Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data	Jun. 30, 2011	Dec. 31, 2010
Receivables, allowance for doubtful accounts	$ 6	$ 6
Aircraft fuel, spare parts and supplies, obsolescence allowance	74	64
Intangibles, accumulated amortization	587	504
Common stock, par value	$ 0.01	$ 0.01
Common shares, authorized	1,000,000,000	1,000,000,000
Common shares, outstanding	330,766,357	327,922,565
United Airlines Inc [Member]
Receivables, allowance for doubtful accounts	5	5
Aircraft fuel, spare parts and supplies, obsolescence allowance	67	61
Intangibles, accumulated amortization	503	473
Common stock, par value	$ 5	$ 5
Common shares, authorized	1,000	1,000
Common shares, outstanding	205	205
Continental Airlines Inc [Member]
Receivables, allowance for doubtful accounts	1	1
Aircraft fuel, spare parts and supplies, obsolescence allowance	7	3
Intangibles, accumulated amortization	$ 84	$ 31
Common stock, par value	$ 0.01	$ 0.01
Common shares, authorized	1,000	1,000
Common shares, outstanding	1,000	1,000