Other Financial Data - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 28, 2019	Sep. 29, 2018
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period			$ (1,276)				$ (1,276)
Total other comprehensive income (loss), net of tax	$ (22)			$ 9			6	$ (9)
Balance at end of period	(1,084)						(1,084)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(2,737)	$ (2,724)	(2,765)	(2,580)	$ (2,508)	$ (2,562)	(2,765)	(2,562)
Total other comprehensive income (loss), net of tax	(22)	(13)	41	9	(72)	54
Balance at end of period	(2,759)	(2,737)	(2,724)	(2,571)	(2,580)	(2,508)	(2,759)	(2,571)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(437)		(444)	(391)		(353)	(444)	(353)
Other comprehensive loss before reclassification adjustment	(33)			(3)			(23)	(33)
Tax expense	0			(1)			(3)	(9)
Total other comprehensive income (loss), net of tax	(33)			(4)			(26)	(42)
Balance at end of period	(470)	(437)		(395)	(391)		(470)	(395)
Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	0		0	0		6	0	6
Reclassification adjustment before tax	0			0			0	(8)
Tax expense (benefit)	0			0			0	2
Total other comprehensive income (loss), net of tax	0			0			0	(6)
Balance at end of period	0	0		0	0		0	0
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(2,300)		$ (2,321)	(2,189)		$ (2,215)	(2,321)	(2,215)
Tax expense (benefit)	(1)			(3)			(7)	(7)
Total other comprehensive income (loss), net of tax	11			13			32	39
Balance at end of period	(2,289)	$ (2,300)		(2,176)	$ (2,189)		(2,289)	(2,176)
Reclassification adjustment - Actuarial net losses into Other income (expense)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification adjustment before tax	16			20			50	57
Reclassification adjustment - Prior service benefits into Other income (expense)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification adjustment before tax	$ (4)			$ (4)			$ (11)	$ (11)