Divestitures (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2011	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on divestitures		$ 0	$ 0	$ 12
Purchase Price for Divestiture of Business	$ 1,500
Segment Reporting, Sales from Divested Businesses		$ 0	$ 0	$ 4