Shareholders' Equity - Before and after-tax components of other comprehensive income (loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 28, 2019	Sep. 29, 2018
Pension and postretirement benefits adjustments, pre-tax:
Amortization of net actuarial loss, pre-tax	$ 25	$ 38	$ 74	$ 115
Amortization of prior service cost, pre-tax	1	2	5	6
Business disposition, pre-tax		7		7
Pension and postretirement benefits adjustments, net, pre-tax	26	47	79	128
Deferred gains (losses) on hedge contracts, pre-tax:
Current deferrals, pre-tax		3	6	1
Reclassification adjustments, pre-tax		(2)	(2)	(3)
Deferred gains (losses) on hedge contracts, net, pre-tax		1	4	(2)
Foreign currency translation adjustments, pre-tax:
Foreign currency translation adjustments, pre-tax	(33)	1	(29)	(25)
Business disposition, pre-tax		6		6
Foreign currency translation adjustments, net, pre-tax	(33)	7	(29)	(19)
Other comprehensive income (loss), pre-tax	(7)	55	54	107
Pension and postretirement benefits adjustments, tax:
Amortization of net actuarial loss, tax	(6)	(9)	(17)	(27)
Amortization of prior service cost, tax			(1)	(1)
Pension and postretirement benefits adjustments, net, tax	(6)	(9)	(18)	(28)
Deferred gains (losses) on hedge contracts, tax:
Current deferrals, tax		(1)	(2)	(1)
Reclassification adjustments, tax		1		1
Deferred gains (losses) on hedge contracts, net, tax			(2)
Foreign currency translation adjustments, tax:
Foreign currency translation adjustments, tax	(1)		(1)	(1)
Foreign currency translation adjustments, net, tax	(1)		(1)	(1)
Other comprehensive income (loss), tax	(7)	(9)	(21)	(29)
Pension and postretirement benefits adjustments, after-tax:
Amortization of net actuarial loss, after-tax	19	29	57	88
Amortization of prior service cost, after-tax	1	2	4	5
Business disposition, after-tax		7		7
Pension and postretirement benefits adjustments, net, after-tax	20	38	61	100
Deferred gains (losses) on hedge contracts, after-tax:
Current deferrals, after-tax		2	4
Reclassification adjustments, after-tax		(1)	(2)	(2)
Deferred gains (losses) on hedge contracts, net, after-tax		1	2	(2)
Foreign currency translation adjustments, after-tax:
Foreign currency translation adjustments, after-tax	(34)	1	(30)	(26)
Business disposition, after-tax		6		6
Foreign currency translation adjustments, net, after tax	(34)	7	(30)	(20)
Other comprehensive income (loss)	$ (14)	$ 46	$ 33	$ 78