Derivative Instruments And Hedging Activities (Fair Value Amounts Of Derivative Instruments Reported On Our Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 209	$ 233
Derivative Liability, Fair Value, Gross Liability	87	145
Derivative, Notional Amount	44,260	59,116
Accrued Interest [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	15	46
Derivative Liability, Fair Value, Gross Liability	4	12
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	168	126
Derivative Liability, Fair Value, Gross Liability	22	10
Derivative, Notional Amount	8,313	14,340
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	164	126
Derivative Liability, Fair Value, Gross Liability	22	9
Derivative, Notional Amount	8,101	14,151
Hedge notional amount associated with debt maturing in five or more years	2,600
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4	0
Derivative Liability, Fair Value, Gross Liability	0	1
Derivative, Notional Amount	212	189
Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	146	112
Receive-fixed Swaps, Fair Value, Gross Liability	0	3
Receive-fixed Swaps, Notional Amount	2,600	6,800
Pay-fixed Swaps, Fair Value, Gross Asset	0	13
Pay-fixed Swaps, Fair Value, Gross Liability	22	3
Pay-fixed Swaps, Notional Amount	4,800	6,800
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	36	105
Derivative Liability, Fair Value, Gross Liability	57	125
Derivative, Notional Amount	35,802	44,466
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	3	0
Derivative Liability, Fair Value, Gross Liability	2	0
Derivative, Notional Amount	127	278
Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2	2
Derivative Liability, Fair Value, Gross Liability	6	10
Derivative, Notional Amount	18	32
Interest Rate Swap [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	17	30
Derivative Liability, Fair Value, Gross Liability	39	51
Derivative, Notional Amount	1,461	6,101
Foreign Exchange Forward [Member] | Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	3	0
Derivative Liability, Fair Value, Gross Liability	2	0
Derivative, Notional Amount	127	278
Futures and Forwards [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	2
Derivative Liability, Fair Value, Gross Liability	0	2
Derivative, Notional Amount	501	1,905
Written Options [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	18	72
Derivative, Notional Amount	16,920	18,220
Written Options [Member] | Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	1	1
Derivative, Notional Amount	1	0
Purchased Options [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	18	73
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	16,920	18,240
Purchased Options [Member] | Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2	2
Derivative Liability, Fair Value, Gross Liability	0	0
Derivative, Notional Amount	0	0
Forward Contracts [Member] | Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	0
Derivative Liability, Fair Value, Gross Liability	5	9
Derivative, Notional Amount	17	32
Other Trading [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	41	107
Derivative Liability, Fair Value, Gross Liability	65	135
Derivative, Notional Amount	35,947	44,776
Secured Debt [Member] | Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	18	1
Receive-fixed Swaps, Fair Value, Gross Liability	0	2
Receive-fixed Swaps, Notional Amount	$ 698	$ 500