Financial Instruments (Effect of Cash Flows Hedges on Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative [Line Items]
Portion of ending balance of gain (loss) expected to be reclassified into earnings over the next twelve months, after-tax	$ (4)
Cash Flow Hedging [Member]
Derivative [Line Items]
Beginning balance	(13)	(29)	(48)	3
Additions and revaluations of derivatives designated as cash flow hedges	(1)	(9)	15	(24)
Clearance of hedge results to earnings	(1)	1	18	(16)
Ending balance	$ (15)	$ (37)	$ (15)	$ (37)