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Employee Benefit Plans - Schedule of Assumptions Used (Details)
12 Months Ended
Sep. 29, 2018
Sep. 30, 2017
Sep. 24, 2016
Pension Benefits [Member]      
Actuarial assumptions [Abstract]      
Weighted-average discount rate used in calculating benefit obligations 4.00% 3.50%  
Average rate of compensation increase 0.00% 0.00%  
Health care cost trend 0.00% 0.00%  
Assumptions used in calculating benefit cost [Abstract]      
Weighted-average discount rate 3.50% 3.125% 3.875%
Average rate of compensation increase 0.00% 0.00% 0.00%
Weighted-average expected long-term rate of return on plan assets 2.50% 2.40% 3.90%
Health care cost trend 0.00% 0.00% 0.00%
Retiree Health and Life Benefits [Member]      
Actuarial assumptions [Abstract]      
Weighted-average discount rate used in calculating benefit obligations 3.75% 3.00%  
Average rate of compensation increase 0.00% 0.00%  
Health care cost trend 6.29% 6.57%  
Assumptions used in calculating benefit cost [Abstract]      
Weighted-average discount rate 3.00% 2.875% 3.50%
Average rate of compensation increase 0.00% 0.00% 0.00%
Weighted-average expected long-term rate of return on plan assets 0.00% 0.00% 0.00%
Health care cost trend 6.57% 6.84% 7.10%