Acquisition and Restructuring Costs (Activity Related To Restructuring-Related Accruals) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Business Acquisition [Line Items]
Beginning balance	$ 287
Additional accruals for business operations and information technology transformation program	48
Accruals for expense control measures	(3)
Payments and adjustments	(178)
Ending balance	154
Employee-Related Costs [Member]
Business Acquisition [Line Items]
Beginning balance	162
Additional accruals for business operations and information technology transformation program	21
Accruals for expense control measures	1
Payments and adjustments	(101)
Ending balance	83
Real Estate Consolidation [Member]
Business Acquisition [Line Items]
Beginning balance	39
Additional accruals for business operations and information technology transformation program	7
Accruals for expense control measures	0
Payments and adjustments	(6)
Ending balance	40
IT Transition Costs [Member]
Business Acquisition [Line Items]
Beginning balance	33
Additional accruals for business operations and information technology transformation program	20
Accruals for expense control measures	0
Payments and adjustments	(36)
Ending balance	17
Fixed-Income Trading Portfolio [Member]
Business Acquisition [Line Items]
Beginning balance	38
Additional accruals for business operations and information technology transformation program	0
Accruals for expense control measures	(9)
Payments and adjustments	(29)
Ending balance	0
Asset And Other Write Offs [Member]
Business Acquisition [Line Items]
Beginning balance	15
Additional accruals for business operations and information technology transformation program	0
Accruals for expense control measures	5
Payments and adjustments	(6)
Ending balance	$ 14