SUPPLEMENTARY OIL AND GAS INFORMATION (UNAUDITED) SUPPLEMENTARY OIL AND GAS INFORMATION (UNAUDITED) (Schedule of Costs Incurred) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property acquisition costs:
Proved properties	$ 0	$ 0	$ 463
Unproved properties	7	61	1,460
Exploration costs	22	1,250	1,482
Development costs	749	1,442	1,270
Total	778	2,753	4,675
Asset Retirement Obligation, Period Increase (Decrease)	37	(80)	(27)
United States oil and gas operations
Property acquisition costs:
General and Administrative Costs Capitalized	78	124	143
Capitalized interest	$ 7	$ 58	$ 88