Income Taxes - Deferred Tax Assets and Liabilities (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Deferred tax assets
Allowance for loan losses	$ 8,712	$ 10,689
Employee benefits	4,308	4,570
Allowance expenses and other	12,393	11,183
Non-U.S. operations	3,537	2,943
Tax attribute carryforwards	1,062	1,547
Gross deferred tax assets	30,012	30,932
Valuation allowance	(689)	(1,303)
Deferred tax assets, net of valuation allowance	29,323	29,629
Deferred tax liabilities
Depreciation and amortization	2,563	2,799
Mortgage servicing rights, net of hedges	5,336	4,396
Leasing transactions	2,242	2,348
Non-U.S operations	3,582	2,790
Other, net	4,340	2,520
Gross deferred tax liabilities	18,063	14,853
Net deferred tax assets	11,260	14,776
Deferred Tax Assets and Liabilities - supplemental information
Operating Loss Carryforwards, Expiration Dates	If not utilized, the U.S. federal net operating loss carryforwards and the state and local net operating loss carryforward will expire between 2027 and 2030; and the U.S. foreign tax credit carryforward will expire in 2022.
Valuation Allowance, Deferred Tax Asset, Change in Amount	614
Internal Revenue Service (IRS) [Member]
Deferred Tax Assets and Liabilities - supplemental information
Non-U.S. subsidiary net operating loss carryforward	1,500
State and Local Jurisdiction [Member]
Deferred Tax Assets and Liabilities - supplemental information
Non-U.S. subsidiary net operating loss carryforward	269
Foreign Country [Member]
Deferred Tax Assets and Liabilities - supplemental information
Non-U.S. subsidiary net operating loss carryforward	$ 525