CONSOLIDATED STATEMENT OF CHANGES IN SHAREHOLDERS' EQUITY - 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, 2014		$ 1,575	$ 0	$ 23,381	$ (17,768)	$ (65)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on preferred stock				(32)
Employee benefit plans, including transfers and other				(1)
Net loss	$ (5)				(5)
Other comprehensive income	11					11
Total shareholders' equity at end of period at Mar. 31, 2015	7,096	1,575	0	23,348	(17,773)	(54)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total common shareholder's equity at end of period	5,521
Total common shareholder's equity at end of period	5,060
Balance at beginning of period at Dec. 31, 2015	6,635	1,575	0	23,245	(18,199)	14
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends on preferred stock				(32)
Employee benefit plans, including transfers and other				2
Net loss	(74)				(74)
Other comprehensive income	7					7
Total shareholders' equity at end of period at Mar. 31, 2016	6,538	$ 1,575	$ 0	$ 23,215	$ (18,273)	$ 21
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total common shareholder's equity at end of period	$ 4,963