Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Receivables, allowance for doubtful accounts	$ 11	$ 18
Aircraft fuel, spare parts and supplies, obsolescence allowance	249	235
Intangibles, accumulated amortization	$ 1,167	$ 1,144
Common stock, par value	$ 0.01	$ 0.01
Common shares, authorized	1,000,000,000	1,000,000,000
Common shares, outstanding	339,304,625	364,609,108
United Airlines, Inc.
Receivables, allowance for doubtful accounts	$ 11	$ 18
Aircraft fuel, spare parts and supplies, obsolescence allowance	249	235
Intangibles, accumulated amortization	$ 1,167	$ 1,144
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