Quarterly report pursuant to Section 13 or 15(d)

Short-term and Long-term Investments, Restricted Deposits - Fair Value of Available-For-Sale Investments with Gross Unrealized Losses by Investment Type and Length of Time (Details)

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Short-term and Long-term Investments, Restricted Deposits - Fair Value of Available-For-Sale Investments with Gross Unrealized Losses by Investment Type and Length of Time (Details) - USD ($)
$ in Millions
Jun. 30, 2021
Dec. 31, 2020
Unrealized Losses    
Less Than 12 Months $ (40) $ (16)
12 Months or More (5) (2)
Fair Value    
Fair Value, Less Than 12 Months 4,165 1,904
Fair Value, 12 Months or More 185 144
Corporate securities    
Unrealized Losses    
Less Than 12 Months (26) (7)
12 Months or More (2) (1)
Fair Value    
Fair Value, Less Than 12 Months 2,245 953
Fair Value, 12 Months or More 77 24
Municipal securities    
Unrealized Losses    
Less Than 12 Months (4) (2)
12 Months or More (1) 0
Fair Value    
Fair Value, Less Than 12 Months 576 238
Fair Value, 12 Months or More 26 0
Asset-backed securities    
Unrealized Losses    
Less Than 12 Months (1) (2)
12 Months or More 0 (1)
Fair Value    
Fair Value, Less Than 12 Months 272 302
Fair Value, 12 Months or More 40 105
Residential mortgage-backed securities    
Unrealized Losses    
Less Than 12 Months (5) 0
12 Months or More 0 0
Fair Value    
Fair Value, Less Than 12 Months 446 59
Fair Value, 12 Months or More 2 2
Commercial mortgage-backed securities    
Unrealized Losses    
Less Than 12 Months (3) (5)
12 Months or More (2) 0
Fair Value    
Fair Value, Less Than 12 Months 228 147
Fair Value, 12 Months or More $ 40 $ 13