Financial Derivatives (Derivatives Not Designated As Hedging Instruments under GAAP) (Details) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Derivative Notional Amount	$ 371,549,000,000	$ 340,317,000,000
Derivative Asset, Fair Value	4,851,000,000	5,234,000,000
Derivative Liability, Fair Value	3,827,000,000	4,027,000,000
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Notional Amount	53,342,000,000	49,061,000,000
Derivative Asset, Fair Value	1,172,000,000	1,261,000,000
Derivative Liability, Fair Value	225,000,000	186,000,000
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative Notional Amount	318,207,000,000	291,256,000,000
Derivative Asset, Fair Value	3,679,000,000	3,973,000,000
Derivative Liability, Fair Value	3,602,000,000	3,841,000,000
Not Designated as Hedging Instrument [Member] | Residential Mortgages [Member]
Derivative [Line Items]
Derivative Notional Amount	100,773,000,000	76,102,000,000
Derivative Asset, Fair Value	806,000,000	846,000,000
Derivative Liability, Fair Value	449,000,000	437,000,000
Not Designated as Hedging Instrument [Member] | Residential Mortgages [Member] | Residential Mortgage Servicing Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	89,786,000,000	68,976,000,000
Derivative Asset, Fair Value	742,000,000	814,000,000
Derivative Liability, Fair Value	428,000,000	416,000,000
Not Designated as Hedging Instrument [Member] | Residential Mortgages [Member] | Loan Sales Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	10,987,000,000	7,126,000,000
Derivative Asset, Fair Value	64,000,000	32,000,000
Derivative Liability, Fair Value	21,000,000	21,000,000
Not Designated as Hedging Instrument [Member] | Commercial Mortgage Banking [Member]
Derivative [Line Items]
Derivative Notional Amount	25,756,000,000	26,290,000,000
Derivative Asset, Fair Value	73,000,000	85,000,000
Derivative Liability, Fair Value	56,000,000	59,000,000
Not Designated as Hedging Instrument [Member] | Commercial Mortgage Banking [Member] | Credit Default Swap [Member]
Derivative [Line Items]
Derivative Notional Amount	83,000,000	95,000,000
Not Designated as Hedging Instrument [Member] | Commercial Mortgage Banking [Member] | Commercial Mortgage Banking Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	25,673,000,000	26,195,000,000
Derivative Asset, Fair Value	73,000,000	85,000,000
Derivative Liability, Fair Value	56,000,000	59,000,000
Not Designated as Hedging Instrument [Member] | Customer Contracts [Member]
Derivative [Line Items]
Derivative Notional Amount	187,110,000,000	183,474,000,000
Derivative Asset, Fair Value	2,765,000,000	2,956,000,000
Derivative Liability, Fair Value	2,594,000,000	2,834,000,000
Not Designated as Hedging Instrument [Member] | Customer Contracts [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	10,895,000,000	12,547,000,000
Derivative Asset, Fair Value	215,000,000	223,000,000
Derivative Liability, Fair Value	202,000,000	240,000,000
Not Designated as Hedging Instrument [Member] | Customer Contracts [Member] | Risk Participation Agreement [Member]
Derivative [Line Items]
Derivative Notional Amount	5,076,000,000	5,124,000,000
Derivative Asset, Fair Value	2,000,000	2,000,000
Derivative Liability, Fair Value	5,000,000	4,000,000
Not Designated as Hedging Instrument [Member] | Customer Contracts [Member] | Customer Related Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	171,139,000,000	165,803,000,000
Derivative Asset, Fair Value	2,548,000,000	2,731,000,000
Derivative Liability, Fair Value	2,387,000,000	2,590,000,000
Not Designated as Hedging Instrument [Member] | Other Risk Management Activity [Member]
Derivative [Line Items]
Derivative Notional Amount	4,568,000,000	5,390,000,000
Derivative Asset, Fair Value	35,000,000	86,000,000
Derivative Liability, Fair Value	503,000,000	511,000,000
Not Designated as Hedging Instrument [Member] | Other Risk Management Activity [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Derivative Notional Amount		833,000,000
Derivative Asset, Fair Value		1,000,000
Not Designated as Hedging Instrument [Member] | Other Risk Management Activity [Member] | Credit Default Swap [Member]
Derivative [Line Items]
Derivative Notional Amount	15,000,000	15,000,000
Not Designated as Hedging Instrument [Member] | Other Risk Management Activity [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	2,519,000,000	2,661,000,000
Derivative Asset, Fair Value	35,000,000	85,000,000
Derivative Liability, Fair Value	18,000,000	1,000,000
Not Designated as Hedging Instrument [Member] | Other Risk Management Activity [Member] | Other Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	2,034,000,000	1,881,000,000
