Subsequent Events (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Dec. 31, 2013	Sep. 30, 2013
Subsequent Event [Line Items]
Permian gas processing initial investment		$ 140
Business Acquisition, Date of Acquisition Agreement	Oct. 21, 2013

Date when the business acquisition agreement was executed, in CCYY-MM-DD format.

No definition available.

Name:	us-gaap_BusinessAcquisitionDateOfAcquisitionAgreement1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration