INVESTMENTS - Summary of Investments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Investments
Investments owned, at fair value	$ 44,119,593	$ 39,013,934
Private Equity
Investments
Investments owned, at fair value	7,517,830	3,301,261
Credit
Investments
Investments owned, at fair value	8,627,571	7,621,320
Investments of Consolidated CFEs
Investments
Investments owned, at fair value	13,293,505	15,573,203
Real Assets
Investments
Investments owned, at fair value	3,279,482	2,302,061
Equity Method - Other
Investments
Investments owned, at fair value	4,146,762	3,324,631
Equity Method - Capital Allocation-Based Income
Investments
Investments owned, at fair value	4,417,855	4,132,171
Other Investments
Investments
Investments owned, at fair value	$ 2,836,588	$ 2,759,287

Value of the investment at close of period. For schedules of investments that are categorized, the value would be aggregated by category. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section 50
-Paragraph 6
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-URI http://asc.fasb.org/extlink&oid=99383244&loc=d3e12121-115841

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 4
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-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611225-123010

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 6
-Subparagraph (SX 210.12-14.Column E.2,3)
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611322-123010

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-12.Column C.3,4)
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611133-123010

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 5
-Subparagraph (SX 210.12-13.Column C.6)
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611282-123010

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant