Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Allowance for credit losses	$ 30,000,000	$ 9,000,000
Obsolescence allowance for aircraft fuel, spare parts and supplies	446,000,000	425,000,000
Accumulated amortization on intangibles	1,454,000,000	$ 1,440,000,000
Allowance for credit losses on notes receivable	$ 549
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)	247,256,855	251,216,381
United Airlines, Inc.
Allowance for credit losses	$ 30,000,000	$ 9,000,000
Obsolescence allowance for aircraft fuel, spare parts and supplies	446,000,000	425,000,000
Accumulated amortization on intangibles	1,454,000,000	$ 1,440,000,000
Allowance for credit losses on notes receivable	$ 549,000,000
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