SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 4) (Predecessor Company, KFN, KKR & Co.)	0 Months Ended
Apr. 30, 2014	Dec. 16, 2013
Predecessor Company \| KFN \| KKR & Co.
Merger transaction
Exchange ratio of share based awards under merger transaction	0.51	0.51

Represents the ratio applied to exchange nonvested equity-based awards other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

No definition available.

Name:	kfn_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsExchangeRatioMergerTransaction
Namespace Prefix:	kfn_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration