Fair Value Measurement- Carrying Amount and Fair Value of Financial Instruments (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Assets:
Loans	$ 73	$ 53
Estimated Fair Value
Assets:
Interest-bearing deposits with the Federal Reserve and other central banks	89,704	96,682
Interest-bearing deposits with banks	18,947	19,505
Federal funds sold and securities purchased under resale agreements	28,268	20,302
Securities held-to-maturity	41,676	21,127
Loans	60,088	56,840
Other financial assets	8,240	8,091
Subtotal assets of consolidated investment management funds, at fair value	246,923	222,547
Liabilities:
Noninterest-bearing deposits	111,622	104,240
Interest-bearing deposits	168,831	160,688
Federal funds purchased and securities sold under repurchase agreements	7,919	11,469
Payables to customers and broker-dealers	21,959	21,181
Borrowings	984	956
Long-term debt	20,711	20,401
Total liabilities	332,026	318,935
Estimated Fair Value | Level 1
Assets:
Securities held-to-maturity	10,462	5,063
Other financial assets	7,167	6,970
Subtotal assets of consolidated investment management funds, at fair value	17,629	12,033
Estimated Fair Value | Level 2
Assets:
Interest-bearing deposits with the Federal Reserve and other central banks	89,704	96,682
Interest-bearing deposits with banks	18,947	19,505
Federal funds sold and securities purchased under resale agreements	28,268	20,302
Securities held-to-maturity	31,214	16,064
Loans	60,088	56,840
Other financial assets	1,073	1,121
Subtotal assets of consolidated investment management funds, at fair value	229,294	210,514
Liabilities:
Noninterest-bearing deposits	111,622	104,240
Interest-bearing deposits	168,831	160,688
Federal funds purchased and securities sold under repurchase agreements	7,919	11,469
Payables to customers and broker-dealers	21,959	21,181
Borrowings	984	956
Long-term debt	20,711	20,401
Total liabilities	332,026	318,935
Carrying Amount
Assets:
Interest-bearing deposits with the Federal Reserve and other central banks	89,704	96,682
Interest-bearing deposits with banks	18,937	19,495
Federal funds sold and securities purchased under resale agreements	28,268	20,302
Securities held-to-maturity	41,237	20,933
Loans	59,906	56,749
Other financial assets	8,240	8,091
Subtotal assets of consolidated investment management funds, at fair value	246,292	222,252
Liabilities:
Noninterest-bearing deposits	111,622	104,240
Interest-bearing deposits	169,637	161,629
Federal funds purchased and securities sold under repurchase agreements	7,919	11,469
Payables to customers and broker-dealers	21,959	21,181
Borrowings	984	956
Long-term debt	20,046	19,917
Total liabilities	$ 332,167	$ 319,392