CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (431)	$ 523	$ 536
Net change in unrealized gains (losses), net of tax, on:
Derivatives designated as cash flow hedges	37	45	261
Securities available-for-sale, not other-than temporarily impaired	0	0	(115)
Other-than-temporarily impaired debt securities available-for-sale	0	0	(1)
Pension and postretirement benefit plan adjustments	42	(2)	15
Foreign currency translation adjustments	0	0	(11)
Other comprehensive income, net of tax	79	43	149
Total comprehensive income (loss)	$ (352)	$ 566	$ 685