Derivative Financial Instruments and Hedging Activities - Income (Losses) Recognized in Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Derivatives, Fair Value [Line Items]
Interest expense	$ 835	$ 947
Operating expenses	358	370
AOCI Attributable to Parent [Member]
Derivatives, Fair Value [Line Items]
Gains (Losses) Recognized In Accumulated Other Comprehensive Loss	(230)	(63)
(Gains) Losses Reclassified From Accumulated Other Comprehensive Income	113	48
Fair Value Hedging [Member] \| Foreign Currency Translation Adjustment [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Gains (Losses) Recognized In Accumulated Other Comprehensive Loss	(5)	(11)
(Gains) Losses Reclassified From Accumulated Other Comprehensive Income	8	11
Cash Flow Hedging [Member] \| Foreign Currency Translation Adjustment [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Gains (Losses) Recognized In Accumulated Other Comprehensive Loss	(219)	(52)
(Gains) Losses Reclassified From Accumulated Other Comprehensive Income	104	39
Cash Flow Hedging [Member] \| Unrealized (Loss) Gain on Hedges [Member] \| Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Gains (Losses) Recognized In Accumulated Other Comprehensive Loss	(6)	0
(Gains) Losses Reclassified From Accumulated Other Comprehensive Income	1	(2)
Interest Expense [Member]
Derivatives, Fair Value [Line Items]
Total	(62)	(65)
Operating Expense [Member]
Derivatives, Fair Value [Line Items]
Total	(105)	(32)
Designated as Hedging Instrument [Member] \| Foreign Currency Translation Adjustment [Member]
Derivatives, Fair Value [Line Items]
Gain (loss) to be reclassified in next twelve months	54
Designated as Hedging Instrument [Member] \| Interest Expense [Member] \| Fair Value Hedging [Member] \| Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Hedged items	(503)	(210)
Interest rate swaps and Foreign currency swaps	431	181
Designated as Hedging Instrument [Member] \| Interest Expense [Member] \| Fair Value Hedging [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Hedged items	0	0
Interest rate swaps and Foreign currency swaps	(12)	(16)
Designated as Hedging Instrument [Member] \| Interest Expense [Member] \| Cash Flow Hedging [Member] \| Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Interest rate swaps and Foreign currency swaps	(1)	3
Designated as Hedging Instrument [Member] \| Interest Expense [Member] \| Cash Flow Hedging [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Interest rate swaps and Foreign currency swaps	(29)	(18)
Designated as Hedging Instrument [Member] \| Operating Expense [Member] \| Fair Value Hedging [Member] \| Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Hedged items	0	0
Interest rate swaps and Foreign currency swaps	0	0
Designated as Hedging Instrument [Member] \| Operating Expense [Member] \| Fair Value Hedging [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Hedged items	40	32
Interest rate swaps and Foreign currency swaps	(39)	(31)
Designated as Hedging Instrument [Member] \| Operating Expense [Member] \| Cash Flow Hedging [Member] \| Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Interest rate swaps and Foreign currency swaps	0	0
Designated as Hedging Instrument [Member] \| Operating Expense [Member] \| Cash Flow Hedging [Member] \| Foreign Currency Swaps [Member]
Derivatives, Fair Value [Line Items]
Interest rate swaps and Foreign currency swaps	(106)	(33)
Not Designated as Hedging Instrument [Member] \| Interest Expense [Member]
Derivatives, Fair Value [Line Items]
Interest rate contracts	52	(5)
Not Designated as Hedging Instrument [Member] \| Operating Expense [Member]
Derivatives, Fair Value [Line Items]
Interest rate contracts	$ 0	$ 0

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

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Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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Amount of gain (loss) included in earnings for the period from the increase (decrease) in fair value of interest rate derivatives not designated as hedging instruments.

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Amount of the cost of borrowed funds accounted for as interest expense.

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Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense.

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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