Financial Instruments - Total Short-Term and Long-Term Investments (Details) - USD ($) $ in Millions		Apr. 01, 2018	Dec. 31, 2017
Financial Instruments [Abstract]
Equity securities		$ 1,085	$ 2,150
Available-for-sale debt securities		7,006	15,362
Held-to-maturity debt securities		1,028	1,138
Total Short-term investments	[1]	9,119	18,650
Equity securities		1,557	1,514
Available-for-sale debt securities		4,833	5,090
Held-to-maturity debt securities		78	4
Private equity investments carried at equity-method or cost		477	408
Total Long-term investments	[1]	6,945	7,015
Held-to-maturity cash equivalents		$ 876	$ 719

[1] Amounts may not add due to rounding.