CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Millions	Total	Preferred stock	Common stock	Additional paid-in capital	Accumulated deficit	Accumulated other comprehensive income (loss)
Balance at beginning of period at Dec. 31, 2013		$ 1,575	$ 0	$ 23,485	$ (18,291)	$ (108)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee benefit plans, including transfers and other				19
Net income (loss)	$ 487				487
Dividends on preferred stock				(93)
Other comprehensive income	35					35
Total shareholders' equity at end of period at Sep. 30, 2014	7,109	1,575	0	23,411	(17,804)	(73)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total common shareholder's equity at end of period	5,534
Total common shareholder's equity at end of period	5,548
Balance at beginning of period at Dec. 31, 2014	7,123	1,575	0	23,381	(17,768)	(65)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Employee benefit plans, including transfers and other				3
Net income (loss)	(258)				(258)
Dividends on preferred stock				(93)
Other comprehensive income	28					28
Total shareholders' equity at end of period at Sep. 30, 2015	6,803	$ 1,575	$ 0	$ 23,291	$ (18,026)	$ (37)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total common shareholder's equity at end of period	$ 5,228