Reinsurance (Reinsurance amounts included in the Statements of Financial Position) (Details) - USD ($) $ in Thousands	Jun. 30, 2020		Dec. 31, 2019
Effects of Reinsurance [Line Items]
Reinsurance recoverables	$ 52,917,099	[1]	$ 40,710,159
Policy loans	1,320,636		1,314,064
Deferred policy acquisition costs	2,120,749	[1]	1,855,698
Other assets	439,055		441,543
Future policy benefits	37,371,656	[1]	25,258,673
Other liabilities	1,473,182	[1]	1,390,876
Impacts of Reinsurance
Effects of Reinsurance [Line Items]
Reinsurance recoverables	52,917,099		40,710,159
Policy loans	(151,049)		(142,262)
Deferred policy acquisition costs	(6,779,267)		(6,989,618)
Deferred sales inducements	(471,999)		(515,968)
Other assets	257,709		258,427
Policyholders’ account balances	4,873,043		4,934,544
Future policy benefits	4,697,373		4,209,817
Other liabilities	995,122		884,641
Unaffiliated activity
Effects of Reinsurance [Line Items]
Reinsurance recoverables	416,400		156,700
Other assets	0		0
Future policy benefits	100		100
Other liabilities	$ 46,800		$ 43,100

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