Stockholders' Equity - Effects of Changes in Noncontrolling Interest (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Aug. 31, 2018	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Noncontrolling Interest [Line Items]
Ownership interest percentage	25.00%
Net income attributable to Expedia Group, Inc.		$ 17	$ 525	$ 1	$ (137)	$ 55	$ 352	$ 57	$ (86)	$ 406	$ 378	$ 282
Net decrease in Expedia Group, Inc.’s paid-in capital related to trivago IPO												0
Net transfers from non-controlling interest										18	6
Change from net income attributable to Expedia Group, Inc. and transfers from non-controlling interest										394	381	250
Additional paid-in capital
Noncontrolling Interest [Line Items]
Net decrease in Expedia Group, Inc.’s paid-in capital related to trivago IPO												(32)
Other										(7)	3	0
Net transfers from non-controlling interest										(7)	3
Air Asia Expedia | Additional paid-in capital
Noncontrolling Interest [Line Items]
Net decrease in Expedia Group, Inc.’s paid-in capital related to trivago IPO										$ (5)	$ 0	0
Trivago
Noncontrolling Interest [Line Items]
Ownership interest percentage		59.50%				59.60%				59.50%	59.60%
Trivago | Additional paid-in capital
Noncontrolling Interest [Line Items]
Net decrease in Expedia Group, Inc.’s paid-in capital related to trivago IPO										$ 0	$ 0	(32)
Investment Group | Additional paid-in capital
Noncontrolling Interest [Line Items]
Net transfers from non-controlling interest										$ (12)	$ 3	$ (32)
Air Asia
Noncontrolling Interest [Line Items]
Equity interests held prior to acquisition	75.00%
Cash consideration	$ 62