Fair Value Of Assets And Liabilities (Fair Value Of Financial Instruments Held By Consolidated Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	$ 1,147.7	$ 2,006.4	$ 1,328.0
Foreign time deposits	28.1	28.6
Assets held for policyholders	11,384.8	12,444.5
Policyholder payables (1)	(11,384.8)	(12,444.5)
Long-term debt (1)	(2,408.8)	(2,075.8)
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1,147.7	2,006.4
Equity investments	283.2	346.6
Trading investments	0.0	15.9
Foreign time deposits	28.1	28.6
Assets held for policyholders	11,384.8	12,444.5
Policyholder payables (1)	(11,384.8)	(12,444.5)
Contingent consideration liability	(40.9)	(57.4)
Long-term debt (1)	(2,408.8)	(2,075.8)
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	1,147.7	2,006.4
Equity investments	283.2	346.6
Trading investments	0.0	15.9
Foreign time deposits	28.1	28.6
Assets held for policyholders	11,384.8	12,444.5
Policyholder payables (1)	(11,384.8)	(12,444.5)
Contingent consideration liability	(40.9)	(57.4)
Long-term debt (1)	$ (2,418.2)	$ (2,258.1)

Contingent Consideration, Fair Value Disclosure

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Any certificate of deposit or savings account held by a bank or other financial institution for a specified period of time. These Foreign time deposits are of a large denomination, have maturity dates of three months or longer, and are combined with marketable securities.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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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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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The fair value of the assets held by the Entity for the benefit of separate account policyholders.

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Amount of liability for variable contracts that meet specified criteria that are backed by assets held in separate accounts and carried at the fair value of those assets.

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Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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