The charge against earnings resulting from the aggregate write down of all assets from their carrying value to their fair value.

+ References+ Details

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References+ Details

- Definition

This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the cost method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

+ References+ Details

Fair Value Measurement (Details 6) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2010	Sep. 30, 2013	Dec. 31, 2011
Financial instruments carried and measured at fair value
Impairment on assets		$ 5.1	$ 5.1	$ 11.5
Carrying value of assets			37,899.0		36,843.7	40,276.3
Impairment of strategic asset	8.7
Non-recurring basis
Financial instruments carried and measured at fair value
Impairment on assets		18.0	22.0
Carrying value of assets	38.0	38.0	42.0
Impairment of strategic asset	$ 8.7