Accumulated Other Comprehensive Income (Components of Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Change in net unrealized gain on Securities available for sale:
Net unrealized gain (loss)	$ 159	$ (3)
Reclassification of impairment charges included in net impairment losses on securities		4
Other reclassifications included in other revenue	(1)
Change in net unrealized gain on securities available for sale	158	1
Other		1
Other comprehensive income, before tax	158	2
Change in net unrealized gain on Securities available for sale:
Net unrealized gain (loss)	(59)	2
Reclassification of impairment charges included in net impairment losses on securities		(2)
Change in net unrealized gain on securities available for sale	(59)
Other comprehensive (loss) income, tax effect	(59)
Change in net unrealized gain on securities available for sale:
Net unrealized gain (loss)	100	(1)
Reclassification of impairment charges included in net impairment losses on securities		2
Other reclassifications included in other revenue	(1)
Change in net unrealized gain on securities available for sale	99	1
Other		1
Other comprehensive income, net of tax	$ 99	$ 2