Revenue - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Residual travel funds (as a percent)	7.00%		7.00%		9.00%
Total operating revenues	$ 6,525	$ 6,220	$ 19,268	$ 17,642
Chase Bank USA Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total operating revenues	$ 526	$ 521	$ 1,600	$ 1,500