Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Defined Benefit Plan Disclosure
Employer match percent	25.00%
Percentage match of eligible compensation contributed to investment selection	2.00%
Profit share expense	$ 33,250	$ 22,524	$ 26,534
Pension Plan
Defined Benefit Plan Disclosure
Total accumulated benefit obligation	1,235,230	$ 1,044,579
Fair values of plan assets	1,170,405
Reduction in service and interest costs for annual pension expense in the next fiscal year			$ 7,000
Estimated net prior service cost that will be amortized in next fiscal year	131
Estimated net actuarial loss that will be amortized in next fiscal year	38,658
Trust for Unqualified Plan
Defined Benefit Plan Disclosure
Estimated future employer contributions in next fiscal year	4,500
Postretirement Benefit Plan
Defined Benefit Plan Disclosure
Plan assets	$ 0
Discount rate	3.00%	4.20%	3.60%
Service cost discount rate	4.30%	3.70%	3.40%
Interest cost discount rate	3.80%	2.80%	2.50%
Assumed annual per capita rate of increase of medical and drug costs for next fiscal year	8.00%
Defined benefit plan, ultimate trend rate	4.50%
Increase in accumulated postretirement benefit obligation due to one percentage point increase in heath care cost trend rate	$ 149
Decrease in accumulated postretirement benefit obligation due to one percentage point decrease in health care cost trend rate	$ 136
Class B Common Stock
Defined Benefit Plan Disclosure
Number of shares owned by the participants under RSP (in shares)	1,431,539
U.S. Plans | Pension Plan
Defined Benefit Plan Disclosure
Fair values of plan assets	$ 1,004,163	$ 878,983	$ 756,274
Assumptions for pension expense, average rate of return on plan assets	5.30%	7.00%	7.50%
Plan assets	$ 35,429	$ 49,967
Discount rate	3.30%	4.30%	4.00%
Service cost discount rate	4.40%	4.20%	4.00%
Interest cost discount rate	4.10%	3.50%	3.20%
U.S. Plans | Equity | Pension Plan
Defined Benefit Plan Disclosure
Actual Plan Asset Allocations	18.00%	21.00%
U.S. Plans | Fixed income securities | Pension Plan
Defined Benefit Plan Disclosure
Actual Plan Asset Allocations		79.00%
Non-U.S. Plans | Pension Plan
Defined Benefit Plan Disclosure
Fair values of plan assets	$ 166,242	$ 145,641	$ 141,906
Assumptions for pension expense, average rate of return on plan assets	3.50%	3.50%	3.60%
Estimated future employer contributions in next fiscal year	$ 7,600
Plan assets	$ 2,575	$ 7,874
Discount rate	1.60%	2.80%	2.50%
Service cost discount rate	2.90%	2.50%	2.00%
Interest cost discount rate	2.60%	2.20%	1.70%
Non-U.S. Plans | Equity | Pension Plan
Defined Benefit Plan Disclosure
Actual Plan Asset Allocations	25.00%	33.00%
Assumptions for pension expense, assumed average asset allocation	30.00%
Non-U.S. Plans | Fixed income securities | Pension Plan
Defined Benefit Plan Disclosure
Assumptions for pension expense, assumed average asset allocation	70.00%