Certain Long-Duration Contracts with Guarantees (Sales Inducements) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement in Deferred Sales Inducements [Roll Forward]
Beginning balance	$ 889,598	$ 1,020,786	$ 978,823
Capitalization	797	2,888	1,551
Amortization - Impact of assumption and experience unlocking and true-ups	100,222	(5,713)	145,141
Amortization - All other	(146,620)	(149,236)	(94,014)
Change in unrealized investment gains and losses	(31,273)	20,873	(10,715)
Ending balance	$ 812,724	$ 889,598	$ 1,020,786