Derivative Financial Instruments (Effect of Derivative Instruments on the Consolidated Statements of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Gain (loss) on interest rate derivative instruments not designated as hedging instruments			$ 128	$ (149)
Cash Flow Hedges [Member] | Interest Rate Contract [Member]
Derivative instruments, gain (loss) recognized in OCI, effective portion, net	(8)	(13)	(33)	207
Cash Flow Hedges [Member] | Interest Rate Contract [Member] | Interest Expense [Member]
Derivative instruments, (gain) loss reclassified from AOCI into income, effective portion, net	(21)	(18)	(61)	(58)
Fair Value Hedges [Member] | Interest Rate Contract [Member]
Derivative instruments, gain (loss) recognized in income, net	53	28	152	77
Fair Value Hedges [Member] | Interest Rate Contract [Member] | Interest Income [Member]
Derivative instruments, gain (loss) recognized in income, net	(5)	(6)	(16)	(16)
Fair Value Hedges [Member] | Interest Rate Contract [Member] | Interest Expense [Member]
Derivative instruments, gain (loss) recognized in income, net	58	34	168	93
Not Designated as Hedging Instrument [Member]
Derivative instruments, gain (loss) recognized in income, net	58	(212)	149	(225)
Not Designated as Hedging Instrument [Member] | Client-Related and Other Risk Management [Member] | Interest Rate Contract [Member] | Other Income [Member]
Gain (loss) on interest rate derivative instruments not designated as hedging instruments	5	5	15	19
Not Designated as Hedging Instrument [Member] | Client-Related and Other Risk Management [Member] | Foreign Exchange Contract [Member] | Other Income [Member]
Gain (loss) on interest rate derivative instruments not designated as hedging instruments	10	(2)	13	6
Not Designated as Hedging Instrument [Member] | Mortgage Banking [Member] | Interest Rate Contract [Member] | Mortgage Banking Income [Member]
Gain (loss) on interest rate derivative instruments not designated as hedging instruments	20	(199)	(7)	(101)
Not Designated as Hedging Instrument [Member] | Residential MSRs [Member] | Interest Rate Contract [Member] | Mortgage Banking Income [Member]
Gain (loss) on interest rate derivative instruments not designated as hedging instruments	$ 23	$ (16)	$ 128	$ (149)