v3.2.0.727
Acquisitions (Detail) - USD ($)
$ / shares in Units, $ in Millions
Jun. 17, 2014
Jun. 30, 2015
Apr. 01, 2015
Dec. 31, 2014
Oct. 31, 2014
Jun. 30, 2014
 [4]
Apr. 28, 2014
Dec. 31, 2013
 [4]
Business Acquisition - To be acquired [Line Items]                
Share Price   $ 101.68            
Business Acquisition [Line Items]                
Unpaid losses and loss expenses   $ 38,230   $ 38,315        
Unearned premiums   8,879   8,222        
Insurance and reinsurance balances receivable   5,757   5,426        
Cash   $ 790 [1],[2]   $ 655 [1],[3]   $ 594   $ 579
The Siam Commercial Samaggi Insurance PCL [Member]                
Business Acquisition [Line Items]                
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage 32.17%           60.86%  
Business Acquisition, Purchase Price Allocation, Goodwill Amount             $ 46  
Business Acquisition, Purchase Price Allocation, Intangible Assets Other than Goodwill             $ 80  
Business Combination Total Ownership Percentage 93.03%              
Business Combination, Consideration Transferred $ 176              
Large Corporate P&C Business Of Itau Seguros [Member]                
Business Acquisition [Line Items]                
Business Acquisition, Purchase Price Allocation, Goodwill Amount         $ 449      
Business Acquisition, Purchase Price Allocation, Intangible Assets Other than Goodwill         60      
Business Acquisition, Cost of Acquired Entity, Expected Cash Consideration         $ 610      
Fireman's Fund high net worth personal lines [Member]                
Business Acquisition [Line Items]                
Business Acquisition, Purchase Price Allocation, Goodwill Amount     $ 208          
Business Acquisition, Purchase Price Allocation, Intangible Assets Other than Goodwill     266          
Business Acquisition, Cost of Acquired Entity, Expected Cash Consideration     365          
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities     858          
Unpaid losses and loss expenses     402          
Unearned premiums     428          
Insurance and reinsurance balances receivable     128          
Cash     620          
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets     $ 749          
The Chubb Corporation [Member]                
Business Acquisition - To be acquired [Line Items]                
Business Acquisition, Cost of Acquired Entity, Expected Cash Consideration Per Share   $ 62.93            
Business Acquisition, Cost of Acquired Entity, Expected Stock Consideration Per Share   0.6019            
Business Acquisition Expected Outstanding Share Ownership To Be Held By Acquired Company Shareholders   137,000,000            
Business Acquisition, Expected Outstanding Share Ownership To Be Held By Acquired Company Shareholders   30.00%            
Business Acquisition, Cost of Acquired Entity, Expected Cash and Stock Consideration   $ 28,300            
Business Acquisition, Expected Financing of Acquisition with Issuance of Senior Notes   5,300            
Business Acquisition, Expected Financing Of Acquisition With Cash   $ 9,000            
[1] ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2015 and December 31, 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2] ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2015, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[3] ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[4] ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At June 30, 2014 and December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.