Company assumed recovery rate.

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- Definition

Credit losses recognized in net income for corporate securities, all or substantially all of which relates to below investment grade securities.

+ References

No definition available.

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- Definition

Equity Securities In Unrealized Loss Position Number

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No definition available.

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- Definition

Equity Securities Largest Single Unrealized Loss

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No definition available.

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- Definition

Equity Securities Total Number

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No definition available.

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- Definition

Fair value of securities transferred from Fixed maturities available for sale to Fixed maturities held to maturity

+ References

No definition available.

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- Definition

Number of fixed maturities in an unrealized loss position.

+ References

No definition available.

+ Details

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- Definition

Largest single unrealized loss in the fixed maturities.

+ References

No definition available.

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- Definition

Total number of fixed maturities.

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No definition available.

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- Definition

Moodys historical mean recovery rate.

+ References

No definition available.

+ Details

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- Definition

Credit losses recognized in net income for mortgage backed securities.

+ References

No definition available.

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- Definition

Percentage of mortgage-backed securities represented by investments in US Government Agency bonds.

+ References

No definition available.

+ Details

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- Definition

Net unrealized appreciation included in other comprehensive income relating to securities upon which a credit impairment was recorded.

+ References

No definition available.

+ Details

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- Definition

Net unrealized depreciation included in accumulated other comprehensive income relating to securities upon which a credit impairment was recorded.

+ References

No definition available.

+ Details

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- Definition

Value of outstanding derivative securities that permit the holder the right to purchase a percentage of equity from the issuer.

+ References

No definition available.

+ Details

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- Details

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

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- Definition

Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

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- Definition

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Investments which are not defined as or included in marketable (debt, equity, or other) securities whose use is restricted in whole or in part, generally by contractual agreements or regulatory requirements. For use in an unclassified balance sheet.

+ References

No definition available.

+ Details

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Investments (Narrative) (Detail) (USD $)	3 Months Ended
Investments (Narrative) (Detail) (USD $)	Mar. 31, 2015 Security	Mar. 31, 2014	Dec. 31, 2014	Mar. 27, 2015	Apr. 30, 2015	Apr. 14, 2015
Investment [Line Items]
Total number of fixed maturities	33,429ace_FixedMaturitiesTotalNumber
Largest single unrealized loss in the fixed maturities	$ 3,000,000
Number of equity securities in an unrealized loss position	78
Total number of equity securities	306ace_EquitySecuritiesTotalNumber
Largest single unrealized loss in the equity securities	1,000,000
Restricted assets in fixed maturities and short-term investments	16,500,000,000us-gaap_RestrictedInvestments		16,300,000,000us-gaap_RestrictedInvestments
Restricted assets in cash	102,000,000		117,000,000
Moodys Historical Mean Recovery Rate	42.00%ace_MoodysHistoricalMeanRecoveryRate
Company Assumed Recovery Rate	32.00%ace_CompanyAssumedRecoveryRate
Net unrealized depreciation included in AOCI	2,000,000		3,000,000
Investments in partially-owned insurance companies	590,000,000		504,000,000
Net unrealized appreciation (depreciation) included in OCI	(4,000,000)	(4,000,000)
Number of fixed maturities in an unrealized loss position	3,313
Credit losses recognized in net income for mortgage-backed securities	0	0
Credit losses recognized in net income for corporate securities	4,000,000	4,000,000
Percentage of mortgage-backed securities represented by investments in US government agency bonds	82.00%		83.00%
ABR Reinsurance Capital Holdings Ltd. [Member]
Investment [Line Items]
Investments in partially-owned insurance companies				70,000,000
Warrants & Rights Outstanding				0.50%
Subsequent Event [Member]
Investment [Line Items]
Fair value of securities transferred from AFS to HTM					1,800,000,000
Subsequent Event [Member] \| ABR Reinsurance Capital Holdings Ltd. [Member]
Investment [Line Items]
Equity Method Investment, Ownership Percentage						11.30%
Investments in partially-owned insurance companies						$ 20,000,000