Employee Benefit Plans - Schedule of Assumptions Used (Details)	12 Months Ended
	Sep. 26, 2015	Sep. 27, 2014	Sep. 28, 2013
Actuarial assumptions [Abstract]
Health care cost trend	4.50%
Assumptions used in calculating benefit cost [Abstract]
Health care cost trend	7.10%
Pension Benefits [Member]
Actuarial assumptions [Abstract]
Weighted-average discount rate used in calculating benefit obligations	3.875%	3.875%
Assumptions used in calculating benefit cost [Abstract]
Weighted-average discount rate	3.875%	4.375%	3.50%
Weighted-average expected long-term rate of return on plan assets	4.90%	4.90%	4.50%
Retiree Health and Life Benefits [Member]
Actuarial assumptions [Abstract]
Weighted-average discount rate used in calculating benefit obligations	3.50%	3.50%
Health care cost trend	7.10%	7.12%
Assumptions used in calculating benefit cost [Abstract]
Weighted-average discount rate	3.50%	3.75%	3.00%
Health care cost trend	7.12%	7.33%	7.53%