SEGMENT REPORTING - Financial Data for KKR's Reportable Segments (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) segment	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment			1
Management, Monitoring and Transaction Fees, Net
Fees and Other	$ 491,503	$ 355,418	$ 1,299,743	$ 1,116,382
Realized Performance Income (Loss)
Carried Interest	543,750	337,459	1,097,673	1,224,235
Investment Income (Loss)
Total Investment Income (Loss)	833,288	177,953	2,748,604	1,289,638
Total Revenues	1,129,666	749,652	2,573,892	2,533,207
Segment Expenses
Compensation and Benefits	560,434	368,513	1,331,070	1,234,317
Occupancy and Related Charges	15,250	15,267	44,787	44,150
Total Expenses	740,090	530,247	1,851,741	1,699,989
Preferred Dividends	8,341	8,341	25,023	25,023
Less: Net Income (Loss) Attributable to Noncontrolling Interests	691,494	196,158	1,985,961	1,137,585
Income Taxes Paid			48,891	34,633
After-tax Distributable Earnings	640,198	153,563	1,490,681	818,552
Total Assets	50,343,948	44,305,639	50,343,948	44,305,639	$ 45,834,719
Investment losses related to the Conversion			729,400
Reportable segments
Management, Monitoring and Transaction Fees, Net
Fees and Other	503,614	355,716	1,283,548	1,096,398
Realized Performance Income (Loss)
Carried Interest	414,609	419,438	959,253	890,310
Incentive Fees	18,001	4,074	52,059	8,384
Total Realized Performance Income (Loss)	432,610	423,512	1,011,312	898,694
Investment Income (Loss)
Net Realized Gains (Losses)	181,026	76,053	286,381	162,684
Interest Income and Dividends	61,717	70,557	205,522	195,275
Total Investment Income (Loss)	242,743	146,610	491,903	357,959
Total Revenues	1,178,967	925,838	2,786,763	2,353,051
Segment Expenses
Compensation and Benefits	469,107	363,247	1,138,149	933,107
Occupancy and Related Charges	14,571	14,672	42,819	42,448
Other Operating Expenses	73,402	70,517	194,868	177,084
Total Expenses	557,080	448,436	1,375,836	1,152,639
Segment Operating Earnings	621,887	477,402	1,410,927	1,200,412
Interest Expense	44,696	45,613	140,362	134,348
Preferred Dividends	8,341	8,341	25,023	25,023
Less: Net Income (Loss) Attributable to Noncontrolling Interests	2,272	1,046	4,557	3,810
Income Taxes Paid	69,880	12,869	103,868	54,228
After-tax Distributable Earnings	496,698	409,533	1,137,117	983,003
Total Assets	18,772,875	15,347,999	18,772,875	15,347,999
Add: One-time Non-recurring Costs			11,500
Management Fees
Management, Monitoring and Transaction Fees, Net
Fees and Other	188,866	178,942	547,765	517,393
Management Fees | Reportable segments
Management, Monitoring and Transaction Fees, Net
Fees and Other	276,595	232,954	789,630	670,807
Transaction Fees
Management, Monitoring and Transaction Fees, Net
Fees and Other	290,404	181,280	619,278	581,410
Transaction Fees | Reportable segments
Management, Monitoring and Transaction Fees, Net
Fees and Other	289,030	179,167	609,800	578,667
Monitoring Fees
Management, Monitoring and Transaction Fees, Net
Fees and Other	20,176	14,478	63,125	58,977
Monitoring Fees | Reportable segments
Management, Monitoring and Transaction Fees, Net
Fees and Other	20,176	14,342	63,100	58,072
Fee Credits
Management, Monitoring and Transaction Fees, Net
Fees and Other	(73,904)	(70,641)	(137,804)	(207,396)
Fee Credits | Reportable segments
Management, Monitoring and Transaction Fees, Net
Fees and Other	(82,187)	(70,747)	(178,982)	(211,148)
Compensation and Benefits
Segment Expenses
Equity based expenses	85,296	72,543	267,767	239,709
Equity Incentive Plan Units | Compensation and Benefits
Segment Expenses
Equity based expenses	$ 59,801	$ 54,921	$ 185,795	$ 149,840