Property, Plant And Equipment (Schedule of Depreciation Rates) (Details)
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12 Months Ended |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
| Pipeline and Other Transmission Assets | Minimum |
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| Property, Plant and Equipment [Line Items] |
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| Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |
1.00%
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1.00%
|
1.50%
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| Pipeline and Other Transmission Assets | Maximum |
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| Property, Plant and Equipment [Line Items] |
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| Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |
1.73%
|
2.55%
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2.55%
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| Storage Facilities | Minimum |
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| Property, Plant and Equipment [Line Items] |
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| Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |
2.19%
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2.19%
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2.19%
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| Storage Facilities | Maximum |
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| Property, Plant and Equipment [Line Items] |
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| Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |
3.00%
|
3.30%
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3.50%
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| Gas Gathering and Processing Facilities | Minimum |
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| Property, Plant and Equipment [Line Items] |
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| Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |
1.67%
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1.67%
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1.67%
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| Gas Gathering and Processing Facilities | Maximum |
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| Property, Plant and Equipment [Line Items] |
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| Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |
2.50%
|
2.50%
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2.50%
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| General Plant, Software, and Other Assets | Minimum |
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| Property, Plant and Equipment [Line Items] |
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| Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |
1.00%
|
1.00%
|
1.00%
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| General Plant, Software, and Other Assets | Maximum |
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| Property, Plant and Equipment [Line Items] |
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| Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service |
10.00%
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10.00%
|
10.00%
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