Accumulated Other Comprehensive Loss and Other Comprehensive Income - Components of accumulated other comprehensive loss (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 01, 2017	Apr. 02, 2016
Components of Accumulated other comprehensive loss
Beginning of period	$ (1,605)	$ (1,398)
Other comprehensive income before reclassifications	24	40
Reclassified from Accumulated other comprehensive loss	26	26
Other comprehensive income	50	66
End of period	(1,555)	(1,332)
Pension and Postretirement Benefits Adjustments
Components of Accumulated other comprehensive loss
Beginning of period	(1,505)	(1,327)
Reclassified from Accumulated other comprehensive loss	24	21
Other comprehensive income	24	21
End of period	(1,481)	(1,306)
Foreign Currency Translation Adjustments
Components of Accumulated other comprehensive loss
Beginning of period	(96)	(47)
Other comprehensive income before reclassifications	22	24
Other comprehensive income	22	24
End of period	(74)	(23)
Deferred Gains (Losses) on Hedge Contracts
Components of Accumulated other comprehensive loss
Beginning of period	(4)	(24)
Other comprehensive income before reclassifications	2	16
Reclassified from Accumulated other comprehensive loss	2	5
Other comprehensive income	$ 4	21
End of period		$ (3)