Basis of Presentation - Business Events (Details) - USD ($) $ in Millions			3 Months Ended			9 Months Ended
	Jun. 01, 2025	Apr. 16, 2025	Sep. 30, 2025	Sep. 30, 2024	Jun. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loans reclassified to held for sale	$ 1,600
Reversal of reserve for credit losses			$ (1,287)	$ (1,356)		$ (3,842)	$ (3,893)
Gain on sale of Accertify			$ 0	$ 0		$ 0	$ 531
Accertify
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of Accertify					$ 531
Gain on sale of Accertify, net of tax					$ 479
CS
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill acquired during period		$ 590