Equity - AOCI Reclassifications Table (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Oil, natural gas and NGL Reclassifications from AOCI	$ 880	$ 2,341	$ 2,693	$ 5,812
Net gain (loss) on Sales of Investments Reclassifications from AOCI	0	0	0	67
Total Reclassification from AOCI	(4,639)	692	(12,450)	1,387
Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total Reclassification from AOCI	5	3	18	8
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) on Sales of Investments Reclassifications from AOCI				(5)
Commodity Contract [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Oil, natural gas and NGL Reclassifications from AOCI	$ 5	$ 3	$ 18	$ 13