v2.4.0.6
Supplemental Information On Oil And Gas Operations (Schedule Of Principal Changes In The Standardized Measure Of Discounted Future Net Cash Flows Attributable To Proved Reserves) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Supplemental Information On Oil And Gas Operations [Abstract]      
Beginning balance $ 16,352 $ 11,403 $ 9,393
Oil, gas and NGL sales, net of production costs (5,794) (4,982) (3,915)
Net changes in prices and production costs 1,875 7,423 (1,672)
Extensions and discoveries, net of future development 3,714 3,048 2,378
Purchase of reserves, net of future development costs 57 23 6
Development costs incurred that reduced future development costs 1,302 1,559 1,012
Revisions of quantity estimates (668) 287 4,051
Sales of reserves in place (2) (815) (37)
Accretion of discount 2,248 1,487 1,281
Net change in income taxes (929) (2,663) (51)
Other, primarily changes in timing and foreign exchange rates (311) (418) (1,043)
Ending balance $ 17,844 $ 16,352 $ 11,403