Restructuring and Related Implementation Charges (Details) (Two Thousand Twelve Restructuring Program [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Duration Of Restructuring Program			4 years
Percent of Restructuring Charges Resulting In Cash Expenditure	75.00%	75.00%
Restructuring and Related Cost, Incurred Cost	$ 102	$ 168
One-time Termination Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Estimated Percent Of Total Cumulative Pretax Charges Of Implementing 2012 Restructuring Program	50.00%	50.00%
Restructuring and Related Cost, Incurred Cost	71	86
Incremental Depreciation And Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Estimated Percent Of Total Cumulative Pretax Charges Of Implementing 2012 Restructuring Program	15.00%	15.00%
Charges Resulting Directly From Exit Activities [Member]
Restructuring Cost and Reserve [Line Items]
Estimated Percent Of Total Cumulative Pretax Charges Of Implementing 2012 Restructuring Program	20.00%	20.00%
Contract Termination [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	8	19
Implementation Of New Strategies [Member]
Restructuring Cost and Reserve [Line Items]
Estimated Percent Of Total Cumulative Pretax Charges Of Implementing 2012 Restructuring Program	15.00%	15.00%
Third party Incremental Cost [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost	13	24
Land and Building [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Incurred Cost		23
Expected Completion Date 2016 | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Program Expected Cost Before Tax	1,100	1,100
Restructuring Program Expected Cost After Tax	775	775
Expected Completion Date 2016 | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Program Expected Cost Before Tax	1,250	1,250
Restructuring Program Expected Cost After Tax	875	875
Expected Completion Date December 2013 | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Program Expected Cost Before Tax	260	260
Restructuring Program Expected Cost After Tax	185	185
Expected Completion Date December 2013 | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Program Expected Cost Before Tax	310	310
Restructuring Program Expected Cost After Tax	$ 220	$ 220