Income Taxes - Net Deferred Tax Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 25, 2011	Dec. 26, 2010
Income Tax Disclosure [Abstract]
Retirement, postemployment and deferred compensation plans	$ 447,156	$ 420,745
Accruals for other employee benefits, compensation, insurance and other	39,572	56,280
Accounts receivable allowances	7,114	9,587
Other	109,946	91,424
Gross deferred tax assets	603,788	578,036
Valuation allowance	(39,824)	0
Net deferred tax assets	563,964	578,036
Property, plant and equipment	143,308	141,052
Intangible assets	42,150	44,568
Investments in joint ventures	15,095	11,796
Other	10,073	56,044
Gross deferred tax liabilities	210,626	253,460
Net deferred tax asset	353,338	324,576
Deferred tax asset – current	73,055	68,875
Deferred tax asset – long-term	$ 280,283	$ 255,701