XML 156 R129.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Segment Information (Operations By Segment) (Detail) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Derivative, Gain (Loss) on Derivative, Net |  |  |  |  |  |  |  |  |  | $ 87 | $ (126) | $ (193)
Net premiums written |  |  |  |  |  |  |  |  |  | 29,244 | 28,145 | 17,713
Net premiums earned |  | $ 7,218 | $ 7,807 | $ 7,237 | $ 6,772 | $ 7,059 | $ 7,688 | $ 7,405 | $ 6,597 | 29,034 | 28,749 | 17,213
Losses and loss expenses |  | 4,272 | 6,247 | 4,146 | 3,789 | 3,855 | 4,269 | 4,254 | 3,674 | 18,454 | 16,052 | 9,484
Policy benefits |  | 176 | 169 | 163 | 168 | 161 | 155 | 146 | 126 | 676 | 588 | 543
Policy Acquisition Costs |  |  |  |  |  |  |  |  |  | 5,781 | 5,904 | 2,941
Administrative expenses |  |  |  |  |  |  |  |  |  | 2,833 | 3,081 | 2,270
Underwriting income (loss) |  |  |  |  |  |  |  |  |  | 1,290 | 3,124 | 1,975
Net Investment Income |  | 797 | 813 | 770 | 745 | 744 | 739 | 708 | 674 | 3,125 | 2,865 | 2,194
Other (Income) Expense |  |  |  |  |  |  |  |  |  | (400) | (222) | (51)
Segment Underwriting Income Loss and Net Investment Income Loss |  |  |  |  |  |  |  |  |  | 4,555 | 6,192 | 4,049
Net realized gains (losses) including OTTI |  | 0 | (10) | 101 | (7) | 365 | 100 | (216) | (394) | 84 | (145) | (420)
Interest expense |  |  |  |  |  |  |  |  |  | 607 | 605 | 300
Other (income) expense |  |  |  |  |  |  |  |  |  | (400) | (222) | (51)
Amortization of Purchased Intangibles |  |  |  |  |  |  |  |  |  | 260 | 19 | 171
Chubb integration expenses |  |  |  |  |  |  |  |  |  | 310 | 492 | 33
(Gains) losses from fair value changes in separate account assets | [1] |  |  |  |  |  |  |  |  | 97 | 11 | (19)
Income tax expense (benefit) |  |  |  |  |  |  |  |  |  | (139) | 815 | 462
Net income |  | $ 1,533 | $ (70) | $ 1,305 | $ 1,093 | $ 1,610 | $ 1,360 | $ 726 | $ 439 | 3,861 | 4,135 | 2,834
North America Commercial P&C Insurance |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Net premiums written |  |  |  |  |  |  |  |  |  | 12,028 | 11,740 | 5,715
Net premiums earned |  |  |  |  |  |  |  |  |  | 12,191 | 12,217 | 5,634
Losses and loss expenses |  |  |  |  |  |  |  |  |  | 8,287 | 7,439 | 3,661
Policy benefits |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
Policy Acquisition Costs |  |  |  |  |  |  |  |  |  | 1,873 | 2,023 | 531
Administrative expenses |  |  |  |  |  |  |  |  |  | 981 | 1,125 | 621
Underwriting income (loss) |  |  |  |  |  |  |  |  |  | 1,050 | 1,630 | 821
Net Investment Income |  |  |  |  |  |  |  |  |  | 1,961 | 1,860 | 1,032
Other (Income) Expense |  |  |  |  |  |  |  |  |  | 1 | (2) | (7)
Segment Underwriting Income Loss and Net Investment Income Loss |  |  |  |  |  |  |  |  |  | 3,010 | 3,492 | 1,860
Amortization of Purchased Intangibles |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
North American Personal P&C [Member] |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Net premiums written |  |  |  |  |  |  |  |  |  | 4,533 | 4,153 | 1,192
Net premiums earned |  |  |  |  |  |  |  |  |  | 4,399 | 4,319 | 948
Losses and loss expenses |  |  |  |  |  |  |  |  |  | 3,265 | 2,558 | 590
Policy benefits |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
Policy Acquisition Costs |  |  |  |  |  |  |  |  |  | 899 | 966 | 69
Administrative expenses |  |  |  |  |  |  |  |  |  | 264 | 363 | 123
Underwriting income (loss) |  |  |  |  |  |  |  |  |  | (29) | 432 | 166
Net Investment Income |  |  |  |  |  |  |  |  |  | 226 | 207 | 25
Other (Income) Expense |  |  |  |  |  |  |  |  |  | 4 | 6 | 2
Segment Underwriting Income Loss and Net Investment Income Loss |  |  |  |  |  |  |  |  |  | 177 | 614 | 111
Amortization of Purchased Intangibles |  |  |  |  |  |  |  |  |  | 16 | 19 | 78
North America Agricultural Insurance |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Segment Income Loss Including Gains Losses On Crop Derivatives |  |  |  |  |  |  |  |  |  | 392 |  |
Derivative, Gain (Loss) on Derivative, Net |  |  |  |  |  |  |  |  |  | 7 |  |
Net premiums written |  |  |  |  |  |  |  |  |  | 1,516 | 1,328 | 1,346
Net premiums earned |  |  |  |  |  |  |  |  |  | 1,508 | 1,316 | 1,364
Losses and loss expenses |  |  |  |  |  |  |  |  |  | 1,036 | 893 | 1,088
Policy benefits |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
Policy Acquisition Costs |  |  |  |  |  |  |  |  |  | 81 | 83 | 69
Administrative expenses |  |  |  |  |  |  |  |  |  | (8) | (6) | 1
Underwriting income (loss) |  |  |  |  |  |  |  |  |  | 399 | 346 | 206
