XML 42 R25.htm IDEA: XBRL DOCUMENT v2.4.0.8

ASSET RETIREMENT OBLIGATION: (Tables)

6 Months Ended

Jun. 30, 2013

ASSET RETIREMENT OBLIGATION:

Summary of the asset retirement obligation activity

The following table summarizes the asset retirement obligation activity for the six months ended June 30, 2013 and 2012 (in millions):

		2013			2012
Balance as of January 1		$	118.2		$	62.0
Closure payments		(0.7		)	—
Accretion expense		4.9			1.7
Balance as of June 30,		$	122.4		$	63.7

X

- Details

Name:	us-gaap_AssetRetirementObligationDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 30

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13201-110859

+ Details

Name:	us-gaap_ScheduleOfChangeInAssetRetirementObligationTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration