Disclosures About Oil and Gas Producing Activities (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2011

Oil And Gas Exploration And Production Industries Tables [Abstract]

Analyses of changes in proven reserves

	United States
	Oil	Natural Gas
	(MBbls)	(MMcf)
Reserves, December 31, 2008	27,007	3,355,788
Extensions, discoveries and additions	5,902	758,659
Production	(1,320)	(172,189)
Revisions	(2,404)	(205,657)
Reserves, December 31, 2009	29,185	3,736,601
Extensions, discoveries and additions	7,369	1,055,047
Production	(1,334)	(205,613)
Revisions	(3,536)	(385,880)
Reserves, December 31, 2010	31,684	4,200,155
Extensions, discoveries and additions	4,592	1,112,147
Production	(1,408)	(236,832)
Revisions	(1,787)	(296,916)
Reserves, December 31, 2011	33,081	4,778,554
	United States
	Oil	Natural Gas
	(MBbls)	(MMcf)
Proved:
Developed	11,462	1,412,562
Undeveloped	15,546	1,943,225
Total Proved - 2008	27,007	3,355,788
Developed	11,627	1,541,813
Undeveloped	17,558	2,194,788
Total Proved - 2009	29,185	3,736,601
Developed	11,013	1,678,697
Undeveloped	20,671	2,521,458
Total Proved - 2010	31,684	4,200,155
Developed	11,794	1,973,391
Undeveloped	21,287	2,805,163
Total Proved - 2011	33,081	4,778,554

Standardized measure

		As of December 31,
		2011		2010		2009
Future cash inflows	$	22,196,913	$	19,186,072	$	12,870,816
Future production costs		(6,113,282)		(5,253,509)		(3,916,222)
Future development costs		(4,294,375)		(3,052,843)		(2,249,993)
Future income taxes		(3,340,516)		(3,198,413)		(1,998,114)
Future net cash flows		8,448,740		7,681,307		4,706,487
Discount at 10%		(4,652,684)		(4,155,739)		(2,679,787)
Standardized measure of discounted
future net cash flows	$	3,796,056	$	3,525,568	$	2,026,700

Summary of changes in the standardized measure of discounted future net cash flows

		December 31,
		2011		2010		2009
Standardized measure, beginning	$	3,525,568	$	2,026,700	$	3,017,686
Net revisions of previous quantity estimates		(446,677)		(592,919)		(216,946)
Extensions, discoveries and other changes		1,654,793		1,601,154		782,763
Changes in future development costs		(741,658)		(606,449)		(103,056)
Sales of oil and gas, net of production costs		(896,434)		(787,409)		(513,958)
Net change in prices and production costs		108,108		1,501,002		(1,772,644)
Development costs incurred during the
period that reduce future development costs		464,880		404,402		395,092
Accretion of discount		499,358		288,713		444,387
Net changes in production rates and other		(338,982)		297,957		(572,380)
Net change in income taxes		(32,900)		(607,583)		565,756
Aggregate changes		270,488		1,498,868		(990,986)
Standardized measure, ending	$	3,796,056	$	3,525,568	$	2,026,700

Costs incurred in oil and gas exploration and development activities

		Years Ended December 31,
		2011		2010		2009
United States
Acquisition costs - unproved properties, net	$	91,983	$	472,339	$	33,176
Exploration		48,998		249,029		102,217
Development		1,372,805		855,110		605,958
Total	$	1,513,786	$	1,576,478	$	741,351

Results of operations for oil and gas producing activities

F. RESULTS OF OPERATIONS FOR OIL AND GAS PRODUCING ACTIVITIES:
			Years Ended December 31,
			2011		2010		2009
	United States
	Oil and gas revenue	$	1,101,796	$	979,386	$	666,762
	Production expenses		(205,363)		(191,978)		(152,804)
	Depletion and depreciation		(346,394)		(241,796)		(201,826)
	Write-down of proved oil and gas properties		-		-		(1,037,000)
	Income taxes		(197,464)		(193,692)		254,429
	Total	$	352,575	$	351,920	$	(470,439)

Capitalized Costs Relating to Oil and Gas Producing Activities

		December 31,		December 31,
		2011		2010
Developed Properties:
Acquisition, equipment, exploration, drilling and environmental costs	$	5,974,604	$	4,575,222
Less: Accumulated depletion, depreciation and amortization		(2,322,982)		(1,985,799)
		3,651,622		2,589,423
Unproven Properties:
Acquisition and exploration costs not being amortized (1), (2)		537,526		486,247
Net capitalized costs - oil and gas properties	$	4,189,148	$	3,075,670

G. CAPITALIZED COSTS RELATING TO OIL AND GAS PRODUCING ACTIVITIES:
			December 31,
			2011		2010
	Developed Properties:
	Acquisition, equipment, exploration, drilling and
	environmental costs	$	5,974,604	$	4,575,222
	Less: accumulated depletion, depreciation and amortization		(2,322,982)		(1,985,799)
			3,651,622		2,589,423
	Unproven Properties:
	Acquisition and exploration costs not being amortized		537,526		486,247
		$	4,189,148	$	3,075,670