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Assumed Life Reinsurance Programs Involving Minimum Benefit Guarantees Under Annuity Contracts (Narrative) (Detail) - USD ($) $ in Millions | Jun. 30, 2015 | Dec. 31, 2014 | Jun. 30, 2014 | Mar. 31, 2014
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Guaranteed Minimum Death Benefit [Member] |  |  |  |
Guaranteed Minimum Benefits [Line Items] |  |  |  |
Reported liabilities | $ 114 | $ 111 |  |
Guaranteed Living Benefit [Member] |  |  |  |
Guaranteed Minimum Benefits [Line Items] |  |  |  |
Reported liabilities | 615 | 663 | $ 486 | $ 483
Fair value derivative adjustment in liability | $ 347 | $ 406 |  |

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- Definition Guaranteed minimum benefit the portion of reported liabilities derived from a fair value derivative adjustment. + References No definition available. + Details
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Balance Type: | credit
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- Definition Guaranteed Minimum Benefits [Line Items] + References No definition available. + Details
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Namespace Prefix: | ace_
Data Type: | xbrli:stringItemType
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- Definition Sum of the amount of expected guaranteed benefits in excess of the projected account balances for minimum guaranteed benefit contracts, as of the balance sheet date, net of reinsurance recoverables, for all guaranteed benefit types. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 80 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6484115&loc=d3e19393-158473 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 20 -Section 55 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=6588021&loc=d3e7104-158389 + Details
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- Details
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- Details
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