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
Sep. 30, 2021
Dec. 31, 2020
Unrealized Losses    
Less Than 12 Months $ (53) $ (16)
12 Months or More (5) (2)
Fair Value    
Fair Value, Less Than 12 Months 5,052 1,699
Fair Value, 12 Months or More 171 144
Corporate securities    
Unrealized Losses    
Less Than 12 Months (35) (7)
12 Months or More (2) (1)
Fair Value    
Fair Value, Less Than 12 Months 3,089 953
Fair Value, 12 Months or More 75 24
Municipal securities    
Unrealized Losses    
Less Than 12 Months (7) (2)
12 Months or More (1) 0
Fair Value    
Fair Value, Less Than 12 Months 929 238
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 334 302
Fair Value, 12 Months or More 36 105
Residential mortgage-backed securities    
Unrealized Losses    
Less Than 12 Months (6) 0
12 Months or More 0 0
Fair Value    
Fair Value, Less Than 12 Months 428 59
Fair Value, 12 Months or More 1 2
Commercial mortgage-backed securities    
Unrealized Losses    
Less Than 12 Months (4) (5)
12 Months or More (2) 0
Fair Value    
Fair Value, Less Than 12 Months 272 147
Fair Value, 12 Months or More $ 33 $ 13