Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 429,371us-gaap_ProfitLoss	$ 341,149us-gaap_ProfitLoss	$ 178,387us-gaap_ProfitLoss
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	314,758us-gaap_DepreciationAndAmortization	296,179us-gaap_DepreciationAndAmortization	165,517us-gaap_DepreciationAndAmortization
Income from unconsolidated affiliates	(205,082)	(130,420)	(67,542)
Loss on impairments and disposals of assets	23,783
Other non-cash items	35,621us-gaap_OtherNoncashIncomeExpense	20,577us-gaap_OtherNoncashIncomeExpense	8,296us-gaap_OtherNoncashIncomeExpense
Distribution of earnings received from unconsolidated affiliates	281,733	82,871
Changes in assets and liabilities:
(Increase) decrease in accounts receivable	(143,810)	(97,507)	18,484
(Increase) decrease in other assets	(13,270)	2,244	(9,925)
Increase (decrease) in accounts payable	(4,286)	(10,492)	8,800
Increase (decrease) in accrued liabilities	(19,545)	59,361	16,113
Increase (decrease) in other long-term liabilities	71,700
Net cash provided by operating activities	770,973	563,962	318,130
Cash flows from investing activities:
Additions to property, plant and equipment	(999,211)	(1,058,599)	(350,500)
Purchase of compression assets	(159,210)
Acquisition of gathering system assets			(2,160,000)
Investments in unconsolidated affiliates	(351,331)	(572,370)	(185,039)
Proceeds from sale of assets	22,094	74,551	9,574
Net cash used in investing activities	(1,487,658)	(1,556,418)	(2,685,965)
Cash flows from financing activities:
Proceeds from long-term debt borrowings	2,699,371	2,015,700	1,387,800
Payments on long-term debt borrowings	(2,402,871)us-gaap_RepaymentsOfLongTermDebt	(1,672,200)us-gaap_RepaymentsOfLongTermDebt	(2,100,700)us-gaap_RepaymentsOfLongTermDebt
Proceeds from issuance of common units	52,155	449,312	569,255
Proceeds from issuance of senior notes	750,000	414,094	2,150,000
Distributions to unitholders	(536,716)us-gaap_PaymentsOfDividends	(389,128)us-gaap_PaymentsOfDividends	(251,720)us-gaap_PaymentsOfDividends
Capital contributions from noncontrolling interests	192,495	151,976
Payments on capital lease obligations	(3,479)	(3,552)
Payments on leasehold improvement financing		(17,798)
Debt issuance costs	(8,929)us-gaap_PaymentsOfDebtIssuanceCosts	(12,414)us-gaap_PaymentsOfDebtIssuanceCosts	(39,626)us-gaap_PaymentsOfDebtIssuanceCosts
Other	(699)	8,701	31,798
Net cash provided by financing activities	741,327	944,691	2,432,807
Net increase (decrease) in cash and cash equivalents	24,642	(47,765)	64,972
Cash and cash equivalents, beginning of period	17,229	64,994	22
Cash and cash equivalents, end of period	41,871	17,229	64,994
Supplemental disclosure of non-cash investing activities:
Changes in accounts payable and other liabilities related to purchases of property, plant and equipment	36,603	7,434	60,427
Changes in other liabilities related to asset retirement obligations	8,494	(1,314)	(133)
Property, plant and equipment acquired under capital lease		(9,370)
Property, plant and equipment acquired through leasehold improvement financing		(17,798)
Supplemental disclosure of cash payments for interest, net of capitalized interest	151,786us-gaap_InterestPaid	39,939us-gaap_InterestPaid	30,292us-gaap_InterestPaid
Supplemental disclosure of cash payments for taxes	2,000us-gaap_IncomeTaxesPaid	3,300us-gaap_IncomeTaxesPaid	2,900us-gaap_IncomeTaxesPaid
Class B Units
Cash flows from financing activities:
Proceeds from issuance of common units			343,000
Class C Units
Cash flows from financing activities:
Proceeds from issuance of common units			$ 343,000

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The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

+ References

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The cash inflow from a borrowing with the highest claim on the assets of the entity in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle, if longer).

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Amount of cash inflow from a noncontrolling interest. Includes, but is not limited to, purchase of additional shares or other increase in noncontrolling interest ownership.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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- Definition

The net cash inflow or outflow from other financing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.

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-Name Accounting Standards Codification

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-SubTopic 10

-Section 45

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3098-108585

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- Definition

The cash inflow from the sale of property, plant and equipment (capital expenditures), software, and other intangible assets.

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-Publisher FASB

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- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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- Definition

The cash outflow for the obligation for a lease meeting the criteria for capitalization (with maturities exceeding one year or beyond the operating cycle of the entity, if longer).

+ References

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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-URI http://asc.fasb.org/extlink&oid=6513228

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Cash outflows under financing arrangements with vendors (seller-financed debt), which had a maturity date at inception of more than one year (or more than one operating cycle, if longer); such debt may have arisen from purchases of property, plant and equipment or other productive assets.

+ References

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- Definition

Amount of asset retirement obligations settled through noncash transactions. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset.

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