Consolidated Balance Sheets (unaudited) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current Assets
Cash and Cash Equivalents	$ 1,305	$ 1,387
Accounts Receivable, Net	776	964
Other Current Assets	370	420
Total Current Assets	2,451	2,771
Property, Plant and Equipment
Oil and Gas Properties (Successful Efforts Method of Accounting)	20,015	19,496
Property, Plant and Equipment, Other	346	344
Total Property, Plant and Equipment, Gross	20,361	19,840
Accumulated Depreciation, Depletion and Amortization	(6,366)	(6,289)
Total Property, Plant and Equipment, Net	13,995	13,551
Goodwill	632	635
Other Noncurrent Assets	632	597
Total Assets	17,710	17,554
Current Liabilities
Accounts Payable - Trade	1,388	1,508
Other Current Liabilities	986	1,024
Total Current Liabilities	2,374	2,532
Long-Term Debt	3,723	3,736
Deferred Income Taxes, Noncurrent	2,249	2,218
Other Noncurrent Liabilities	850	810
Total Liabilities	9,196	9,296
Commitments and Contingencies
Shareholders' Equity
Preferred Stock - Par Value $1.00 per share; 4 Million Shares Authorized, None Issued	0	0
Common Stock - Par Value $0.01 per share; 500 Million Shares Authorized; 199 Million and 198 Million Shares Issued, respectively	2	2
Additional Paid in Capital	3,353	3,304
Accumulated Other Comprehensive Loss	(109)	(113)
Treasury Stock, at Cost; 19 Million Shares	(662)	(648)
Retained Earnings	5,930	5,713
Total Shareholders’ Equity	8,514	8,258
Total Liabilities and Shareholders’ Equity	$ 17,710	$ 17,554