Fair Value Measurements - Financial Assets and Liabilities at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2017	Jan. 01, 2017
Equity Securities
Financial assets and liabilities at fair value
Equity investments	$ 394	$ 520
Unrealized Gain	367	757
Unrealized loss	10	68
Level 1
Financial assets and liabilities at fair value
Equity method investments, fair market disclosure	751	1,209
Debt securities	0
Level 2
Financial assets and liabilities at fair value
Equity method investments, fair market disclosure	0
Debt securities	5,310	12,087
Level 3
Financial assets and liabilities at fair value
Equity method investments, fair market disclosure	0
Debt securities	0
Interest Rate Contract
Financial assets and liabilities at fair value
Non-current assets included in interest rate contracts	7	23
Non-current liabilities included in interest rate contracts	9	382
Equity Contract
Financial assets and liabilities at fair value
Derivative Instruments in Hedges, Liabilities, at Fair Value	0	57
Equity Contract | Level 2
Financial assets and liabilities at fair value
Derivative Instruments in Hedges, Liabilities, at Fair Value	0
Designated as Hedging Instrument
Financial assets and liabilities at fair value
Derivative assets	349
Derivative liabilities	329
Designated as Hedging Instrument | Level 1
Financial assets and liabilities at fair value
Derivative assets	0
Derivative liabilities	0
Designated as Hedging Instrument | Level 2
Financial assets and liabilities at fair value
Derivative assets	349	778
Derivative liabilities	329	1,162
Designated as Hedging Instrument | Level 3
Financial assets and liabilities at fair value
Derivative assets	0
Derivative liabilities	0
Designated as Hedging Instrument | Interest Rate Contract
Financial assets and liabilities at fair value
Derivative assets	7
Derivative liabilities	15
Designated as Hedging Instrument | Interest Rate Contract | Level 1
Financial assets and liabilities at fair value
Derivative assets	0
Derivative liabilities	0
Designated as Hedging Instrument | Interest Rate Contract | Level 2
Financial assets and liabilities at fair value
Derivative assets	7	31
Derivative liabilities	15	382
Designated as Hedging Instrument | Interest Rate Contract | Level 3
Financial assets and liabilities at fair value
Derivative assets	0
Derivative liabilities	0
Designated as Hedging Instrument | Foreign exchange contracts
Financial assets and liabilities at fair value
Derivative assets	342
Derivative liabilities	314
Designated as Hedging Instrument | Foreign exchange contracts | Level 1
Financial assets and liabilities at fair value
Derivative assets	0
Derivative liabilities	0
Designated as Hedging Instrument | Foreign exchange contracts | Level 2
Financial assets and liabilities at fair value
Derivative assets	342	747
Derivative liabilities	314	723
Designated as Hedging Instrument | Foreign exchange contracts | Level 3
Financial assets and liabilities at fair value
Derivative assets	0
Derivative liabilities	0
Not Designated as Hedging Instrument | Foreign exchange contracts
Financial assets and liabilities at fair value
Derivative assets	38
Derivative liabilities	38
Not Designated as Hedging Instrument | Foreign exchange contracts | Level 1
Financial assets and liabilities at fair value
Derivative assets	0
Derivative liabilities	0
Not Designated as Hedging Instrument | Foreign exchange contracts | Level 2
Financial assets and liabilities at fair value
Derivative assets	38	34
Derivative liabilities	38	$ 57
Not Designated as Hedging Instrument | Foreign exchange contracts | Level 3
Financial assets and liabilities at fair value
Derivative assets	0
Derivative liabilities	$ 0