Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Receivables, allowance for doubtful accounts	$ 12	$ 7
Aircraft fuel, spare parts and supplies, obsolescence allowance	111	89
Intangibles, accumulated amortization	762	670
Common stock, par value	$ 0.01	$ 0.01
Common shares, authorized	1,000,000,000	1,000,000,000
Common shares, outstanding	332,439,588	330,906,192
United Air Lines Inc
Receivables, allowance for doubtful accounts	10	5
Aircraft fuel, spare parts and supplies, obsolescence allowance	81	73
Intangibles, accumulated amortization	575	534
Common stock, par value	$ 5	$ 5
Common shares, authorized	1,000	1,000
Common shares, issued	205	205
Common shares, outstanding	205	205
Continental Airlines Inc
Receivables, allowance for doubtful accounts	2	2
Aircraft fuel, spare parts and supplies, obsolescence allowance	30	16
Intangibles, accumulated amortization	$ 187	$ 136
Common stock, par value	$ 0.01	$ 0.01
Common shares, authorized	1,000	1,000
Common shares, issued	1,000	1,000
Common shares, outstanding	1,000	1,000