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, 2023	Dec. 31, 2022
Unrealized Losses
Less Than 12 Months	$ (162)	$ (620)
12 Months or More	(1,231)	(744)
Fair Value
Fair Value, Less Than 12 Months	5,170	10,075
Fair Value, 12 Months or More	11,331	5,747
U.S. Treasury securities and obligations of U.S. government corporations and agencies
Unrealized Losses
Less Than 12 Months	(1)	(5)
12 Months or More	(12)	(11)
Fair Value
Fair Value, Less Than 12 Months	161	342
Fair Value, 12 Months or More	247	184
Corporate securities
Unrealized Losses
Less Than 12 Months	(76)	(340)
12 Months or More	(674)	(438)
Fair Value
Fair Value, Less Than 12 Months	2,470	5,368
Fair Value, 12 Months or More	6,393	3,400
Municipal securities
Unrealized Losses
Less Than 12 Months	(44)	(142)
12 Months or More	(250)	(138)
Fair Value
Fair Value, Less Than 12 Months	1,308	2,437
Fair Value, 12 Months or More	2,211	995
Asset-backed securities
Unrealized Losses
Less Than 12 Months	(7)	(29)
12 Months or More	(45)	(41)
Fair Value
Fair Value, Less Than 12 Months	486	786
Fair Value, 12 Months or More	946	486
Residential mortgage-backed securities
Unrealized Losses
Less Than 12 Months	(23)	(55)
12 Months or More	(149)	(66)
Fair Value
Fair Value, Less Than 12 Months	517	629
Fair Value, 12 Months or More	786	352
Commercial mortgage-backed securities
Unrealized Losses
Less Than 12 Months	(11)	(49)
12 Months or More	(101)	(50)
Fair Value
Fair Value, Less Than 12 Months	228	513
Fair Value, 12 Months or More	$ 748	$ 330