Income Tax (Income Loss from Continuing Operations Before Income Tax Expense from Domestic and Foreign Operations) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income from continuing operations:
Domestic	$ 5,335	$ 2,540	$ 3,153
Foreign	56	282	545
Income (loss) from continuing operations before provision for income tax	$ 5,391	$ 2,822	$ 3,698