Fair Value Measurements and Financial Instruments - Schedule of Assets and Liabilities that are Measured at Fair Value on a Recurring Basis (Details) - Recurring - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Money market funds
Assets
Money market funds	$ 3,007	$ 2,781
Government bonds
Assets
Other investments	1	1
Equity investments
Assets
Other investments		3
Gross foreign exchange contracts
Assets
Derivatives	42	38
Liabilities
Derivatives	9	5
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds
Assets
Money market funds	3,007	2,781
Quoted Prices in Active Markets for Identical Assets (Level 1) | Government bonds
Assets
Other investments	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity investments
Assets
Other investments		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Gross foreign exchange contracts
Assets
Derivatives	0	0
Liabilities
Derivatives	0	0
Significant Other Observable Inputs (Level 2) | Money market funds
Assets
Money market funds	0	0
Significant Other Observable Inputs (Level 2) | Government bonds
Assets
Other investments	1	1
Significant Other Observable Inputs (Level 2) | Equity investments
Assets
Other investments		3
Significant Other Observable Inputs (Level 2) | Gross foreign exchange contracts
Assets
Derivatives	42	38
Liabilities
Derivatives	9	5
Significant Unobservable Inputs (Level 3) | Money market funds
Assets
Money market funds	0	0
Significant Unobservable Inputs (Level 3) | Government bonds
Assets
Other investments	0	0
Significant Unobservable Inputs (Level 3) | Equity investments
Assets
Other investments		0
Significant Unobservable Inputs (Level 3) | Gross foreign exchange contracts
Assets
Derivatives	0	0
Liabilities
Derivatives	$ 0	$ 0