Details about Accumulated Other Comprehensive Income Components (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Salaries And Related Costs
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of unrecognized loss and prior service cost	$ 10	[1]	$ 4	[1],[2]	$ 48	[1]	$ 13	[1],[2]
Fuel Oil Contract | Cash Flow Hedging | Aircraft Fuel
Accumulated Other Comprehensive Income (Loss) [Line Items]
Fuel contracts-reclassifications of (gains) losses into earnings	(14)	[1]	38	[1]	4	[1]	107	[1]
United Airlines, Inc. | Salaries And Related Costs
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of unrecognized loss and prior service cost	10	[1]	4	[1],[2]	48	[1]	13	[1],[2]
United Airlines, Inc. | Income Tax Benefit Expense
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax expense on other comprehensive income					6
United Airlines, Inc. | Fuel Oil Contract | Cash Flow Hedging | Aircraft Fuel
Accumulated Other Comprehensive Income (Loss) [Line Items]
Fuel contracts-reclassifications of (gains) losses into earnings	$ (14)	[1]	$ 38	[1]	$ 4	[1]	$ 107	[1]

[1] Income tax expense offset by Company's valuation allowance.

[2] This accumulated other comprehensive income component is included in the computation of net periodic pension costs (see Note 5 of this report for additional details.)