Acquisitions and Sales of Other Assets (Purchase Price Allocation) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Significant Acquisitions and Disposals [Line Items]
Current assets	$ 3,204
Property, plant and equipment	23,279
Goodwill	12,467
Other long-term assets, excluding goodwill	9,994
Total assets	48,944
Current liabilities, including current maturities of long-term debt	3,581
Long-term liabilities, preferred stock and noncontrolling interests	10,546
Long-term debt	16,746
Total liabilities and preferred stock	30,873
Total estimated purchase price	$ 18,071

The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition.

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The amount of acquisition cost of a business combination allocated to assets acquired.

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The amount of acquisition cost of a business combination allocated to current assets.

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The amount of acquisition cost of a business combination allocated to current liabilities of the acquired entity.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Amount of goodwill arising from a business combination, which is the excess of the cost of the acquired entity over the amounts assigned to assets acquired and liabilities assumed.

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The amount of acquisition cost of a business combination allocated to liabilities assumed.

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The amount of acquisition cost of a business combination allocated to noncurrent assets.

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The amount of acquisition cost of a business combination allocated to the noncurrent portion of the long-term debt assumed from the acquired entity.

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Amount of acquisition cost of a business combination allocated to other noncurrent liabilities not separately disclosed.

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The amount of acquisition cost of a business combination allocated to property, plant and equipment to be used in ongoing operations.

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