XML 56 R43.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Asset Retirement Obligations (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2014
Asset Retirement Obligation [Abstract] |
Changes to Asset Retirement Obligation | The following table describes changes to the asset retirement obligation liability (dollars in millions):
| Year Ended December 31
| 2014 |  | 2013
Asset retirement obligation at beginning of period | $ | 32.0 |  |  | $ | 5.1 |
Acquisition | 4.1 |  |  | 23.8 |
Liabilities incurred | — |  |  | 3.2 |
Accretion expense | 1.0 |  |  | 0.3 |
Payments | (0.1 | ) |  | — |
Revisions in estimated cash flows | — |  |  | (0.4 | )
Asset retirement obligation at end of period | $ | 37.0 |  |  | $ | 32.0 |

X
- Details
Name: | us-gaap_AssetRetirementObligationAbstract
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