Pension and Other Postretirement Benefits - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 26, 2014
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plans	$ 85
Expected contributions to plans	12
Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to other postretirement benefit plans	5
Expected contributions to plans	$ 5