Consolidated Statement of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred taxes on postretirement	$ 24	$ 25	$ (15)
Deferred taxes on unrealized gain (loss), other, tax effect	0	(13)	7
Net income (loss)	539	977	(3,074)
Fuel derivative contracts
Deferred taxes on unrealized gain (loss) on derivatives, tax effect	(44)	142	2
Interest rate derivatives
Deferred taxes on unrealized gain (loss) on derivatives, tax effect	$ 6	$ 2	$ (8)