Consolidated Statement Of Changes In Shareholders' Equity (USD $) In Millions, except Share data	Total USD ($)	Parent [Member] USD ($)	Common Stock [Member] USD ($)	Additional Paid In Capital [Member] USD ($)	Retained Earnings [Member] USD ($)	Accumulated Other Comprehensive Income (Loss) [Member] USD ($)	Treasury Stock [Member] USD ($)	Preferred Stock [Member]	Preferred Stock Of Subsidiary And Noncontrolling Interest [Member] USD ($)
Balance as of at Dec. 31, 2014	$ 3,950	$ 3,929	$ 281	$ 3,128	$ 2,858	$ 21	$ (2,359)		$ 21
Balance (in preferred stock shares) as of at Dec. 31, 2014	0							1,315
Balance (in common stock shares) as of at Dec. 31, 2014	281,352,782		281,352,782				(89,409,887)
Net income (loss)	69	69			69
Total other comprehensive income (loss)	1	1				1
Share-based compensation, net of tax of $9	(4)	(4)	1	(4)			(1)
Share-based compensation (in shares)			317,917				(114,065)
Treasury shares acquired	(76)	(76)					(76)
Treasury shares acquired (in shares)							(8,573,120)
Balance as of at Mar. 31, 2015	$ 3,940	$ 3,919	$ 282	$ 3,124	$ 2,927	$ 22	$ (2,436)		$ 21
Balance (in preferred stock shares) as of at Mar. 31, 2015	0							1,315
Balance (in common stock shares) as of at Mar. 31, 2015	281,670,699		281,670,699				(98,097,072)