Investments - Investments - VIEs (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Variable Interest Entity, Primary Beneficiary, Maximum Loss Exposure, Amount	$ 0	$ 0
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount	1,400	1,300
Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule of Investments [Line Items]
Variable Interest Entity, Reporting Entity Involvement, Commitments	$ 801	$ 768