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Acquisitions Acquisitions (narrative) (Details) - USD ($)
$ in Millions
3 Months Ended
Jan. 14, 2016
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
Business Acquisition [Line Items]        
Goodwill   $ 15,387   $ 15,332
The Chubb Corporation [Member]        
Business Acquisition [Line Items]        
Purchase price $ 29,500      
Cash consideration paid by Chubb Limited to common shareholders of Chubb Corp 14,300      
Equity Issued in Business Combination, Fair Value Disclosure 15,200      
Business Combination, Consideration Transferred 29,800      
Goodwill 10,500      
Additional Paid-in Capital [Member]        
Business Acquisition [Line Items]        
Attributed Value Equity Awards Assumed in Acquisition   (260) $ (310)  
Additional Paid-in Capital [Member] | The Chubb Corporation [Member]        
Business Acquisition [Line Items]        
Attributed Value Equity Awards Assumed in Acquisition $ 323 $ 0 $ 323