Quarterly report pursuant to Section 13 or 15(d)

Short-term and Long-term Investments, Restricted Deposits - Narrative (Details)

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Short-term and Long-term Investments, Restricted Deposits - Narrative (Details)
$ in Millions
6 Months Ended
Jun. 30, 2022
USD ($)
position
Dec. 31, 2021
USD ($)
Schedule Of Investments And Restricted Deposits By Type [Line Items]    
Accrued interest income | $ $ 107 $ 96
Positions from which gross unrealized losses were generated 5,998  
Total investment positions 6,773  
Commercial mortgage-backed securities    
Schedule Of Investments And Restricted Deposits By Type [Line Items]    
Investments recorded at fair value that carry rating of AAA Plus, weighted average (in years) 4 years  
Rated Securities | External Credit Rating, Investment Grade | Investment Securities    
Schedule Of Investments And Restricted Deposits By Type [Line Items]    
Percentage of investments in rated securities carry an investment grade rating by nationally recognized statistical rating organizations 98.00%