Balance Sheet Effect of Derivative Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Notional	$ 85,767	$ 83,713
Fair Value of Derivative Assets	823	859
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(161)	(136)
Derivative Asset	662	723
Fair Value of Derivative Liabilities	378	167
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	(161)	(136)
Derivative Liability	217	31
Designated as Hedging Instrument [Member] \| Fair Value Hedging [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Notional	24,202	23,203
Fair Value of Derivative Assets	572	602
Fair Value of Derivative Liabilities	38	38
Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Notional	57,897	56,558
Fair Value of Derivative Assets	157	168
Fair Value of Derivative Liabilities	132	89
Not Designated as Hedging Instrument [Member] \| Foreign Exchange Contract [Member]
Derivative [Line Items]
Notional	1,265	1,527
Fair Value of Derivative Assets	0	18
Fair Value of Derivative Liabilities	41	1
Not Designated as Hedging Instrument [Member] \| Cross Currency Interest Rate Contract [Member]
Derivative [Line Items]
Notional	2,403	2,425
Fair Value of Derivative Assets	94	71
Fair Value of Derivative Liabilities	$ 167	$ 39

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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