CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (LOSS) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (705)	$ 4	$ 180	$ 183	$ 47	$ (782)	$ (545)	$ 235	$ (338)	$ (1,045)	$ 1,018
Net change in unrealized gains (losses), net of tax:
Securities available-for-sale									(1,010)	109	786
Other-than-temporarily impaired debt securities available-for-sale									0	0	1
Other-than-temporarily impaired debt securities held-to-maturity										0	(11)
Adjustment to reverse other-than-temporary impairment on securities held-to-maturity due to deconsolidation of a variable interest entity									0	0	142
Derivatives designated as cash flow hedges									118	28	(142)
Pension and post-retirement benefit plan									8	6	(3)
Total other comprehensive income (loss)									(877)	143	795
Comprehensive income (loss)									(1,215)	(902)	1,813
Other than Temporary Impairment Losses, Investments, Portion in Other Comprehensive Loss, Net of Tax, Including Portion Attributable to Noncontrolling Interest and VIE, Held-to-maturity Securities									$ (7)	$ 0	$ (153)