STOCK-BASED EMPLOYEE COMPENSATION (Assumed Stock Options Narrative) (Details) (USD $)	12 Months Ended			0 Months Ended	7 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	May 21, 2013 KAYAK [Member]	Dec. 31, 2013 KAYAK [Member]	Dec. 31, 2013 KAYAK [Member] Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercised, total intrinsic value	$ 44,900,000	$ 75,200,000	$ 77,100,000		$ 236,900,000
Number of options vested (in shares)				408,716
Amount of options vested				260,900,000
Number of options unvested (in shares)				131,463
Fair value of unvested options				57,400,000
Weighted average fair value of unvested options (in dollars per share)				$ 443.92
Assumed unvested employee stock options vesting during period (in shares)					65,293
Fair value of stock options vested during the period					30,900,000
Stock-based compensation expense	140,526,000	71,565,000	65,724,000			30,900,000
Stock-based compensation expense, not yet recognized				$ 57,400,000	$ 16,600,000
Total future compensation cost related to unvested share-based awards, expected period of recognition						2 years 1 month