INVESTMENTS, AT FAIR VALUE - Investments, at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	$ 17,720,189	$ 19,488,737
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	44.40%	50.80%
Equity Securities, Fair Value	22,191,699	18,883,889
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	55.60%	49.20%
Securities Sold Short:	(140,251)	(126,530)
Total investments, at fair value	39,911,888	38,372,626
Total investments, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	100.00%	100.00%
Proceeds from securities sold short	137,092	123,575
Equity securities:
Schedule Of Investments In Marketable Securities [Line Items]
Securities Sold Short:	(140,251)	(126,530)
United States: | Fixed income securities:
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities cost	12,008,435	13,320,475
Fixed income securities, Fair Value	12,089,569	13,698,904
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	30.30%	35.70%
United States: | Fixed income securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	3,017,755	5,072,283
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	7.60%	13.20%
United States: | Fixed income securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	801,959	697,300
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	2.00%	1.80%
United States: | Fixed income securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	650,336	565,151
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	1.60%	1.50%
United States: | Fixed income securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	554,115	1,013,230
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	1.40%	2.60%
United States: | Fixed income securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	600,570	658,932
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	1.50%	1.70%
United States: | Fixed income securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	1,768,600	1,957,259
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	4.40%	5.10%
United States: | Fixed income securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	1,130,614	908,662
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	2.80%	2.40%
United States: | Fixed income securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	1,094,476	826,008
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	2.70%	2.20%
United States: | Fixed income securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	289,046	282,101
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.70%	0.70%
United States: | Fixed income securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	2,182,098	1,717,978
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	5.60%	4.50%
United States: | Equity securities:
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities cost	11,104,484	11,637,988
Equity Securities, Fair Value	14,240,613	13,281,294
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	35.70%	34.60%
United States: | Equity securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	3,164,000	3,289,347
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	7.90%	8.60%
United States: | Equity securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	482,521	444,735
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	1.20%	1.20%
United States: | Equity securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	570,839	448,412
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	1.40%	1.20%
United States: | Equity securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	6,474,365	6,001,493
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	16.30%	15.60%
United States: | Equity securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	310,582	134,239
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.80%	0.30%
United States: | Equity securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	1,840,900	1,201,156
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	4.60%	3.10%
United States: | Equity securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	227,608	199,003
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.60%	0.50%
United States: | Equity securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	923,933	1,407,850
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	2.30%	3.70%
United States: | Equity securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	51,881	15,022
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.10%	0.00%
United States: | Equity securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	193,984	140,037
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.50%	0.40%
Europe: | Fixed income securities:
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities cost	3,349,740	4,383,068
Fixed income securities, Fair Value	3,885,082	4,486,075
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	9.70%	11.70%
Europe: | Fixed income securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	1,519,530	1,607,822
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	3.80%	4.20%
Europe: | Fixed income securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	159,489	486,037
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.40%	1.30%
Europe: | Fixed income securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	295,942	272,079
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.70%	0.70%
Europe: | Fixed income securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	612,123	627,161
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	1.50%	1.60%
Europe: | Fixed income securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	39,189	19,585
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.10%	0.00%
Europe: | Fixed income securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	378,797	531,770
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	1.00%	1.40%
Europe: | Fixed income securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	22,216	5,397
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.10%	0.00%
Europe: | Fixed income securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	663,984	717,294
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	1.70%	1.90%
Europe: | Fixed income securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	175,231	190,369
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.40%	0.50%
Europe: | Fixed income securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	18,581	28,561
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.00%	0.10%
Europe: | Equity securities:
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities cost	4,111,171	2,960,210
Equity Securities, Fair Value	4,526,108	3,475,119
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	11.30%	9.10%
Europe: | Equity securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	198,045	117,485
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.50%	0.30%
Europe: | Equity securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	385,595	1,336,420
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	1.00%	3.50%
Europe: | Equity securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	129,207	91,724
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.30%	0.20%
Europe: | Equity securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	2,763,198	1,553,598
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	6.90%	4.10%
Europe: | Equity securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	13,084	0
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.00%	0.00%
Europe: | Equity securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	784,524	1,388
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	2.00%	0.00%
Europe: | Equity securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	1,341	335
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.00%	0.00%
Europe: | Equity securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	249,732	374,169
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.60%	1.00%
Europe: | Equity securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	1,382	0
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.00%	0.00%
Asia and other: | Fixed income securities:
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities cost	1,639,694	1,298,868
Fixed income securities, Fair Value	1,745,538	1,303,758
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	4.40%	3.40%
Asia and other: | Fixed income securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	93,087	680,273
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.20%	1.80%
Asia and other: | Fixed income securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	25,424	3,615
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.10%	0.00%
Asia and other: | Fixed income securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	74,167	47,776
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.20%	0.10%
Asia and other: | Fixed income securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	159,369	22,186
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.40%	0.10%
Asia and other: | Fixed income securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	31,057	1,622
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.10%	0.00%
Asia and other: | Fixed income securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	1,247,793	290,639
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	3.10%	0.80%
Asia and other: | Fixed income securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	21,842	33,260
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.10%	0.10%
Asia and other: | Fixed income securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	84,107	92,974
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.20%	0.20%
Asia and other: | Fixed income securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	1,884	1,939
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.00%	0.00%
Asia and other: | Fixed income securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	6,808	129,474
Fixed income securities, Fair value as a percentage of investments of consolidated funds (as a percent)	0.00%	0.30%
Asia and other: | Equity securities:
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities cost	2,734,160	1,726,145
Equity Securities, Fair Value	3,424,978	2,127,476
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	8.60%	5.50%
Asia and other: | Equity securities: | Consumer discretionary
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	422,731	99,527
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	1.10%	0.30%
Asia and other: | Equity securities: | Consumer staples
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	42,937	42,688
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.10%	0.10%
Asia and other: | Equity securities: | Energy
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	267,494	213,490
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.70%	0.60%
Asia and other: | Equity securities: | Financials
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	1,211,033	973,745
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	3.00%	2.50%
Asia and other: | Equity securities: | Health care
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	8,124	71
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.00%	0.00%
Asia and other: | Equity securities: | Industrials
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	1,136,934	613,020
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	2.90%	1.60%
Asia and other: | Equity securities: | Information technology
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	130,714	75,583
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.30%	0.20%
Asia and other: | Equity securities: | Materials
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	63,395	51,296
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.20%	0.10%
Asia and other: | Equity securities: | Telecommunication services
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	17,719	6,044
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.00%	0.00%
Asia and other: | Equity securities: | Utilities
Schedule Of Investments In Marketable Securities [Line Items]
Equity Securities, Fair Value	$ 123,897	$ 52,012
Equity Securities, Fair value as a percentage of investments of consolidated funds as of December 31, (as a percent)	0.30%	0.10%