Organization, Description of Business and Basis of Presentation (Changes from New Accounting Pronouncements) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Item Effected [Line Items]
Distributions from operations of non-controlled entities	$ 147,950	$ 97,691
Net Cash Provided by (Used in) Operating Activities	863,781	813,701
Distributions from returns of investments in non-controlled entities	1,786	52,738
Net Cash Provided by (Used in) Investing Activities	101,437	(435,276)
Property, Plant and Equipment, Gross	7,570,759			$ 7,235,468
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(1,835,824)			(1,682,633)
Property, Plant and Equipment, Net	5,734,935			5,552,835
Investments in non-controlled entities	1,005,392			1,082,511
Deferred revenue	121,247			117,795
Other noncurrent liabilities	64,425			30,350
Limited partner unitholders	2,665,620			2,267,231
Accounting Standards Update 2014-09 [Member]
Item Effected [Line Items]
Property, Plant and Equipment, Gross	7,570,759		$ 7,243,984
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(1,835,824)		(1,682,958)
Property, Plant and Equipment, Net	5,734,935		5,561,026
Investments in non-controlled entities	1,005,392		1,083,013
Deferred revenue	121,247		115,894
Other noncurrent liabilities	64,425		34,969
Limited partner unitholders	2,665,620		2,273,206
Previously Reported [Member]
Item Effected [Line Items]
Distributions from operations of non-controlled entities		78,562
Net Cash Provided by (Used in) Operating Activities		794,572
Distributions from returns of investments in non-controlled entities		71,867
Net Cash Provided by (Used in) Investing Activities		(416,147)
Restatement Adjustment [Member] | Accounting Standards Update 2016-15 [Member]
Item Effected [Line Items]
Distributions from operations of non-controlled entities		19,129
Net Cash Provided by (Used in) Operating Activities		19,129
Distributions from returns of investments in non-controlled entities		(19,129)
Net Cash Provided by (Used in) Investing Activities		$ (19,129)
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Item Effected [Line Items]
Property, Plant and Equipment, Gross	7,555,758			7,235,468
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(1,835,259)			(1,682,633)
Property, Plant and Equipment, Net	5,720,499			5,552,835
Investments in non-controlled entities	1,004,890			1,082,511
Deferred revenue	129,458			117,795
Other noncurrent liabilities	56,567			30,350
Limited partner unitholders	2,650,329			$ 2,267,231
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Item Effected [Line Items]
Property, Plant and Equipment, Gross	15,001		8,516
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(565)		(325)
Property, Plant and Equipment, Net	14,436		8,191
Investments in non-controlled entities	502		502
Deferred revenue	(8,211)		(1,901)
Other noncurrent liabilities	7,858		4,619
Limited partner unitholders	$ 15,291		$ 5,975