Variable Interest Entity and Equity Method Investment (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended						3 Months Ended	6 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Common Units	Jun. 30, 2012 Common Units	Jun. 30, 2013 Non-controlling Interest	Jun. 30, 2012 Non-controlling Interest	Jun. 30, 2012 As previously reported	Jun. 30, 2012 As previously reported	Dec. 31, 2012 As previously reported	Jun. 30, 2012 As previously reported Common Units	Jun. 30, 2012 As previously reported Non-controlling Interest
Variable Interest Entities and Equity Method Investment
Balance			$ 3,111,398	$ 1,395,242	$ 2,097,404	$ 642,522	$ 261,463	$ 189		$ 1,502,067	$ 3,215,591	$ 679,309	$ 70,227
Distributions paid			(215,015)	(155,144)	(214,903)	(155,073)	(112)	(71)		(158,010)		(155,073)	(2,937)
Contributions from non-controlling interest			685,219	1,101			685,219	1,101		1,940			1,940
Deferred income tax impact from changes in equity			(28,077)	(42,854)	(28,077)	(42,854)				(42,592)		(42,592)
Net income	85,498	186,533	64,367	202,307	68,241	202,928	(3,874)	(621)	187,136	203,409		202,928	481
Balance	$ 3,482,316	$ 2,256,269	$ 3,482,316	$ 2,256,269	$ 2,273,759	$ 1,503,140	$ 456,026	$ 598	$ 2,362,431	$ 2,362,431	$ 3,215,591	$ 1,540,189	$ 69,711