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Investments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
Investments (Details) - USD ($) $ in Millions	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019	Dec. 31, 2019
Investments
Fair Value	$ 1,178		$ 1,178		$ 1,434
Total trading short-term investments	1,178		1,178		1,434
Change in unrealized gains (losses) on trading securities	113	$ 38	(97)	$ 126
Domestic equity securities
Investments
Fair Value	546		546		706
Domestic debt securities
Investments
Fair Value	389		389		409
Foreign equity securities
Investments
Fair Value	100		100		189
Foreign equity securities \| Denominated in foreign currencies
Investments
Fair Value Equity	0		0		62
Foreign equity securities \| Denominated in Euros
Investments
Fair Value Equity					32
Foreign equity securities \| Denominated in Japanese Yen
Investments
Fair Value Equity					12
Foreign equity securities \| Denominated in British pounds
Investments
Fair Value Equity					8
Foreign equity securities \| Denominated in other foreign currencies
Investments
Fair Value Equity					10
Foreign debt securities
Investments
Fair Value	54		54		43
Foreign debt securities \| Denominated in foreign currencies
Investments
Fair Value	15		15		13
High yield securities
Investments
Fair Value	46		46		56
Money market funds held in trading accounts
Investments
Fair Value	24		24		12
Collateralized loan obligations
Investments
Fair Value	14		14		15
Other trading securities
Investments
Fair Value	$ 5		$ 5		$ 4