Consolidations and Transfers of Financial Assets Types of VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Assets	$ 3,985,749	$ 3,503,319
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Conclusion to Consolidate, Change in Facts and Circumstances, Amount		$ 1,200