Derivative Liability, Fair Value	485,000,000	510,000,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Residential Mortgage Servicing Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	35,043,000,000	32,459,000,000
Derivative Asset, Fair Value	709,000,000	777,000,000
Derivative Liability, Fair Value	396,000,000	394,000,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Commercial Mortgage Banking Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	3,793,000,000	3,801,000,000
Derivative Asset, Fair Value	62,000,000	67,000,000
Derivative Liability, Fair Value	49,000,000	48,000,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Customer Related Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	149,054,000,000	146,008,000,000
Derivative Asset, Fair Value	2,455,000,000	2,632,000,000
Derivative Liability, Fair Value	2,350,000,000	2,559,000,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swaption [Member] | Residential Mortgage Servicing Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	3,176,000,000	1,498,000,000
Derivative Asset, Fair Value	23,000,000	29,000,000
Derivative Liability, Fair Value	21,000,000	22,000,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swaption [Member] | Commercial Mortgage Banking Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	439,000,000	439,000,000
Derivative Asset, Fair Value	1,000,000	2,000,000
Derivative Liability, Fair Value	1,000,000	1,000,000
Not Designated as Hedging Instrument [Member] | Interest Rate Swaption [Member] | Customer Related Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	4,496,000,000	3,361,000,000
Derivative Asset, Fair Value	59,000,000	62,000,000
Derivative Liability, Fair Value	17,000,000	12,000,000
Not Designated as Hedging Instrument [Member] | Future [Member] | Residential Mortgage Servicing Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	19,177,000,000	22,084,000,000
Not Designated as Hedging Instrument [Member] | Future [Member] | Loan Sales Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	40,000,000	58,000,000
Not Designated as Hedging Instrument [Member] | Future [Member] | Commercial Mortgage Banking Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	20,146,000,000	19,913,000,000
Not Designated as Hedging Instrument [Member] | Future [Member] | Customer Related Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	2,433,000,000	3,112,000,000
Not Designated as Hedging Instrument [Member] | Future Options [Member] | Residential Mortgage Servicing Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	30,000,000,000	12,225,000,000
Derivative Asset, Fair Value	6,000,000	4,000,000
Derivative Liability, Fair Value	3,000,000
Not Designated as Hedging Instrument [Member] | Residential Mortgage Loan Commitment [Member] | Loan Sales Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	2,437,000,000	1,852,000,000
Derivative Asset, Fair Value	21,000,000	22,000,000
Not Designated as Hedging Instrument [Member] | Commercial Mortgage Loan Commitment [Member] | Commercial Mortgage Banking Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	1,295,000,000	2,042,000,000
Derivative Asset, Fair Value	10,000,000	16,000,000
Derivative Liability, Fair Value	6,000,000	10,000,000
Not Designated as Hedging Instrument [Member] | Bond Option [Member] | Loan Sales Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	300,000,000	300,000,000
Derivative Asset, Fair Value	4,000,000
Not Designated as Hedging Instrument [Member] | Caps Floors Sold [Member] | Customer Related Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	5,142,000,000	4,846,000,000
Derivative Liability, Fair Value	15,000,000	16,000,000
Not Designated as Hedging Instrument [Member] | Caps Floors Purchased [Member] | Customer Related Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	6,462,000,000	6,339,000,000
Derivative Asset, Fair Value	28,000,000	34,000,000
Not Designated as Hedging Instrument [Member] | Mortgage Backed Securities Commitments [Member] | Residential Mortgage Servicing Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	2,390,000,000	710,000,000
Derivative Asset, Fair Value	4,000,000	4,000,000
Derivative Liability, Fair Value	8,000,000
Not Designated as Hedging Instrument [Member] | Mortgage Backed Securities Commitments [Member] | Loan Sales Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	8,210,000,000	4,916,000,000
Derivative Asset, Fair Value	39,000,000	10,000,000
Derivative Liability, Fair Value	21,000,000	21,000,000
Not Designated as Hedging Instrument [Member] | Mortgage Backed Securities Commitments [Member] | Customer Related Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Notional Amount	3,552,000,000	2,137,000,000
Derivative Asset, Fair Value	6,000,000	3,000,000
Derivative Liability, Fair Value	$ 5,000,000	$ 3,000,000