Revenue from Contract with Customers (Schedule of Prospective Adoption) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Item Effected [Line Items]
Revenues	$ 638,020	$ 572,848	$ 1,960,890	$ 1,834,362
Depreciation and amortization	56,228	49,909	161,726	146,103
Property, Plant and Equipment, Gross	7,570,759		7,570,759			$ 7,235,468
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,835,824		1,835,824			1,682,633
Property, Plant and Equipment, Net	5,734,935		5,734,935			5,552,835
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	1,005,392		1,005,392			1,082,511
Deferred revenue	121,247		121,247			117,795
Other noncurrent liabilities	64,425		64,425			30,350
Limited partner unitholders	2,665,620		2,665,620			2,267,231
Accounting Standards Update 2014-09 [Member]
Item Effected [Line Items]
Depreciation and amortization	56,228		161,726
Property, Plant and Equipment, Gross	7,570,759		7,570,759		$ 7,243,984
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,835,824		1,835,824		1,682,958
Property, Plant and Equipment, Net	5,734,935		5,734,935		5,561,026
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	1,005,392		1,005,392		1,083,013
Deferred revenue	121,247		121,247		115,894
Other noncurrent liabilities	64,425		64,425		34,969
Limited partner unitholders	2,665,620		2,665,620		2,273,206
Accounting Standards Update 2014-09 [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Item Effected [Line Items]
Depreciation and amortization	56,108		161,486
Property, Plant and Equipment, Gross	7,555,758		7,555,758			7,235,468
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	1,835,259		1,835,259			1,682,633
Property, Plant and Equipment, Net	5,720,499		5,720,499			5,552,835
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	1,004,890		1,004,890			1,082,511
Deferred revenue	129,458		129,458			117,795
Other noncurrent liabilities	56,567		56,567			30,350
Limited partner unitholders	2,650,329		2,650,329			$ 2,267,231
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Item Effected [Line Items]
Depreciation and amortization	120		240
Property, Plant and Equipment, Gross	15,001		15,001		8,516
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	565		565		325
Property, Plant and Equipment, Net	14,436		14,436		8,191
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	502		502		502
Deferred revenue	(8,211)		(8,211)		(1,901)
Other noncurrent liabilities	7,858		7,858		4,619
Limited partner unitholders	15,291		15,291		$ 5,975
Service [Member]
Item Effected [Line Items]
Revenues	488,775	$ 446,935	1,392,960	$ 1,272,845
Service [Member] | Accounting Standards Update 2014-09 [Member]
Item Effected [Line Items]
Revenues	488,775		1,392,960
Service [Member] | Accounting Standards Update 2014-09 [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Item Effected [Line Items]
Revenues	486,801		1,383,404
Service [Member] | Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Item Effected [Line Items]
Revenues	$ 1,974		$ 9,556