Consolidated Statement of Capital - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) in Partners' Capital
Beginning Balance	$ 5,080,081	$ 4,595,574	$ 4,480,226
Contributions	3,347,260	3,697,533	3,067,104
Distributions	(4,192,345)	(3,617,099)	(3,165,285)
Shares contributed by parent company	(10,000)
Net income	361,066	403,238	212,615
Other comprehensive income	890	835	914
Ending Balance	4,586,952	5,080,081	4,595,574
General Partner's Capital Class A Common Units | Class A Common Units
Increase (Decrease) in Partners' Capital
Beginning Balance	4,734,873	4,248,736	4,127,414
Contributions	3,315,582	3,697,440	3,067,104
Distributions	(4,190,480)	(3,611,900)	(3,153,197)
Shares contributed by parent company	(10,000)
Net income	351,897	400,597	207,415
Ending Balance	4,201,872	4,734,873	4,248,736
Limited Partner's Capital
Increase (Decrease) in Partners' Capital
Beginning Balance	0	0	0
Ending Balance	0	0	0
Noncontrolling Interests In Other Partnerships
Increase (Decrease) in Partners' Capital
Beginning Balance	348,314	350,779	357,667
Contributions	31,678	93
Distributions	(1,865)	(5,199)	(12,088)
Net income	9,169	2,641	5,200
Ending Balance	387,296	348,314	350,779
Accumulated Other Comprehensive (Loss) Income
Increase (Decrease) in Partners' Capital
Beginning Balance	(3,106)	(3,941)	(4,855)
Other comprehensive income	890	835	914
Ending Balance	$ (2,216)	$ (3,106)	$ (3,941)