Nature of Operations and Significant Accounting Policies - Contractholder and Policyholder Liabilities (Details) - Individual Life insurance	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Contractholder and Policyholder Liabilities
Participating business as a percentage of life insurance in force (as a percent)	3.00%	4.00%	5.00%
Participating business as a percentage of life insurance policies in force (as a percent)	17.00%	18.00%	20.00%
Participating business as a percentage of life insurance premiums (as a percent)	17.00%	22.00%	24.00%

Percentage of participating insurance contract to insurance contracts in force.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 50
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=6483535&loc=d3e16392-158451

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.14(b)(1))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Name:	us-gaap_ParticipatingPoliciesAsPercentageOfGrossInsuranceInForce
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant