Fair Value (Fair Value Measurement - Reconciliation of Level 3 Assets And Liabilities) (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
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	$ 74	$ 115	$ 99	$ 1,151
Net realized/unrealized gains (losses) included in earnings, Assets	4	55	9	(93)
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	(911)
Issuances, Assets	0	0	0	60
Settlements, Assets	(17)	8	(50)	(29)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		3
Fair Value, Assets, Ending balance	61	178	61	178
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	47	0	38
Mortgage Servicing Rights [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance				952
Net realized/unrealized gains (losses) included in earnings, Assets	0	0	0	(101)
Net realized/unrealized gains (losses) included in other comprehensive income, Assets				0
Purchases, Assets				0
Sales, Assets				(911)
Issuances, Assets				60
Settlements, Assets				0
Fair Value, Assets, Ending balance		0		0
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)				0
Retained Interest [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	74	124	100	154
Net realized/unrealized gains (losses) included in earnings, Assets	4	8	9	19
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	(17)	(11)	(48)	(52)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		0
Fair Value, Assets, Ending balance	61	121	61	121
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		(9)		45
Gain (Loss) Included in Earnings, Net Derivative Asset (Liability)		47		(11)
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)		19		23
Fair Value, Net Derivative Asset (Liability), Ending balance		57		57
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		47		38
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			(1)	47
Gain (Loss) Included in Earnings, Net Derivative Asset (Liability)			0	(51)
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)			(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)			0	0
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		(9)		(2)
Gain (Loss) Included in Earnings, Net Derivative Asset (Liability)		47		40
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)		19		19
Fair Value, Net Derivative Asset (Liability), Ending balance		57		57
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)		47		38
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				(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