Investments - Equity Security Investments (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Amortized Cost
Equity securities with readily determinable fair values	$ 136	$ 61
Equity securities with no readily determinable fair value	187	183
Hybrid equity securities	58	58
Total	381	302
Carrying Value
Equity securities with readily determinable fair values	126	64
Equity securities with no readily determinable fair value	196	192
Hybrid equity securities	25	47
Total	$ 347	$ 303