XBRL Cloud: Business Report

Rendering

Component: (Network and Table)
Network	2416403 - Disclosure - Fair Value (Table of reconciliation for assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs) (Details) (http://www.cna.com/role/FairValueTableOfReconciliationForAssetsAndLiabilitiesMeasuredAtFairValueOnRecurringBasisUsingSignificantUnobservableInputsDetails)
Table	Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table]

Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0000021175 (http://www.sec.gov/CIK)

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	Period [Axis]
	2016-01-01 - 2016-12-31										2015-01-01 - 2015-12-31
	Asset Class [Axis]										Asset Class [Axis]
	Corporate and other bonds [Member]	States, municipalities and political subdivisions [Member]	Residential mortgage-backed [Member]	Commercial Mortgage Backed Securities [Member]	Other asset-backed [Member]	Total asset-backed [Member]	Fixed maturity securities [Member]	Equity securities [Member]	Life settlement contracts, included in Other assets [Member]	Asset Class [Domain]	Corporate and other bonds [Member]	States, municipalities and political subdivisions [Member]	Residential mortgage-backed [Member]	Commercial Mortgage Backed Securities [Member]	Other asset-backed [Member]	Total asset-backed [Member]	Fixed maturity securities [Member]	Equity securities [Member]	Life settlement contracts, included in Other assets [Member]	Asset Class [Domain]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	168,000,000	2,000,000	134,000,000	22,000,000	53,000,000	209,000,000	379,000,000	20,000,000	74,000,000	473,000,000	162,000,000	94,000,000	189,000,000	83,000,000	655,000,000	927,000,000	1,183,000,000	16,000,000	82,000,000	1,281,000,000
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	1,000,000	0	3,000,000	(1,000,000)	(2,000,000)	0	1,000,000	(1,000,000)	5,000,000	5,000,000	(2,000,000)	1,000,000	5,000,000	7,000,000	3,000,000	15,000,000	14,000,000	0	25,000,000	39,000,000
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	1,000,000	0	(5,000,000)	(1,000,000)	1,000,000	(5,000,000)	(4,000,000)	0	0	(4,000,000)	(3,000,000)	0	(3,000,000)	(4,000,000)	3,000,000	(4,000,000)	(7,000,000)	(1,000,000)	0	(8,000,000)
Purchases	163,000,000	0	15,000,000	32,000,000	86,000,000	133,000,000	296,000,000	0	0	296,000,000	65,000,000	0	81,000,000	23,000,000	130,000,000	234,000,000	299,000,000	4,000,000	0	303,000,000
Sales	(36,000,000)	0	0	0	(25,000,000)	(25,000,000)	(61,000,000)	0	0	(61,000,000)	(13,000,000)	0	0	0	(263,000,000)	(263,000,000)	(276,000,000)	0	0	(276,000,000)
Settlements	(103,000,000)	(1,000,000)	(14,000,000)	(17,000,000)	(1,000,000)	(32,000,000)	(136,000,000)	0	(21,000,000)	(157,000,000)	(35,000,000)	(10,000,000)	(35,000,000)	(17,000,000)	(52,000,000)	(104,000,000)	(149,000,000)	0	(33,000,000)	(182,000,000)
Transfers into Level 3	0	0	56,000,000	3,000,000	2,000,000	61,000,000	61,000,000	0	0	61,000,000	40,000,000	0	14,000,000	17,000,000	7,000,000	38,000,000	78,000,000	1,000,000	0	79,000,000
Transfers out of Level 3	(64,000,000)	0	(60,000,000)	(25,000,000)	(57,000,000)	(142,000,000)	(206,000,000)	0	0	(206,000,000)	(46,000,000)	(83,000,000)	(117,000,000)	(87,000,000)	(430,000,000)	(634,000,000)	(763,000,000)	0	0	(763,000,000)
Balance, Ending, Assets	130,000,000	1,000,000	129,000,000	13,000,000	57,000,000	199,000,000	330,000,000	19,000,000	58,000,000	407,000,000	168,000,000	2,000,000	134,000,000	22,000,000	53,000,000	209,000,000	379,000,000	20,000,000	74,000,000	473,000,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0	0	0	0	(2,000,000)	(3,000,000)	(5,000,000)	(2,000,000)	0	0	0	0	0	(2,000,000)	0	1,000,000	(1,000,000)