Reinsurance (Reinsurance amounts included in the Statements of Financial Position) (Details) - USD ($) $ in Thousands	Sep. 30, 2020		Dec. 31, 2019
Effects of Reinsurance [Line Items]
Reinsurance recoverables	$ 51,051,073	[1]	$ 40,710,159
Policy loans	1,322,235		1,314,064
Deferred policy acquisition costs	2,250,899	[1]	1,855,698
Other assets	412,805		441,543
Future policy benefits	35,511,798	[1]	25,258,673
Other liabilities	1,545,986	[1]	1,390,876
Impacts of Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables	51,051,073		40,710,159
Policy loans	(153,586)		(142,262)
Deferred policy acquisition costs	(6,552,679)		(6,989,618)
Deferred sales inducements	(438,280)		(515,968)
Other assets	239,345		258,427
Policyholders’ account balances	4,851,192		4,934,544
Future policy benefits	4,818,739		4,209,817
Other liabilities	1,040,850		884,641
Unaffiliated activity
Effects of Reinsurance [Line Items]
Reinsurance recoverables	362,700		156,700
Other assets	200		200
Future policy benefits	200		200
Other liabilities	$ 35,900		$ 43,100

[1] September 30, 2020 amounts include the impacts of the January 1, 2020 adoption of ASU 2016-13. See Note 2 for details.