Segment Information Reconciliation of Total Segment Margin to Income Before Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Segment Information [Abstract]
Total segment margin	$ 358rgp_SegmentMargin	$ 225rgp_SegmentMargin
Operation and maintenance	(133)us-gaap_OperatingCostsAndExpenses	(78)us-gaap_OperatingCostsAndExpenses
General and administrative	(36)us-gaap_GeneralAndAdministrativeExpense	(33)us-gaap_GeneralAndAdministrativeExpense
Gain on asset sales, net	0us-gaap_GainLossOnDispositionOfAssets	2us-gaap_GainLossOnDispositionOfAssets
Depreciation, depletion and amortization	(158)us-gaap_DepreciationAndAmortization	(94)us-gaap_DepreciationAndAmortization
Income from unconsolidated affiliates	50	43
Interest expense, net	(82)us-gaap_InterestExpense	(56)us-gaap_InterestExpense
Other income and deductions, net	3us-gaap_OtherNonoperatingIncomeExpense	2us-gaap_OtherNonoperatingIncomeExpense
INCOME BEFORE INCOME TAXES	$ 2	$ 11

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Total revenues less cost of good sold for each reporting segment

+ References

No definition available.

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- Definition

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

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- Definition

Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

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- Definition

The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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- Definition

The portion of earnings or loss from continuing operations before income taxes that is attributable to domestic operations.

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- Definition

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

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Amount of the cost of borrowed funds accounted for as interest expense.

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- Definition

Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Excludes Selling, General and Administrative Expense.

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No definition available.

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- Definition

The net amount of other income and expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income (expense) recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) net gains or losses on securities, (d) unusual costs, (e) gains or losses on foreign exchange transactions, and (f) miscellaneous other income and expense items.

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