Basis of Presentation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Dec. 31, 2012
Production Expense
Lease Operating Expense	$ 117		$ 105
Production Tax Expense	43		38
Transportation and Gathering Expense	27		20
Total	187		163
Other Operating (Income) Expense, Net
Gain on Divestitures	(15)	[1]	0	[1]
Other, Net	7		12
Total	(8)		12
Other Non-Operating (Income) Expense, Net
Deferred Compensation Expense	10	[2]	3	[2]
Other (Income) Expense, Net	0		(4)
Total	10		(1)
Accounts Receivable, Net
Commodity Sales	266				349
Joint Interest Billings	395				486
Other	125				139
Allowance for Doubtful Accounts	(10)				(10)
Total	776				964
Other Current Assets
Inventories, Current	97				90
Commodity Derivative Assets	36				63
Deferred Income Taxes, Net	83				106
Probable Insurance Claims	17	[3]			45	[3]
Assets Held-for-Sale	63	[4]			45	[4]
Prepaid Expenses and Other Current Assets	74				71
Total	370				420
Other Noncurrent Assets
Equity Method Investments	423				367
Mutual Fund Investments	109				103
Commodity Derivative Assets	13				21
Other Assets, Noncurrent	87				106
Total	632				597
Other Current Liabilities
Production and Ad Valorem Taxes	107				113
Commodity Derivative Liabilities	44				7
Income Taxes Payable	202				203
Asset Retirement Obligations	69				69
Interest Payable	40				55
CONSOL Installment Payment	325	[5]			324	[5]
Current Portion of FPSO Lease Obligation	49				48
Liabilities Associated with Assets Held for Sale	14	[4]			12	[4]
Other	136				193
Total	986				1,024
Other Noncurrent Liabilities
Deferred Compensation Liabilities	247				229
Asset Retirement Obligations	330				333
Accrued Benefit Costs	118				116
Commodity Derivative Liabilities	9				3
Other	146				129
Total	$ 850				$ 810

[1] See Note 3. Divestitures

[2] Amounts represent increases in the fair value of shares of our common stock held in a rabbi trust.

[3] 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.

[4] Assets held for sale consist primarily of North Sea and onshore US oil and gas properties. Liabilities associated with assets held for sale consist primarily of asset retirement obligations related to these assets.

[5] See Note 5. Debt.