Financial Instruments - Investments - Unrealized Gains and Losses Related to Equity Securities (Details) - USD ($) $ in Millions		3 Months Ended	6 Months Ended
		Jul. 01, 2018	Jul. 01, 2018
Financial Instruments [Abstract]
Net gains recognized during the period on equity securities	[1]	$ 232	$ 330
Less: Net gains recognized during the period on equity securities sold during the period		(19)	(31)
Unrealized gains (losses) on equity securities		$ 213	$ 299

[1] The second quarter of 2018 includes $226 million of unrealized net gains reflecting the adoption of a new accounting standard in the first quarter of 2018 and $7 million of unrealized gains on other equity securities. The first six months of 2018 includes $337 million of unrealized net gains reflecting the adoption of a new accounting standard in the first quarter of 2018 and $7 million of unrealized losses on other equity securities. For additional information, see Note 1B and Note 4.