Segment Information (Details 1) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Corporate and other information
OPERATING (LOSS) INCOME	$ 647	$ 663	$ (225)

The net result for the period of deducting operating expenses from operating revenues.

No definition available.

Name:	us-gaap_OperatingIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration