Capital Stock (Tables)

12 Months Ended

Dec. 31, 2011

Capital Stock/Accumulated Other Comprehensive Income (Loss) [Abstract]

Common stock outstanding

	2011		2010		2009
Balance, beginning of year		382,391,742		336,436,972		334,710,064
Shares issued for stock-based compensation plans:
Treasury shares issued		144,313		363,263		404,232
Common shares issued		1,581,588		1,864,498		1,322,676
Equity offering (BP acquisitions)		—		26,450,000		—
Mariner consideration		—		17,277,009		—
Balance, end of year		384,117,643		382,391,742		336,436,972

Net Income (Loss) per Common Share

	2011						2010						2009
	Income		Shares		Per Share		Income		Shares		Per Share		Loss			Shares		Per Share
	(In millions, except per share amounts)
Basic:
Income (loss) attributable to common stock	$	4,508		384	$	11.75	$	3,000		352	$	8.53	$	(292	)		336	$	(.87	)
Effect of Dilutive Securities:
Mandatory Convertible Preferred Stock	$	76		14			$	32		5			$	—			—
Stock options and other		—		2				—		2				—			—
Diluted:
Income (loss) attributable to common stock, including assumed conversions	$	4,584		400	$	11.47	$	3,032		359	$	8.46	$	(292	)		336	$	(.87	)

Description of stock based compensation plans and related costs

	2011		2010		2009
	(In millions)
Stock-based compensation expensed:
General and administrative	$	69	$	98	$	67
Lease operating expenses		44		66		37
Stock-based compensation capitalized		42		71		46
	$	155	$	235	$	150

Summary of stock options issued under the stock option plans

	2011
	Shares Under Option			Weighted Average Exercise Price
	(In thousands)
Outstanding, beginning of year		5,861		$	80.30
Granted		1,336			126.61
Exercised		(878	)		63.61
Forfeited or expired		(227	)		104.74
Outstanding, end of year(1)		6,092			91.95
Expected to vest(1)		2,135			109.28
Exercisable, end of year(1)		3,422			77.74
Available for grant, end of year		25,408
Weighted average fair value of options granted during the year	$	42.20

(1) As of December 31, 2011, the weighted average remaining contractual life for options outstanding, expected to vest, and exercisable is 6.6 years, 8.5 years, and 5.1 years, respectively. The aggregate intrinsic value of options outstanding, expected to vest and exercisable at year-end was $62 million, $4 million, and $58 million, respectively. The weighted-average grant-date fair value of options granted during the years 2011, 2010, and 2009 was $42.20, $34.12, and $29.71, respectively.

Risk-free rate is based on the U S Treasury yield curve

	2011			2010			2009
Expected volatility		34.47	%		35.02	%		38.73	%
Expected dividend yields		0.47	%		0.60	%		0.73	%
Expected term (in years)		5.5			5.5			5.5
Risk-free rate		1.95	%		2.31	%		2.06	%

Restricted Stock

Restricted Stock	Shares			Weighted- Average Grant- Date Fair Value
	(In thousands)
Non-vested at January 1, 2011		2,210		$	100.72
Granted		888			124.16
Vested		(829	)		102.12
Forfeited		(154	)		86.61
Non-vested at December 31, 2011		2,115			109.31

Conditional Restricted Stock

Conditional Restricted Stock Award	Shares			Weighted- Average Grant- Date Fair Value(1)
	(In thousands)
Non-vested at January 1, 2011		523		$	141.86
Granted		586			91.29
Vested		(2	)		118.31
Forfeited		(88	)		115.67
Non-vested at December 31, 2011		1,019			115.10

(1) The fair value of each conditional restricted stock unit award is estimated as of the date of grant using a Monte Carlo simulation with the following assumptions used for all grants made under the plan: (i) a three-year continuous risk-free interest rate; (ii) a constant volatility assumption based on the historical realized stock price volatility of the Company and the designated peer group; and (iii) the historical stock prices and expected dividends of the common stock of the Company and its designated peer group.

Number of shares contingently issuable

	Shares Subject to Conditional Grants
	2011			2010			2009
	(In thousands)
2008 Share Appreciation Program
Outstanding, beginning of year		1,485			2,592			2,814
Granted		—			25			93
Forfeited or cancelled		(113	)		(1,132	)		(315	)
Outstanding, end of year(1)		1,372			1,485			2,592
Weighted-average fair value of grants outstanding(2)	$	71.28		$	71.16		$	79.61
2005 Share Appreciation Plan
Outstanding, beginning of year		400			1,103			2,001
Issued(3)		(398	)		(678	)		(815	)
Forfeited or cancelled		(2	)		(25	)		(83	)
Outstanding, end of year		—			400			1,103
Weighted-average fair value of grants outstanding(4)	$	—		$	21.64		$	24.29

(1) Represents shares issuable upon target achievement and vesting of awards related to the $216 and $162 per share price goals of 1,372,190 and zero shares, respectively, at December 31, 2011;1,485,210 and zero shares, respectively, at December 31, 2010; and 1,556,160 and 1,035,640 shares, respectively, at December 31, 2009.

(2) The fair value of each Share Price Goal conditional grant is estimated as of the date of grant using a Monte Carlo simulation with the following weighted-average assumptions used for all grants made under the plan: (i) risk-free interest rate of 2.98 percent; (ii) expected volatility of 28.31 percent; and (iii) expected dividend yield of .54 percent.

(3) The total fair value of these awards vested during 2011, 2010, and 2009 was approximately $9 million, $18 million, and $21 million, respectively.

(4) The fair value of each Share Price Goal conditional grant is estimated as of the date of grant using a Monte Carlo simulation with the following weighted-average assumptions used for all grants made under the plan: (i) risk-free interest rate of 3.95 percent; (ii) expected volatility of 28.02 percent; and (iii) expected dividend yield of .57 percent.

Summary of amounts recognized as expense and capitalized cost for each plan

	For the Year Ended December 31,
	2011		2010		2009
	(In millions)
2008 Share Appreciation Program
Compensation expense	$	8	$	49	$	23
Compensation expense, net of tax		5		31		15
Capitalized costs		5		27		13
2005 Share Appreciation Plan
Compensation expense	$	1	$	6	$	6
Compensation expense, net of tax		1		4		4
Capitalized costs		1		3		3