Investment Securities (Gains and Losses Related to Investment Securities) (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
Investments, Debt and Equity Securities [Abstract]
Gross realized gains from sales of available-for-sale securities	$ 1		$ 30		$ 16		$ 87
Gross realized losses from sales of available-for-sale securities	(1)		(30)		(1)		(82)
Gross losses from other-than-temporary impairment	0		(6)		(1)		(6)
Losses reclassified (from) to other comprehensive income	(2)		(1)		(10)		(4)
Gains (losses) related to investment securities, net	(2)		(7)		4		(5)
Impairment associated with expected credit losses	(1)		0		(10)		0
Impairment Associated With Management's Intent To Sell The Impaired Securities Prior To Their Recovery In Value	0		6		0		6
Impairment associated with adverse changes in timing of expected future cash flows	(1)		(1)		(1)		(4)
Net impairment losses	$ (2)	[1]	$ (7)	[1]	$ (11)	[1]	$ (10)	[1]

[1] Net impairment losses