Investments - Equity Security Investments (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Amortized Cost
Equity securities with readily determinable fair values	$ 126	$ 61
Equity securities with no readily determinable fair value	203	183
Hybrid equity securities	57	58
Total	386	302
Carrying Value
Equity securities with readily determinable fair values	124	64
Equity securities with no readily determinable fair value	212	192
Hybrid equity securities	43	47
Total	$ 379	$ 303