Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Basic earnings per share: [Abstract]
Net income (loss)	$ 173		$ 132		$ 549		$ 118
Less: Undistributed earnings allocated to participating securities	5		3		15		3
Net income (loss) available to common stockholders	168		129		534		115
Basic weighted average shares	187,104,785	[1]	188,931,800	[1]	188,428,870	[1]	189,094,678	[1]
Net income (loss) per basic common share	$ 0.9		$ 0.68		$ 2.83		$ 0.61
Diluted earnings per share: [Abstract]
Net income (loss)	173		132		549		118
Less: Undistributed earnings allocated to participating securities	5		2		14		2
Less: mark-to-market gain (loss) on warrants	18		29		32		6
Net income (loss) available to common stockholders	$ 150		$ 101		$ 503		$ 110
Basic weighted average shares	187,104,785	[1]	188,931,800	[1]	188,428,870	[1]	189,094,678	[1]
Stock options	1,029,777		1,282,576		1,126,134		1,230,599
Warants	289,756		2,366,688		2,061,719		2,705,912
Diluted weighted average shares	188,424,318		192,581,064		191,616,723		193,031,189
Net income (loss) per diluted common share	$ 0.8		$ 0.52		$ 2.62		$ 0.57
Unvested Restricted Stock And Units That Receive Nonforfeitable Dividends Or Dividend Equivalents That Have Met Service Condition	270,142		569,673		315,018		636,570

[1] Includes 270,142 and 569,673 of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend equivalents for the three months ended June 30, 2014 and 2013, respectively. Includes 315,018 and 636,570 of participating securities that met the service condition and were eligible to receive nonforfeitable dividends or dividend equivalents for the six months ended June 30, 2014 and 2013, respectively.