Reinsurance (Life Insurance In Force) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Reinsurance Disclosures [Abstract]
Direct gross life insurance face amount in force	$ 1,003,826,363	$ 951,643,226
Assumed gross life insurance face amount in force	39,643,598	40,546,369
Reinsurance ceded	(970,292,346)	(913,655,428)
Net life insurance face amount in force	$ 73,177,615	$ 78,534,167

Amount of life insurance issued and outstanding assumed from other entity, as disclosed in supplementary reinsurance information. Includes, but is not limited to, dividend and adjustment to face value.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column D
-Subsection 17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
-Paragraph 2
-Subparagraph (SX 210.12-17(Column D))
-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

+ Details

Name:	srt_LifeInsuranceInForceAssumed
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of life insurance issued and outstanding ceded to other entity, as disclosed in supplementary reinsurance information. Includes, but is not limited to, dividend and adjustment to face value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column C
-Subsection 17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
-Paragraph 2
-Subparagraph (SX 210.12-17(Column C))
-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

+ Details

Name:	srt_LifeInsuranceInForceCeded
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, before effect of reinsurance, of life insurance issued and outstanding, as disclosed in supplementary reinsurance information. Includes, but is not limited to, dividend and adjustment to face value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column B
-Subsection 17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
-Paragraph 2
-Subparagraph (SX 210.12-17(Column B))
-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

+ Details

Name:	srt_LifeInsuranceInForceGross
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after effect of reinsurance, of life insurance issued and outstanding, as disclosed in supplementary reinsurance information. Includes, but is not limited to, dividend and adjustment to face value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column E
-Subsection 17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
-Paragraph 2
-Subparagraph (SX 210.12-17(Column E))
-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

+ Details

Name:	srt_LifeInsuranceInForceNet
Namespace Prefix:	srt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_ReinsuranceDisclosuresAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration