Reserves for Credit Losses - Changes in Loan Reserve (Details) - USD ($) $ in Millions			12 Months Ended
	Jun. 01, 2025	Dec. 01, 2024	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 loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance			5,679	5,118	3,747
Provisions	$ (144)	$ (49)	4,067	4,109	3,839
Other			31	(33)	18
Ending Balance			5,909	5,679	5,118
Recoveries			988	730	537
Foreign currency translation adjustments			32	(33)	18
Card Member loans | Principal
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net write-offs			(3,176)	(2,894)	(2,043)
Card Member loans | Interest and fees
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net write-offs			$ (692)	$ (621)	$ (443)