Fair Value Measurements - Financial Assets and Liabilities at Fair Value (Details) - USD ($) $ in Millions	Apr. 01, 2018	Dec. 31, 2017
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	$ 354
Derivatives designated as hedging instruments : Liabilities	288
Available-for-sale Securities, Equity Securities	731	$ 751
Available-for-sale Securities	2,967	5,310
Quoted prices in active markets for identical assets and liabilities Level 1
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	0
Derivatives designated as hedging instruments : Liabilities	0
Available-for-sale Securities, Equity Securities	731	751
Available-for-sale Securities	0
Significant other observable inputs Level 2
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	354	349
Derivatives designated as hedging instruments : Liabilities	288	329
Available-for-sale Securities, Equity Securities	0
Available-for-sale Securities	2,967
Significant unobservable inputs Level 3
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	0
Derivatives designated as hedging instruments : Liabilities	0
Available-for-sale Securities, Equity Securities	0
Available-for-sale Securities	0
Interest Rate Contract
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	1,100	1,100
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	3
Derivatives designated as hedging instruments : Liabilities	19
Derivative Assets, Noncurrent	2	7
Derivative Liabilities, Noncurrent - interest swap	14	9
Interest Rate Contract \| Quoted prices in active markets for identical assets and liabilities Level 1
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	0
Derivatives designated as hedging instruments : Liabilities	0
Interest Rate Contract \| Significant other observable inputs Level 2
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	3	7
Derivatives designated as hedging instruments : Liabilities	19	15
Derivative Liability	83	165
Interest Rate Contract \| Significant unobservable inputs Level 3
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	0
Derivatives designated as hedging instruments : Liabilities	0
Foreign exchange contracts
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	35,300	34,500
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	351
Derivatives designated as hedging instruments : Liabilities	269
Derivatives not designated as hedging instruments : Assets	25
Derivatives not designated as hedging instruments : Liabilities	53
Foreign exchange contracts \| Quoted prices in active markets for identical assets and liabilities Level 1
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	0
Derivatives designated as hedging instruments : Liabilities	0
Derivatives not designated as hedging instruments : Assets	0
Derivatives not designated as hedging instruments : Liabilities	0
Foreign exchange contracts \| Significant other observable inputs Level 2
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	351	342
Derivatives designated as hedging instruments : Liabilities	269	314
Derivatives not designated as hedging instruments : Assets	25	38
Derivatives not designated as hedging instruments : Liabilities	53	38
Derivative Asset	478	418
Derivative Liability	364	402
Foreign exchange contracts \| Significant unobservable inputs Level 3
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	0
Derivatives designated as hedging instruments : Liabilities	0
Derivatives not designated as hedging instruments : Assets	0
Derivatives not designated as hedging instruments : Liabilities	0
Cross currency interest rate swaps
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	2,300	2,300
Equity Securities
Financial assets and liabilities at fair value
Available-for-sale Securities, Equity Securities	$ 731	$ 751

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Aggregate fair value of all derivative assets designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

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Aggregate fair value of all derivative liabilities designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

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Fair value as of the balance sheet date of all foreign currency derivative assets not designated as hedging instruments.

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Fair value as of the balance sheet date of all foreign currency derivative liabilities not designated as hedging instruments.

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