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Investments (Tables)

3 Months Ended

Mar. 31, 2012

Investments

Summary of the cost, gross unrealized gains and losses and fair value of investments classified as available-for-sale

December 31, 2011

					Gross Unrealized
											Fair Value
		Cost			Gains			Losses
Equity securities		$	97.6		$	1.4		$	(12.7	)	$	86.3

March 31, 2012

					Gross Unrealized
		Cost			Gains			Losses			Fair Value
Equity securities		$	92.1		$	12.0		$	(2.6	)	$	101.5

Summary of the Company's realized gains and losses on investments classified as available-for-sale

		For the Three Months Ended March 31,
		2011			2012
Gains		$	0.2		$	—
Losses			—			—
Net realized gains		$	0.2		$	—

Summary of the cost, gross unrealized gains and losses and fair value of investments classified as trading securities

December 31, 2011

					Gross Unrealized
											Fair Value
		Cost			Gains			Losses
Equity securities		$	13.5		$	0.9		$	(0.3	)	$	14.1

March 31, 2012

					Gross Unrealized
											Fair Value
		Cost			Gains			Losses
Equity securities		$	9.6		$	11.5		$	—		$	21.1

Summary of the Company's realized gains and losses on investments classified as trading securities

		For the Three Months Ended March 31,
		2011			2012
Gains		$	0.2		$	0.5
Losses			(0.3	)		(0.3	)
Net realized gains (losses)		$	(0.1	)	$	0.2

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- Definition

Tabular disclosure of the realized and unrealized gains and losses reported in the statement of income which have resulted from the sale and holding of available-for-sale securities.

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Tabular disclosure of available-for-sale securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt.

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Tabular disclosure of the realized and unrealized gains and losses reported in the statement of income which have resulted from the sale and holding of marketable securities, respectively, as well as the sale or disposal of cost method investments. Such amounts would include realized gains and losses on the sale or disposal of trading, available-for-sale, and held-to-maturity securities, unrealized gains and losses on trading securities, unrealized gains and losses on available-for-sale and held-to-maturity securities transferred to the trading securities category, realized gains and losses on the sale or disposal of cost method investments, and losses recognized for other than temporary impairments (OTTI) of such investments.

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Tabular disclosure of trading securities (and certain trading assets) which consist of all investments in certain debt and equity securities (and other assets) that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time) or for which an entity has elected the fair value option. Trading generally reflects active and frequent buying and selling, and trading securities are generally used with the objective of generating profits on short-term differences in price, but this category of investments may also include items which are not intended to be sold in the near term or for which the fair value option has been elected.

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