Expenses (Activity Related To Restructuring-Related Accruals) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2012	$ 262
Additional accruals for Business Operations and Information Technology Transformation program	8
Additional accruals for 2012 expense control measures	2	1
Payments and adjustments	(103)
Balance as of June 30, 2013	169	262
Employee- Related Costs
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2012	195
Additional accruals for Business Operations and Information Technology Transformation program	5
Additional accruals for 2012 expense control measures	(1)
Payments and adjustments	(83)
Balance as of June 30, 2013	116
Real Estate Consolidation
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2012	49
Additional accruals for Business Operations and Information Technology Transformation program	4
Additional accruals for 2012 expense control measures	0
Payments and adjustments	(10)
Balance as of June 30, 2013	43
Information Technology Costs
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2012	5
Additional accruals for Business Operations and Information Technology Transformation program	(1)
Additional accruals for 2012 expense control measures	0
Payments and adjustments	(4)
Balance as of June 30, 2013	0
Asset and Other Write-Offs
Restructuring Reserve [Roll Forward]
Balance as of December 31, 2012	13
Additional accruals for Business Operations and Information Technology Transformation program	0
Additional accruals for 2012 expense control measures	3
Payments and adjustments	(6)
Balance as of June 30, 2013	$ 10