Net Investment Income |  |  |  |  |  |  |  |  |  | 25 | 20 | 23
Other (Income) Expense |  |  |  |  |  |  |  |  |  | 2 | 1 | 1
Segment Underwriting Income Loss and Net Investment Income Loss |  |  |  |  |  |  |  |  |  | 393 | 336 | 198
Amortization of Purchased Intangibles |  |  |  |  |  |  |  |  |  | 29 | 29 | 30
Overseas General Insurance |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Net premiums written |  |  |  |  |  |  |  |  |  | 8,341 | 8,124 | 6,634
Net premiums earned |  |  |  |  |  |  |  |  |  | 8,131 | 8,132 | 6,471
Losses and loss expenses |  |  |  |  |  |  |  |  |  | 4,281 | 4,005 | 3,052
Policy benefits |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
Policy Acquisition Costs |  |  |  |  |  |  |  |  |  | 2,221 | 2,136 | 1,581
Administrative expenses |  |  |  |  |  |  |  |  |  | 982 | 1,057 | 997
Underwriting income (loss) |  |  |  |  |  |  |  |  |  | 647 | 934 | 841
Net Investment Income |  |  |  |  |  |  |  |  |  | 610 | 600 | 534
Other (Income) Expense |  |  |  |  |  |  |  |  |  | (4) | (11) | (17)
Segment Underwriting Income Loss and Net Investment Income Loss |  |  |  |  |  |  |  |  |  | 1,216 | 1,497 | 1,331
Amortization of Purchased Intangibles |  |  |  |  |  |  |  |  |  | 45 | 48 | 61
Global Reinsurance |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Net premiums written |  |  |  |  |  |  |  |  |  | 685 | 676 | 828
Net premiums earned |  |  |  |  |  |  |  |  |  | 704 | 710 | 849
Losses and loss expenses |  |  |  |  |  |  |  |  |  | 561 | 325 | 290
Policy benefits |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
Policy Acquisition Costs |  |  |  |  |  |  |  |  |  | 177 | 187 | 214
Administrative expenses |  |  |  |  |  |  |  |  |  | 44 | 52 | 49
Underwriting income (loss) |  |  |  |  |  |  |  |  |  | (78) | 146 | 296
Net Investment Income |  |  |  |  |  |  |  |  |  | 273 | 263 | 300
Other (Income) Expense |  |  |  |  |  |  |  |  |  | (1) | (4) | (6)
Segment Underwriting Income Loss and Net Investment Income Loss |  |  |  |  |  |  |  |  |  | 196 | 413 | 602
Amortization of Purchased Intangibles |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
Life Insurance |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Management underwriting income loss Insurance |  |  |  |  |  |  |  |  |  | 263 |  |
Net premiums written |  |  |  |  |  |  |  |  |  | 2,141 | 2,124 | 1,998
Net premiums earned |  |  |  |  |  |  |  |  |  | 2,101 | 2,055 | 1,947
Losses and loss expenses |  |  |  |  |  |  |  |  |  | 739 | 663 | 601
Policy benefits |  |  |  |  |  |  |  |  |  | 676 | 588 | 543
Policy Acquisition Costs |  |  |  |  |  |  |  |  |  | 530 | 509 | 476
Administrative expenses |  |  |  |  |  |  |  |  |  | 303 | 307 | 291
Underwriting income (loss) |  |  |  |  |  |  |  |  |  | (147) | (12) | 36
Net Investment Income |  |  |  |  |  |  |  |  |  | 313 | 283 | 265
Other (Income) Expense |  |  |  |  |  |  |  |  |  | (84) | 5 | 23
Segment Underwriting Income Loss and Net Investment Income Loss |  |  |  |  |  |  |  |  |  | 248 | 263 | 276
Amortization of Purchased Intangibles |  |  |  |  |  |  |  |  |  | 2 | 3 | 2
(Gains) losses from fair value changes in separate account assets |  |  |  |  |  |  |  |  |  | 97 |  |
Corporate and Other |  |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Net premiums written |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
Net premiums earned |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
Losses and loss expenses |  |  |  |  |  |  |  |  |  | 285 | 169 | 202
Policy benefits |  |  |  |  |  |  |  |  |  | 0 | 0 | 0
Policy Acquisition Costs |  |  |  |  |  |  |  |  |  | 0 | 0 | 1
Administrative expenses |  |  |  |  |  |  |  |  |  | 267 | 183 | 188
Underwriting income (loss) |  |  |  |  |  |  |  |  |  | (552) | (352) | (391)
Net Investment Income |  |  |  |  |  |  |  |  |  | (283) | (368) | 15
Other (Income) Expense |  |  |  |  |  |  |  |  |  | (318) | (217) | (47)
Segment Underwriting Income Loss and Net Investment Income Loss |  |  |  |  |  |  |  |  |  | (685) | (423) | (329)
Net realized gains (losses) including OTTI |  |  |  |  |  |  |  |  |  | 84 | (145) | (420)
Interest expense |  |  |  |  |  |  |  |  |  | 607 | 605 | 300
Amortization of Purchased Intangibles |  |  |  |  |  |  |  |  |  | 168 | (80) | 0
Chubb integration expenses |  |  |  |  |  |  |  |  |  | 310 | 492 | 33
Income tax expense (benefit) |  |  |  |  |  |  |  |  |  | (139) | 815 | 462
Net income |  |  |  |  |  |  |  |  |  | $ (1,379) | $ (2,480) | $ (1,544)
[1] | (1) Related to (gains) losses from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP.

