Investment Securities (Gains and Losses Related to Investment Securities) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]
Gross realized gains from sales of available-for-sale securities	$ 48	$ 11	$ 64	$ 98
Gross realized losses from sales of available-for-sale securities	(48)	(5)	(49)	(87)
Gross losses from other-than-temporary impairment	0	(13)	(1)	(19)
Losses reclassified (from) to other comprehensive income	0	3	(10)	(1)
Gains (losses) related to investment securities, net	0	(4)	4	(9)
Impairment associated with expected credit losses	0	(8)	(10)	(8)
Impairment Associated With Management's Intent To Sell The Impaired Securities Prior To Their Recovery In Value	0	0	0	6
Impairment associated with adverse changes in timing of expected future cash flows	0	(2)	(1)	(6)
Net impairment losses	$ 0	$ (10)	$ (11)	$ (20)