Shareholders' Equity - Changes in AOCI (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 29, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance		$ (3,778)	$ (2,820)
Cumulative-effect adjustments	[1]		(638)
Other comprehensive income, pretax		306	157
Provision for income tax, net		(59)	(60)
Other comprehensive income, net of tax		247	97
Ending Balance		(3,531)	(3,361)
Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance		(71)	(94)
Cumulative-effect adjustments	[1]		(4)
Other comprehensive income, pretax		70	40
Provision for income tax, net		(17)	(8)
Other comprehensive income, net of tax		53	32
Ending Balance		(18)	(66)
Unrealized Gains on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance		0	19
Cumulative-effect adjustments	[1]		(19)
Other comprehensive income, pretax		1	0
Provision for income tax, net		0	0
Other comprehensive income, net of tax		1	0
Ending Balance		1	0
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance		102	402
Cumulative-effect adjustments	[1]		0
Other comprehensive income, pretax		47	(130)
Provision for income tax, net		0	0
Other comprehensive income, net of tax		47	(130)
Ending Balance		149	272
Changes in Retirement Plans’ Funded Status
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance		(3,809)	(3,147)
Cumulative-effect adjustments	[1]		(615)
Other comprehensive income, pretax		188	247
Provision for income tax, net		(42)	(52)
Other comprehensive income, net of tax		146	195
Ending Balance		$ (3,663)	$ (3,567)

[1] Reflects the cumulative effects of ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, and ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which we adopted on January 1, 2018.