Summary of Significant Accounting Policies - Card Member Loans HFS (Details) - USD ($) $ in Millions			12 Months Ended
	Jun. 01, 2025	Dec. 01, 2024	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Reversal of reserve for credit losses			$ (5,256)	$ (5,185)	$ (4,923)
Card Member loans
Disaggregation of Revenue [Line Items]
Loans reclassified to held-for-sale	$ 1,600	$ 758
Reversal of reserve for credit losses	$ 144	$ 49	$ (4,067)	$ (4,109)	$ (3,839)