Income Taxes - Components of Income Tax Expense/(Benefit) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components of income tax expense/(benefit)
Income Tax Expense, Prior Undistributed Earnings of Foreign Subsidiaries to be Distributed	$ 80,000,000
Current income tax expense
U.S. federal	3,225,000,000	3,719,000,000	4,001,000,000
Non-U.S.	1,782,000,000	1,183,000,000	2,712,000,000
U.S. state and local	1,496,000,000	1,178,000,000	1,744,000,000
Total current income tax expense	6,503,000,000	6,080,000,000	8,457,000,000
Deferred income tax expense/ (benefit)
U.S. federal	2,238,000,000	2,109,000,000	(753,000,000)
Non-U.S.	(327,000,000)	102,000,000	169,000,000
U.S. state and local	(781,000,000)	(518,000,000)	(384,000,000)
Total deferred income tax expense/(benefit)	1,130,000,000	1,693,000,000	(968,000,000)
Total income tax expense/ (benefit) before extraordinary gain	7,633,000,000	7,773,000,000	7,489,000,000
Components of income tax expense/(benefit), supplemental information
Tax Adjustments, Settlements, and Unusual Provisions	200,000,000	76,000,000	485,000,000
Income Tax Effects Allocated Directly to Equity	1,900,000,000	927,000,000	1,800,000,000
Pretax Undistributed Foreign Earnings Of Subsidiaries	3,100,000,000
Cumulative Pretax Undistributed Foreign Earnings Of Subsidiaries	25,100,000,000
Deferred Tax Liabilities, Undistributed Foreign Earnings	3,582,000,000	2,790,000,000
Tax expense applicable to securities gains and losses	822,000,000	617,000,000	1,100,000,000
Pro Forma [Member]
Components of income tax expense/(benefit), supplemental information
Deferred Tax Liabilities, Undistributed Foreign Earnings	$ 5,700,000,000