Investments (Net Unrealized Gains Losses on Investments by Asset Class) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Gain (Loss) on Securities [Line Items]
Net Unrealized Gains (Losses) on Investments	$ 240,359	$ 2,369,109	$ 736,930
Fixed maturities | Available-for-sale | OTTI
Gain (Loss) on Securities [Line Items]
Net Unrealized Gains (Losses) on Investments			14,309
Fixed maturities | Available-for-sale | All other
Gain (Loss) on Securities [Line Items]
Net Unrealized Gains (Losses) on Investments			722,310
Fixed maturities | Available-for-sale | With an allowance
Gain (Loss) on Securities [Line Items]
Net Unrealized Gains (Losses) on Investments	3	2
Fixed maturities | Available-for-sale | Without an allowance
Gain (Loss) on Securities [Line Items]
Net Unrealized Gains (Losses) on Investments	215,813	2,407,478
Derivatives designated as cash flow hedges
Gain (Loss) on Securities [Line Items]
Net Unrealized Gains (Losses) on Investments	24,543	(43,000)	(287)
Affiliated notes
Gain (Loss) on Securities [Line Items]
Net Unrealized Gains (Losses) on Investments	0	4,629	598
Other investments
Gain (Loss) on Securities [Line Items]
Net Unrealized Gains (Losses) on Investments	$ 0	$ 0	$ 0