Shareholders' Equity - Accumulated Other Comprehensive Loss and Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	9 Months Ended
	Oct. 03, 2020	Sep. 28, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	$ (1,847)
End of period	(1,717)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(1,847)	$ (1,762)
Other comprehensive income before reclassifications	23	(26)
Reclassified from Accumulated other comprehensive loss	107	59
End of period	(1,717)	(1,729)
Pensions and Postretirement Benefits Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(1,811)	(1,727)
Other comprehensive income before reclassifications	0	0
Reclassified from Accumulated other comprehensive loss	110	61
End of period	(1,701)	(1,666)
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	(36)	(32)
Other comprehensive income before reclassifications	25	(30)
Reclassified from Accumulated other comprehensive loss	0	0
End of period	(11)	(62)
Deferred Gains (Losses) on Hedge Contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning of period	0	(3)
Other comprehensive income before reclassifications	(2)	4
Reclassified from Accumulated other comprehensive loss	(3)	(2)
End of period	$ (5)	$ (1)