Segments (Details) $ in Millions	3 Months Ended			6 Months Ended		12 Months Ended
	Jun. 30, 2019 USD ($)	Mar. 31, 2019 segment	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) segment	Jun. 30, 2018 USD ($)	Dec. 31, 2018 segment
Segment Reporting [Abstract]
Number of reportable segments | segment		3		3		1
Segment Reporting Information [Line Items]
Total net revenues	$ 2,687		$ 2,640	$ 5,330	$ 5,220
Total operating income	561		406	1,170	985
Interest and other, net	(51)		301	13	269
Income before income taxes	510		707	1,183	1,254
U.S.
Segment Reporting Information [Line Items]
Total net revenues	1,057		1,055	2,115	2,129
Germany
Segment Reporting Information [Line Items]
Total net revenues	393		407	777	799
United Kingdom
Segment Reporting Information [Line Items]
Total net revenues	369		369	725	725
South Korea
Segment Reporting Information [Line Items]
Total net revenues	300		304	598	587
Rest of world
Segment Reporting Information [Line Items]
Total net revenues	568		505	1,115	980
Operating Segments
Segment Reporting Information [Line Items]
Total net revenues	2,687		2,640	5,330	5,220
Operating Segments | Marketplace
Segment Reporting Information [Line Items]
Total net revenues	2,157		2,135	4,319	4,237
Total operating income	691		639	1,463	1,327
Operating Segments | StubHub
Segment Reporting Information [Line Items]
Total net revenues	264		246	494	478
Total operating income	11		5	37	36
Operating Segments | Classifieds
Segment Reporting Information [Line Items]
Total net revenues	271		259	527	505
Total operating income	102		98	194	185
Elimination of inter-segment net revenue
Segment Reporting Information [Line Items]
Total net revenues	(5)		0	(10)	0
Corporate and other costs
Segment Reporting Information [Line Items]
Total operating income	(243)		(336)	(524)	(563)
Net transaction revenues | Operating Segments | Marketplace
Segment Reporting Information [Line Items]
Total net revenues	1,887		1,837	3,772	3,629
Net transaction revenues | Operating Segments | StubHub
Segment Reporting Information [Line Items]
Total net revenues	243		240	466	471
Marketing services and other revenues | Operating Segments | Marketplace
Segment Reporting Information [Line Items]
Total net revenues	270		298	547	608
Marketing services and other revenues | Operating Segments | StubHub
Segment Reporting Information [Line Items]
Total net revenues	$ 21		$ 6	$ 28	$ 7