Interest Expense (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Interest Expense [Abstract]
Interest expense before capitalization	$ 431	$ 379	$ 361
Capitalized interest	(39)	(22)	(31)
Interest Expense	392	357	330
Interest Paid, Net	353	348	320
Interest Costs Incurred, Capitalized, Prior Period Reclassification Adjustment		$ 13