SEGMENT REPORTING - Earnings (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Segment Reporting Information [Line Items]
Segment Revenues	$ 1,259	$ 1,154
Total segment compensation and benefits	(456)	(424)
Total segment facilities, technology and professional fees	(98)	(89)
Total segment travel and other operating expenses	(88)	(65)
Segment Earnings		576
Operating Segments
Segment Reporting Information [Line Items]
Segment Revenues	1,259	1,154
Total segment compensation and benefits	(456)	(424)
Total segment facilities, technology and professional fees	(98)	(89)
Total segment travel and other operating expenses	(88)	(65)
Segment Earnings	617	576
Operating Segments \| Infrastructure
Segment Reporting Information [Line Items]
Segment Revenues	270	227
Total segment compensation and benefits	(68)	(60)
Total segment facilities, technology and professional fees	(17)	(14)
Total segment travel and other operating expenses	(11)	(9)
Segment Earnings	174	144
Operating Segments \| Energy
Segment Reporting Information [Line Items]
Segment Revenues	174	135
Total segment compensation and benefits	(49)	(41)
Total segment facilities, technology and professional fees	(9)	(5)
Total segment travel and other operating expenses	(9)	(5)
Segment Earnings	107	84
Operating Segments \| Private equity
Segment Reporting Information [Line Items]
Segment Revenues	120	103
Total segment compensation and benefits	(66)	(56)
Total segment facilities, technology and professional fees	(14)	(14)
Total segment travel and other operating expenses	(8)	(5)
Segment Earnings	32	28
Operating Segments \| Real estate
Segment Reporting Information [Line Items]
Segment Revenues	251	316
Total segment compensation and benefits	(98)	(98)
Total segment facilities, technology and professional fees	(22)	(22)
Total segment travel and other operating expenses	(10)	(10)
Segment Earnings	121	186
Operating Segments \| Credit
Segment Reporting Information [Line Items]
Segment Revenues	444	373
Total segment compensation and benefits	(175)	(169)
Total segment facilities, technology and professional fees	(36)	(34)
Total segment travel and other operating expenses	(50)	(36)
Segment Earnings	$ 183	$ 134