Reserve for Property-Liability Insurance Claims and Claims Expense (Tables)

3 Months Ended

Mar. 31, 2018

Reserve for Property-Liability Insurance Claims and Claims Expense [Abstract]

Schedule of liability for unpaid claims and claims adjustment expense

Rollforward of the reserve for property and casualty insurance claims and claims expense
	Three months ended March 31,
($ in millions)	2018			2017
Balance as of January 1	$	26,325		$	25,250
Less reinsurance recoverables	6,471			6,184
Net balance as of January 1	19,854			19,066
SquareTrade acquisition as of January 3, 2017	—			17
Incurred claims and claims expense related to:
Current year	5,200			5,513
Prior years	(51		)	(97		)
Total incurred	5,149			5,416
Claims and claims expense paid related to:
Current year	2,260			2,239
Prior years	3,115			2,815
Total paid	5,375			5,054
Net balance as of March 31	19,628			19,445
Plus reinsurance recoverables	6,487			6,183
Balance as of March 31	$	26,115		$	25,628