Fair Value (Fair Value Measurement - Reconciliation of Level 3 Assets And Liabilities) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ 0	$ 0	$ 0	$ 0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	36	74	50	99
Net realized/unrealized gains (losses) included in earnings, Assets	1	4	9	9
Net realized/unrealized gains (losses) included in other comprehensive income, Assets	0	0	0	0
Purchases, Assets	0	0	0	0
Sales, Assets	(4)	0	(4)	0
Issuances, Assets	1	0	2	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(5)	(17)	(28)	(50)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0	0	3
Fair Value, Assets, Ending balance	29	61	29	61
Loans Held-for-Sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0		0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	4		3
Net realized/unrealized gains (losses) included in earnings, Assets	0		1
Net realized/unrealized gains (losses) included in other comprehensive income, Assets	0		0
Purchases, Assets	0		0
Sales, Assets	(4)		(4)
Issuances, Assets	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	0		0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0		0
Fair Value, Assets, Ending balance	0		0
Retained Interest [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Assets, Beginning balance	32	74	47	100
Net realized/unrealized gains (losses) included in earnings, Assets	1	4	8	9
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	1	0	2	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	(5)	(17)	(28)	(48)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0	0	0	0
Fair Value, Assets, Ending balance	$ 29	61	$ 29	61
Interest Rate Contract [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)				0
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Net Derivative Asset (Liability), Beginning balance				(1)
Gain (Loss) Included in Earnings, Net Derivative Asset (Liability)				0
Gain (Loss) Included in Other Comprehensive Income (Loss), Net Derivative Asset (Liability)				0
Purchases, Net Derivative Asset (Liability)				0
Sales, Net Derivative Asset (Liability)				0
Issuances, Net Derivative Asset (Liability)				0
Settlements, Net Derivative Asset (Liability)				(2)
Transfers out of Level 3, Net Derivative Asset (Liability)				3
Fair Value, Net Derivative Asset (Liability), Ending balance		$ 0		$ 0