Shareholders' Equity (Adjustments to Accumulated Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Class of Stock [Line Items]
Net interest revenue	$ 546	$ 619	$ 1,718	$ 1,916
Net gains (losses) from sales of available-for-sale securities			11
Processing fees and other revenue	326	172	23	19
Total reclassifications out of AOCI	531	654	1,557	1,551
Reclassification out of Accumulated Other Comprehensive Income [Member]
Class of Stock [Line Items]
Total reclassifications out of AOCI	2		18
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	0		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	(4)		(7)
Net realized gasin from sales of available-for-sale securities, tax	(2)		(4)
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	0		4
Held-to-maturity securities, Losses reclassified (from) to other comprehensive income	1		3
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	1		3
Net Unrealized Losses on Retirement Plans | Reclassification out of Accumulated Other Comprehensive Income [Member]
Class of Stock [Line Items]
Compensation and employee benefits expense	5		15
Amortization of actuarial loses, tax	3		9
Foreign Currency Translation | Reclassification out of Accumulated Other Comprehensive Income [Member]
Class of Stock [Line Items]
Processing fees and other revenue	0		1
Sale foreign entites, tax	$ 1		$ 1