Divestitures (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2011	Mar. 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		10	30	10	1,450
Proceeds from divestiture of business, excluding amounts placed in escrow	1,426
Amount Placed In Escrow Included In Proceeds From Divestiture Of Business	24
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal			38	15	778
Gain On Divestiture Of Business Net Of Tax			26	12	545
Disposal Group, Including Discontinued Operation, Revenue			$ 58	$ 122	$ 141