Fair Value Measurements - Financial Assets Liabilities Summary (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	$ 503,915	$ 509,779	$ 526,687
Total assets	$ 879,987	$ 896,843	$ 861,395	$ 880,559
Total level 3 financial assets as a percentage of total assets	2.80%	2.80%	2.80%
Total level 3 financial assets as a percentage of total financial assets at fair value	4.80%	4.90%	4.60%
Total financial liabilities at fair value	$ 274,802	$ 287,653	$ 280,939
Total level 3 financial liabilities as a percentage of total financial liabilities at fair value	6.90%	6.70%	6.00%
Counterparty and Cash Collateral Netting [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	$ (100,211)	$ (102,715)	$ (90,612)
Total financial liabilities at fair value	(50,650)	(51,496)	(41,430)
Investments in funds at NAV [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	6,859	7,008	7,757
Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	146,775	129,627	153,051
Total financial liabilities at fair value	62,631	62,841	59,798
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	426,203	451,127	432,445
Total financial liabilities at fair value	243,800	256,973	245,759
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total financial assets at fair value	24,289	24,732	24,046
Total financial liabilities at fair value	$ 19,021	$ 19,335	$ 16,812