XML 93 R86.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Summary of Significant Accounting Policies - Intangible Assets and Goodwill (Details) | 12 Months Ended
--- | ---
Dec. 31, 2016 CAD reporting_unit | Dec. 31, 2015 CAD
Finite-Lived Intangible Assets [Line Items] |  |
Impairment test (years) | 5 years |
Number of reporting units | reporting_unit | 12 |
Goodwill impairment loss | CAD | CAD 0 | CAD 0
Minimum |  |
Finite-Lived Intangible Assets [Line Items] |  |
Intangible asset amortization rate | 1.00% | 1.00%
Maximum |  |
Finite-Lived Intangible Assets [Line Items] |  |
Intangible asset amortization rate | 50.00% | 50.00%
Computer software |  |
Finite-Lived Intangible Assets [Line Items] |  |
Weighted Average Remaining Service Life | 4 years | 4 years
Computer software | Minimum |  |
Finite-Lived Intangible Assets [Line Items] |  |
Service Life Ranges | 3 years | 3 years
Computer software | Maximum |  |
Finite-Lived Intangible Assets [Line Items] |  |
Service Life Ranges | 10 years | 10 years
Land, transmission and water rights |  |
Finite-Lived Intangible Assets [Line Items] |  |
Weighted Average Remaining Service Life | 57 years | 37 years
Land, transmission and water rights | Minimum |  |
Finite-Lived Intangible Assets [Line Items] |  |
Service Life Ranges | 30 years | 30 years
Land, transmission and water rights | Maximum |  |
Finite-Lived Intangible Assets [Line Items] |  |
Service Life Ranges | 80 years | 80 years
Other |  |
Finite-Lived Intangible Assets [Line Items] |  |
Weighted Average Remaining Service Life | 15 years | 15 years
Other | Minimum |  |
Finite-Lived Intangible Assets [Line Items] |  |
Service Life Ranges | 10 years | 10 years
Other | Maximum |  |
Finite-Lived Intangible Assets [Line Items] |  |
Service Life Ranges | 104 years | 104 years

X
- Definition Finite-Lived Intangible Assets, Amortization Rate + References No definition available. + Details
Name: | fts_FiniteLivedIntangibleAssetsAmortizationRate
Namespace Prefix: | fts_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Goodwill, Impairment Test, Period + References No definition available. + Details
Name: | fts_GoodwillImpairmentTestPeriod
Namespace Prefix: | fts_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Remaining amortization period of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetsRemainingAmortizationPeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13854-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13777-109266 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 + Details
Name: | us-gaap_GoodwillImpairmentLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Reporting Unit -URI http://asc.fasb.org/extlink&oid=6523643 + Details
Name: | us-gaap_NumberOfReportingUnits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_ComputerSoftwareIntangibleAssetMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=fts_LandTransmissionandWaterRightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_OtherIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |