Revenue - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 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	$ 7,037	$ 6,728	$ 12,743	$ 11,422
Chase Bank USA Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total operating revenues	$ 540	$ 522	$ 1,100	$ 1,000