Consolidated Statements Of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Revenues and other income:
Oil and gas	$ 910		$ 729
Sales of purchased oil and gas	147		56
Interest and other	4		0
Derivative losses, net	(104)		(42)
Gain on disposition of assets, net	6		24
Total revenues and other income	963		767
Costs and expenses:
Oil and gas production	165		150
Production and ad valorem taxes	57		52
Depletion, depreciation and amortization	221		212
Purchased oil and gas	143		56
Exploration and abandonments	31		18
General and administrative	81		62
Accretion of discount on asset retirement obligations	3		3
Interest	45		51
Other	15		20
Costs and Expenses	761		624
Income from continuing operations before income taxes	202		143
Income tax provision	(53)		(50)
Income from continuing operations	149		93
Income (loss) from discontinued operations, net of tax	(26)		16
Net income	123		109
Net income attributable to noncontrolling interests	0		(8)
Net income attributable to common stockholders	123		101
Basic earnings per share:
Income from continuing operations	$ 1.03		$ 0.65
Income (loss) from discontinued operations	$ (0.18)		$ 0.12
Net income	$ 0.85		$ 0.77
Diluted earnings per share:
Income from continuing operations	$ 1.03		$ 0.63
Income (loss) from discontinued operations	$ (0.18)		$ 0.12
Net income	$ 0.85		$ 0.75
Weighted average shares outstanding:
Basic	143		129
Diluted	143	[1]	133	[1]
Dividends declared per share	$ 0.04		$ 0.04
Amounts attributable to common stockholders:
Income from continuing operations	149		85
Income (loss) from discontinued operations, net of tax	(26)		16
Net income	$ 123		$ 101

[1] (a)Options to purchase 98,819 shares of the Company's common stock were excluded from the diluted income per share calculations for the three months ended March 31, 2013 because they would have been anti-dilutive to the calculation.