Balance Sheet Effect of Derivative Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Notional	$ 137,924	$ 133,452
Derivative Asset, Current	623	802
Derivative Asset, Noncurrent	356	746
Derivative Asset	979	1,548
Derivative Liability, Current	532	568
Derivative Liability, Noncurrent	844	344
Derivative Liability	1,376	912
Held collateral	16	15
Posted collateral	59	38
Designated as Hedging Instrument [Member] \| Foreign Exchange Contract [Member] \| Cash Flow Hedging [Member]
Derivative [Line Items]
Notional	16,848	19,595
Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Fair Value Hedging [Member]
Derivative [Line Items]
Notional	27,769	28,008
Not Designated as Hedging Instrument [Member] \| Foreign Exchange Contract [Member]
Derivative [Line Items]
Notional	18,694	20,679
Not Designated as Hedging Instrument [Member] \| Cross-currency interest rate swap contracts [Member]
Derivative [Line Items]
Notional	5,649	4,006
Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Notional	68,226	60,504
Not Designated as Hedging Instrument [Member] \| Commodity Contract [Member]
Derivative [Line Items]
Notional	738	660
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member]
Derivative [Line Items]
Fair Value of Assets	979	1,548
Fair Value of Liabilities	1,376	912
Counterparty Netting, Not Offset	351	618
Counterparty Netting, Not Offset	351	618
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Designated as Hedging Instrument [Member] \| Foreign Exchange Contract [Member] \| Cash Flow Hedging [Member]
Derivative [Line Items]
Fair Value of Assets	196	407
Fair Value of Liabilities	137	306
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Fair Value Hedging [Member]
Derivative [Line Items]
Fair Value of Assets	112	248
Fair Value of Liabilities	632	135
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Not Designated as Hedging Instrument [Member] \| Foreign Exchange Contract [Member]
Derivative [Line Items]
Fair Value of Assets	210	172
Fair Value of Liabilities	98	302
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Not Designated as Hedging Instrument [Member] \| Cross-currency interest rate swap contracts [Member]
Derivative [Line Items]
Fair Value of Assets	206	408
Fair Value of Liabilities	166	28
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Fair Value of Assets	250	276
Fair Value of Liabilities	298	137
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Not Designated as Hedging Instrument [Member] \| Commodity Contract [Member]
Derivative [Line Items]
Fair Value of Assets	5	37
Fair Value of Liabilities	$ 45	$ 4

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

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