Equity (Reclassification out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total net unrealized investment gains (losses)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	$ 7,074	$ (54,472)	$ (2,549)
Accumulated Other   Comprehensive  Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	7,074	(54,472)	(2,549)
Amounts reclassified from AOCI | Total net unrealized investment gains (losses)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	(7,074)	54,472	(2,549)
Amounts reclassified from AOCI | Accumulated Other   Comprehensive  Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amounts reclassified from AOCI	(7,074)	54,472	(2,549)
Amounts reclassified from AOCI | Net unrealized investment gains (losses) on available-for-sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized Gain (Loss) on Investments	(7,236)	46,738	(13,340)
Amounts reclassified from AOCI | Currency/Interest Rate | Cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Unrealized Gain (Loss) on Investments	$ 162	$ 7,734	$ 15,889