PLANT, PROPERTY AND EQUIPMENT (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
PLANT, PROPERTY AND EQUIPMENT
Cost	$ 437.3	$ 445.9
Accumulated Depreciation	138.8	133.3
Net Book Value	298.5	312.6
Pipeline
PLANT, PROPERTY AND EQUIPMENT
Cost	290.0	290.1
Accumulated Depreciation	110.0	100.6
Net Book Value	180.0	189.5
Compression
PLANT, PROPERTY AND EQUIPMENT
Cost	104.8	113.4
Accumulated Depreciation	19.5	24.5
Net Book Value	85.3	88.9
Metering and other
PLANT, PROPERTY AND EQUIPMENT
Cost	42.4	42.2
Accumulated Depreciation	9.3	8.2
Net Book Value	33.1	34.0
Under construction
PLANT, PROPERTY AND EQUIPMENT
Cost	0.1	0.2
Net Book Value	$ 0.1	$ 0.2

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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