STATEMENT OF CONSOLIDATED OPERATIONS (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
REVENUES AND OTHER:
Oil and gas production revenues									$ 16,947	$ 16,810	$ 12,183
Other									131	78	(91)
Total revenues and other	4,391	4,179	3,972	4,536	4,297	4,328	4,338	3,925	17,078	16,888	12,092
Depreciation, depletion, and amortization:
Recurring									5,183	4,095	3,083
Additional									1,926	109
Asset retirement obligation accretion									232	154	111
Lease operating expenses									2,968	2,605	2,032
Gathering and transportation									303	296	178
Taxes other than income									862	899	690
General and administrative									531	459	380
Merger, acquisitions & transition									31	20	183
Financing costs, net									165	158	229
Total operating expenses									12,201	8,795	6,886
INCOME BEFORE INCOME TAXES									4,877	8,093	5,206
Current income tax provision									2,199	2,263	1,222
Deferred income tax provision									677	1,246	952
NET INCOME	668	180	356	797	1,189	1,002	1,259	1,134	2,001	4,584	3,032
Preferred stock dividends									76	76	32
INCOME ATTRIBUTABLE TO COMMON STOCK	$ 649	$ 161	$ 337	$ 778	$ 1,170	$ 983	$ 1,240	$ 1,115	$ 1,925	$ 4,508	$ 3,000
NET INCOME PER COMMON SHARE:
Basic	$ 1.66	$ 0.41	$ 0.87	$ 2.02	$ 3.05	$ 2.56	$ 3.23	$ 2.91	$ 4.95	$ 11.75	$ 8.53
Diluted	$ 1.64	$ 0.41	$ 0.86	$ 2.00	$ 2.98	$ 2.50	$ 3.17	$ 2.86	$ 4.92	$ 11.47	$ 8.46
WEIGHTED-AVERAGE NUMBER OF COMMON SHARES OUTSTANDING:
Basic									389	384	352
Diluted									391	400	359
DIVIDENDS DECLARED PER COMMON SHARE									$ 0.68	$ 0.60	$ 0.60