Reserves for Credit Losses - Change in Receivables Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provisions	$ 5,185	$ 4,923	$ 2,182
Card Member receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	174	229	64
Provisions	774	880	627
Net write-offs	(773)	(937)	(462)
Other	(4)	2	0
Ending Balance	171	174	229
Recoveries	304	297	257
Card Member receivables | Foreign Currency Translation Adjustments
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Foreign currency translation adjustments	$ (4)	$ 1	$ 2