Financial Derivatives (Derivatives Not Designated as Hedging Instruments under GAAP) (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
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	$ 22	$ 217	$ 1	$ 319
Residential Mortgages [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	(30)	137	(35)	242
Residential Mortgages [Member] | Residential Mortgage Servicing Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	(172)	123	(211)	206
Residential Mortgages [Member] | Loan Sales Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	142	14	176	36
Commercial Mortgage Banking [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	1	19	6	20
Commercial Mortgage Banking [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	1	19	7	21
Commercial Mortgage Banking [Member] | Credit Default Swap [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments			(1)	(1)
Customer Contracts [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	63	26	101	76
Customer Contracts [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	67	(9)	86	27
Customer Contracts [Member] | Credit Default Swap [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	(2)	(1)	(3)	(2)
Customer Contracts [Member] | Equity Contract [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments		(3)	(3)	(5)
Customer Contracts [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	(2)	39	21	56
Other Risk Management Activity [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	(12)	35	(71)	(19)
Other Risk Management Activity [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	4	(8)	4	(7)
Other Risk Management Activity [Member] | Credit Default Swap [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments				(1)
Other Risk Management Activity [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	2	(1)	2	(1)
Other Risk Management Activity [Member] | Other Contract [Member]
Derivatives, Fair Value [Line Items]
Total gains (losses) from derivatives not designated as hedging instruments	$ (18)	$ 44	$ (77)	$ (10)