Retirement and Post-Retirement Employee Benefit Plans Net Periodic Cost (Details) - USD ($) $ in Thousands		12 Months Ended
	Apr. 02, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		$ 16,231	$ 15,345	$ 17,754
Interest cost		21,850	22,330	19,334
Expected return on assets		(25,744)	(23,601)	(22,955)
Amortization of prior service cost		(192)	(136)	(141)
Recognized actuarial loss		13,322	13,777	19,066
Net periodic pension cost		25,467	27,715	33,058
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		3,971	3,607	3,039
Interest cost		4,943	4,966	4,755
Amortization of transition asset		0	0	0
Amortization of prior service cost		0	0	0
Recognized actuarial loss		2,343	1,948	2,918
Settlements	$ 3,200	0	4,539	3,160
Net periodic pension cost		11,257	15,060	13,872
Effect on Net Periodic Cost Due To Discount Rate Change, Remaining Fiscal Year	$ (100)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		15,583	16,784	18,800
Interest cost		14,385	15,951	12,964
Expected return on assets		(6,431)	(5,167)	(3,988)
Amortization of transition asset		272	274	1,081
Amortization of prior service cost		(1,644)	(1,450)	(1,450)
Recognized actuarial loss		0	631	4,196
Net periodic pension cost		$ 22,165	$ 27,023	$ 31,603