Special Purpose Entities, Including Variable Interest Entities - Supplemental Information about Loans Held as Assets and Long-Term Debt Associated with Consolidated Variable Interest Entities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Variable Interest Entities [Line Items]
Long-term debt	$ 512	$ 508
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Long-term debt	2,925	2,967
Long-term debt, Estimated fair value	2,671	2,710
Loans Unpaid Principal Balance	1,730	1,787
Long Term Debt Unpaid Principal Balance	$ 2,889	$ 2,952