Statement of Consolidated Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Oil and gas production revenues:
Oil and gas production revenues	$ 5,367	$ 6,510	[1]	$ 12,795	[1]
Other	(34)	98	[1]	285	[1]
Gain (loss) on divestiture	21	281	[1],[2]	(1,608)	[1],[2]
Total revenues and other	5,354	6,889	[1]	11,472	[1]
OPERATING EXPENSES:
Lease operating expenses	1,494	1,854	[1]	2,238	[1]
Gathering and transportation	200	211	[1]	273	[1]
Taxes other than income	126	282	[1]	577	[1]
Exploration Expense	473	2,771	[1]	2,499	[1]
General and administrative	410	380	[1]	453	[1]
Oil and gas property and equipment
Depreciation, depletion, and amortization	2,618	3,300	[2]	4,526	[2]
Asset retirement obligation accretion	156	145	[1],[2]	154	[1],[2]
Impairments	1,103	9,472	[1],[2]	7,102	[1],[2]
Transaction, reorganization, and separation	39	132	[1]	67	[1]
Financing costs, net	417	511	[1]	413	[1]
Total operating expenses	7,036	19,058	[1]	18,302	[1]
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(1,682)	(12,169)	[1]	(6,830)	[1]
Current income tax provision	391	435	[1]	1,281	[1]
Deferred income tax benefit	(833)	(1,445)	[1],[2]	(1,799)	[1],[2]
Net loss from continuing operations including noncontrolling interest	(1,240)	(11,159)	[1]	(6,312)	[1]
Net income (loss) from discontinued operations, net of tax	(33)	492	[1]	(1,707)	[1]
NET LOSS INCLUDING NONCONTROLLING INTEREST	(1,273)	(10,667)	[1],[2],[3],[4]	(8,019)	[1],[2],[3],[4]
Net income (loss) attributable to noncontrolling interest	132	(315)	[1]	341	[1]
Net income (loss) attributable to common shareholders	(1,405)	(10,352)	[1]	(8,360)	[1]
NET INCOME (LOSS) ATTRIBUTABLE TO COMMON SHAREHOLDERS:
Net loss from continuing operations attributable to common shareholders	(1,372)	(10,844)	[1]	(6,653)	[1]
Net income (loss) from discontinued operations	(33)	492	[1],[2]	(1,707)	[1],[2]
Net income (loss) attributable to common shareholders	$ (1,405)	$ (10,352)	[1]	$ (8,360)	[1]
BASIC AND DILUTED NET INCOME (LOSS) PER COMMON SHARE:
Basic and diluted net loss from continuing operations per share	$ (3.62)	$ (28.70)	[1]	$ (17.32)	[1]
Basic and diluted net loss from discontinued operations per share	(0.09)	1.30	[1]	(4.44)	[1]
Basic and diluted net loss per share	$ (3.71)	$ (27.40)	[1]	$ (21.76)	[1]
WEIGHTED-AVERAGE NUMBER OF COMMON SHARES OUTSTANDING:
Basic (in shares)	379	378	[1]	384	[1]
Diluted (in shares)	379	378	[1]	384	[1]
DIVIDENDS DECLARED PER COMMON SHARE	$ 1.00	$ 1.00	[1],[4]	$ 1.00	[1],[4]
Oil and gas property and equipment [Member]
Oil and gas property and equipment
Depreciation, depletion, and amortization	$ 2,460	$ 2,976	[1]	$ 4,195	[1]
Other assets [Member]
Oil and gas property and equipment
Depreciation, depletion, and amortization	158	324	[1]	331	[1]
Oil [Member]
Oil and gas production revenues:
Oil and gas production revenues	4,172	5,107	[1]	10,110	[1]
Natural Gas [Member]
Oil and gas production revenues:
Oil and gas production revenues	967	1,176	[1]	2,017	[1]
Natural Gas Liquids [Member]
Oil and gas production revenues:
Oil and gas production revenues	$ 228	$ 227	[1]	$ 668	[1]

[1] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.

[2] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.

[3] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.

[4] Financial information for 2015, 2014, and 2013 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.