Dividends From Subsidiaries And Statutory Financial Information (Schedule of Combined Net Income and Policyholders' Surplus in Accordance with Statutory Accounting Practices) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Insurance [Abstract]
Amount available for dividend distribution without prior approval from regulatory authorities	$ 721,000
Net income	771,990	$ 601,564	$ 1,099,953
Policyholders' surplus	6,188,121	$ 6,013,062	$ 5,587,930
Increase in BIC's statutory capital and surplus	$ 200,000
Total Adjusted Capital percentage threshold	200.00%
BIC's Total Adjusted Capital balance	$ 5,989,000
BIC's Total Adjusted Capital balance as percentage of RBC Authorized Control Level	388.00%