Range of interest rates used to calculate future benefit liabilities for disability insurance.

No definition available.

Name:	mlic_DisabilityInsuranceInterestRate
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Data Type:	num:percentItemType
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Period Type:	duration

- Definition

Range of interest rates used to calculate future benefit liabilities for individual and group traditional fixed annuities.

+ References

No definition available.

+ Details

Name:	mlic_IndividualAndGroupTraditionalFixedAnnuitiesInterestRate
Namespace Prefix:	mlic_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Range of credited interest rate applied to all applicable product policyholder deposits during the stated period.

+ References

No definition available.

+ Details

Name:	mlic_LiabilityForPolicyholderContractDepositsCreditedInterestRateAllApplicableProducts
Namespace Prefix:	mlic_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Range of interest rates used to calculate future benefit liabilities for non-medical health insurance.

+ References

No definition available.

+ Details

Name:	mlic_NonMedicalHealthInsuranceInterestRate
Namespace Prefix:	mlic_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

Name:	us-gaap_LiabilityForFuturePolicyBenefitsAndPolicyholderContractDepositsAssumptionsAbstract
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Ratio with total life insurance premiums in numerator and total GAAP premiums in the denominator.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

+ Details

Name:	us-gaap_LifePremiumsAsPercentageOfGrossPremiums
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This percent places participating policies in the numerator and insurance contracts in force in the denominator. Participating insurance contracts allow policyholders to share in the experience of the entity, primarily through policy dividends.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.14(b)(1))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 50

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6483535&loc=d3e16392-158451

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 14

-Subparagraph b

-Article 7

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Maximum interest rate for traditional life contracts in the range of interest rates used to calculate future benefits to be paid to or on behalf of policyholders and related expenses less the present value of future net premiums using assumptions such as estimates of expected investment yields, mortality, morbidity, terminations and expenses, applicable at the time the insurance contracts are made and costs of settling insured claims and costs incurred in the claims settlement process of traditional life.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph b

-Article 7

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.13(b))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 40

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6482852&loc=d3e14931-158439

+ Details

Name:	us-gaap_TraditionalLifeInterestRateHighEnd
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Minimum interest rate for traditional life contracts in the range of interest rates used to calculate future benefits to be paid to or on behalf of policyholders and related expenses less the present value of future net premiums using assumptions such as estimates of expected investment yields, mortality, morbidity, terminations and expenses, applicable at the time the insurance contracts are made and costs of settling insured claims and costs incurred in the claims settlement process of traditional life.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 13

-Subparagraph b

-Article 7

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 40

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6482852&loc=d3e14931-158439

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.(a),13(b))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_TraditionalLifeInterestRateLowEnd
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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Namespace Prefix:
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- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentAxis=mlic_NonparticipatingLifeInsurancePoliciesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentAxis=mlic_ParticipatingLifeInsurancePoliciesMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Insurance (Insurance Liabilities Assumptions and Ratios - Narrative) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Liability for Future Policy Benefits and Policyholder Account Balances [Abstract]
Participating business as a percentage of gross life insurance policies in-force	5.00%	5.00%
Participating business as a percentage of the gross life insurance premiums	27.00%	28.00%	29.00%
Minimum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest rate assumptions for the aggregate future policy benefit liabilities for individual and group traditional fixed annuities after annuitization	1.00%
Interest rate assumptions for the aggregate future policy benefit liabilities for non-medical health insurance	4.00%
Interest rate assumptions for the aggregate future policy benefit liabilities for disabled lives	3.00%
Interest rate range credited to policyholder account balances	1.00%
Maximum
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest rate assumptions for the aggregate future policy benefit liabilities for individual and group traditional fixed annuities after annuitization	11.00%
Interest rate assumptions for the aggregate future policy benefit liabilities for non-medical health insurance	7.00%
Interest rate assumptions for the aggregate future policy benefit liabilities for disabled lives	8.00%
Interest rate range credited to policyholder account balances	13.00%
Participating Life Insurance Policies [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest rate assumptions for the aggregate future policy benefit liabilities for traditional life insurance policies, low end	3.00%
Interest rate assumptions for the aggregate future policy benefit liabilities for traditional life insurance policies, high end	7.00%
Nonparticipating Life Insurance Policies [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Interest rate assumptions for the aggregate future policy benefit liabilities for traditional life insurance policies, low end	2.00%
Interest rate assumptions for the aggregate future policy benefit liabilities for traditional life insurance policies, high end	11.00%