Acquisition and Divestitures - Summary of Unpaid Principal Balance to Fair Value of Loans and Leases by Portfolio Segment (Details) - USD ($) $ in Millions		Apr. 01, 2022	Dec. 31, 2023	Jan. 01, 2023	Dec. 31, 2022	Jan. 01, 2022	Dec. 31, 2021	Jan. 01, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principal balance			$ 2,166		$ 2,439		$ 2,060
Allowance for credit losses at acquisition				$ (2,439)		$ (2,060)		$ (1,893)
Non PCD Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principal balance		$ 32,896
Other discount	[1]	(260)
Fair value		32,636
PCD Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principal balance	[2]	3,411
Allowance for credit losses at acquisition	[2]	(99)
Other discount		(107)
Fair value		$ 3,205

[1] Includes approximately $242 million of principal balances not expected to be collected.

[2] The unpaid principal balance and allowance for credit losses at acquisition is net of charge-offs of $33 million recognized on the PCD loans.