Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Allowance for credit losses	$ 11	$ 9
Obsolescence allowance for aircraft fuel, spare parts and supplies	464	425
Accumulated amortization on intangibles	1,467	$ 1,440
Allowance for credit losses on notes receivable	$ 553
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares, authorized (in shares)	1,000,000,000	1,000,000,000
Common shares, outstanding (in shares)	290,982,216	251,216,381
United Airlines, Inc.
Allowance for credit losses	$ 11	$ 9
Obsolescence allowance for aircraft fuel, spare parts and supplies	464	425
Accumulated amortization on intangibles	1,467	$ 1,440
Allowance for credit losses on notes receivable	$ 553
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares, authorized (in shares)	1,000	1,000
Common shares, issued (in shares)	1,000	1,000
Common shares, outstanding (in shares)	1,000	1,000