v3.2.0.727

Shareholders' equity Shareholders' Equity (Tables) | 6 Months Ended
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Jun. 30, 2015
Shareholders' equity [Abstract] |
Dividends Declared [Table Text Block] | The following table presents dividend distributions per Common Share in Swiss francs (CHF) and U.S. dollars (USD):
| Three Months Ended |  |  | Six Months Ended |
| June 30 |  |  | June 30 |
| 2015 |  |  | 2014 |  |  | 2015 |  |  | 2014 |
CHF |  |  | USD |  |  | CHF |  |  | USD |  |  | CHF |  |  | USD |  |  | CHF |  |  | USD |
Dividends – par value reduction | — |  |  | $ |  |  |  | 0.58 |  |  | $ | 0.65 |  |  | 0.62 |  |  | $ | 0.65 |  |  | 1.03 |  |  | $ | 1.16 |
Dividends – distributed from capital contribution reserves | 0.62 |  |  | 0.67 |  |  | — |  |  | — |  |  | 0.62 |  |  | 0.67 |  |  | 0.20 |  |  | 0.24 |
Total dividend distributions per common share | 0.62 |  |  | $ | 0.67 |  |  | 0.58 |  |  | $ | 0.65 |  |  | 1.24 |  |  | $ | 1.32 |  |  | 1.23 |  |  | $ | 1.40 |
Share Repurchase Program [Table Text Block] | The following table presents repurchases of ACE's Common Shares conducted in a series of open market transactions under the Board authorizations:
(in millions of U.S. dollars, except share data) | Three Months Ended June 30 |  |  | Six Months Ended June 30 |
2015 |  |  | 2014 |  |  | 2015 |  |  | 2014 |
Number of shares repurchased | 3,650,200 |  |  | 2,306,000 |  |  | 6,677,663 |  |  | 5,793,882 |
Cost of shares repurchased | $ | 394 |  |  | $ | 237 |  |  | $ | 734 |  |  | $ | 569 |
Repurchase authorization remaining at end of period | $ | 766 |  |  | $ | 1,374 |  |  | $ | 766 |  |  | $ | 1,374 |

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- Definition Table showing information related to share repurchase programs [Table Text Block] + References No definition available. + Details
Name: | ace_ShareRepurchaseProgramTableTextBlock
Namespace Prefix: | ace_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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- Definition Shareholders' Equity [Abstract] + References No definition available. + Details
Name: | ace_ShareholdersequityAbstract
Namespace Prefix: | ace_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Tabular disclosure of information related to dividends declared, including paid and unpaid dividends. + References No definition available. + Details
Name: | us-gaap_DividendsDeclaredTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration