Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Receivables, allowance for doubtful accounts	$ 18	$ 22
Aircraft fuel, spare parts and supplies, obsolescence allowance	235	169
Intangibles, accumulated amortization	$ 1,144	$ 1,049
Common stock, par value	$ 0.01	$ 0.01
Common shares, authorized	1,000,000,000	1,000,000,000
Common shares, outstanding	364,609,108	374,525,916
United Airlines, Inc.
Receivables, allowance for doubtful accounts	$ 18	$ 22
Aircraft fuel, spare parts and supplies, obsolescence allowance	235	169
Intangibles, accumulated amortization	$ 1,144	$ 1,049
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