Derivative Instruments And Hedging Activities (Fair Value Amounts Of Derivative Instruments Reported On Our Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 299	$ 263
Derivative Liability, Fair Value, Gross Liability	176	252
Notional amount	67,942	81,200
Accrued Interest [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	34	50
Derivative Liability, Fair Value, Gross Liability	9	17
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	184	118
Derivative Liability, Fair Value, Gross Liability	33	7
Notional amount	17,437	18,764
Interest Rate Swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	182	118
Derivative Liability, Fair Value, Gross Liability	33	7
Notional amount	17,204	18,554
Hedge notional amount associated with debt maturing in five or more years	2,200
Foreign Exchange Forward [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	2	0
Derivative Liability, Fair Value, Gross Liability	0	0
Notional amount	233	210
Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Receive-fixed Swaps, Fair Value, Gross Asset	182	97
Receive-fixed Swaps, Fair Value, Gross Liability	0	1
Receive-fixed Swaps, Notional Amount	5,700	4,700
Pay-fixed Swaps, Fair Value, Gross Asset	0	21
Pay-fixed Swaps, Fair Value, Gross Liability	33	6
Pay-fixed Swaps, Notional Amount	11,500	13,900
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	110	138
Derivative Liability, Fair Value, Gross Liability	131	161
Notional amount	50,296	60,847
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	5
Derivative Liability, Fair Value, Gross Liability	1	78
Notional amount	161	1,514
Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4	2
Derivative Liability, Fair Value, Gross Liability	11	6
Notional amount	48	75
Interest Rate Swap [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	50	40
Derivative Liability, Fair Value, Gross Liability	71	65
Notional amount	6,353	11,979
Foreign Exchange Forward [Member] | Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	5
Derivative Liability, Fair Value, Gross Liability	1	4
Notional amount	161	304
Futures and Forwards [Member] | Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	5	4
Derivative Liability, Fair Value, Gross Liability	4	2
Notional amount	7,850	18,886
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	56	94
Notional amount	18,007	14,823
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	3	3
Notional amount	1	1
Purchased Options [Member] | Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	55	94
Derivative Liability, Fair Value, Gross Liability	0	0
Notional amount	18,086	15,159
Purchased Options [Member] | Equity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4	2
Derivative Liability, Fair Value, Gross Liability	0	0
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	8	3
Notional amount	47	74
Swap [Member] | Foreign Exchange 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	0	74
Notional amount	0	1,210
Other Trading [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	115	145
Derivative Liability, Fair Value, Gross Liability	143	245
Notional amount	$ 50,505	$ 62,436