Financial Instruments and Fair Value Measurements - Summary of Financial Instruments by Significant Categories and Fair Value Measurement on a Recurring Basis (Details) - Fair Value Measurement on a Recurring Basis - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	$ 780	$ 119
Amortized Cost	467	538
Gross Unrealized Gains	0	2
Gross Unrealized Losses	(5)	(2)
Fair Value	462	538
Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	685	25
Fair Value	0	0
Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	0	0
Fair Value	237	303
Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	95	94
Fair Value	225	235
Asset-backed securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	43	49
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	0
Fair Value	41	49
Asset-backed securities | Level 2 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Asset-backed securities | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	41	49
Asset-backed securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Corporate bonds | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	141	167
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(1)	(1)
Fair Value	140	167
Corporate bonds | Level 2 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Corporate bonds | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	114	137
Corporate bonds | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	26	30
Agency securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	25	17
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	0
Fair Value	24	17
Agency securities | Level 2 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Agency securities | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	2	2
Agency securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	22	15
U.S. treasuries | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	239	285
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(1)	(1)
Fair Value	238	285
U.S. treasuries | Level 2 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
U.S. treasuries | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	72	106
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	166	179
Certificate of deposit | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	11	11
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	11	11
Certificate of deposit | Level 2 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Certificate of deposit | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value		0
Certificate of deposit | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	11	11
Other debt securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	8	9
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	8	9
Other debt securities | Level 2 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Other debt securities | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	8	9
Other debt securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Money market mutual funds | Level 1
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	777	97
Money market mutual funds | Level 1 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	685	4
Money market mutual funds | Level 1 | Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	0	0
Money market mutual funds | Level 1 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	92	93
U.S. treasuries | Level 2
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	3	22
U.S. treasuries | Level 2 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	0	21
U.S. treasuries | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	0	0
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	$ 3	$ 1