Variable Interest Entities and Securitization Activities - Proceeds from New Securitization Transactions and Sales of Loans (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Variable Interest Entities and Securitization Activities [Abstract]
New transactions	$ 9,717	$ 3,605	$ 16,599	$ 6,126
Retained interests	$ 2,091	$ 1,077	$ 4,191	$ 2,652

Cash flows between transferor and a transferee attributable to the transferor's interests related to a securitization, asset-backed financing arrangement, or similar transfer in which the transferor will have continuing involvement with the transferred financial assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in the transferred financial assets).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (d)(5)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481326/860-20-50-3

Name:	us-gaap_CashFlowsBetweenTransfereeAndTransferorReceiptsOnInterestsThatContinueToBeHeldOther
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration