SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Noncontrolling Interests Held by KKR Holdings (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Calculation of Noncontrolling Interest [Abstract]
Capital contributions	$ 1,270,723	$ 528,833
Capital distributions	(930,232)	(343,083)
Noncontrolling Interests held by KKR Holdings
Calculation of Noncontrolling Interest [Abstract]
Balance at the beginning of the period	4,793,475	4,293,337
Net income (loss) attributable to noncontrolling interests held by KKR Holdings	121,002	216,432
Other comprehensive income (loss), net of tax	3,143	4,920
Impact of the exchange of KKR Holdings units to KKR & Co. L.P. common units	(33,775)	(35,904)
Equity-based and other non-cash compensation	32,695	61,093
Capital contributions	39	37
Capital distributions	(57,167)	(56,637)
Transfer of interests under common control and Other (See Note 15 Equity)	0	7,919
Balance at the end of the period	$ 4,859,412	$ 4,491,197