STOCK-BASED EMPLOYEE COMPENSATION (Assumed Stock Options Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended		1 Months Ended	3 Months Ended			3 Months Ended		4 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013 KAYAK [Member]	Sep. 30, 2013 KAYAK [Member]	Jun. 30, 2013 KAYAK [Member]	May 21, 2013 KAYAK [Member]	Sep. 30, 2013 KAYAK [Member] Employee Stock Option [Member]	Jun. 30, 2013 KAYAK [Member] Employee Stock Option [Member]	Sep. 30, 2013 KAYAK [Member] Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercised, total intrinsic value					$ 197,500,000	$ 29,000,000
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)						34,835	15,923
Fair value of stock options vested during the period						15,400,000	7,600,000
Stock-based compensation expense	34,551,000	17,555,000	90,996,000	51,690,000					12,000,000	11,000,000
Stock-based compensation expense not yet recognized						$ 27,300,000		$ 57,400,000
Total future compensation cost related to unvested Share-Based Awards, expected period of recognition											2 years 1 month