CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 204	$ 1	$ 455	$ 284
Net change in unrealized gains (losses), net of tax:
Investment securities	5	(87)	(236)	218
Other-than-temporarily impaired debt securities held-to-maturity	0	6	0	9
Derivatives designated as cash flow hedges	(32)	(5)	(20)	(40)
Pension and post-retirement benefit plans	0	0	1	0
Total other comprehensive income (loss)	(27)	(86)	(255)	187
Comprehensive income (loss)	$ 177	$ (85)	$ 200	$ 471