Reconciliation of Earnings Per Share (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Earnings Per Share [Line Items]
Earnings (loss) from continuing operations	$ 118		$ 219		$ 301		$ 524
Effect of dilutive securities	0	[1]	0	[1]	0	[1]	0	[1]
Earnings (loss) from continuing operations - assuming dilution	118		219		301		524
Average common shares outstanding	434.8		428.6		434.5		429.4
Average common shares outstanding - assuming dilution	438.2		430.5		439.3		433.4
Basic earnings (loss) from continuing operations per common share	$ 0.27		$ 0.51		$ 0.69		$ 1.22
Diluted earnings (loss) from continuing operations per common share	$ 0.27		$ 0.51		$ 0.68		$ 1.21
Restricted Stock Performance Share Plan
Earnings Per Share [Line Items]
Effect of dilutive securities	3.4		1.9		4.8		4.0
Stock Options
Earnings Per Share [Line Items]
Effect of dilutive securities	$ 0	[2]	$ 0	[2]	$ 0	[2]	$ 0	[2]

[1] Securities are not included in the table in periods when antidilutive.

[2] Options to purchase 12.1 million shares and 17.0 million shares for the three months ended June 30, 2012 and 2011, respectively, and options to purchase 12.1 million shares and 17.0 million shares for the six months ended June 30, 2012 and 2011, respectively, were not included in the computation of diluted common shares outstanding because their exercise price exceeded the average market price of the Company's common stock for each respective reporting period.