Equity Equity - Reclassification Out of AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Oil, natural gas and NGL	$ 3,288	$ 5,391	$ 10,354
Gains (losses) on purchases or exchanges of debt	236	279	(197)
NET INCOME (LOSS)	(4,399)	(14,635)	$ 2,056
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
NET INCOME (LOSS)	16	24
Commodity Contract [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Oil, natural gas and NGL	16	23
Foreign Exchange Contract [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gains (losses) on purchases or exchanges of debt	$ 0	$ 1