Acquisitions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	$ 81	$ 0	$ 134	$ 87
Zeno Office Solutions, Inc. [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Apr. 01, 2013
Payments to Acquire Businesses, Net of Cash Acquired	59
Impika [Member]
Business Acquisition [Line Items]
Business Acquisition, Effective Date of Acquisition	Feb. 28, 2013
Payments to Acquire Businesses, Net of Cash Acquired	52
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired			$ 20
Number of Businesses Acquired			2