XML 51 R39.htm IDEA: XBRL DOCUMENT v3.21.1
Investments - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2020
Mar. 31, 2021
Investments, Debt and Equity Securities [Abstract]    
Gross realized investment gains $ 5  
Debt securities held to maturity   $ 138
Amortized Cost, Due in one year or less   122
Amortized Cost, Due one year through five years   $ 16