Occupancy Expense And Information Systems And Communications Expense (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 sqft years	Dec. 31, 2010	Dec. 31, 2009
Occupancy Expense And Information Systems And Communications Expense [Abstract]
Total depreciation expense	$ 368	$ 373	$ 380
Leased Area, square feet	1,025,000
Underground parking garage, square feet	366,000
Non-cancelable capital leases Period	20
Subleased building, square feet	153,390
Non-cancelable lease maturity date	September 2023
Leased area of office building, square feet	362,000
Capital lease period	20
Capital lease maturity date	December 2028
Period for cancellation of capital lease	15
Net book value of capital leases with the related liability recorded in long term debt	565	606
Interest expense related to capital lease obligations	43	44	47
Accumulated amortization of assets related to capital leases	273	230
Rental expense, net of sublease revenue	232	241	230
Sublease revenue	12	12	17
Future minimum sublease rental commitments for capital lease	32
Future minimum sublease rental commitments for operating lease	$ 19