Fair Value Measurements - Schedule of Fair Value of Investment Assets (Details) - Fair Value - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	$ 172	$ 214
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	5	2
Level 1 | Exchange-traded Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	5	2
Level 1 | Corporate Bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0	0
Level 1 | Government Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0	0
Level 1 | Asset-backed Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0	0
Level 1 | Time Deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0	0
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	172	214
Level 2 | Exchange-traded Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0	0
Level 2 | Corporate Bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	78	71
Level 2 | Government Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	60	42
Level 2 | Asset-backed Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	34	35
Level 2 | Time Deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	0	66
Total
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	177	216
Total | Exchange-traded Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	5	2
Total | Corporate Bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	78	71
Total | Government Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	60	42
Total | Asset-backed Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	34	35
Total | Time Deposits
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total Investments at Fair Value	$ 0	$ 66