Fair Value Measurements - Financial Assets and Liabilities at Fair Value (Details) - USD ($) $ in Millions	Jul. 01, 2018	Dec. 31, 2017
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	$ 593
Derivatives designated as hedging instruments : Liabilities	707
Available-for-sale Securities, Equity Securities	697	$ 751
Available-for-sale Securities	9,031	5,310
Total Gross Assets	651	463
Credit Support Agreement (CSA)	(295)	(76)
Total Net Asset	356	387
Total Gross Liabilities	778	605
Credit Support Agreement (CSA)	(421)	(238)
Total Net Liabilities	357	367
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	697	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	593	425
Derivatives designated as hedging instruments : Liabilities	707	567
Available-for-sale Securities, Equity Securities	0
Available-for-sale Securities	9,031
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 [Member]
Financial assets and liabilities at fair value
Derivative, Notional Amount	1,100	1,100
Derivatives designated as hedging instruments : Assets	46
Derivatives designated as hedging instruments : Liabilities	236
Derivative Assets, Noncurrent	0	7
Derivative Liabilities, Noncurrent - interest swap	0	9
Interest Rate Contract [Member] | 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 [Member] | Significant other observable inputs Level 2
Financial assets and liabilities at fair value
Derivatives designated as hedging instruments : Assets	46	7
Derivatives designated as hedging instruments : Liabilities	236	165
Interest Rate Contract [Member] | 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
Financial assets and liabilities at fair value
Derivative, Notional Amount	37,000	34,500
Derivatives designated as hedging instruments : Assets	547
Derivatives designated as hedging instruments : Liabilities	471
Derivatives not designated as hedging instruments : Assets	58
Derivatives not designated as hedging instruments : Liabilities	71
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	547	418
Derivatives designated as hedging instruments : Liabilities	471	402
Derivatives not designated as hedging instruments : Assets	58	38
Derivatives not designated as hedging instruments : Liabilities	71	38
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
Financial assets and liabilities at fair value
Derivative, Notional Amount	5,300	2,300
Equity Securities
Financial assets and liabilities at fair value
Available-for-sale Securities, Equity Securities	$ 697	$ 751