Service Fees and Other Revenue and Other Expenses - Other Expenses (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Service Fees and Other Revenue and Other Expenses [Abstract]
Data processing and equipment	$ 751	$ 725	$ 2,176	$ 2,083
Professional services	623	579	1,755	1,576
Gain on sale of Accertify	0	0	0	(531)
Other	406	476	1,181	1,166
Total Other expenses	$ 1,780	$ 1,780	$ 5,112	$ 4,294