The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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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.

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The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity.

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Aggregate cash proceeds received from a combination of transactions in which noncurrent assets are sold, which may include the sale of a business, an investment in an affiliate (including an equity method investee), property, plant and equipment and intangible assets. Excludes sales of trading, available-for-sale, and held-to-maturity securities.

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Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

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Net carrying amount of the assets and liabilities in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), when the reporting entity is not the VIE's primary beneficiary.

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Subsequent Event (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
Subsequent Event (Details) - USD ($) $ in Millions	Apr. 30, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Subsequent Event [Line Items]
Equity Method Investments		$ 6,544		$ 7,821
Preferred Stock, Value		35		$ 35
Payments to Acquire Equity Method Investments		$ 99	$ 21
Jackalope Gas Gathering Services LLC [Member]
Subsequent Event [Line Items]
Equity Method Investment, Ownership Percentage		50.00%
Subsequent Event [Member] \| Jackalope Gas Gathering Services LLC [Member]
Subsequent Event [Line Items]
Proceeds from Sales of Business, Affiliate and Productive Assets	$ 485
Variable Interest Entity, Not Primary Beneficiary [Member] \| Investments [Domain] \| Jackalope Gas Gathering Services LLC [Member]
Subsequent Event [Line Items]
Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets and Liabilities, Net		$ 358