Equity - AOCI Reclassifications Table (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Oil, natural gas and NGL Reclassifications from AOCI	$ 1,085	$ 1,766
Net gain (loss) on Sales of Investments Reclassifications from AOCI	0	67
Total Reclassification from AOCI	(3,720)	466
Reclassification out of Accumulated Other Comprehensive Income [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total Reclassification from AOCI	10	6
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	$ 10	$ 11