Investments Investments (Rollforward of Allowance for Credit Losses) (Details) (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Jun. 30, 2020	Jun. 30, 2020
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning balance (1)	[1]	$ 28,332
Additions for credit losses not previously recorded		25,041	$ 56,412
Reduction for securities with credit losses due to intent to sell		(3,187)	(6,226)
Ending balance		50,186	50,186
Corporate Securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning balance (1)	[1]	28,332
Additions for credit losses not previously recorded		18,417	46,749
Reduction for securities with credit losses due to intent to sell		0	0
Ending balance		46,749	46,749
Commercial Mortgage Backed Securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning balance (1)	[1]	0
Additions for credit losses not previously recorded		5,847	8,338
Reduction for securities with credit losses due to intent to sell		(3,187)	(5,678)
Ending balance		2,660	2,660
Residential Mortgage Backed Securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning balance (1)	[1]	0
Additions for credit losses not previously recorded		777	777
Reduction for securities with credit losses due to intent to sell		0	0
Ending balance		777	777
Other Asset Backed Securities
Debt Securities, Available-for-sale, Allowance for Credit Loss [Line Items]
Beginning balance (1)	[1]	0
Additions for credit losses not previously recorded		0	548
Reduction for securities with credit losses due to intent to sell		0	(548)
Ending balance		$ 0	$ 0

[1] (1) The allowance for credit loss associated with available for sale fixed maturity securities was applied prospectively upon adoption of authoritative guidance effective January 1, 2020. See Note 1 for further details.