Segments (Details) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($)	Mar. 31, 2019 segment	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) segment	Sep. 30, 2018 USD ($)	Dec. 31, 2018 segment
Segment Reporting [Abstract]
Number of reportable segments | segment		3		3		1
Net Revenues
Total consolidated net revenue	$ 2,649		$ 2,649	$ 7,979	$ 7,869
Operating income (loss)
Total operating income	532		556	1,702	1,541
Interest and other, net	(142)		392	(129)	661
Income before income taxes	390		948	1,573	2,202
U.S.
Net Revenues
Total consolidated net revenue	1,089		1,084	3,204	3,213
Germany
Net Revenues
Total consolidated net revenue	364		381	1,141	1,180
United Kingdom
Net Revenues
Total consolidated net revenue	345		363	1,070	1,088
South Korea
Net Revenues
Total consolidated net revenue	288		290	886	877
Rest of world
Net Revenues
Total consolidated net revenue	563		531	1,678	1,511
Operating Segments
Net Revenues
Total consolidated net revenue	2,649		2,649	7,979	7,869
Operating Segments | Marketplace
Net Revenues
Total consolidated net revenue	2,083		2,104	6,402	6,341
Operating income (loss)
Total operating income	639		637	2,102	1,964
Operating Segments | StubHub
Net Revenues
Total consolidated net revenue	306		291	800	769
Operating income (loss)
Total operating income	31		31	68	67
Operating Segments | Classifieds
Net Revenues
Total consolidated net revenue	265		254	792	759
Operating income (loss)
Total operating income	109		99	303	284
Elimination of inter-segment net revenue
Net Revenues
Total consolidated net revenue	(5)		0	(15)	0
Corporate and other costs
Operating income (loss)
Total operating income	(247)		(211)	(771)	(774)
Net transaction revenues | Operating Segments | Marketplace
Net Revenues
Total consolidated net revenue	1,829		1,803	5,601	5,432
Net transaction revenues | Operating Segments | StubHub
Net Revenues
Total consolidated net revenue	286		286	752	757
Marketing services and other revenues | Operating Segments | Marketplace
Net Revenues
Total consolidated net revenue	254		301	801	909
Marketing services and other revenues | Operating Segments | StubHub
Net Revenues
Total consolidated net revenue	$ 20		$ 5	$ 48	$ 12