Balance Sheet Effect of Derivative Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional	$ 136,470	$ 142,760
Derivative Asset, Current	500	681
Derivative Asset, Noncurrent	491	540
Derivative Asset	991	1,221
Derivative Liability, Current	868	601
Derivative Liability, Noncurrent	368	312
Derivative Liability	1,236	913
Held collateral	26	19
Posted collateral	63	59
Designated as Hedging Instrument [Member] \| Foreign Exchange Contract [Member] \| Cash Flow Hedging [Member]
Derivative [Line Items]
Notional	15,310	15,972
Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Fair Value Hedging [Member]
Derivative [Line Items]
Notional	23,894	22,989
Designated as Hedging Instrument [Member] \| Commodity Contract [Member] \| Cash Flow Hedging [Member]
Derivative [Line Items]
Notional	597	327
Not Designated as Hedging Instrument [Member] \| Foreign Exchange Contract [Member]
Derivative [Line Items]
Notional	22,171	20,695
Not Designated as Hedging Instrument [Member] \| Cross-currency interest rate swap contracts [Member]
Derivative [Line Items]
Notional	6,331	5,235
Not Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Notional	67,726	76,904
Not Designated as Hedging Instrument [Member] \| Commodity Contract [Member]
Derivative [Line Items]
Notional	441	638
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member]
Derivative [Line Items]
Fair Value of Assets	991	1,221
Fair Value of Liabilities	1,236	913
Counterparty Netting, Not Offset	529	434
Counterparty Netting, Not Offset	529	434
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	183	391
Fair Value of Liabilities	429	110
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	217	158
Fair Value of Liabilities	143	208
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Designated as Hedging Instrument [Member] \| Commodity Contract [Member] \| Cash Flow Hedging [Member]
Derivative [Line Items]
Fair Value of Assets	4	0
Fair Value of Liabilities	9	20
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	221	202
Fair Value of Liabilities	129	99
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	146	232
Fair Value of Liabilities	216	157
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	216	235
Fair Value of Liabilities	295	274
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Not Designated as Hedging Instrument [Member] \| Commodity Contract [Member]
Derivative [Line Items]
Fair Value of Assets	4	3
Fair Value of Liabilities	$ 15	$ 45

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

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