SEGMENT REPORTING - Earnings (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Segment Reporting [Line Items]
Segment Revenues	$ 1,317	$ 1,142	$ 2,576	$ 2,296
Total segment compensation and benefits	(478)	(421)	(934)	(845)
Total segment facilities, technology and professional fees	(100)	(86)	(198)	(175)
Total segment travel and other operating expenses	(99)	(68)	(187)	(133)
Segment Earnings	640	567	1,257	1,143
Operating Segments
Segment Reporting [Line Items]
Segment Revenues	1,317	1,142	2,576	2,296
Total segment compensation and benefits	(478)	(421)	(934)	(845)
Total segment facilities, technology and professional fees	(100)	(86)	(198)	(175)
Total segment travel and other operating expenses	(99)	(68)	(187)	(133)
Segment Earnings	640	567	1,257	1,143
Operating Segments \| Infrastructure
Segment Reporting [Line Items]
Segment Revenues	270	235	540	462
Total segment compensation and benefits	(79)	(64)	(147)	(124)
Total segment facilities, technology and professional fees	(20)	(14)	(37)	(28)
Total segment travel and other operating expenses	(14)	(9)	(25)	(17)
Segment Earnings	157	148	331	293
Operating Segments \| Energy
Segment Reporting [Line Items]
Segment Revenues	186	161	360	296
Total segment compensation and benefits	(55)	(38)	(104)	(79)
Total segment facilities, technology and professional fees	(10)	(7)	(19)	(12)
Total segment travel and other operating expenses	(12)	(9)	(21)	(15)
Segment Earnings	109	107	216	190
Operating Segments \| Private equity
Segment Reporting [Line Items]
Segment Revenues	129	110	249	213
Total segment compensation and benefits	(66)	(58)	(132)	(114)
Total segment facilities, technology and professional fees	(14)	(16)	(28)	(30)
Total segment travel and other operating expenses	(8)	(8)	(16)	(13)
Segment Earnings	41	28	73	56
Operating Segments \| Real estate
Segment Reporting [Line Items]
Segment Revenues	258	259	509	575
Total segment compensation and benefits	(99)	(91)	(197)	(189)
Total segment facilities, technology and professional fees	(23)	(19)	(45)	(41)
Total segment travel and other operating expenses	(11)	(10)	(21)	(20)
Segment Earnings	125	139	246	325
Operating Segments \| Credit
Segment Reporting [Line Items]
Segment Revenues	474	377	918	750
Total segment compensation and benefits	(179)	(170)	(354)	(339)
Total segment facilities, technology and professional fees	(33)	(30)	(69)	(64)
Total segment travel and other operating expenses	(54)	(32)	(104)	(68)
Segment Earnings	$ 208	$ 145	$ 391	$ 279