Income Taxes Reconciliation of the tax provision at the U.S. Federal Statutory Rate to the provision for income taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Reconciliation, Income Tax Expense (Benefit), at Federal Statutory Income Tax Rate	$ 2,785	$ 2,584	$ 2,033
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	35.00%	35.00%	35.00%
Income Tax Reconciliation, State and Local Income Taxes	136	129	66
Effective Income Tax Rate Reconciliation, State and Local Income Taxes	1.70%	1.70%	1.10%
Income Tax Reconciliation, Tax Settlements, State and Local	(29)	(3)	(40)
Effective Income Tax Rate Reconciliation, Tax Settlements, State and Local	(0.40%)	0.00%	(0.70%)
Income Tax Reconciliation, Tax Exempt Income	(63)	(65)	(70)
Effective Income Tax Rate Reconciliation, Tax Exempt Income	(0.80%)	(0.90%)	(1.20%)
Income Tax Reconciliation, Nondeductible Expense	10	64	0
Effective Income Tax Rate Reconciliation, Nondeductible Expense	0.10%	0.90%	0.00%
Income Tax Reconciliation, Other Adjustments	(22)	40	(3)
Effective Income Tax Rate Reconciliation, Other Adjustments	(0.20%)	0.50%	0.00%
Provision for income taxes	$ 2,817	$ 2,749	$ 1,986
Effective Income Tax Rate, Continuing Operations	35.40%	37.20%	34.20%