Risk Management (Schedule Of Largest Notional Amounts Of The Positions To Buy Or Sell Foreign Currency) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Euro
Foreign Currency Contracts
Notional amount of foreign currency derivatives	$ 214	$ (132)
Chinese Renminbi
Foreign Currency Contracts
Notional amount of foreign currency derivatives	(161)	(181)
Norwegian Krone
Foreign Currency Contracts
Notional amount of foreign currency derivatives	(90)	(95)
Australian Dollar
Foreign Currency Contracts
Notional amount of foreign currency derivatives	(42)	(17)
British Pound
Foreign Currency Contracts
Notional amount of foreign currency derivatives	$ 34	$ 257