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Investments Distribution by External Credit Rating for Fixed Maturity Securities (Details) $ in Millions | Mar. 31, 2018 USD ($)
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Schedule of Available-for-sale Securities |
Fixed Maturity Securities | $ 44,500.1
Accumulated Gross Unrealized Gain on Securities | 4,641.3
Accumulated Gross Unrealized Loss on Securities | $ 293.1
Percent of Fixed Maturity Securities in Unrealized Loss Position | 100.00%
External Credit Rating, Investment Grade |
Schedule of Available-for-sale Securities |
Fixed Maturity Securities | $ 41,233.8
Accumulated Gross Unrealized Gain on Securities | 4,527.8
Accumulated Gross Unrealized Loss on Securities | $ 198.7
Percent of Fixed Maturity Securities in Unrealized Loss Position | 67.80%
External Credit Rating, Non Investment Grade |
Schedule of Available-for-sale Securities |
Fixed Maturity Securities | $ 3,266.3
Accumulated Gross Unrealized Gain on Securities | 113.5
Accumulated Gross Unrealized Loss on Securities | $ 94.4
Percent of Fixed Maturity Securities in Unrealized Loss Position | 32.20%

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