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, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Basic earnings per share: [Abstract]
Net income (loss)	$ 120	$ (178)	$ 376	$ (14)
Less: Undistributed earnings allocated to participating securities	4	0	10	0
Net income (loss) available to common stockholders	116	(178)	366	(14)
Basic weighted average shares	189,169,042	189,163,527	189,101,884	189,135,587
Net income (loss) per basic common share	$ 0.61	$ (0.94)	$ 1.93	$ (0.07)
Diluted earnings per share: [Abstract]
Net income (loss)	120	(178)	376	(14)
Less: Undistributed earnings allocated to participating securities	3	0	9	0
Less: mark-to-market gain (loss) on warrants	30	0	14	0
Net income (loss) available to common stockholders	$ 87	$ (178)	$ 353	$ (14)
Basic weighted average shares	189,169,042	189,163,527	189,101,884	189,135,587
Stock options	1,111,816	0	1,170,182	0
Warants	2,626,013	0	2,779,370	0
Diluted weighted average shares	192,906,871	189,163,527	193,051,436	189,135,587
Net income (loss) per diluted common share	$ 0.45	$ (0.94)	$ 1.83	$ (0.07)
Unvested Restricted Stock And Units That Receive Nonforfeitable Dividends Or Dividend Equivalents That Have Met Service Condition	270,443	549,265	337,827	628,692