v3.2.0.727
Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Operations) (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Jun. 30, 2015
Jun. 30, 2014
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]        
Net premiums written $ 4,784 $ 4,559 $ 8,860 $ 8,744
Net premiums earned 4,360 4,332 8,287 8,302
Net investment income 562 556 1,113 1,109
Equity in earnings of subsidiaries 0 0 0 0
Net realized gains (losses) including OTTI 126 (73) 37 (177)
Losses and loss expenses 2,417 2,388 4,539 4,549
Policy benefits 153 144 295 258
Policy acquisition costs and administrative expenses 1,305 1,324 2,566 2,587
Interest (income) expense 71 72 139 143
Other (income) expense 17 (25) 12 (42)
Income tax expense (benefit) 143 133 263 226
Net income (loss) 942 779 1,623 1,513
Comprehensive income (loss) 397 1,348 1,039 2,456
ACE Limited (Parent Guarantor)        
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]        
Net premiums written 0 0 0 0
Net premiums earned 0 0 0 0
Net investment income 0 1 1 1
Equity in earnings of subsidiaries 901 745 1,549 1,447
Net realized gains (losses) including OTTI 0 0 0 0
Losses and loss expenses 0 0 0 0
Policy benefits 0 0 0 0
Policy acquisition costs and administrative expenses 18 22 32 39
Interest (income) expense (7) (9) (15) (19)
Other (income) expense (57) (50) (98) (92)
Income tax expense (benefit) 5 4 8 7
Net income (loss) 942 779 1,623 1,513
Comprehensive income (loss) 397 1,348 1,039 2,456
ACE INA Holdings Inc (Subsidiary Issuer)        
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]        
Net premiums written 0 0 0 0
Net premiums earned 0 0 0 0
Net investment income 0 1 1 1
Equity in earnings of subsidiaries 296 231 500 411
Net realized gains (losses) including OTTI (2) 8 (2) 7
Losses and loss expenses 0 0 0 0
Policy benefits 0 0 0 0
Policy acquisition costs and administrative expenses 7 8 13 14
Interest (income) expense 69 70 138 141
Other (income) expense (4) 6 (7) 20
Income tax expense (benefit) (27) (25) (53) (55)
Net income (loss) 249 181 408 299
Comprehensive income (loss) (91) 511 (67) 777
Other ACE Limited Subsidiaries        
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]        
Net premiums written 4,784 4,559 8,860 8,744
Net premiums earned 4,360 4,332 8,287 8,302
Net investment income 562 554 1,111 1,107
Equity in earnings of subsidiaries 0 0 0 0
Net realized gains (losses) including OTTI 128 (81) 39 (184)
Losses and loss expenses 2,417 2,388 4,539 4,549
Policy benefits 153 144 295 258
Policy acquisition costs and administrative expenses 1,280 1,294 2,521 2,534
Interest (income) expense 9 11 16 21
Other (income) expense 78 19 117 30
Income tax expense (benefit) 165 154 308 274
Net income (loss) 948 795 1,641 1,559
Comprehensive income (loss) 403 1,364 1,057 2,502
Consolidating Adjustments and Eliminations        
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]        
Net premiums written 0 0 0 0
Net premiums earned 0 0 0 0
Net investment income 0 0 0 0
Equity in earnings of subsidiaries (1,197) (976) (2,049) (1,858)
Net realized gains (losses) including OTTI 0 0 0 0
Losses and loss expenses 0 0 0 0
Policy benefits 0 0 0 0
Policy acquisition costs and administrative expenses 0 0 0 0
Interest (income) expense 0 0 0 0
Other (income) expense 0 0 0 0
Income tax expense (benefit) 0 0 0 0
Net income (loss) (1,197) (976) (2,049) (1,858)
Comprehensive income (loss) $ (312) $ (1,875) $ (990) $ (3,279)