Investments (Current Equity Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Equity Securities [Line Items]
Equity securities	$ 392	$ 953
Exchange Traded Funds [Member]
Equity Securities [Line Items]
Equity securities	288	822
Common Equity Securities [Member]
Equity Securities [Line Items]
Equity securities	26	43
Private Equity Funds [Member]
Equity Securities [Line Items]
Equity securities	$ 78	$ 88