v3.3.1.900

Property, plant and equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, plant and equipment
Property, plant and equipment, gross	$ 1,014.0	$ 1,158.7
Less accumulated depreciation	236.3	195.8
Property, Plant and Equipment, Net, Total	777.7	962.9
Depreciation expense	59.0	64.6	$ 64.4
Impairment of property, plant and equipment	76.6	9.6
Land
Property, plant and equipment
Property, plant and equipment, gross	5.2	5.7
Office equipment, machinery and other
Property, plant and equipment
Property, plant and equipment, gross	$ 5.6	4.4
Office equipment, machinery and other | Minimum
Property, plant and equipment
Depreciable Lives	3 years
Office equipment, machinery and other | Maximum
Property, plant and equipment
Depreciable Lives	10 years
Leasehold improvements
Property, plant and equipment
Property, plant and equipment, gross		0.5
Leasehold improvements | Minimum
Property, plant and equipment
Depreciable Lives	7 years
Leasehold improvements | Maximum
Property, plant and equipment
Depreciable Lives	15 years
Asset retirement obligation.
Property, plant and equipment
Property, plant and equipment, gross	$ 27.4	29.3
Asset retirement obligation. | Minimum
Property, plant and equipment
Depreciable Lives	1 year
Asset retirement obligation. | Maximum
Property, plant and equipment
Depreciable Lives	43 years
Plant in service
Property, plant and equipment
Property, plant and equipment, gross	$ 975.8	$ 1,118.8
Plant in service | Minimum
Property, plant and equipment
Depreciable Lives	1 year
Plant in service | Maximum
Property, plant and equipment
Depreciable Lives	45 years

X

- Definition

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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