Investment Securities (Gains and Losses Related to Investment Securities) (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Gross realized gains from sales of available-for-sale securities	$ 30,000,000		$ 32,000,000		$ 87,000,000		$ 51,000,000
Gross realized losses from sales of available-for-sale securities(1)	(30,000,000)	[1]	(46,000,000)	[1]	(82,000,000)	[1]	(46,000,000)	[1]
Gross losses from other-than-temporary impairment	0		(21,000,000)		0		(46,000,000)
Losses reclassified (from) to other comprehensive income	(7,000,000)		8,000,000		(10,000,000)		25,000,000
Gains (losses) related to investment securities, net	(7,000,000)		(27,000,000)		(5,000,000)		(16,000,000)
Impairment associated with expected credit losses	0		(9,000,000)		0		(13,000,000)
Impairment associated with management's intent to sell impaired securities prior to recovery in value	(6,000,000)		0		(6,000,000)		0
Impairment associated with adverse changes in timing of expected future cash flows	(1,000,000)		(4,000,000)		(4,000,000)		(8,000,000)
Net impairment losses recognized in consolidated statement of income	7,000,000		13,000,000		10,000,000		21,000,000
Available for sale, amortized cost	100,065,000,000				100,065,000,000				108,563,000,000
GREECE
Available-For-Sale and Held-To-Maturity-Securities [Line Items]
Gross realized losses from sales of available-for-sale securities(1)			46,000,000
Available for sale, amortized cost			$ 91,000,000				$ 91,000,000

[1] In the three months ended June 30, 2012, we sold all of our Greek securities, which had an aggregate carrying value of approximately $91 million, and recorded a pre-tax loss of $46 million in our consolidated statement of income.