Fair Value Measurement- Carrying Amount and Fair Value of Financial Instruments (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Estimated Fair Value
Assets:
Interest-bearing deposits with the Federal Reserve and other central banks	$ 78,125	$ 90,110
Interest-bearing deposits with banks	40,914	43,936
Federal funds sold and securities purchased under resale agreements	7,004	6,593
Securities held-to-maturity	11,845	8,389
Loans	46,800	44,031
Other financial assets	5,500	5,842
Subtotal assets of consolidated investment management funds, at fair value	190,188	198,901
Liabilities:
Noninterest-bearing deposits	80,915	93,019
Interest-bearing deposits	158,638	153,030
Federal funds purchased and securities sold under repurchase agreements	8,602	7,427
Payables to customers and broker-dealers	14,986	16,095
Borrowings	1,033	1,883
Long-term debt	20,360	19,397
Total liabilities	284,534	290,851
Estimated Fair Value | Level 1
Assets:
Securities held-to-maturity	2,277	1,070
Other financial assets	4,440	4,727
Subtotal assets of consolidated investment management funds, at fair value	6,717	5,797
Estimated Fair Value | Level 2
Assets:
Interest-bearing deposits with the Federal Reserve and other central banks	78,125	90,110
Interest-bearing deposits with banks	40,914	43,936
Federal funds sold and securities purchased under resale agreements	7,004	6,593
Securities held-to-maturity	9,568	7,319
Loans	46,800	44,031
Other financial assets	1,060	1,115
Subtotal assets of consolidated investment management funds, at fair value	183,471	193,104
Liabilities:
Noninterest-bearing deposits	80,915	93,019
Interest-bearing deposits	158,638	153,030
Federal funds purchased and securities sold under repurchase agreements	8,602	7,427
Payables to customers and broker-dealers	14,986	16,095
Borrowings	1,033	1,883
Long-term debt	20,360	19,397
Total liabilities	284,534	290,851
Carrying Amount
Assets:
Interest-bearing deposits with the Federal Reserve and other central banks	78,125	90,110
Interest-bearing deposits with banks	40,888	43,910
Federal funds sold and securities purchased under resale agreements	7,004	6,593
Securities held-to-maturity	11,678	8,205
Loans	46,667	44,010
Other financial assets	5,500	5,842
Subtotal assets of consolidated investment management funds, at fair value	189,862	198,670
Liabilities:
Noninterest-bearing deposits	80,915	93,019
Interest-bearing deposits	158,757	153,076
Federal funds purchased and securities sold under repurchase agreements	8,602	7,427
Payables to customers and broker-dealers	14,986	16,095
Borrowings	1,033	1,883
Long-term debt	19,513	18,530
Total liabilities	$ 283,806	$ 290,030