Investments (Investee Summarized Financial Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Subsidiary or Equity Method Investee [Line Items]
Revenues	$ 317	$ 317	$ 635	$ 640
Operating Expenses	(601)	(628)	(1,223)	(1,373)
Operating loss	(284)	(311)	(588)	(733)
Net loss from continuing operations before non-controlling interests	(416)	(431)	(878)	(992)
Net loss from discontinued operations before non-controlling interests	$ 0	$ (7)	$ 0	$ (6)