NET INCOME (LOSS) ATTRIBUTABLE TO KKR & CO. INC. PER SHARE OF CLASS A COMMON STOCK (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 16, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
NET INCOME (LOSS) ATTRIBUTABLE TO KKR & CO. INC. PER SHARE OF CLASS A COMMON STOCK
Net Income (Loss) Attributable to KKR & Co. Inc. Class A Common Stockholders		$ 640,198	$ 153,563	$ 1,490,681	$ 818,552
Preferred stock dividend rate (as a percent)	7.375%
Weighted Average KKR Holdings Units
Weighted Average KKR Holdings Units (in shares)		303,531,232	341,214,527	319,080,563	346,716,489
Class A Common Stock
NET INCOME (LOSS) ATTRIBUTABLE TO KKR & CO. INC. PER SHARE OF CLASS A COMMON STOCK
Net Income (Loss) Attributable to KKR & Co. Inc. Class A Common Stockholders		$ 640,198	$ 153,563	$ 1,490,681	$ 818,552
Excess of carrying value over consideration transferred on redemption of KFN 7.375% Series A LLC Preferred Shares		0	0	3,102	0
Net Income (Loss) Available to KKR & Co. Inc. Class A Common Stockholders		$ 640,198	$ 153,563	$ 1,493,783	$ 818,552
Basic Net Income (Loss) Per Share of Class A Common Stock
Weighted Average Shares of Class A Common Stock Outstanding - Basic (in shares)		525,240,214	471,758,886	507,981,387	463,941,084
Net Income (Loss) Attributable to KKR & Co. Inc. Per Share of Class A Common Stock - Basic (in dollars per share)		$ 1.22	$ 0.33	$ 2.94	$ 1.76
Diluted Net Income (Loss) Per Share of Class A Common Stock
Weighted Average Shares of Class A Common Stock Outstanding - Basic (in shares)		525,240,214	471,758,886	507,981,387	463,941,084
Weighted Average Unvested Shares of Class A Common Stock and Other Exchangeable Securities (in shares)		20,432,739	35,114,291	20,485,003	37,674,551
Weighted Average Shares of Class A Common Stock Outstanding - Diluted (in shares)		545,672,953	506,873,177	528,466,390	501,615,635
Net Income (Loss) Attributable to KKR & Co. Inc. Per Share of Class A Common Stock - Diluted (in dollars per share)		$ 1.17	$ 0.30	$ 2.83	$ 1.63
Class A Common Stock | Market Condition Awards
Weighted Average KKR Holdings Units
Weighted Average KKR Holdings Units (in shares)		5,000,000		5,000,000