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Investments (Fair Value and Gross Pre-Tax Net Unrealized Loss of Securities By Length of Time) (Details) - USD ($) $ in Thousands | Jun. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Percent Of Securities of Amortized Cost In An Unrealized Unrecognized Loss Position |  | 1.00% | 2.00%
AFS Fixed Income Securities [Member] |  |  |
AFS Fair Value, Less than 12 Months |  | $ 421,272 | $ 2,142,433
AFS Unrealized Losses, Less than 12 months | [1] | (4,902) | (36,948)
AFS Fair Value, 12 months or longer |  | 243,180 | 275,174
AFS Unrealized Losses, 12 months or longer | [1] | (3,978) | (8,119)
AFS Fair Value |  | 664,452 | 2,417,607
AFS Unrealized Losses | [1] | (8,880) | (45,067)
AFS Fixed Income Securities [Member] | U.S. Government and Government Agencies [Member] |  |  |
AFS Fair Value, Less than 12 Months |  | 0 | 6,693
AFS Unrealized Losses, Less than 12 months | [1] | 0 | (174)
AFS Fair Value, 12 months or longer |  | 5,508 | 23,163
AFS Unrealized Losses, 12 months or longer | [1] | (20) | (418)
AFS Fair Value |  | 5,508 | 29,856
AFS Unrealized Losses | [1] | (20) | (592)
AFS Fixed Income Securities [Member] | Foreign Government [Member] |  |  |
AFS Fair Value, Less than 12 Months |  |  | 12,208
AFS Unrealized Losses, Less than 12 months | [1] |  | (93)
AFS Fair Value, 12 months or longer |  |  | 1,482
AFS Unrealized Losses, 12 months or longer | [1] |  | (14)
AFS Fair Value |  |  | 13,690
AFS Unrealized Losses | [1] |  | (107)
AFS Fixed Income Securities [Member] | Obligations of States and Political Subdivisions [Member] |  |  |
AFS Fair Value, Less than 12 Months |  | 739 | 196,798
AFS Unrealized Losses, Less than 12 months | [1] | (6) | (2,074)
AFS Fair Value, 12 months or longer |  | 0 | 42,821
AFS Unrealized Losses, 12 months or longer | [1] | 0 | (557)
AFS Fair Value |  | 739 | 239,619
AFS Unrealized Losses | [1] | (6) | (2,631)
AFS Fixed Income Securities [Member] | Corporate Securities [Member] |  |  |
AFS Fair Value, Less than 12 Months |  | 94,964 | 1,041,952
AFS Unrealized Losses, Less than 12 months | [1] | (2,260) | (23,649)
AFS Fair Value, 12 months or longer |  | 46,527 | 78,953
AFS Unrealized Losses, 12 months or longer | [1] | (2,142) | (4,316)
AFS Fair Value |  | 141,491 | 1,120,905
AFS Unrealized Losses | [1] | (4,402) | (27,965)
AFS Fixed Income Securities [Member] | Collateralized Loan Obligations and Other Asset Backed Securities [Member] |  |  |
AFS Fair Value, Less than 12 Months |  | 231,823 | 516,106
AFS Unrealized Losses, Less than 12 months | [1] | (2,318) | (6,750)
AFS Fair Value, 12 months or longer |  | 151,572 | 16,800
AFS Unrealized Losses, 12 months or longer | [1] | (1,623) | (193)
AFS Fair Value |  | 383,395 | 532,906
AFS Unrealized Losses | [1] | (3,941) | (6,943)
AFS Fixed Income Securities [Member] | Commercial Mortgage Backed Securities [Member] |  |  |
AFS Fair Value, Less than 12 Months |  | 59,639 | 229,338
AFS Unrealized Losses, Less than 12 months | [1] | (183) | (2,548)
AFS Fair Value, 12 months or longer |  | 24,882 | 66,294
AFS Unrealized Losses, 12 months or longer | [1] | (54) | (1,200)
AFS Fair Value |  | 84,521 | 295,632
AFS Unrealized Losses | [1] | (237) | (3,748)
AFS Fixed Income Securities [Member] | Residential Mortgage Backed Securities [Member] |  |  |
AFS Fair Value, Less than 12 Months |  | 34,107 | 139,338
AFS Unrealized Losses, Less than 12 months | [1] | (135) | (1,660)
AFS Fair Value, 12 months or longer |  | 14,691 | 45,661
AFS Unrealized Losses, 12 months or longer | [1] | (139) | (1,421)
AFS Fair Value |  | 48,798 | 184,999
AFS Unrealized Losses | [1] | $ (274) | $ (3,081)
[1] | Gross unrealized losses include non-OTTI unrealized amounts and OTTI losses recognized in AOCI.

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