Segment Information - Revenue by Services and Geographic Area (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 2,747	$ 3,558	$ 3,153	$ 2,609	$ 2,559	$ 3,276	$ 2,880	$ 2,508	$ 12,067	$ 11,223	$ 10,060
United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									6,869	6,202	5,542
All other countries
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									5,198	5,021	4,518
Lodging
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									8,472	7,712	6,851
Air
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									869	881	784
Advertising and media
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									1,103	1,092	1,073
Other
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									1,623	1,538	1,352
Sales Channel, Through Intermediary | Merchant
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									6,459	5,950	5,394
Sales Channel, Through Intermediary | Agency
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									3,165	3,010	2,687
Sales Channel, Through Intermediary | Advertising and media
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									1,103	1,092	1,073
Sales Channel, Through Intermediary | Vrbo
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									1,340	1,171	906
Corporate & Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									(258)	$ (393)	$ (414)
Bodybuilding.com | Corporate & Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									$ 58