Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net income	$ 131,123	$ 103,972
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	138,519	79,160
Income from unconsolidated affiliates	(58,753)	(28,958)
Other non-cash items	6,676	3,709
Changes in assets and liabilities:
Increase in accounts receivable	(23,592)	(27,017)
(Increase) decrease in other assets	1,905	(1,649)
Decrease in accounts payable	(10,896)	(11,742)
Increase in accrued liabilities	32,598	18,923
Net cash provided by operating activities	217,580	136,398
Cash flows from investing activities:
Additions to property, plant and equipment	(545,594)	(140,921)
Investments in unconsolidated affiliates	(263,710)	(43,153)
Proceeds from sale of assets	31,696	5,599
Net cash used in investing activities	(777,608)	(178,475)
Cash flows from financing activities:
Proceeds from long-term debt borrowings	875,500	519,900
Payments on long-term debt borrowings	(659,300)	(1,084,100)
Proceeds from issuance of common units	399,922
Proceeds from issuance of senior notes		750,000
Distributions to unitholders	(177,430)	(120,475)
Capital contributions from noncontrolling interests	71,414
Debt issuance costs	(5,377)	(13,874)
Other adjustments	8,328	5,722
Net cash provided by financing activities	513,057	57,173
Net increase (decrease) in cash and cash equivalents	(46,971)	15,096
Cash and cash equivalents, beginning of period	64,994	22
Cash and cash equivalents, end of period	18,023	15,118
Supplemental disclosure of non-cash investing activities:
Changes in accounts payable and other liabilities related to purchases of property, plant and equipment	(25,244)	10,853
Changes in other liabilities related to asset retirement obligations	$ 105	$ 313