INVESTMENTS, AT FAIR VALUE - Investments, at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	$ 38,764,427	$ 38,372,626
Equity securities, Fair value as a percentage of investments of consolidated funds	53.20%	49.20%
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	46.80%	50.80%
Total investments, at fair value, Fair Value as a Percentage of Investments of Consolidated Funds as of	100.00%	100.00%
Securities sold short – equities	(120,598)	(126,530)
Fixed income securities [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	18,163,836	19,488,737
Fixed income securities [Member] | United States [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	13,152,913	13,698,904
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	33.90%	35.70%
Fixed income securities [Member] | United States [Member] | Consumer discretionary [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	3,754,991	5,072,283
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	9.70%	13.20%
Fixed income securities [Member] | United States [Member] | Consumer staples [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	850,671	697,300
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	2.20%	1.80%
Fixed income securities [Member] | United States [Member] | Energy [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	709,682	565,151
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	1.80%	1.50%
Fixed income securities [Member] | United States [Member] | Financials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	551,391	1,013,230
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	1.40%	2.60%
Fixed income securities [Member] | United States [Member] | Health care [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	724,472	658,932
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	1.90%	1.70%
Fixed income securities [Member] | United States [Member] | Industrials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	1,840,898	1,957,259
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	4.70%	5.10%
Fixed income securities [Member] | United States [Member] | Information technology [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	1,244,353	908,662
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	3.20%	2.40%
Fixed income securities [Member] | United States [Member] | Materials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	1,081,165	826,008
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	2.80%	2.20%
Fixed income securities [Member] | United States [Member] | Telecommunication services [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	332,734	282,101
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.90%	0.70%
Fixed income securities [Member] | United States [Member] | Utilities [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	2,062,556	1,717,978
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	5.30%	4.50%
Fixed income securities [Member] | Europe [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	3,886,459	4,486,075
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	10.00%	11.70%
Fixed income securities [Member] | Europe [Member] | Consumer discretionary [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	1,509,502	1,607,822
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	3.90%	4.20%
Fixed income securities [Member] | Europe [Member] | Consumer staples [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	154,953	486,037
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.40%	1.30%
Fixed income securities [Member] | Europe [Member] | Energy [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	282,569	272,079
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.70%	0.70%
Fixed income securities [Member] | Europe [Member] | Financials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	531,437	627,161
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	1.40%	1.60%
Fixed income securities [Member] | Europe [Member] | Health care [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	25,159	19,585
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.10%	0.00%
Fixed income securities [Member] | Europe [Member] | Industrials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	502,857	531,770
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	1.30%	1.40%
Fixed income securities [Member] | Europe [Member] | Information technology [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	7,280	5,397
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Fixed income securities [Member] | Europe [Member] | Materials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	681,813	717,294
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	1.80%	1.90%
Fixed income securities [Member] | Europe [Member] | Telecommunication services [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	172,840	190,369
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.40%	0.50%
Fixed income securities [Member] | Europe [Member] | Utilities [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	18,049	28,561
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.10%
Fixed income securities [Member] | Asia and other [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	1,124,464	1,303,758
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	2.90%	3.40%
Fixed income securities [Member] | Asia and other [Member] | Consumer discretionary [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	124,192	680,273
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.30%	1.80%
Fixed income securities [Member] | Asia and other [Member] | Consumer staples [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	19,488	3,615
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.10%	0.00%
Fixed income securities [Member] | Asia and other [Member] | Energy [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	62,885	47,776
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.20%	0.10%
Fixed income securities [Member] | Asia and other [Member] | Financials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	117,585	22,186
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.30%	0.10%
Fixed income securities [Member] | Asia and other [Member] | Health care [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	0	1,622
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Fixed income securities [Member] | Asia and other [Member] | Industrials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	676,076	290,639
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	1.70%	0.80%
Fixed income securities [Member] | Asia and other [Member] | Information technology [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	18,648	33,260
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.10%
Fixed income securities [Member] | Asia and other [Member] | Materials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	97,568	92,974
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.30%	0.20%
Fixed income securities [Member] | Asia and other [Member] | Telecommunication services [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	834	1,939
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Fixed income securities [Member] | Asia and other [Member] | Utilities [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Fixed income securities, Fair Value	7,188	129,474
Total fixed income securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.30%
