Investments and Related Matters Other Segments (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2015	Dec. 31, 2014
Schedule of Investments [Line Items]
Investments	$ 13,661	$ 13,661	$ 14,500
Other Segments [Member]
Schedule of Investments [Line Items]
Equity method investments	309	309	298
Other investments	202	202	241
Investments	511	511	539
Energy Segment [Member]
Schedule of Investments [Line Items]
Investments	0	0	$ 77
Proceeds from Sale of Available-for-sale Securities	38	68
Cost basis of available for sale securities sold during the period		48
Reclassification adjustment from AOCI for sale of securities, before tax		20
Cost basis of available for sale securities transferred to trading securities		26
Available-for-sale Securities, Transfers to Trading, Gains (Losses)		$ 12
Trading Securities, Realized Gain	$ 1

Cost basis of available for sale securities sold during the period

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- Definition

Cost basis of available for sale securities transferred to trading securities

+ References

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- Definition

This item represents the difference between the gross amount of gains (losses) included in earnings for transfers of securities from the available-for-sale category into the trading category. Such net gain (loss) included in earnings represents the net unrealized gain (loss) which had been included in other comprehensive income and is associated with the securities transferred from the available-for-sale category to the trading category.

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- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

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-Publisher FASB

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- Definition

Sum of the carrying amounts as of the balance sheet date of all investments.

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Amount before tax of reclassification adjustment from accumulated other comprehensive income for unrealized gain (loss) realized upon the sale of available-for-sale securities.

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- Definition

Other investments not otherwise specified in the taxonomy.

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The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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This item represents the gain realized during the period from the sale of trading securities.

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