Financial Instruments - Investments - Unrealized Gains and Losses Related to Equity Securities (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 29, 2020	Mar. 31, 2019
Financial Instruments [Abstract]
Net gains recognized during the period on investments in equity securities	[1],[2]	$ 255	$ (111)
Less: Net gains recognized during the period on equity securities sold during the period		(19)	(5)
Net unrealized gains during the reporting period on equity securities still held at the reporting date	[3]	$ 274	$ (106)

[1] The losses in the first quarter of 2020, include, among other things, unrealized losses of $134 million related to our investment in Allogene. The gains in the first quarter of 2019 included, among other things, unrealized gains of $43 million related to our investment in Allogene. For additional information on investments, see Note 7B.

[2] The net gains on investments in equity securities are reported in Other (income)/deductions––net. For additional information, see Note 4.

[3] Included in net unrealized (gains)/losses are observable price changes on equity securities without readily determinable fair values. Since January 1, 2018, there were cumulative impairments and downward adjustments of $58 million and upward adjustments of $60 million. Impairments, downward and upward adjustments were not significant in the first quarter of 2020 and 2019.