Computation of Earnings (Loss) Per Basic/Diluted Common Share (Details) (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
Numerator:
Consolidated net income (loss)	$ (23)	$ 56	$ 474	$ 837
Less: Distributed earnings to unvested share-based awards that participate in earnings	0	0	(5)	(4)
Less: Undistributed earnings allocated to unvested share-based awards that participate in earnings	0	(1)	(7)	(14)
Numerator for basic earnings (loss) per common share-income (loss) available to common shareholders	$ (23)	$ 55	$ 462	$ 819
Denominator:
Denominator for basic earnings per common share - weighted-average common shares outstanding (in shares)	718	1,122	714	1,118
Effect of potential dilutive common shares under the treasury stock method:
Employee stock options and others (in shares)	0	12	11	9
Denominator for diluted earnings per common share - weighted-average common shares outstanding plus dilutive effect of employee stock options and others (in shares)	718	1,134	725	1,127
Basic earnings (loss) per common share (in dollars per share)	$ (0.03)	$ 0.05	$ 0.65	$ 0.73
Diluted earnings (loss) per common share (in dollars per share)	$ (0.03)	$ 0.05	$ 0.64	$ 0.73
Common stock weighted-average shares, unvested restricted stock rights (in shares)	14	24	16	25
Options
Antidilutive [Line Items]
Antidilutive securities excluded from computation of diluted earnings per share (in shares)	10	2	1	8
Restricted Stocks
Antidilutive [Line Items]
Antidilutive securities excluded from computation of diluted earnings per share (in shares)	5		4