Debt (Debt With A Contractual Term Greater Than One Year) (Detail) - USD ($) $ in Thousands	Apr. 01, 2018	Dec. 31, 2017	Mar. 26, 2017
Debt Instrument [Line Items]
Gross long-term debt	$ 5,981,190	$ 5,714,527	$ 6,017,858
Less: current portion of long-term debt, net of unamortized discount and debt issuance costs	(1,872,679)	(1,127,269)	(697,061)
Long-term debt, net	4,108,511	4,587,258	5,320,797
Secured Debt
Debt Instrument [Line Items]
Less: unamortized discount and debt issuance costs	(337)	(461)	(1,022)
Gross long-term debt	724,266	806,860	1,112,592
Secured Debt | Asset-backed Canadian commercial paper conduit facility
Debt Instrument [Line Items]
Long-term debt, gross	158,162	174,779	141,013
Secured Debt | Asset-Backed U.S. Commercial Paper Conduit Facility VIE [Member]
Debt Instrument [Line Items]
Long-term debt, gross	281,311	279,457	286,205
Secured Debt | Asset-backed securitization debt
Debt Instrument [Line Items]
Long-term debt, gross	285,130	353,085	686,396
Unsecured Debt
Debt Instrument [Line Items]
Less: unamortized discount and debt issuance costs	(20,564)	(19,821)	(22,222)
Unsecured Debt | 2.15% Medium-term notes due in 2020, issued February 2015
Debt Instrument [Line Items]
Long-term debt, gross	$ 600,000	$ 600,000	$ 600,000
Debt instrument, stated percentage	2.15%	2.15%	2.15%
Unsecured Debt | 1.55% Medium-term notes due in 2017, issued November 2014
Debt Instrument [Line Items]
Long-term debt, gross	$ 0	$ 0	$ 400,000
Debt instrument, stated percentage	1.55%	1.55%	1.55%
Unsecured Debt | 6.80% Medium-term notes due in 2018, issued May 2008
Debt Instrument [Line Items]
Long-term debt, gross	$ 877,488	$ 877,488	$ 877,488
Debt instrument, stated percentage	6.80%	6.80%	6.80%
Unsecured Debt | 2.25% Medium-term notes due in 2019, issued January 2016
Debt Instrument [Line Items]
Long-term debt, gross	$ 600,000	$ 600,000	$ 600,000
Debt instrument, stated percentage	2.25%	2.25%	2.25%
Unsecured Debt | Floating-Rate Medium Term Notes due 2019 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 150,000	$ 150,000	$ 150,000
Unsecured Debt | Two Point Four Percent Medium-Term Notes Due 2019 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 600,000	$ 600,000	$ 600,000
Debt instrument, stated percentage	2.40%	2.40%	2.40%
Unsecured Debt | Two Point Four Percent Medium-Term Notes Due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 350,000	$ 350,000	$ 350,000
Debt instrument, stated percentage	2.40%	2.40%	2.40%
Unsecured Debt | Two Point Eighty-five Percent Medium-Term Notes Due 2021 [Member] [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 600,000	$ 600,000	$ 600,000
Debt instrument, stated percentage	2.85%	2.85%	2.85%
Unsecured Debt | Two Point Fifty-five Percent Medium-Term Notes Due 2022 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 400,000	$ 400,000	$ 0
Debt instrument, stated percentage	2.55%	2.55%	2.55%
Unsecured Debt | Three Point Thirty-five Percent Medium Term Notes Due 2023 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 350,000	$ 0	$ 0
Debt instrument, stated percentage	3.35%	3.35%	3.35%
Unsecured Debt | Three Point Five Percent Senior Unsecured Notes Due 2025 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 450,000	$ 450,000	$ 450,000
Debt instrument, stated percentage	3.50%	3.50%	3.50%
Unsecured Debt | Four Point Six Two Five Percent Senior Unsecured Notes Due 2045 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 300,000	$ 300,000	$ 300,000
Debt instrument, stated percentage	4.625%	4.625%	4.625%