XML 58 R47.htm IDEA: XBRL DOCUMENT v3.8.0.1
Claim and Claim Adjustment Expense Reserves - Reconciliation of Claim and Claim Adjustment Expense Reserves (Detail) - CNA Financial [Member] - USD ($)
$ in Millions
 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Liability for Claims and Claims Adjustment Expense [Line Items]    
Gross reserves, beginning of year $ 22,343 $ 22,663
Ceded reserves, beginning of year 4,094 4,087
Net reserves, beginning of year 18,249 18,576
Net incurred claim and claim adjustment expenses:    
Provision for insured events of current year 3,949 3,799
Decrease in provision for insured events of prior years (284) (332)
Amortization of discount 138 134
Total net incurred 3,803 3,601
Net payments attributable to:    
Current year events (560) (591)
Prior year events (3,401) (3,209)
Total net payments (3,961) (3,800)
Foreign currency translation adjustment and other 110 39
Net reserves, end of period 18,201 18,416
Ceded reserves, end of period 4,008 4,256
Gross reserves, end of period $ 22,209 $ 22,672