Financial Derivatives (Derivatives Designated in GAAP Hedge Relationships - Cash Flow Hedges) (Details) (Cash Flow Hedging [Member], Interest Rate Contracts [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Derivatives, Fair Value [Line Items]
Gain (Loss) on Derivatives Recognized in OCI (Effective Portion)	$ (193)	$ 154	$ (179)	$ 207
Interest Income [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	80	116	186	232
Noninterest Income [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ 8	$ 32	$ 23	$ 59