Policyholder Contract Liabilities - Narrative (Details) - FHLB of Chicago - United Insurance - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank, amount of advances	$ 466.4	$ 614.5
Payments of FHLBank borrowings	$ 302.0	$ 381.1

Amount of cash outflow for repayment of Federal Home Loan Bank (FHLBank) borrowing, classified as financing activity.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

Name:	us-gaap_RepaymentsOfFederalHomeLoanBankBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration