Income Taxes (Components of Net Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Oct. 02, 2020	Sep. 27, 2019
Obligations related to:
Defined benefit pension plans	$ 55,949	$ 56,854
Other employee benefit plans	132,613	149,276
Net operating losses	197,987	241,033
Foreign tax credit	87,259	84,553
Other credits	6,808	13,881
Contract revenues and costs	70,733	51,579
Investments	49,848	23,204
Lease liability	154,979
Deferred rent	0	21,847
Restructuring	11,974	8,205
Valuation allowance	(140,578)	(153,257)
Gross deferred tax assets	627,572	497,175
Deferred tax liabilities:
Depreciation and amortization	(240,097)	(177,002)
Lease right of use asset	(89,824)
Unremitted earnings	(17,295)	(29,761)
Partnership investment	(66,082)	0
Other, net	(6,593)	(8,890)
Gross deferred tax liabilities	(419,891)	(215,653)
Net deferred tax assets	$ 207,681	$ 281,522

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