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, 2022	Dec. 31, 2021
Variable Interest Entities [Line Items]
Long-term debt	$ 2,242	$ 2,230
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entities [Line Items]
Long-term debt	4,124	4,216
Long-term debt, Estimated fair value	3,701	4,056
Loans Unpaid Principal Balance	2,257	2,363
Long Term Debt Unpaid Principal Balance	$ 3,439	$ 3,579