Consolidated Statements Of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013
Revenues and other income:
Oil and gas	$ 967		$ 820	$ 2,795		$ 2,296
Sales of purchased oil and gas	202		82	554		194
Interest and other	2		8	9		3
Derivative gains (losses), net	341		(102)	19		0
Gain (loss) on disposition of assets, net	1		(1)	11		206
Total revenues and other income	1,513		807	3,388		2,699
Costs and expenses:
Oil and gas production	168		150	493		440
Production and ad valorem taxes	58		49	169		147
Depletion, depreciation and amortization	274		222	734		650
Purchased oil and gas	194		85	535		196
Exploration and abandonments	22		30	80		65
General and administrative	81		72	244		200
Accretion of discount on asset retirement obligations	3		3	9		9
Interest	46		45	138		139
Other	20		24	55		65
Costs and Expenses	866		680	2,457		1,911
Income from continuing operations before income taxes	647		127	931		788
Income tax provision	(236)		(48)	(319)		(281)
Income from continuing operations	411		79	612		507
Income (loss) from discontinued operations, net of tax	(37)		19	(113)		52
Net income	374		98	499		559
Net income attributable to noncontrolling interests	0		(7)	0		(30)
Net income attributable to common stockholders	374		91	499		529
Basic earnings per share:
Income from continuing operations	$ 2.84		$ 0.51	$ 4.24		$ 3.49
Income (loss) from discontinued operations	$ (0.26)		$ 0.14	$ (0.79)		$ 0.38
Net income	$ 2.58		$ 0.65	$ 3.45		$ 3.87
Diluted earnings per share:
Income from continuing operations	$ 2.84		$ 0.51	$ 4.23		$ 3.44
Income (loss) from discontinued operations	$ (0.26)		$ 0.14	$ (0.79)		$ 0.38
Net income	$ 2.58		$ 0.65	$ 3.44		$ 3.82
Weighted average shares outstanding:
Basic	143		139	143		135
Diluted	143	[1]	139	143	[1]	137	[1]
Dividends declared per share	$ 0.04		$ 0.04	$ 0.08		$ 0.08
Amounts attributable to common stockholders:
Income from continuing operations	411		72	612		477
Income (loss) from discontinued operations, net of tax	(37)		19	(113)		52
Net income attributable to common stockholders	$ 374		$ 91	$ 499		$ 529

[1] (a)The Company excluded 33,591 shares and 11,197 shares attributable to unvested performance units from the diluted income per share calculations for the three and nine months ended September 30, 2014, respectively, because they would have been anti-dilutive to the calculation. Options to purchase 34,842 shares of the Company's common stock were excluded from the diluted income per share calculations for the nine months ended September 30, 2013 because they would have been anti-dilutive to the calculation.