Basis of Presentation and Summary of Significant Accounting Policies (Details) $ / shares in Units, shares in Millions, $ in Millions			3 Months Ended			9 Months Ended
	May 14, 2019 USD ($) $ / shares shares	Mar. 26, 2019 USD ($)	Sep. 30, 2019 USD ($) renewal_option	Jun. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) renewal_option segment	Sep. 30, 2018 USD ($)	May 16, 2019 $ / shares	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
Subsidiary, Sale of Stock [Line Items]
Number of operating segments | segment						5
Number of reportable segments | segment						5
Gain on conversion of convertible notes				$ 327
Gain on extinguishment of convertible notes and settlement of derivatives			$ 0	444	$ 0	$ 444	$ 0
Embedded derivative liability income (expense)			0	117	(89)	58	(491)
Share-based compensation expense			$ 401		$ 64	$ 4,353	$ 147
Additional deferred tax asset due to stock-based compensation expense				$ 1,100
Number of renewal options | renewal_option			1			1
Lease renewal term			14 years			14 years
Termination option period						1 year
ROU assets generated from leased assets outside of the U.S. (Less than)			11.00%			11.00%
Operating lease right-of-use assets			$ 1,538			$ 1,538
Operating lease, liability			1,656			1,656
Built-to-suit assets, derecognized amounts			(1,537)			(1,537)				$ (1,641)
Deferred tax liability, derecognized built-to-suit assets			1,038			1,038				1,072
Built-to-suit assets, derecognized financing obligation reclassified			1,393			1,393				1,312
Accumulated deficit			$ 15,266			$ 15,266				$ 7,865
ASU 2016-02
Subsidiary, Sale of Stock [Line Items]
Operating lease right-of-use assets									$ 888
Operating lease, liability									963
Built-to-suit assets, derecognized amounts									392
Built to suit assets, financing obligation									350
Deferred tax liability, derecognized built-to-suit assets									9
Built-to-suit assets, derecognized financing obligation reclassified									60
Accumulated deficit									$ 9
Maximum
Subsidiary, Sale of Stock [Line Items]
Operating and finance leases, term of contract						76 years
Careem Inc.
Subsidiary, Sale of Stock [Line Items]
Asset acquisition, consideration transferred		$ 3,100
Asset acquisition, consideration transferred, debt instruments		1,700
Asset acquisition, consideration transferred, cash		$ 1,400
IPO
Subsidiary, Sale of Stock [Line Items]
Stock issued during period (in shares) | shares	180.0
Stock price (in dollars per share) | $ / shares	$ 45.00							$ 45.00
Proceeds from issuance of common stock	$ 8,000
Conversion of shares (in shares) | shares	905.0
Exercise of common stock warrants (in shares) | shares	0.2
Share-based compensation expense	$ 3,600
Shares withheld to meet tax withholding requirements (in shares) | shares	29.0
Shares withheld to meet tax withholding requirement, value	$ 1,300
IPO | Common Stock
Subsidiary, Sale of Stock [Line Items]
Stock issued during period (in shares) | shares	76.0
IPO | Holders of 2021 Convertible Notes and 2022 Convertible Notes
Subsidiary, Sale of Stock [Line Items]
Conversion of Convertible Notes to common stock in connection with initial public offering (in shares) | shares	94.0
Underwriters' discounts and commissions
Subsidiary, Sale of Stock [Line Items]
Payments of stock issuance costs	$ 106