Financial Instruments (Effect of Cash Flows Hedges on Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Derivative [Line Items]
Portion of ending balance expected to be reclassified into earnings over the next twelve months, after-tax	$ (13)
Cash Flow Hedging [Member]
Derivative [Line Items]
Beginning Balance	(48)	3
Additions and revaluations of derivatives designated as cash flow hedges	24	(9)
Clearance of hedge results to earnings	11	(6)
Ending Balance	$ (13)	$ (12)