Derivative Financial Instruments (Derivative Classifications and Hedging Relationships) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivative financial instruments, notional values	$ 59,318	$ 72,795
Total derivative asset	864	1,450
Amounts subject to master netting arrangements not offset due to policy election, assets column	(514)	(797)
Cash collateral (received) posted	(44)	(41)
Net amount	306	612
Total derivative liability	(970)	(1,437)
Amounts subject to master netting arrangements not offset due to policy election, liabilities column	514	797
Cash collateral (received) posted	386	607
Net amount	(70)	(33)
Cash Flow Hedges [Member] | Interest Rate Contract [Member] | Pay Fixed Swaps [Member] | Three Month LIBOR Funding [Member]
Designated notional values, derivatives as cash flow hedges	4,300	6,035
Cash flow hedge derivative instrument assets at fair value	0	0
Cash flow hedge derivative instrument liabilities at fair value	(203)	(298)
Fair Value Hedges [Member] | Interest Rate Contract [Member]
Notional value of derivatives as fair value hedge	7,345	1,332
Fair value hedge assets	102	182
Fair value hedge liabilities	(89)	(160)
Fair Value Hedges [Member] | Interest Rate Contract [Member] | Received Fixed Swaps And Option Trades [Member] | Long-term Debt [Member]
Notional value of derivatives as fair value hedge	6,822	800
Fair value hedge assets	102	182
Fair value hedge liabilities	(3)	0
Fair Value Hedges [Member] | Interest Rate Contract [Member] | Pay Fixed Swaps [Member] | Commercial Loans [Member]
Notional value of derivatives as fair value hedge	178	187
Fair value hedge assets	0	0
Fair value hedge liabilities	(3)	(7)
Fair Value Hedges [Member] | Interest Rate Contract [Member] | Pay Fixed Swaps [Member] | Municipal Securities [Member]
Notional value of derivatives as fair value hedge	345	345
Fair value hedge assets	0	0
Fair value hedge liabilities	(83)	(153)
Not Designated as Hedging Instrument [Member]
Notional amount of other derivatives not designated as hedging instruments	47,673	65,428
Total derivative asset	762	1,268
Total derivative liability	(678)	(979)
Not Designated as Hedging Instrument [Member] | Client-Related and Other Risk Management [Member]
Notional amount of other derivatives not designated as hedging instruments	19,414	22,750
Total derivative asset	411	715
Total derivative liability	(446)	(748)
Not Designated as Hedging Instrument [Member] | Client-Related and Other Risk Management [Member] | Interest Rate Contract [Member] | Receive Fixed Swaps [Member]
Notional amount of other derivatives not designated as hedging instruments	8,619	9,352
Total derivative asset	370	687
Total derivative liability	(37)	0
Not Designated as Hedging Instrument [Member] | Client-Related and Other Risk Management [Member] | Interest Rate Contract [Member] | Pay Fixed Swaps [Member]
Notional amount of other derivatives not designated as hedging instruments	8,401	9,464
Total derivative asset	31	0
Total derivative liability	(396)	(717)
Not Designated as Hedging Instrument [Member] | Client-Related and Other Risk Management [Member] | Interest Rate Contract [Member] | Other Swaps [Member]
Notional amount of other derivatives not designated as hedging instruments	2,010	3,400
Total derivative asset	8	24
Total derivative liability	(10)	(28)
Not Designated as Hedging Instrument [Member] | Client-Related and Other Risk Management [Member] | Foreign Exchange Contract [Member]
Notional amount of other derivatives not designated as hedging instruments	384	534
Total derivative asset	2	4
Total derivative liability	(3)	(3)
Not Designated as Hedging Instrument [Member] | Mortgage Banking [Member] | Interest Rate Contract [Member]
Notional amount of other derivatives not designated as hedging instruments	5,500	15,165
Total derivative asset	45	71
Total derivative liability	(28)	(22)
Not Designated as Hedging Instrument [Member] | Mortgage Banking [Member] | Interest Rate Contract [Member] | Other Swaps [Member]
Notional amount of other derivatives not designated as hedging instruments	531	215
Total derivative asset	8	6
Total derivative liability	(7)	(2)
Not Designated as Hedging Instrument [Member] | Mortgage Banking [Member] | Interest Rate Contract [Member] | Interest Rate Lock Commitments [Member]
Notional amount of other derivatives not designated as hedging instruments	1,869	6,064
Total derivative asset	3	55
Total derivative liability	(14)	(1)
Not Designated as Hedging Instrument [Member] | Mortgage Banking [Member] | Interest Rate Contract [Member] | When Issued Securities And Forward Rate Agreements And Forward Commitments [Member]
Notional amount of other derivatives not designated as hedging instruments	3,100	8,886
Total derivative asset	34	10
Total derivative liability	(7)	(19)
Not Designated as Hedging Instrument [Member] | MSRs [Member] | Interest Rate Contract [Member]
Notional amount of other derivatives not designated as hedging instruments	22,759	27,513
Total derivative asset	306	482
Total derivative liability	(204)	(209)
Not Designated as Hedging Instrument [Member] | MSRs [Member] | Interest Rate Contract [Member] | Receive Fixed Swaps [Member]
Notional amount of other derivatives not designated as hedging instruments	6,139	5,178
Total derivative asset	36	110
Total derivative liability	(141)	(27)
Not Designated as Hedging Instrument [Member] | MSRs [Member] | Interest Rate Contract [Member] | Pay Fixed Swaps [Member]
Notional amount of other derivatives not designated as hedging instruments	5,449	5,389
Total derivative asset	89	7
Total derivative liability	(29)	(94)
Not Designated as Hedging Instrument [Member] | MSRs [Member] | Interest Rate Contract [Member] | Option Trades [Member]
Notional amount of other derivatives not designated as hedging instruments	9,415	14,510
Total derivative asset	181	363
Total derivative liability	(31)	(88)
Not Designated as Hedging Instrument [Member] | MSRs [Member] | Interest Rate Contract [Member] | When Issued Securities And Forward Rate Agreements And Forward Commitments [Member]
Notional amount of other derivatives not designated as hedging instruments	1,756	2,406
Total derivative asset	0	2
Total derivative liability	(3)	0
Not Designated as Hedging Instrument [Member] | MSRs [Member] | Interest Rate Contract [Member] | Futures Contracts [Member]
Notional amount of other derivatives not designated as hedging instruments	0	30
Total derivative asset	0	0
Total derivative liability	$ 0	$ 0