Service Fees and Other Revenue and Other Expenses - Other Expenses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Service Fees and Other Revenue and Other Expenses [Abstract]
Data processing and equipment	$ 705	$ 657
Professional services	541	455
Other	400	364
Total Other expenses	$ 1,646	$ 1,476