XML 55 R45.htm IDEA: XBRL DOCUMENT v3.8.0.1
Investments - Cost, Gross Unrealized Gains and Losses, and Estimated Fair Value of Trading Investments in Fixed Income Maturities (Details) - USD ($)
$ in Millions
Sep. 30, 2017
Dec. 31, 2016
Statement [Line Items]    
Fair Market Value $ 1,665.0 $ 1,265.7
U.S. government    
Statement [Line Items]    
Cost or Amortized Cost 160.6 82.8
Gross Unrealized Gains 0.6 0.4
Gross Unrealized Losses (0.6) (0.8)
Fair Market Value 160.6 82.4
Municipal    
Statement [Line Items]    
Cost or Amortized Cost 32.4 15.7
Gross Unrealized Gains 0.0 0.0
Gross Unrealized Losses (0.1) (0.2)
Fair Market Value 32.3 15.5
Corporate    
Statement [Line Items]    
Cost or Amortized Cost 1,029.8 817.8
Gross Unrealized Gains 17.9 9.9
Gross Unrealized Losses (2.7) (7.1)
Fair Market Value 1,045.0 820.6
Non-U.S. government-backed corporate    
Statement [Line Items]    
Cost or Amortized Cost 2.0  
Gross Unrealized Gains 0.0  
Gross Unrealized Losses 0.0  
Fair Market Value 2.0  
Non-U.S. government    
Statement [Line Items]    
Cost or Amortized Cost 203.5 203.4
Gross Unrealized Gains 7.8 3.5
Gross Unrealized Losses (0.4) (4.1)
Fair Market Value 210.9 202.8
Asset-backed    
Statement [Line Items]    
Cost or Amortized Cost 11.0 14.5
Gross Unrealized Gains 0.1 0.0
Gross Unrealized Losses 0.0 0.0
Fair Market Value 11.1 14.5
Agency mortgage-backed    
Statement [Line Items]    
Cost or Amortized Cost 203.1 130.6
Gross Unrealized Gains 0.7 0.2
Gross Unrealized Losses (0.7) (0.9)
Fair Market Value 203.1 129.9
Total fixed income securities — Trading    
Statement [Line Items]    
Cost or Amortized Cost 1,642.4 1,264.8
Gross Unrealized Gains 27.1 14.0
Gross Unrealized Losses (4.5) (13.1)
Fair Market Value 1,665.0 1,265.7
Total short-term investments — Trading    
Statement [Line Items]    
Cost or Amortized Cost 90.3 185.4
Gross Unrealized Gains 0.0 0.0
Gross Unrealized Losses 0.0 0.0
Fair Market Value 90.3 185.4
Total equity securities — Trading    
Statement [Line Items]    
Cost or Amortized Cost 407.2 554.3
Gross Unrealized Gains 68.7 55.4
Gross Unrealized Losses (7.3) (25.0)
Fair Market Value 468.6 584.7
Total catastrophe bonds — Trading    
Statement [Line Items]    
Cost or Amortized Cost 33.5 42.5
Gross Unrealized Gains 0.0 0.0
Gross Unrealized Losses (3.2) 0.0
Fair Market Value 30.3 42.5
Total    
Statement [Line Items]    
Cost or Amortized Cost 2,173.4 2,047.0
Gross Unrealized Gains 95.8 69.4
Gross Unrealized Losses (15.0) (38.1)
Fair Market Value $ 2,254.2 $ 2,078.3