SCHEDULE IV - REINSURANCE (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Life insurance in force
Life insurance in force, Gross amount	$ 119,024us-gaap_LifeInsuranceInForceGross	$ 512,105us-gaap_LifeInsuranceInForceGross	$ 505,436us-gaap_LifeInsuranceInForceGross
Life insurance in force, Ceded to other companies	97,574us-gaap_LifeInsuranceInForceCeded	195,414us-gaap_LifeInsuranceInForceCeded	208,967us-gaap_LifeInsuranceInForceCeded
Life insurance in force, Assumed from other companies	305,313us-gaap_LifeInsuranceInForceAssumed	28,060us-gaap_LifeInsuranceInForceAssumed	28,211us-gaap_LifeInsuranceInForceAssumed
Life insurance in force, Net amount	326,763us-gaap_LifeInsuranceInForceNet	344,751us-gaap_LifeInsuranceInForceNet	324,680us-gaap_LifeInsuranceInForceNet
Life insurance in force, Percentage of amount assumed to net	93.40%	8.10%	8.70%
Premiums and contract charges
Premiums and contract charges, Goss amount	1,084us-gaap_DirectPremiumsEarned	2,093us-gaap_DirectPremiumsEarned	2,121us-gaap_DirectPremiumsEarned
Premiums and contract charges, Ceded to other companies	392	618	654
Premiums and contract charges, Assumed from other companies	744us-gaap_AssumedPremiumsEarned	192us-gaap_AssumedPremiumsEarned	155us-gaap_AssumedPremiumsEarned
Premiums and contract charges, Net amount	1,436all_PremiumsAndContractChargesEarnedNet	1,667all_PremiumsAndContractChargesEarnedNet	1,622all_PremiumsAndContractChargesEarnedNet
Premiums and contract charges, Percentage of amount assumed to net	51.80%us-gaap_PremiumsPercentageAssumedToNet	11.50%us-gaap_PremiumsPercentageAssumedToNet	9.60%us-gaap_PremiumsPercentageAssumedToNet
Reinsurance or coinsurance income netted against premiums ceded	0	0	0
Life insurance
Premiums and contract charges
Premiums and contract charges, Goss amount	1,022	1,969	1,978
Premiums and contract charges, Ceded to other companies	353	532	550
Premiums and contract charges, Assumed from other companies	674	125	95
Premiums and contract charges, Net amount	1,343	1,562	1,523
Premiums and contract charges, Percentage of amount assumed to net	50.20%	8.00%	6.20%
Accident and health insurance
Premiums and contract charges
Premiums and contract charges, Goss amount	62	124	143
Premiums and contract charges, Ceded to other companies	39	86	104
Premiums and contract charges, Assumed from other companies	70	67	60
Premiums and contract charges, Net amount	$ 93	$ 105	$ 99
Premiums and contract charges, Percentage of amount assumed to net	75.30%	63.80%	60.60%

Represents the amount of reinsurance or coinsurance income netted against premiums ceded.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of earned premiums and contract charges that are assumed and earned by another insurer as a result of reinsurance arrangements.

+ References

No definition available.

+ Details

Name:	all_CededPremiumsAndContractChargesEarned
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, after premiums and contract charges ceded to other entities and premiums and contract charges assumed by the entity, of premiums and contract charges earned.

+ References

No definition available.

+ Details

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Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of earned premiums assumed from other entities.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 17

-Article 12

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 235

-Section S99

-Paragraph 2

-Subparagraph (SX 210.12-17)

-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.1)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 605

-Section 50

-Paragraph 1

-Subparagraph (b),(c)(2)

-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 1

-Article 7

+ Details

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

- Definition

Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 17

-Article 12

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 235

-Section S99

-Paragraph 2

-Subparagraph (SX 210.12-17)

-URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.1)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 1

-Article 7

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 605

-Section 50

-Paragraph 1

-Subparagraph (b),(c)(1)

-URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547

+ Details

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

- Definition

Amount of life insurance issued and outstanding assumed from other entities. Includes, but not limited to, dividends and adjustments to face value.

+ References

+ Details

Name:	us-gaap_LifeInsuranceInForceAssumed
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of life insurance issued and outstanding ceded to other entities. Includes, but not limited to, dividends and adjustments to face value.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before contracts ceded to other entities and contracts assumed by the entity of life insurance issued and outstanding. Includes, but not limited to, dividends and adjustments to face value.

+ References

+ Details

Name:	us-gaap_LifeInsuranceInForceGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount after contracts ceded to other entities and contracts assumed by the entity of life insurance issued and outstanding. Includes, but not limited to, dividends and adjustments to face value.

+ References

+ Details

Name:	us-gaap_LifeInsuranceInForceNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Definition

Percentage of assumed life insurance issued and outstanding contracts to life insurance issued and outstanding after contracts ceded to other entities and contracts assumed by the entity. Includes, but not limited to, dividends and adjustments to face value.

+ References

+ Details

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

- Definition

Percentage of assumed premiums earned by the entity to net premiums earned.

+ References

+ Details

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

- Details

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

- Details

Name:	us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentAxis=us-gaap_AccidentAndHealthInsuranceSegmentMember
Namespace Prefix:
Data Type:	na
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- Details

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Data Type:	na
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