STATEMENT OF CONSOLIDATED OPERATIONS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Oil and gas production revenues:
Oil and gas production revenues	$ 5,887	$ 5,367	$ 6,510
Derivative instrument gains (losses), net	(135)	0	0
Other	44	(34)	98
Gain on divestiture	627	21	281
Total revenues and other	6,423	5,354	6,889
OPERATING EXPENSES:
Lease operating expenses	1,400	1,494	1,854
Gathering and transportation	179	200	211
Taxes other than income	151	126	282
Exploration	549	473	2,771
General and administrative	395	410	380
Transaction, reorganization, and separation	16	39	132
Oil and gas property and equipment
Depreciation, depletion, and amortization	2,280	2,618	3,300
Asset retirement obligation accretion	130	156	145
Impairments	8	1,103	9,472
Financing costs, net	397	417	511
Total operating expenses	5,505	7,036	19,058
NET INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	918	(1,682)	(12,169)
Current income tax provision	595	391	435
Deferred income tax benefit	(1,180)	(833)	(1,445)
NET INCOME (LOSS) FROM CONTINUING OPERATIONS INCLUDING NONCONTROLLING INTEREST	1,503	(1,240)	(11,159)
Net income (loss) from discontinued operations, net of tax	0	(33)	492
NET INCOME (LOSS) INCLUDING NONCONTROLLING INTEREST	1,503	(1,273)	(10,667)
Net income (loss) attributable to noncontrolling interest	199	132	(315)
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON STOCK	1,304	(1,405)	(10,352)
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON SHAREHOLDERS:
Net income (loss) from continuing operations attributable to common shareholders	1,304	(1,372)	(10,844)
Net income (loss) from discontinued operations	0	(33)	492
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON STOCK	$ 1,304	$ (1,405)	$ (10,352)
NET INCOME (LOSS) PER COMMON SHARE:
Basic net income (loss) from continuing operations per share (in USD per share)	$ 3.42	$ (3.62)	$ (28.70)
Basic net income (loss) from discontinued operations per share (in USD per share)	0.00	(0.09)	1.30
Basic net income (loss) per share (in USD per share)	3.42	(3.71)	(27.40)
DILUTED NET INCOME (LOSS) PER COMMON SHARE:
Diluted net income (loss) from continuing operations per share (in USD per share)	3.41	(3.62)	(28.70)
Diluted net income (loss) from discontinued operations per share (in USD per share)	0.00	(0.09)	1.30
Diluted net income (loss) per share (in USD per share)	$ 3.41	$ (3.71)	$ (27.40)
WEIGHTED-AVERAGE NUMBER OF COMMON SHARES OUTSTANDING:
Basic (in shares)	381	379	378
Diluted (in shares)	383	379	378
DIVIDENDS DECLARED PER COMMON SHARE (in USD per share)	$ 1.00	$ 1.00	$ 1.00
Oil and gas property and equipment
Oil and gas property and equipment
Depreciation, depletion, and amortization	$ 2,136	$ 2,460	$ 2,976
Other assets
Oil and gas property and equipment
Depreciation, depletion, and amortization	144	158	324
Oil
Oil and gas production revenues:
Oil and gas production revenues	4,598	4,172	5,107
Natural Gas
Oil and gas production revenues:
Oil and gas production revenues	959	967	1,176
Natural Gas Liquids
Oil and gas production revenues:
Oil and gas production revenues	$ 330	$ 228	$ 227