Loans Receivable and Allowance for Credit Losses - Allowance for Credit Losses Narrative (Details) $ in Millions	Dec. 31, 2023 USD ($) qtr	Sep. 30, 2023 qtr	Jun. 30, 2023 qtr	Dec. 31, 2022 USD ($)
Financing Receivable, Allowance for Credit Losses
Life time loss rate, period span	8
Financing receivable and off balance sheet credit loss allowance | $	$ 706			$ 622
C&I
Financing Receivable, Allowance for Credit Losses
Life time loss rate, period span		8	11