Investments - Amortized Cost Versus Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	$ 628	$ 1,280
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total	628	1,280
Cash equivalents
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	608	1,231
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total	608	1,231
Cash equivalents | Money market funds
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	503	1,002
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total	503	1,002
Cash equivalents | U.S. government and government agency debt securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	105	229
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total	105	229
Short-term marketable securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	20	49
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total	20	49
Short-term marketable securities | U.S. government and government agency debt securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost	20	47
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Total	$ 20	47
Short-term marketable securities | Corporate debt securities
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost		2
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Total		$ 2