Leases - Lease costs (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 28, 2019	Sep. 28, 2019
Lease cost
Operating lease cost	$ 33	$ 100
Finance lease cost:
Amortization of right of use assets	1	2
Interest on lease liabilities	1	1
Variable lease cost	3	7
Short-term lease cost	12	35
Total lease cost	$ 50	$ 145