Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Liabilities
Other Short-term Borrowings	$ 27,200,000,000	$ 26,636,000,000
Stockholders' equity
Preferred stock, par value (actual number)	$ 1.00	$ 1.00
Preferred stock, shares authorized (actual number)	200,000,000	200,000,000
Preferred stock, shares issued (actual number)	995,750	905,750
Common stock, par value (actual number)	$ 1.00	$ 1.00
Common stock, shares authorized (actual number)	9,000,000,000	9,000,000,000
Common stock, shares issued (actual number)	4,104,933,895	4,104,933,895
Shares held in RSU Trust, shares (actual number)	479,126	479,126
Treasury stock, shares (actual number)	315,155,539	300,981,690
Limited program-wide credit enhancement	3,100,000,000	3,100,000,000
Trading assets
Assets
Assets Pledged	121,341,000,000	108,784,000,000
Securities
Assets
Assets Pledged	73,241,000,000	71,167,000,000
Other assets
Assets
Assets Pledged	1,105,000,000	1,127,000,000
Fair Value, Measurements, Recurring [Member] | Fair value
Assets
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	25,616,000,000	24,258,000,000
Securities borrowed	5,411,000,000	10,177,000,000
Available-for-sale securities	365,737,000,000	371,145,000,000
Loans, at fair value	2,161,000,000	2,555,000,000
Liabilities
Deposits, Fair Value Disclosure	6,029,000,000	5,733,000,000
Federal funds purchased and securities loaned or sold under repurchase agreements	4,380,000,000	4,388,000,000
Other Short-term Borrowings	13,818,000,000	11,591,000,000
Accounts payable and other liabilities, measured at fair value	33,000,000	36,000,000
Long-term debt and junior subordinated deferrable interest debentures	30,655,000,000	30,788,000,000
Other assets | Fair Value, Measurements, Recurring [Member] | Fair value
Assets
Other Assets, Fair Value Disclosure	16,153,000,000	16,458,000,000
Long Term Beneficial Interests | Fair Value, Measurements, Recurring [Member] | Fair value
Liabilities
Beneficial Interest, Fair Value Disclosure	$ 1,130,000,000	$ 1,170,000,000