Commitments and Contingencies (Details) - Jun. 30, 2015 - USD ($) $ in Millions	Total
Commitments and Contingencies [Abstract]
Commitments for the drilling and development of investment properties	$ 7.2
Commitments for asset retirement obligations included in estimated capital commitments	3.8
Commitments for the drilling and development of investment properties expected to be incurred in the next 12 months	$ 2.0

Commitments for asset retirement obligations included in estimated capital commitments.

No definition available.

Name:	cik1455741_CommitmentsForAssetRetirementObligationsIncludedInEstimatedCapitalCommitments
Namespace Prefix:	cik1455741_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant