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
Property acquisition costs:
Unproved properties	$ 7	$ 61
Exploration costs	22	1,250
Development costs	749	1,442
Total	778	2,753
Asset Retirement Obligation, Period Increase (Decrease)	37	(80)
United States oil and gas operations
Property acquisition costs:
General and Administrative Costs Capitalized	78	124
Capitalized interest	$ 7	$ 58