Restructuring of Operations - Additional Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended						3 Months Ended												3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 employee	Jun. 30, 2012	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2013 Fiscal Year 2013	Jun. 30, 2013 Thereafter	Jun. 30, 2013 Total Restructuring Costs including Cost Associated with Discontinued Operations	Mar. 31, 2013 Total Restructuring Costs including Cost Associated with Discontinued Operations	Jun. 30, 2012 Total Restructuring Costs including Cost Associated with Discontinued Operations	Mar. 31, 2012 Total Restructuring Costs including Cost Associated with Discontinued Operations	Mar. 31, 2013 Discontinued Operations	Jun. 30, 2012 Discontinued Operations	Mar. 31, 2012 Discontinued Operations	Jun. 30, 2013 Employee Termination Benefits	Jun. 30, 2012 Employee Termination Benefits	Mar. 31, 2012 Employee Termination Benefits	Mar. 31, 2013 Employee Termination Benefits	Dec. 31, 2012 Employee Termination Benefits	Jun. 30, 2013 Exit Costs	Jun. 30, 2012 Exit Costs	Mar. 31, 2012 Exit Costs	Mar. 31, 2013 Exit Costs	Dec. 31, 2012 Exit Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 4	$ 19	$ 6	$ 24					$ 4	$ 3	$ 20	$ 6	$ 1	$ 1	$ 1	$ 3	$ 7	$ 4			$ 1	$ 13	$ 2
Estimated reduction of employees over the next two years (in employees)			400
Restructuring and related activities, completion date period			3 years
Restructuring accruals	$ 25		$ 25		$ 33	$ 40	$ 9	$ 16								$ 14			$ 21	$ 27	$ 11			$ 12	$ 13