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	Sep. 30, 2024	Dec. 31, 2023
Variable Interest Entities [Line Items]
Long-term debt	$ 518	$ 508
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Long-term debt	2,996	2,967
Long-term debt, Estimated fair value	2,738	2,710
Loans Unpaid Principal Balance	1,738	1,787
Long Term Debt Unpaid Principal Balance	$ 2,944	$ 2,952