Retirement and Other Employee Benefits - Pension and Postretirement Health Care Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Postretirement Health Care Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	0	1	1	2
Expected return on plan assets	(3)	(2)	(8)	(7)
Amortization of:
Unrecognized net loss	1	1	3	3
Unrecognized prior service benefit	(3)	(4)	(11)	(11)
Net periodic pension benefits	(5)	(4)	(15)	(13)
U.S. | Pension Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0
Interest cost	36	50	108	152
Expected return on plan assets	(57)	(69)	(169)	(207)
Amortization of:
Unrecognized net loss	15	11	44	35
Unrecognized prior service benefit	0	0	0	0
Net periodic pension benefits	(6)	(8)	(17)	(20)
Non-U.S. | Pension Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	1	2
Interest cost	7	9	21	29
Expected return on plan assets	(21)	(20)	(63)	(62)
Amortization of:
Unrecognized net loss	4	4	11	12
Unrecognized prior service benefit	(1)	0	(1)	0
Net periodic pension benefits	$ (11)	$ (7)	$ (31)	$ (19)