Retirement Plans Components of Net Periodic Pension and Other Postretirement Benefit Costs (Credits) (Details) - Pension Benefits - USD ($) $ in Millions	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 2	$ 2
Interest cost	37	36	40
Expected return on plan assets	(49)	(52)	(48)
Amortization of net loss	4	3	4
Settlements	12	0	18
Net periodic pension benefit costs (credits)	$ 6	$ (11)	$ 16