XML 108 R93.htm IDEA: XBRL DOCUMENT
v3.10.0.1

SHAREHOLDERS' EQUITY (Narrative (Details) | Jun. 30, 2018 | Mar. 31, 2017
--- | --- | ---
Noncontrolling Interest, Ownership Percentage by Parent | 100.00% |
Empire |  |
Noncontrolling Interest, Ownership Percentage by Parent | 100.00% | 79.00%
Tilden |  |
Noncontrolling Interest, Ownership Percentage by Parent | 100.00% | 85.00%

X
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | clf_NameofOperationAxis=clf_EmpireMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | clf_NameofOperationAxis=clf_TildenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |