Discontinued Operations - Narrative (Details) - USD ($) shares in Millions, $ in Millions		3 Months Ended			9 Months Ended
	Feb. 13, 2020	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jul. 17, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of business					$ 0	$ (52)
Transaction service agreement, fees	$ 40
Transaction service agreement, extension term	12 months
Cost of net revenues			$ 656	$ 530	1,731	1,580
Intercompany
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net revenues			2	4	9	13
Cost of net revenues			2	4	9	13
Minimum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transaction service agreement, term	12 months
Maximum
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transaction service agreement, term	18 months
StubHub
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income taxes of discontinued operations			(2)	1	891	12
StubHub | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received for business disposal	$ 4,050
Proceeds received for business disposal	4,100
Proceeds received for business disposal, net of income taxes and transaction costs	3,200
Income taxes of discontinued operations	900
Gain on sale of business	$ 3,900
Classifieds
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income taxes of discontinued operations			$ 31	$ 23	$ 43	$ 119
Classifieds | Discontinued Operations, Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Amount of consideration to be received, subject to adjustments							$ 9,200
Classifieds | Discontinued Operations, Held-for-sale | Forecast
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of business		$ 2,500
Number of shares to be received from the sale		540