CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (shares)	20,000,000	20,000,000
Preferred stock, shares outstanding (shares)	7,251,515	7,251,515
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common Stock, Shares Authorized	1,000,000,000	1,000,000,000
Common Stock, Shares, Issued	665,060,856	664,944,232
Treasury stock, shares	1,586,305	1,614,312
Cash and cash equivalents	$ 2,051	$ 4,108
Short-term derivative assets ($5 and $16 attributable to our VIE)	387	879
Proved oil and natural gas properties ($488 and $488 attributable to our VIE)	62,161	58,594
Less: accumulated depreciation, depletion and amortization (($361) and ($251) attributable to our VIE)	(50,302)	(39,043)
Other current liabilities ($11 and $15 attributable to our VIE)	2,649	3,061
Variable Interest Entities, Primary Beneficiary [Member]
Cash and cash equivalents	1	1
Short-term derivative assets ($5 and $16 attributable to our VIE)	5	16
Proved oil and natural gas properties ($488 and $488 attributable to our VIE)	488	488
Less: accumulated depreciation, depletion and amortization (($361) and ($251) attributable to our VIE)	(361)	(251)
Other current liabilities ($11 and $15 attributable to our VIE)	$ 11	$ 15