Basis of Presentation (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Production Expense
Lease Operating Expense	$ 137		$ 103		$ 393		$ 309
Production and Ad Valorem Taxes	51		31		137		112
Transportation and Gathering Expense	33		24		89		71
Total	221		158		619		492
Other Operating (Income) Expense, Net
Other, Net	6		(2)		27		19
Total	6		(2)		27		19
Other Non-Operating (Income) Expense, Net
Deferred Compensation (Income) Expense	10	[1]	7	[1]	24	[1]	(1)	[1]
Other (Income) Expense, Net	(1)		(3)		(3)		3
Total	9		4		21		2
Accounts Receivable, Net
Commodity Sales	514				514				349
Joint Interest Billings	389				389				486
Other	80				80				139
Allowance for Doubtful Accounts	(10)				(10)				(10)
Total	973				973				964
Other Current Assets
Inventories, Current	116				116				90
Commodity Derivative Assets	15				15				63
Deferred Income Taxes, Net	20				20				106
Probable Insurance Claims	0				0				45	[2]
Assets Held-for-Sale	99	[3]			99	[3]			45	[3]
Prepaid Expenses and Other Current Assets	78				78				71
Total	328				328				420
Other Noncurrent Assets
Equity Method Investments	414				414				367
Mutual Fund Investments	113				113				103
Commodity Derivative Assets	31				31				21
Other Assets	83				83				106
Total	641				641				597
Other Current Liabilities
Production and Ad Valorem Taxes	102				102				113
Commodity Derivative Liabilities	39				39				7
Income Taxes Payable	155				155				203
Asset Retirement Obligations	69				69				69
Interest Payable	41				41				55
Current Portion of Long Term Debt	200	[4]			200	[4]			324	[4]
Current Portion of FPSO and Other Capital Lease Obligations	51				51				48
Liabilities Associated with Assets Held for Sale	44				44				12
Other	173				173				193
Total	874				874				1,024
Other Noncurrent Liabilities
Deferred Compensation Liabilities	265				265				229
Asset Retirement Obligations	348				348				333
Accrued Benefit Costs	122				122				116
Other	130				130				132
Total	$ 865				$ 865				$ 810

[1] Amounts represent increases (decreases) in the fair value of shares of our common stock held in a rabbi trust.

[2] Amounts represent the costs incurred to date of the Leviathan-2 appraisal well and expected well abandonment costs in excess of the insurance deductible less insurance proceeds received to date.

[3] Assets held for sale consist primarily of North Sea oil and gas properties and non-core onshore US properties in New Mexico. Liabilities associated with assets held for sale consist primarily of asset retirement obligations related to these assets. See Note 3. Divestitures.

[4] See Note 5. Debt