Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2015	Sep. 26, 2014	Sep. 25, 2015	Sep. 26, 2014
Statement of Comprehensive Income [Abstract]
Net of income taxes benefits on unrealized gains on hedging instruments	$ 3	$ 1	$ 2
Income taxes on amortization of net loss and prior service cost previously recognized	$ 7	$ 1	18	$ 4
Income tax expense on net gain arising during the period			$ 5