Acquisition and Restructuring Costs (Activity Related To Restructuring-Related Accruals) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Restructuring Reserve [Roll Forward]
Beginning balance	$ 287
Additional accruals for business operations and information technology transformation program	67
Net accruals for 2011 expense control measures	(1)
Accruals for 2012 expense control measures	133
Payments and adjustments	(224)
Ending balance	262
Employee-Related Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	162
Additional accruals for business operations and information technology transformation program	27
Net accruals for 2011 expense control measures	3
Accruals for 2012 expense control measures	129
Payments and adjustments	(126)
Ending balance	195
Real Estate Consolidation [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	39
Additional accruals for business operations and information technology transformation program	20
Net accruals for 2011 expense control measures	0
Accruals for 2012 expense control measures	0
Payments and adjustments	(10)
Ending balance	49
IT Transition Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	33
Additional accruals for business operations and information technology transformation program	20
Net accruals for 2011 expense control measures	0
Accruals for 2012 expense control measures	0
Payments and adjustments	(48)
Ending balance	5
Fixed-Income Trading Portfolio [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	38
Additional accruals for business operations and information technology transformation program	0
Net accruals for 2011 expense control measures	(9)
Accruals for 2012 expense control measures	0
Payments and adjustments	(29)
Ending balance	0
Asset And Other Write Offs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	15
Additional accruals for business operations and information technology transformation program	0
Net accruals for 2011 expense control measures	5
Accruals for 2012 expense control measures	4
Payments and adjustments	(11)
Ending balance	$ 13