XML 54 R41.htm IDEA: XBRL DOCUMENT v3.10.0.1
Fair Value (Fair Value of Financial Instruments) (Details) - USD ($)
$ in Millions
Jun. 30, 2018
Dec. 31, 2017
Carrying Value [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and cash equivalents $ 244.9 $ 376.4
Financial Assets carried at [1] 9,208.6 9,371.8
Carrying Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through AOCI [Member] | Other Investments [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1]   3.6
Carrying Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through AOCI [Member] | Debt Securities [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1] 7,729.9 7,779.7
Carrying Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through AOCI [Member] | Equity Securities [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1]   576.5
Carrying Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through Net Income [Member] | Other Investments [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1] 286.8 122.8
Carrying Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through Net Income [Member] | Equity Securities [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1] 554.0  
Carrying Value [Member] | Cost Approach Valuation Technique [Member] | Amortized Cost/Cost [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and cash equivalents [1] 244.9 376.4
Carrying Value [Member] | Cost Approach Valuation Technique [Member] | Amortized Cost/Cost [Member] | Other Investments [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1] 393.0 512.8
Carrying Value [Member] | Cost Approach Valuation Technique [Member] | Amortized Cost [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt 787.1 786.9
Estimated Fair Value [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and cash equivalents 244.9 376.4
Financial Assets carried at [1] 9,210.0 9,377.3
Debt 838.6 865.7
Estimated Fair Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through AOCI [Member] | Other Investments [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1]   3.6
Estimated Fair Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through AOCI [Member] | Debt Securities [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1] 7,729.9 7,779.7
Estimated Fair Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through AOCI [Member] | Equity Securities [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1]   576.5
Estimated Fair Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through Net Income [Member] | Other Investments [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1] 286.8 122.8
Estimated Fair Value [Member] | Income Approach Valuation Technique [Member] | Fair Value Through Net Income [Member] | Equity Securities [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1] 554.0  
Estimated Fair Value [Member] | Cost Approach Valuation Technique [Member] | Amortized Cost/Cost [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Cash and cash equivalents [1] 244.9 376.4
Estimated Fair Value [Member] | Cost Approach Valuation Technique [Member] | Amortized Cost/Cost [Member] | Other Investments [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of investments [1] 394.4 518.3
Estimated Fair Value [Member] | Cost Approach Valuation Technique [Member] | Amortized Cost [Member]    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Debt $ 838.6 $ 865.7
[1] Due to the adoption of ASU No. 2016-01, certain classifications are not comparable to the prior year. See Note 2 – “New Accounting Pronouncements”.