The number of limited partner units issued.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 5

-Subparagraph (SAB TOPIC 4.F)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187171-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 272

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70434-108055

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 4

-Section F

Name:	us-gaap_LimitedPartnersCapitalAccountUnitsIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Subsequent Event (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 10, 2015	Mar. 31, 2015	Dec. 31, 2014
Subsequent Event [Line Items]
Common units, issued		95,029,218	95,029,218
Subsequent Event [Member]
Subsequent Event [Line Items]
Common units, issued	4,600,000
Sale of Stock, Price Per Share	$ 44.42
Partners' Capital Account, Public Sale of Units Net of Offering Costs	$ 198