Employee Future Benefits (Actuarial Assumptions) (Details) - Pension Plan	12 Months Ended
	Dec. 29, 2019	Dec. 30, 2018	Dec. 31, 2017
UNITED STATES
Discount rate applied for:
Accrued benefit obligation	3.30%	4.30%	3.60%
Net periodic pension cost	4.30%	3.60%	4.20%
Expected long-term rate of return on plan assets	6.80%	6.80%	7.00%
Expected long-term return on assets, (in Years)	30 years
UNITED KINGDOM
Discount rate applied for:
Accrued benefit obligation	1.90%	2.70%	2.40%
Net periodic pension cost	1.70%	2.40%	2.20%
Expected long-term rate of return on plan assets	3.90%	4.20%	4.00%
Expected long-term return on assets, (in Years)	9 years