Fair Value of Pension Plan Assets by Level within Fair Value Hierarchy (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 28, 2014		Dec. 29, 2013		Dec. 30, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	$ 3,030,363	[1]	$ 2,978,584	[1]
Fair value of pension plan liabilities	(4,550)	[1]	(11,502)	[1]
Cash and other	16,701	[1]	61,385	[1]
Fair value of pension plan assets	3,042,514	[1]	3,028,467	[1]
U.S. government-related securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	4,005	[1]	3,313	[1]
Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	4,090	[1]	4,607	[1]
Other government bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	4,562	[1]	4,947	[1]
Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	25,010	[1]	30,455	[1]
Corporate stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	924,294	[1]	892,883	[1]
Real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	109,102	[1]	98,909	[1]
Equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	890,201	[1]	908,673	[1]
Fixed Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	316,720	[1]	213,698	[1]
Interest in reg. invest. companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	196,765	[1]	323,639	[1]
Interest in 103-12 investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	24,359	[1]	28,691	[1]
Partnership/joint venture interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	182,281	[1]	184,952	[1]
Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	345,839	[1]	272,676	[1]
Derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	3,135	[1]	11,141	[1]
Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of pension plan liabilities	(4,550)	[1]	(11,502)	[1]
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	1,083,253	[1]	1,173,934	[1]
Fair value of pension plan liabilities	(13)	[1]	(8)	[1]
Cash and other	14,039	[1]	60,271	[1]
Fair value of pension plan assets	1,097,279	[1]	1,234,197	[1]
Level 1 | U.S. government-related securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 1 | Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 1 | Other government bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 1 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 1 | Corporate stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	924,294	[1]	892,883	[1]
Level 1 | Real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 1 | Equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 1 | Fixed Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	6,592	[1]	0	[1]
Level 1 | Interest in reg. invest. companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	152,359	[1]	281,029	[1]
Level 1 | Interest in 103-12 investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 1 | Partnership/joint venture interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 1 | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 1 | Derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	8	[1]	22	[1]
Level 1 | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of pension plan liabilities	(13)	[1]	(8)	[1]
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	1,365,970	[1]	1,305,784	[1]
Fair value of pension plan liabilities	(2,529)	[1]	(9,486)	[1]
Cash and other	2,662	[1]	1,114	[1]
Fair value of pension plan assets	1,366,103	[1]	1,297,412	[1]
Level 2 | U.S. government-related securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	4,005	[1]	3,313	[1]
Level 2 | Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	3,995	[1]	4,210	[1]
Level 2 | Other government bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	4,562	[1]	4,947	[1]
Level 2 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	24,628	[1]	29,599	[1]
Level 2 | Corporate stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 2 | Real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 2 | Equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	890,201	[1]	908,673	[1]
Level 2 | Fixed Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	310,128	[1]	213,698	[1]
Level 2 | Interest in reg. invest. companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	44,406	[1]	42,610	[1]
Level 2 | Interest in 103-12 investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	24,359	[1]	28,691	[1]
Level 2 | Partnership/joint venture interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	36,517	[1]	36,402	[1]
Level 2 | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	20,166	[1]	22,685	[1]
Level 2 | Derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	3,003	[1]	10,956	[1]
Level 2 | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of pension plan liabilities	(2,529)	[1]	(9,486)	[1]
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	581,140	[1]	498,866	[1]	388,601
Fair value of pension plan liabilities	(2,008)	[1]	(2,008)	[1]
Cash and other	0	[1]	0	[1]
Fair value of pension plan assets	579,132	[1]	496,858	[1]
Level 3 | U.S. government-related securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 3 | Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	95	[1]	397	[1]	0
Level 3 | Other government bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 3 | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	382	[1]	856	[1]	797
Level 3 | Corporate stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 3 | Real estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	109,102	[1]	98,909	[1]	97,385
Level 3 | Equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 3 | Fixed Income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 3 | Interest in reg. invest. companies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 3 | Interest in 103-12 investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	0	[1]	0	[1]
Level 3 | Partnership/joint venture interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	145,764	[1]	148,550	[1]	130,995
Level 3 | Hedge funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	325,673	[1]	249,991	[1]	158,924
Level 3 | Derivative contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets only	124	[1]	163	[1]	500
Level 3 | Derivative liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of pension plan liabilities	$ (2,008)	[1]	$ (2,008)	[1]	$ (2,008)

[1] We use a Dec. 31 measurement date for our retirement plans.