Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Disclosure Earnings Per Share Schedule Of Basic And Diluted Earnings Per Share [Abstract]
Net income (loss)	$ (178)		$ 581		$ (14)		$ 591
Basic weighted average shares	193,104,610	[1]	193,926,953	[1]	193,810,351	[1]	193,700,328	[1]
Stock options and warrants	0		1,014,280		0		1,063,289
Diluted weighted average shares	193,104,610		194,941,233		193,810,351		194,763,617
Basic	$ (0.92)		$ 2.99		$ (0.07)		$ 3.05
Diluted	$ (0.92)		$ 2.98		$ (0.07)		$ 3.03
Unvested restricted stock and units that receive nonforfeitable dividends or dividend equivalents	4,490,348		5,597,797		5,303,456		5,400,564

[1] Includes 4,490,348 and 5,597,797 of unvested restricted stock and units that receive nonforfeitable dividends or dividend equivalents for the three months ended June 30, 2013 and 2012,respectively. Includes 5,303,456 and 5,400,564 of unvested restricted stock and units that receive nonforfeitable dividends or dividend equivalents for the six months endedJune 30, 2013 and 2012, respectively.