Balance Sheet Effect of Derivative Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Derivative, Collateral, Obligation to Return Cash	$ 2	$ 0
Notional	103,070	96,452
Fair Value of Derivative Assets	2,087	924
Fair Value of Derivative Liabilities	201	243
Designated as Hedging Instrument [Member] \| Fair Value Hedging [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Notional	35,581	28,964
Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Notional	62,637	62,638
Not Designated as Hedging Instrument [Member] \| Foreign Exchange Contract [Member]
Derivative [Line Items]
Notional	1,302	1,713
Not Designated as Hedging Instrument [Member] \| Cross Currency Interest Rate Contract [Member]
Derivative [Line Items]
Notional	3,550	3,137
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member]
Derivative [Line Items]
Fair Value of Derivative Assets	2,087	924
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(147)	(167)
Derivative Asset	1,940	757
Fair Value of Derivative Liabilities	201	243
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	(147)	(167)
Derivative Liability	54	76
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Designated as Hedging Instrument [Member] \| Fair Value Hedging [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Fair Value of Derivative Assets	1,572	670
Fair Value of Derivative Liabilities	0	16
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Fair Value of Derivative Assets	173	159
Fair Value of Derivative Liabilities	185	112
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Not Designated as Hedging Instrument [Member] \| Foreign Exchange Contract [Member]
Derivative [Line Items]
Fair Value of Derivative Assets	84	22
Fair Value of Derivative Liabilities	1	4
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Not Designated as Hedging Instrument [Member] \| Cross Currency Interest Rate Contract [Member]
Derivative [Line Items]
Fair Value of Derivative Assets	258	73
Fair Value of Derivative Liabilities	$ 15	$ 111

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

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-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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