Fair Value Measurement - Carrying Value and Estimated Fair Value (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financial assets
Cash and due from banks	$ 27,831,000,000	$ 39,771,000,000	$ 53,723,000,000	$ 59,602,000,000
Deposits with banks	484,477,000,000	316,051,000,000
Federal funds sold and securities purchased under resale agreements	215,803,000,000	248,116,000,000
Securities, held-to-maturity	51,154,000,000	23,731,000,000
Financial liabilities
Commercial paper	66,344,000,000	57,848,000,000
Beneficial interests issued by consolidated VIEs	52,362,000,000	49,617,000,000
Trading assets and liabilities average balances Abstract
Trading assets - debt and equity instruments	327,259,000,000	340,449,000,000	349,337,000,000
Trading assets - derivative receivables	67,123,000,000	72,629,000,000	85,744,000,000
Trading liabilities - debt and equity instruments	84,707,000,000	77,706,000,000	69,001,000,000
Trading liabilities - derivative payables	54,758,000,000	64,553,000,000	76,162,000,000
Carrying value
Financial assets
Cash and due from banks	27,800,000,000	39,800,000,000
Deposits with banks	484,500,000,000	316,100,000,000
Accrued interest and accounts receivable	70,100,000,000	65,200,000,000
Federal funds sold and securities purchased under resale agreements	187,200,000,000	223,000,000,000
Securities borrowed	109,400,000,000	107,700,000,000
Securities, held-to-maturity	49,300,000,000	24,000,000,000
Loans, net of allowance for loan losses	740,500,000,000	720,100,000,000
Other	58,100,000,000	58,200,000,000
Financial liabilities
Deposits	1,354,600,000,000	1,281,100,000,000
Federal funds purchased and securities loaned or sold under repurchase agreements	189,100,000,000	175,700,000,000
Commercial paper	66,300,000,000	57,800,000,000
Other borrowed funds	15,500,000,000	14,700,000,000
Accounts payable and other liabilities	176,700,000,000	160,200,000,000
Beneficial interests issued by consolidated VIEs	50,200,000,000	47,600,000,000
Long-term debt and junior subordinated deferrable interest debentures	246,600,000,000	239,000,000,000
Wholesale lending-related commitments	600,000,000	700,000,000
Estimate of Fair Value
Financial assets
Cash and due from banks	27,800,000,000	39,800,000,000
Deposits with banks	484,500,000,000	316,100,000,000
Accrued interest and accounts receivable	70,100,000,000	65,200,000,000
Federal funds sold and securities purchased under resale agreements	187,200,000,000	223,000,000,000
Securities borrowed	109,400,000,000	107,700,000,000
Securities, held-to-maturity	51,200,000,000	23,700,000,000
Loans, net of allowance for loan losses	744,900,000,000	720,200,000,000
Other	62,800,000,000	61,900,000,000
Financial liabilities
Deposits	1,354,800,000,000	1,281,500,000,000
Federal funds purchased and securities loaned or sold under repurchase agreements	189,100,000,000	175,700,000,000
Commercial paper	66,300,000,000	57,800,000,000
Other borrowed funds	15,500,000,000	14,700,000,000
Accounts payable and other liabilities	176,500,000,000	160,000,000,000
Beneficial interests issued by consolidated VIEs	50,200,000,000	47,500,000,000
Long-term debt and junior subordinated deferrable interest debentures	255,400,000,000	246,800,000,000
Wholesale lending-related commitments	1,600,000,000	1,000,000,000
Estimate of Fair Value | Level 1
Financial assets
Cash and due from banks	27,800,000,000	39,800,000,000
Deposits with banks	480,400,000,000	309,700,000,000
Accrued interest and accounts receivable	0	0
Federal funds sold and securities purchased under resale agreements	0	0
Securities borrowed	0	0
Securities, held-to-maturity	0	0
Loans, net of allowance for loan losses	0	0
Other	0	0
Financial liabilities
Deposits	0	0
Federal funds purchased and securities loaned or sold under repurchase agreements	0	0
Commercial paper	0	0
Other borrowed funds		0
Accounts payable and other liabilities	0	0
Beneficial interests issued by consolidated VIEs	0	0
Long-term debt and junior subordinated deferrable interest debentures	0	0
Wholesale lending-related commitments	0	0
Estimate of Fair Value | Level 2
Financial assets
Cash and due from banks	0	0
Deposits with banks	4,100,000,000	6,400,000,000
Accrued interest and accounts receivable	70,000,000,000	64,900,000,000
Federal funds sold and securities purchased under resale agreements	187,200,000,000	223,000,000,000
Securities borrowed	109,400,000,000	107,700,000,000
Securities, held-to-maturity	51,200,000,000	23,700,000,000
Loans, net of allowance for loan losses	21,800,000,000	23,000,000,000
Other	55,700,000,000	54,500,000,000
Financial liabilities
Deposits	1,353,600,000,000	1,280,300,000,000
Federal funds purchased and securities loaned or sold under repurchase agreements	189,100,000,000	175,700,000,000
Commercial paper	66,300,000,000	57,800,000,000
Other borrowed funds	15,500,000,000	14,700,000,000
Accounts payable and other liabilities	173,700,000,000	158,200,000,000
Beneficial interests issued by consolidated VIEs	48,200,000,000	44,300,000,000
Long-term debt and junior subordinated deferrable interest debentures	251,600,000,000	240,800,000,000
Wholesale lending-related commitments	0	0
Estimate of Fair Value | Level 3
Financial assets
Cash and due from banks	0	0
Deposits with banks	0	0
Accrued interest and accounts receivable	100,000,000	300,000,000
Federal funds sold and securities purchased under resale agreements	0	0
Securities borrowed	0	0
Securities, held-to-maturity	0	0
Loans, net of allowance for loan losses	723,100,000,000	697,200,000,000
Other	7,100,000,000	7,400,000,000
Financial liabilities
Deposits	1,200,000,000	1,200,000,000
Federal funds purchased and securities loaned or sold under repurchase agreements	0	0
Commercial paper	0	0
Other borrowed funds	0	0
Accounts payable and other liabilities	2,800,000,000	1,800,000,000
Beneficial interests issued by consolidated VIEs	2,000,000,000	3,200,000,000
Long-term debt and junior subordinated deferrable interest debentures	3,800,000,000	6,000,000,000
Wholesale lending-related commitments	$ 1,600,000,000	$ 1,000,000,000