Accumulated Other Comprehensive Income (Components of Other Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Change in net unrealized gain on Securities available for sale:
Net unrealized gain (loss)	$ 126	$ (477)	$ 285	$ (480)
Reclassification of impairment charges included in net impairment losses on securities		3		7
Other reclassifications included in other revenue	(1)	(3)	(2)	(3)
Change in net unrealized gain on securities available for sale	125	(477)	283	(476)
Other				1
Other comprehensive income (loss), before tax	125	(477)	283	(475)
Change in net unrealized gain on Securities available for sale:
Net unrealized gain (loss)	(47)	179	(106)	181
Reclassification of impairment charges included in net impairment losses on securities				(2)
Other reclassifications included in other revenue		1		1
Change in net unrealized gain on securities available for sale	(47)	180	(106)	180
Other comprehensive (loss) income, tax effect	(47)	180	(106)	180
Change in net unrealized gain on securities available for sale:
Net unrealized gain (loss)	79	(298)	179	(299)
Reclassification of impairment charges included in net impairment losses on securities		3		5
Other reclassifications included in other revenue	(1)	(2)	(2)	(2)
Change in net unrealized gain on securities available for sale	78	(297)	177	(296)
Other				1
Other comprehensive income (loss), net of tax	$ 78	$ (297)	$ 177	$ (295)