Allowance for Credit Losses and Reserve for Unfunded Lending Commitments - Summary of Loss Sharing Arrangements (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Change in estimated partner reimbursements that decreased/(increased) provision for credit losses	$ 2,795	$ 677
Loss sharing agreements
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Expected reimbursement from loss sharing partners, beginning balance	1,558	1,450
Financing Receivable, Allowance for Credit Loss, Writeoff	(201)	(107)
Change in estimated partner reimbursements that decreased/(increased) provision for credit losses	484	23
Expected reimbursement from loss sharing partners, ending balance	$ 1,841	$ 1,366