Variable Interest Entities - Unpaid Principal (Details) - Variable Interest Entity, Primary Beneficiary - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
FG VIEs’ assets	$ 283	$ 279
FG VIEs' liabilities with recourse	17	21
FG VIEs’ liabilities without recourse	17	19
Unpaid principal balance for FG VIEs’ assets that were 90 days or more past due	50	52
Unpaid principal for FG VIEs’ liabilities with recourse	$ 353	$ 388