Acquisitions and Sales of Other Assets (Narrative - Change in PPA) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Jul. 02, 2012 Progress Merger [Member]	Dec. 31, 2013 Purchase Price Allocation Adjustments [Member] Progress Merger [Member]
Significant Acquisitions and Disposals [Line Items]
Current assets			$ 3,204
Property, plant and equipment			23,141	(138)
Goodwill	16,340	16,365	12,469	2
Other long-term assets, excluding goodwill			9,990	(4)
Current liabilities, including current maturities of long-term debt			3,593	12
Long-term liabilities, preferred stock and noncontrolling interests			$ 10,394	$ (152)