Reserves for Credit Losses - Change in Receivables Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provisions	$ 5,256	$ 5,185	$ 4,923
Card Member receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	171	174	229
Provisions	751	774	880
Net write-offs	(745)	(773)	(937)
Other	3	(4)	2
Ending Balance	180	171	174
Recoveries	297	304	297
Card Member receivables | Foreign Currency Translation Adjustments
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Foreign currency translation adjustments	(3)	4	(1)
Other loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	194	126	59
Provisions	335	256	174
Net write-offs	(242)	(207)
Other	1	(1)	0
Ending Balance	323	194	126
Other loans | Principal
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net write-offs	(198)	(180)	(104)
Recoveries	34	20	14
Other loans | Interest and fees
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net write-offs	$ (9)	$ (7)	$ (3)