SUPPLEMENTARY OIL AND GAS INFORMATION (UNAUDITED) SUPPLEMENTARY OIL AND GAS INFORMATION (UNAUDITED) (Schedule of Capitalized Costs) (Details) $ in Millions	3 Months Ended							12 Months Ended
	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) $ / Boe	Dec. 31, 2015 USD ($) $ / Boe	Dec. 31, 2014 USD ($) $ / Boe
Oil and Gas Exploration and Production Industries Disclosures [Abstract]
Properties subject to amortization				$ 24,538				$ 27,507	$ 24,538	$ 16,547
Accumulated amortization				(22,276)				(27,433)	(22,276)	(7,360)
Total				2,262				74	2,262	9,187
Impairment of Oil and Gas Properties	$ 239	$ 291	$ 3,800	$ 3,700	$ 3,700	$ 2,700	$ 3,100	$ 4,317	$ 13,144	$ 3,737
Average Depletion Depreciation and Amortization Expense Per Unit of Production | $ / Boe								17.58	33.46	39.74