Fair Value (Fair Value Measurement - Reconciliation of Level 3 Assets And Liabilities) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	$ 84	$ 1,061	$ 99	$ 1,151
Net realized/unrealized gains (losses) included in earnings, Assets	4	(17)	5	(148)
Net realized/unrealized gains (losses) included in other comprehensive income, Assets	0	0	0	0
Purchases, Assets	0	0	0	0
Sales, Assets	0	(911)	0	(911)
Issuances, Assets	0	6	0	60
Settlements, Assets	(14)	(24)	(33)	(37)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		3
Fair Value, Assets, Ending balance	74	115	74	115
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	(26)	0	(125)
Mortgage Servicing Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance		917		952
Net realized/unrealized gains (losses) included in earnings, Assets	0	(12)	0	(101)
Net realized/unrealized gains (losses) included in other comprehensive income, Assets		0		0
Purchases, Assets		0		0
Sales, Assets		(911)		(911)
Issuances, Assets		6		60
Settlements, Assets		0		0
Fair Value, Assets, Ending balance		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(12)		(101)
Retained Interest [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	84	139	100	154
Net realized/unrealized gains (losses) included in earnings, Assets	4	9	5	11
Net realized/unrealized gains (losses) included in other comprehensive income, Assets	0	0	0	0
Purchases, Assets	0	0	0	0
Sales, Assets	0	0	0	0
Issuances, Assets	0	0	0	0
Settlements, Assets	(14)	(24)	(31)	(41)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		0
Fair Value, Assets, Ending balance	74	124	74	124
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Derivative Financial Instruments, Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Net Derivative Asset (Liability), Beginning balance		5		45
Gain (Loss) Included in Earnings, Net Derivative Asset (Liability)		(14)		(58)
Gain (Loss) Included in Other Comprehensive Income (Loss), Net Derivative Asset (Liability)		0		0
Purchases, Net Derivative Asset (Liability)		0		0
Sales, Net Derivative Asset (Liability)		0		0
Issuances, Net Derivative Asset (Liability)		0		0
Settlements, Net Derivative Asset (Liability)		0		4
Fair Value, Net Derivative Asset (Liability), Ending balance		(9)		(9)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(14)		(24)
Interest Rate Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Net Derivative Asset (Liability), Beginning balance		5	(1)	47
Gain (Loss) Included in Earnings, Net Derivative Asset (Liability)		(5)	0	(51)
Gain (Loss) Included in Other Comprehensive Income (Loss), Net Derivative Asset (Liability)		0	0	0
Purchases, Net Derivative Asset (Liability)		0	0	0
Sales, Net Derivative Asset (Liability)		0	0	0
Issuances, Net Derivative Asset (Liability)		0	0	0
Settlements, Net Derivative Asset (Liability)		0	(2)	4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3			78
Transfers out of Level 3, Net Derivative Asset (Liability)			3
Fair Value, Net Derivative Asset (Liability), Ending balance	0	0	0	0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(6)	0	(15)
Foreign Exchange Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Net Derivative Asset (Liability), Beginning balance		0		(2)
Gain (Loss) Included in Earnings, Net Derivative Asset (Liability)		(9)		(7)
Gain (Loss) Included in Other Comprehensive Income (Loss), Net Derivative Asset (Liability)		0		0
Purchases, Net Derivative Asset (Liability)		0		0
Sales, Net Derivative Asset (Liability)		0		0
Issuances, Net Derivative Asset (Liability)		0		0
Settlements, Net Derivative Asset (Liability)		0		0
Fair Value, Net Derivative Asset (Liability), Ending balance		(9)		(9)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		(8)		(9)
Fair Value, Inputs, Level 3 [Member] | Mortgage Servicing Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net realized/unrealized gains (losses) included in earnings, Assets		(12)		(101)
Interest Rate Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3			$ 81