Other Financial Data - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 26, 2020	Jun. 27, 2020	Mar. 28, 2020	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Sep. 26, 2020	Sep. 28, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period			$ (683)				$ (683)
Other comprehensive income, net of tax	$ 42			$ (22)			7	$ 6
Balance at end of period	(740)						(740)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(2,475)	$ (2,566)	(2,440)	(2,737)	$ (2,724)	$ (2,765)	(2,440)	(2,765)
Other comprehensive income, net of tax	42	91	(126)	(22)	(13)	41
Balance at end of period	(2,433)	(2,475)	(2,566)	(2,759)	(2,737)	(2,724)	(2,433)	(2,759)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(470)		(410)	(437)		(444)	(410)	(444)
Other comprehensive income (loss) before reclassification adjustment	34			(33)			(27)	(23)
Tax expense	(4)			0			(3)	(3)
Other comprehensive income, net of tax	30			(33)			(30)	(26)
Balance at end of period	(440)	(470)		(470)	(437)		(440)	(470)
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(2,005)		$ (2,030)	(2,300)		$ (2,321)	(2,030)	(2,321)
Other comprehensive income, net of tax	12			11			37	32
Tax expense	(4)			(1)			(9)	(7)
Balance at end of period	(1,993)	$ (2,005)		(2,289)	$ (2,300)		(1,993)	(2,289)
Reclassification adjustment - Actuarial net losses into Other income
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification adjustment before tax	20			16			58	50
Reclassification adjustment - Prior service benefits into Other expense
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification adjustment before tax	$ (4)			$ (4)			$ (12)	$ (11)