Shareholders' Equity - Accumulated Other Comprehensive Loss and Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	6 Months Ended
	Jul. 03, 2021	Jul. 04, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	$ (1,739)
Other comprehensive loss before reclassifications	(11)	$ (15)
Reclassified from Accumulated other comprehensive loss	74	71
End of period	(1,676)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(1,739)	(1,847)
End of period	(1,676)	(1,791)
Pension and Postretirement Benefits Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(1,780)	(1,811)
Other comprehensive loss before reclassifications	0	0
Reclassified from Accumulated other comprehensive loss	60	73
End of period	(1,720)	(1,738)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	42	(36)
Other comprehensive loss before reclassifications	(17)	(10)
Reclassified from Accumulated other comprehensive loss	14	0
End of period	39	(46)
Deferred Gains (Losses) on Hedge Contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(1)	0
Other comprehensive loss before reclassifications	6	(5)
Reclassified from Accumulated other comprehensive loss	0	(2)
End of period	$ 5	$ (7)