Details about Accumulated Other Comprehensive Income Components (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Salaries And Related Costs
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of unrecognized losses and prior service cost (credit)	[1]	$ 5	$ 10
Miscellaneous, Net
Accumulated Other Comprehensive Income (Loss) [Line Items]
Available-for-sale securities-reclassifications of gains into earnings			(1)
Fuel Oil Contract | Cash Flow Hedging | Aircraft Fuel
Accumulated Other Comprehensive Income (Loss) [Line Items]
Fuel contracts-reclassifications of losses into earnings		$ 138	$ 161

[1] This AOCI component is included in the computation of net periodic pension and other postretirement costs (see Note 5 of this report for additional information).