Fair Value (Available-For-Sale Debt Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Fair Value Disclosure [Line Items]
Amortized Cost	$ 134.8	$ 131.4
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1.0	1.3
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(0.4)	(0.8)
Fair Value	135.4	131.9
Government [Member]
Fair Value Disclosure [Line Items]
Amortized Cost	33.8	30.8
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0.3	0.3
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0.0	(0.2)
Fair Value	34.1	30.9
Corporate Debt Securities [Member]
Fair Value Disclosure [Line Items]
Amortized Cost	101.0	100.6
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0.7	1.0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(0.4)	(0.6)
Fair Value	$ 101.3	$ 101.0

Fair Value Disclosure [Line Items]

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

+ References

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-Publisher FASB

-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

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

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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

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

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous 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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