Income Taxes - Components of (Loss)/Income Before Income Taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Components of (Loss)/Income Before Income Taxes [Line Items]
Income/(loss) from continuing operations before income taxes	$ (3,217)	$ (4,250)	$ (1,804)
United States [Member]
Components of (Loss)/Income Before Income Taxes [Line Items]
Income/(loss) from continuing operations before income taxes	(3,351)	(4,446)	(1,889)
Outside of the U.S. [Member]
Components of (Loss)/Income Before Income Taxes [Line Items]
Income/(loss) from continuing operations before income taxes	$ 134	$ 196	$ 85