Reserves for Credit Losses - Changes in Other Loan Reserve (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Provisions for credit losses	$ 985	$ 1,287	$ 3,320	$ 3,842
Other Loans
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning reserves	312	272	323	194
Provisions for credit losses	84	62	194	245
Other	0	0	0	1
Ending reserves	335	287	335	287
Other Loans | Principal
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net write-offs	(59)	(45)	(174)	(146)
Recoveries	11	10	31	25
Other Loans | Interest and fees
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Net write-offs	$ (3)	$ (2)	$ (8)	$ (7)