Derivatives (Details 2-Fair Value Hedges) (Fair Value Hedging [Member]) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2011 Interest Rate Contract [Member] USD ($)	Dec. 31, 2013 Foreign Exchange Contract [Member] NOK	Dec. 31, 2012 Foreign Exchange Contract [Member] NOK	Dec. 31, 2013 Debentures Due 2017 [Member] Interest Rate Contract [Member] USD ($)	Dec. 31, 2012 Debentures Due 2017 [Member] Interest Rate Contract [Member] USD ($)	Dec. 31, 2013 Notes Due 2018 [Member] Interest Rate Contract [Member] USD ($)
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	$ 1,450	2,387	3,043	$ 600	$ 600	$ 300
Interest Rate Swaps	$ 29
Weighted-average, LIBOR-based, floating rate				4.65%	4.70%	4.50%
Derivative, Average Forward Exchange Rate		6.060	5.780