Partners' Capital And Distributions (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	9 Months Ended
	Sep. 26, 2014	Sep. 30, 2014	Sep. 26, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Partners Capital And Distributions [Line Items]
Sale of Stock, Price Per Share			$ 50.71
Partners' Capital Account, Public Sale of Units Net of Offering Costs	$ 225.60
Common units, issued		93,290,985	4,600,000			88,690,985
Common units, outstanding		93,290,985				88,690,985	88,691,000		81,202,752
Conversion Feature, Minimum Distribution Coverage Ratio		1.1
Distribution paid per common unit		$ 0.5650		$ 0.5500	$ 0.5350	$ 0.5225	$ 0.5100	$ 0.4975
Waiver Units Class 1 [Member]
Partners Capital And Distributions [Line Items]
Waiver units authorized		1,738,000
Waiver Units Class 3 [Member]
Partners Capital And Distributions [Line Items]
Waiver units authorized		1,750,000
Waiver units issued		1,738,000
Waiver Units Class 4 [Member]
Partners Capital And Distributions [Line Items]
Waiver units authorized		1,750,000
Waiver units issued		1,738,000
Waiver units outstanding		1,738,000
Class A [Member]
Partners Capital And Distributions [Line Items]
Common units, outstanding		93,250,988
Class B [Member]
Partners Capital And Distributions [Line Items]
Common units, outstanding		39,997
Class Two [Member]
Partners Capital And Distributions [Line Items]
Conversion Feature, Minimum Distribution Coverage Ratio		1.1
Class Three [Member]
Partners Capital And Distributions [Line Items]
Conversion Feature, Minimum Distribution Coverage Ratio		1.1
Class Four [Member]
Partners Capital And Distributions [Line Items]
Conversion Feature, Minimum Distribution Coverage Ratio		1.1
Conversion feature threshold, quarterly distribution, minimum, per unit		0.52
Waiver Units Class2 [Member]
Partners Capital And Distributions [Line Items]
Waiver units authorized		1,750,000
Waiver units issued		1,738,000