Postretirement Benefit Plans - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 2013	Mar. 25, 2012
Defined Benefit Plan Disclosure [Line Items]
Recognition of previously deferred post retirement benefit plan amounts	$ 254,000,000	$ 203,000,000
Recognition of previously deferred post retirement benefit plan amounts, tax	139,000,000	111,000,000
Qualified defined benefit pension plans
Defined Benefit Plan Disclosure [Line Items]
Planned defined benefit plan contributions by employer in the current fiscal year	$ 1,500,000,000

The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the plan in the current remaining fiscal period. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions.

No definition available.

Name:	us-gaap_DefinedBenefitPlanEstimatedFutureEmployerContributionsInCurrentFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant