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	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	$ 270	$ 119
Amortized Cost	521	538
Gross Unrealized Gains	0	2
Gross Unrealized Losses	(16)	(2)
Fair Value	505	538
Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	181	25
Fair Value	0	0
Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	0	0
Fair Value	279	303
Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	89	94
Fair Value	226	235
Money market mutual funds | Level 1
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	228	97
Money market mutual funds | Level 1 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	139	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:	89	93
U.S. treasuries | Level 2
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	42	22
U.S. treasuries | Level 2 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Cash equivalents:	42	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:	0	1
Asset-backed securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	46	49
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	0
Fair Value	44	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	44	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	163	167
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(5)	(1)
Fair Value	158	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	128	137
Corporate bonds | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	30	30
Agency securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	23	17
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	0
Fair Value	22	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	4	2
Agency securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	18	15
U.S. treasuries | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	271	285
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(8)	(1)
Fair Value	263	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	94	106
U.S. treasuries | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	169	179
Certificate of deposits | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	9	11
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	9	11
Certificate of deposits | Level 2 | Cash and cash equivalents
Fair Value, Financial Instruments [Line Items]
Fair Value	0	0
Certificate of deposits | Level 2 | Investments
Fair Value, Financial Instruments [Line Items]
Fair Value		0
Certificate of deposits | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	9	11
Other debt securities | Level 2
Fair Value, Financial Instruments [Line Items]
Amortized Cost	9	9
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	9	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	9	9
Other debt securities | Level 2 | Restricted Cash, Cash Equivalents and Investments
Fair Value, Financial Instruments [Line Items]
Fair Value	$ 0	$ 0