0	0	49
Exercise of Stock Options	2	15	0	0	0	17
Tax Benefits Related to Exercise of Stock Options	0	5	0	0	0	5
Restricted Stock Awards, Net	2	(2)	0	0	0	0
Cash Dividends	0	0	0	0	(126)	(126)
Purchase of Treasury Stock	0	0	0	(1)	0	(1)
Oil and Gas Cash Flow Hedges Realized Amounts Reclassified Into Earnings	0	0	36	0	0	36
Net Change in Other	0	0	(1)	0	0	(1)
Balance at Dec. 31, 2009	645	2,260	(75)	(615)	3,942	6,157
Net Income (Loss)	0	0	0	0	725	725	[1]
Stock-based Compensation Expense	0	54	0	0	0	54
Exercise of Stock Options	5	42	0	0	0	47
Tax Benefits Related to Exercise of Stock Options	0	25	0	0	0	25
Restricted Stock Awards, Net	1	(1)	0	0	0	0
Cash Dividends	0	0	0	0	(127)	(127)
Purchase of Treasury Stock	0	0	0	(13)	0	(13)
Rabbi Trust Shares Sold	0	5	0	4	0	9
Oil and Gas Cash Flow Hedges Realized Amounts Reclassified Into Earnings	0	0	12	0	0	12
Interest Rate Cash Flow Hedges Unrealized Change in Fair Value	0	0	(41)	0	0	(41)
Net Change in Other	0	0	0	0	0	0
Balance at Dec. 31, 2010	651	2,385	(104)	(624)	4,540	6,848
Net Income (Loss)	0	0	0	0	453	453	[2]
Stock-based Compensation Expense	0	58	0	0	0	58
Exercise of Stock Options	3	35	0	0	0	38
Tax Benefits Related to Exercise of Stock Options	0	15	0	0	0	15
Restricted Stock Awards, Net	2	(2)	0	0	0	0
Cash Dividends	0	0	0	0	(143)	(143)
Purchase of Treasury Stock	0	0	0	(17)	0	(17)
Rabbi Trust Shares Sold	0	6	0	3	0	9
Interest Rate Cash Flow Hedges Unrealized Change in Fair Value	0	0	15	0	0	15
Net Change in Other	0	0	(11)	0	0	(11)
Balance at Dec. 31, 2011	$ 656	$ 2,497	$ (100)	$ (638)	$ 4,850	$ 7,265

[1] First quarter 2010 included the following: $145 million gain on commodity derivative instruments, including unrealized mark-to-market gain of $147 million (See Note 10. Derivative Instruments and Hedging Activities). Second quarter 2010 included the following: $96 million gain on commodity derivative instruments, including unrealized mark-to-market gain of $63 million (See Note 10. Derivative Instruments and Hedging Activities); and $26 million rig contract termination expense due to the Deepwater Moratorium. Third quarter 2010 included the following: $38 million gain on commodity derivative instruments, including unrealized mark-to-market gain of $5 million (See Note 10. Derivative Instruments and Hedging Activities); $114 million gain on sale of non-core onshore US assets (See Note 3. Acquisitions and Divestitures); and $100 million asset impairment charges (See Note 4. Asset Impairments). Fourth quarter 2010 included the following: $122 million loss on commodity derivative instruments, including unrealized mark-to-market loss of $145 million (See Note 10. Derivative Instruments and Hedging Activities); and $44 million asset impairment charges (See Note 4. Asset Impairments).

[2] First quarter 2011 included the following: $8 million asset impairment charges (See Note 4. Asset Impairments); and $286 million loss on commodity derivative instruments, including unrealized mark-to-market loss of $303 million (See Note 10. Derivative Instruments and Hedging Activities). Second quarter 2011 included the following: $143 million gain on commodity derivative instruments, including unrealized mark-to-market gain of $142 million (See Note 10. Derivative Instruments and Hedging Activities); $25 million pre-tax gain on divestitures due to the completed transfer of assets and exit from Ecuador (See Note 3. Acquisitions and Divestitures); and $131 million asset impairment charges (See Note 4. Asset Impairments). Third quarter 2011 included the following: $322 million gain on commodity derivative instruments, including unrealized mark-to-market gain of $300 million (See Note 10. Derivative Instruments and Hedging Activities). Fourth quarter 2011 included the following: $620 million asset impairment charges (See Note 4. Asset Impairments); and $137 million loss on commodity derivative instruments, including unrealized mark-to-market loss of $162 million (See Note 10. Derivative Instruments and Hedging Activities).