Shareholders' Equity (Adjustments to Accumulated Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Class of Stock [Line Items]
Net interest revenue	$ 596	$ 672	$ 1,172	$ 1,297
Processing fees and other revenue	(55)	(299)	(303)	(153)
Total reclassifications out of AOCI	571	480	1,026	897
Reclassification out of Accumulated Other Comprehensive Income [Member]
Class of Stock [Line Items]
Total reclassifications out of AOCI	11		16
Net Unrealized Gains (Losses) on Cash Flow Hedges | Interest-rate contracts | Reclassification out of Accumulated Other Comprehensive Income [Member]
Class of Stock [Line Items]
Net interest revenue	1		2
Interest-rate contracts, tax	1		1
Net Unrealized Gains (Losses) on Available-for-Sale Securities | Reclassification out of Accumulated Other Comprehensive Income [Member]
Class of Stock [Line Items]
Net gains (losses) from sales of available-for-sale securities	0		(3)
Net realized gasin from sales of available-for-sale securities, tax	0		(2)
Other-Than-Temporary Impairment on Held-to-Maturity Securities | Reclassification out of Accumulated Other Comprehensive Income [Member]
Class of Stock [Line Items]
Available-for-sale securities, Losses reclassified (from) to other comprehensive income	4		4
Held-to-maturity securities, Losses reclassified (from) to other comprehensive income	0		2
Other-than-temporary impairment on available-for-sale securities related to factors other than credit, tax	2		2
Other-than-temporary impairment on available-for-sale securities related to factors other than credit, tax	0		2
Unrealized Losses on Retirement Plans | Reclassification out of Accumulated Other Comprehensive Income [Member]
Class of Stock [Line Items]
Compensation and employee benefits expense	5		10
Amortization of actuarial loses, tax	3		6
Foreign Currency Translation | Reclassification out of Accumulated Other Comprehensive Income [Member]
Class of Stock [Line Items]
Processing fees and other revenue	1		1
Sale foreign entites, tax	$ 1		$ 1