Retirement Plans, Net Pension Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Retirement Plans [Abstract]
Service cost	$ 2	$ 0	$ 0
Interest cost	12	11	11
Amortization of net actuarial loss	6	2	3
Expected return on plan assets	(24)	(17)	(17)
Net periodic benefit expense (income)	$ (4)	$ (4)	$ (3)