Other Financial Data - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 27, 2020	Mar. 28, 2020	Jun. 29, 2019	Mar. 30, 2019	Jun. 27, 2020	Jun. 29, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period		$ (683)			$ (683)
Other comprehensive income, net of tax	$ 91		$ (13)		(35)	$ 28
Balance at end of period	(815)				(815)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(2,566)	(2,440)	(2,724)	$ (2,765)	(2,440)	(2,765)
Other comprehensive income, net of tax	91	(126)	(13)	41
Balance at end of period	(2,475)	(2,566)	(2,737)	(2,724)	(2,475)	(2,737)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(548)	(410)	(414)	(444)	(410)	(444)
Other comprehensive income (loss) before reclassification adjustment	75		(24)		(61)	10
Tax benefit (expense)	3		1		1	(3)
Other comprehensive income, net of tax	78		(23)		(60)	7
Balance at end of period	(470)	(548)	(437)	(414)	(470)	(437)
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(2,018)	(2,030)	(2,310)	(2,321)	(2,030)	(2,321)
Other comprehensive income, net of tax	13		10		25	21
Tax expense (benefit)	(2)		(3)		(5)	(5)
Balance at end of period	(2,005)	$ (2,018)	(2,300)	$ (2,310)	(2,005)	(2,300)
Reclassification adjustment - Actuarial net losses into Other income
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification adjustment before tax	19		17		38	33
Reclassification adjustment - Prior service benefits into Other expense
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification adjustment before tax	$ (4)		$ (4)		$ (8)	$ (7)