X
- Definition Gains Losses On Fair Value Changes In Separate Account Assets + References No definition available. + Details
Name: | cb_GainsLossesOnFairValueChangesInSeparateAccountAssets
Namespace Prefix: | cb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Management Underwriting Income Loss Insurance + References No definition available. + Details
Name: | cb_ManagementUnderwritingIncomeLossInsurance
Namespace Prefix: | cb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Segment Income Loss Including Gains Losses On Crop Derivatives + References No definition available. + Details
Name: | cb_SegmentIncomeLossIncludingGainsLossesOnCropDerivatives
Namespace Prefix: | cb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Segment Underwriting Income Loss, Net Investment Income Loss, and Other Income expense allocated to the segment + References No definition available. + Details
Name: | cb_SegmentUnderwritingIncomeLossandNetInvestmentIncomeLoss
Namespace Prefix: | cb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Earned premium less incurred losses, loss adjustment expenses, and other underwriting expenses. + References No definition available. + Details
Name: | cb_UnderwritingIncomeLossInsurance
Namespace Prefix: | cb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
Name: | us-gaap_AmortizationOfIntangibleAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Costs incurred to effect a business combination which have been expensed during the period. Such costs could include business integration costs, systems integration and conversion costs, and severance and other employee-related costs. + References No definition available. + Details
Name: | us-gaap_BusinessCombinationIntegrationRelatedCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of amortization expense (reversal of expense) for deferred policy acquisition costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(7)(a)) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 30 -Section 35 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=95462302&loc=d3e10157-158409 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column I)) -URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574960-122915 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-18(Column I)) -URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e575016-122915 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 20 -Section 45 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6480726&loc=d3e6691-158385 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=35755530&loc=d3e11264-158415 + Details
Name: | us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5618551-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
Name: | us-gaap_DerivativeGainLossOnDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (c)-(e) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(c),9(a)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27405-111563 + Details
Name: | us-gaap_GainLossOnInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.4) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_GeneralAndAdministrativeExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of the cost of borrowed funds accounted for as interest expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.9) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 + Details
Name: | us-gaap_InterestExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of expense (income) recognized due to changes in the accrued obligation to policyholders that relates to insured events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65670824&loc=d3e14764-158437 + Details
Name: | us-gaap_LiabilityForFuturePolicyBenefitsPeriodExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The portion of profit or loss for the period, net of income taxes, which is attributable to the parent. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(22)) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(18)) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(20)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_NetIncomeLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(2)) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16(Column G)) -URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574960-122915 + Details
Name: | us-gaap_NetInvestmentIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of income (expense) related to nonoperating activities, classified as other. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.9) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_OtherNonoperatingIncomeExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The net amount of other operating income and expenses, the components of which are not separately disclosed on the income statement, from items that are associated with the entity's normal revenue producing operations. + References No definition available. + Details
Name: | us-gaap_OtherOperatingIncomeExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.5) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6480758&loc=d3e6811-158387 + Details
Name: | us-gaap_PolicyholderBenefitsAndClaimsIncurredNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums earned. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.1) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13(c)) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 2 -Subparagraph (SX 210.12-17) -URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915 + Details
Name: | us-gaap_PremiumsEarnedNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, after premiums ceded to other entities and premiums assumed by the entity, of premiums written. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 + Details
Name: | us-gaap_PremiumsWrittenNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_SegmentReportingInformationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cb_SegmentNorthAmericaCommercialPCInsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cb_SegmentInsuranceNorthAmericanPersonalPCMemberMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cb_SegmentInsuranceNorthAmericanAgricultureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cb_SegmentInsuranceOverseasGeneralMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cb_SegmentGlobalReMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cb_SegmentLifeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=cb_SegmentCorporateAndOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |