Divestitures (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Jan. 31, 2011	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase Price for Divestiture of Business	$ 1,500
Proceeds from Divestiture of Businesses			30	10	1,450
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal		12	38	15
Segment Reporting, Sales from Divested Businesses		$ 4	$ 58	$ 122