CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenues	$ 3,684	$ 4,908	$ 5,168	$ 4,868	$ 5,041	$ 4,310	$ 3,711	$ 3,341	$ 18,628	$ 16,403	$ 14,830
Cost of sales:
Production and delivery									11,691	10,266	10,687
Cost, Depreciation, Amortization and Depletion									1,754	1,714	2,530
Impairment of Oil and Gas Properties									0	0	4,317
Total cost of sales									13,445	11,980	17,534
Selling, general and administrative expenses									443	477	597
Exploration Expense									105	93	63
Environmental obligations and shutdown costs									89	244	14
Net gain on sales of assets	(82)	(70)	(45)	(11)	(15)	(33)	(10)	(23)	(208)	(81)	(649)
Total costs and expenses									13,874	12,713	17,559
Operating income (loss)	316	1,315	1,664	1,459	1,479	928	686	597	4,754	3,690	(2,729)
Interest expense, net									(945)	(801)	(755)
Net gain on early extinguishment and exchanges of debt									7	21	26
Other income (expense), net									76	(8)	(14)
Income (loss) from continuing operations before income taxes and equity in affiliated companies’ net earnings									3,892	2,902	(3,472)
Provision for (benefit from) income taxes									(991)	(883)	(371)
Equity in affiliated companies’ net earnings									8	10	11
Net income (loss) from continuing operations	374	668	1,039	828	1,193	242	326	268	2,909	2,029	(3,832)
Net (loss) income from discontinued operations	4	(4)	(4)	(11)	16	3	9	38	(15)	66	(193)
Net income (loss)	378	664	1,035	817	1,209	245	335	306	2,894	2,095	(4,025)
Net income from continuing operations attributable to noncontrolling interests									(292)	(274)	(227)
Net income attributable to noncontrolling interests: Discontinued Operations					0	0	(1)	(3)	0	(4)	(63)
Gain on redemption and preferred dividends attributable to redeemable noncontrolling interest									0	0	161
Net income (loss) attributable to common stockholders	$ 485	$ 556	$ 869	$ 692	$ 1,041	$ 280	$ 268	$ 228	$ 2,602	$ 1,817	$ (4,154)
Basic net income (loss) per share attributable to common stockholders:
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.33	$ 0.38	$ 0.60	$ 0.48	$ 0.71	$ 0.19	$ 0.18	$ 0.13	$ 1.80	$ 1.21	$ (2.96)
Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share	0.00	0.00	0.00	(0.01)	0.01	0.00	0.00	0.03	(0.01)	0.04	(0.20)
Earnings Per Share, Basic	0.33	0.38	0.60	0.47	0.72	0.19	0.18	0.16	1.79	1.25	(3.16)
Diluted net income (loss) per share attributable to common stockholders:
Income (Loss) from Continuing Operations, Per Diluted Share	0.33	0.38	0.59	0.48	0.70	0.19	0.18	0.13	1.79	1.21	(2.96)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0.00	0.00	0.00	(0.01)	0.01	0.00	0.00	0.03	(0.01)	0.04	(0.20)
Earnings Per Share, Diluted	$ 0.33	$ 0.38	$ 0.59	$ 0.47	$ 0.71	$ 0.19	$ 0.18	$ 0.16	$ 1.78	$ 1.25	$ (3.16)
Weighted Average Number of Shares Outstanding, Basic	1,450,000,000	1,450,000,000	1,449,000,000	1,449,000,000	1,448,000,000	1,448,000,000	1,447,000,000	1,446,000,000	1,449,000,000	1,447,000,000	1,318,000,000
Weighted Average Number of Shares Outstanding, Diluted	1,457,000,000.00	1,458,000,000.00	1,458,000,000.00	1,458,000,000.00	1,455,000,000	1,454,000,000	1,453,000,000	1,454,000,000	1,458,000,000.00	1,454,000,000	1,318,000,000
Dividends declared per share of common stock (in dollars per share)									$ 0.2	$ 0	$ 0