Equity securities [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	20,600,591	18,883,889
Securities sold short – equities	(120,598)	(126,530)
Equity securities [Member] | United States [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	13,134,705	13,281,294
Equity securities, Fair value as a percentage of investments of consolidated funds	33.90%	34.60%
Equity securities [Member] | United States [Member] | Consumer discretionary [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	2,973,559	3,289,347
Equity securities, Fair value as a percentage of investments of consolidated funds	7.70%	8.60%
Equity securities [Member] | United States [Member] | Consumer staples [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	470,065	444,735
Equity securities, Fair value as a percentage of investments of consolidated funds	1.20%	1.20%
Equity securities [Member] | United States [Member] | Energy [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	563,676	448,412
Equity securities, Fair value as a percentage of investments of consolidated funds	1.50%	1.20%
Equity securities [Member] | United States [Member] | Financials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	5,636,471	6,001,493
Equity securities, Fair value as a percentage of investments of consolidated funds	14.50%	15.60%
Equity securities [Member] | United States [Member] | Health care [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	250,276	134,239
Equity securities, Fair value as a percentage of investments of consolidated funds	0.60%	0.30%
Equity securities [Member] | United States [Member] | Industrials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	1,554,872	1,201,156
Equity securities, Fair value as a percentage of investments of consolidated funds	4.00%	3.10%
Equity securities [Member] | United States [Member] | Information technology [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	243,756	199,003
Equity securities, Fair value as a percentage of investments of consolidated funds	0.60%	0.50%
Equity securities [Member] | United States [Member] | Materials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	1,225,018	1,407,850
Equity securities, Fair value as a percentage of investments of consolidated funds	3.20%	3.70%
Equity securities [Member] | United States [Member] | Telecommunication services [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	40,796	15,022
Equity securities, Fair value as a percentage of investments of consolidated funds	0.10%	0.00%
Equity securities [Member] | United States [Member] | Utilities [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Total investments, at fair value	176,216	140,037
Equity securities, Fair value as a percentage of investments of consolidated funds	0.50%	0.40%
Equity securities [Member] | Europe [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	4,593,817	3,475,119
Equity securities, Fair value as a percentage of investments of consolidated funds	11.90%	9.10%
Equity securities [Member] | Europe [Member] | Consumer discretionary [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	167,589	117,485
Equity securities, Fair value as a percentage of investments of consolidated funds	0.50%	0.30%
Equity securities [Member] | Europe [Member] | Consumer staples [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	747,302	1,336,420
Equity securities, Fair value as a percentage of investments of consolidated funds	1.90%	3.50%
Equity securities [Member] | Europe [Member] | Energy [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	77,901	91,724
Equity securities, Fair value as a percentage of investments of consolidated funds	0.20%	0.20%
Equity securities [Member] | Europe [Member] | Financials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	2,876,742	1,553,598
Equity securities, Fair value as a percentage of investments of consolidated funds	7.40%	4.10%
Equity securities [Member] | Europe [Member] | Health care [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	12,850	0
Equity securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Equity securities [Member] | Europe [Member] | Industrials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	462,977	1,388
Equity securities, Fair value as a percentage of investments of consolidated funds	1.20%	0.00%
Equity securities [Member] | Europe [Member] | Information technology [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	1,398	335
Equity securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Equity securities [Member] | Europe [Member] | Materials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	246,176	374,169
Equity securities, Fair value as a percentage of investments of consolidated funds	0.70%	1.00%
Equity securities [Member] | Europe [Member] | Telecommunication services [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	882	0
Equity securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Equity securities [Member] | Asia and other [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	2,872,069	2,127,476
Equity securities, Fair value as a percentage of investments of consolidated funds	7.40%	5.50%
Equity securities [Member] | Asia and other [Member] | Consumer discretionary [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	554,280	99,527
Equity securities, Fair value as a percentage of investments of consolidated funds	1.40%	0.30%
Equity securities [Member] | Asia and other [Member] | Consumer staples [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	25,462	42,688
Equity securities, Fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Equity securities [Member] | Asia and other [Member] | Energy [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	251,661	213,490
Equity securities, Fair value as a percentage of investments of consolidated funds	0.70%	0.60%
Equity securities [Member] | Asia and other [Member] | Financials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	955,794	973,745
Equity securities, Fair value as a percentage of investments of consolidated funds	2.50%	2.50%
Equity securities [Member] | Asia and other [Member] | Health care [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	810	71
Equity securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Equity securities [Member] | Asia and other [Member] | Industrials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	809,879	613,020
Equity securities, Fair value as a percentage of investments of consolidated funds	2.10%	1.60%
Equity securities [Member] | Asia and other [Member] | Information technology [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	82,707	75,583
Equity securities, Fair value as a percentage of investments of consolidated funds	0.20%	0.20%
Equity securities [Member] | Asia and other [Member] | Materials [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	54,050	51,296
Equity securities, Fair value as a percentage of investments of consolidated funds	0.10%	0.10%
Equity securities [Member] | Asia and other [Member] | Telecommunication services [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	7,934	6,044
Equity securities, Fair value as a percentage of investments of consolidated funds	0.00%	0.00%
Equity securities [Member] | Asia and other [Member] | Utilities [Member]
Schedule Of Investments In Marketable Securities [Line Items]
Equity securities, Fair Value	$ 129,492	$ 52,012
Equity securities, Fair value as a percentage of investments of consolidated funds	0.30%	0.10%