Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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-Publisher FASB
-Name Accounting Standards Codification
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This item represents the cost of equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments for other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of investments in equity securities and other forms of securities that provide ownership interests classified as available-for-sale, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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-Publisher FASB
-Name Accounting Standards Codification
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This item represents the total unrealized gain (loss) included in earnings for the period as a result of holding marketable securities categorized as trading, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period.

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The amount of other than temporary impairment (OTTI) losses on equity securities, OTTI related to credit losses on debt securities, and OTTI losses on debt securities when the entity intends to sell the securities or it is more likely than not that the entity will be required to sell the securities before recovery of its amortized cost basis. Additionally, this item includes OTTI losses recognized during the period on investments accounted for under the cost method of accounting.

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The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value of investments in trading equity securities and other forms of trading securities that provide ownership interests.

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Marketable Investment Securities Marketable Investment Securities (Details 3) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Proceeds from Sale of Available-for-sale Securities [Abstract]
Proceeds from Sale of Available-for-sale Securities		$ 8.9		$ 31.0
Available-for-sale Securities, Gross Realized Gains				2.8
Equity securities
Gain (Loss) on Investments [Line Items]
Available-for-sale Securities, Equity Securities, Current					$ 87.1
Trading Securities, Equity					52.5
Available-for-sale Equity Securities, Amortized Cost Basis					97.5
Available-for-sale Equity Securities, Accumulated Gross Unrealized Gain, before Tax					7.9
Available-for-sale Equity Securities, Accumulated Gross Unrealized Loss, before Tax					$ 18.4
Other Nonoperating Income (Expense) [Member] \| Equity securities
Gain (Loss) on Investments [Line Items]
Other-than-temporary impairment loss on available-for-sale securities				$ 3.3
Gain (Loss) on Investments [Member] \| Equity securities
Gain (Loss) on Investments [Line Items]
Unrealized Gains on Securities	$ 41.9		$ 5.4