Chubb (CHB) 10-Q 7 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013
Document And Entity Information [Abstract]	'
Document Type	'10-Q
Amendment Flag	'false
Document Period End Date	30-Sep-13
Document Fiscal Year Focus	'2013
Document Fiscal Period Focus	'Q3
Trading Symbol	'CB
Entity Registrant Name	'CHUBB CORP
Entity Central Index Key	'0000020171
Current Fiscal Year End Date	'--12-31
Entity Filer Category	'Large Accelerated Filer
Entity Common Stock, Shares Outstanding	251,759,971

CONSOLIDATED_STATEMENTS_OF_INC

CONSOLIDATED STATEMENTS OF INCOME (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues	'	'	'	'
Premiums Earned	$3,027	$2,977	$9,026	$8,911
Investment Income	358	383	1,098	1,174
Other Revenues	'	2	12	7
Realized Investment Gains (Losses), Net	'	'	'	'
Total Other-Than-Temporary Impairment Losses on Investments	-4	-5	-11	-40
Other-Than-Temporary Impairment Losses on Investments Recognized in Other Comprehensive Income	'	-2	'	-4
Other Realized Investment Gains, Net	22	7	346	147
Total Realized Investment Gains, Net	18	'	335	103
Total Revenues	3,403	3,362	10,471	10,195
Losses and Expenses	'	'	'	'
Losses and Loss Expenses	1,600	1,597	4,862	5,164
Amortization of Deferred Policy Acquisition Costs	619	620	1,823	1,803
Other Insurance Operating Costs and Expenses	368	341	1,085	1,058
Investment Expenses	11	9	37	30
Other Expenses	3	3	20	9
Corporate Expenses	63	65	193	198
Total Losses and Expenses	2,664	2,635	8,020	8,262
Income Before Federal and Foreign Income Tax	739	727	2,451	1,933
Federal and Foreign Income Tax	198	194	675	490
Net Income	$541	$533	$1,776	$1,443
Net Income Per Share	'	'	'	'
Basic	$2.11	$1.99	$6.83	$5.32
Diluted	$2.10	$1.98	$6.80	$5.29
Dividends Declared Per Share	$0.44	$0.41	$1.32	$1.23

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]	'	'	'	'
Net Income	$541	$533	$1,776	$1,443
Other Comprehensive Income (Loss), Net of Tax	'	'	'	'
Change in Unrealized Appreciation of Investments	-3	229	-699	350
Change in Unrealized Other-Than-Temporary Impairment Losses on Investments	'	'	'	2
Foreign Currency Translation Gains (Losses)	-41	20	-63	-17
Change in Postretirement Benefit Costs Not Yet Recognized in Net Income	15	12	46	40
Total Other Comprehensive Income (Loss) Net of Tax	-29	261	-716	375
Comprehensive Income	$512	$794	$1,060	$1,818

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Assets	'	'
Short Term Investments	$1,881	$2,528
Fixed Maturities (cost $36,246 and $35,398)	37,610	38,076
Equity Securities (cost $1,163 and $1,244)	1,821	1,663
Other Invested Assets	1,665	1,954
TOTAL INVESTED ASSETS	42,977	44,221
Cash	46	50
Accrued Investment Income	428	424
Premiums Receivable	2,145	2,185
Reinsurance Recoverable on Unpaid Losses and Loss Expenses	1,778	1,941
Prepaid Reinsurance Premiums	306	337
Deferred Policy Acquisition Costs	1,268	1,206
Deferred Income Tax	202	'
Goodwill	467	467
Other Assets	1,450	1,353
TOTAL ASSETS	51,067	52,184
Liabilities	'	'
Unpaid Losses and Loss Expenses	23,397	23,963
Unearned Premiums	6,450	6,361
Long Term Debt	3,300	3,575
Dividend Payable to Shareholders	113	108
Deferred Income Tax	'	162
Accrued Expenses and Other Liabilities	2,186	2,188
TOTAL LIABILITIES	35,446	36,357
Shareholders' Equity	'	'
Common Stock - $1 Par Value; 371,980,460 Shares	372	372
Paid-In Surplus	150	178
Retained Earnings	21,443	20,009
Accumulated Other Comprehensive Income	715	1,431
Treasury Stock, at Cost - 120,220,489 and 110,217,445 Shares	-7,059	-6,163
TOTAL SHAREHOLDERS' EQUITY	15,621	15,827
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$51,067	$52,184

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, except Share data, unless otherwise specified
Statement Of Financial Position [Abstract]	'	'
Fixed Maturities, cost	$36,246	$35,398
Equity Securities, cost	$1,163	$1,244
Common Stock, Par Value	$1	$1
Common Stock, Shares Issued	371,980,460	371,980,460
Treasury Stock, Shares	120,220,489	110,217,445

CONSOLIDATED_STATEMENTS_OF_SHA

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $)	Total	Common Stock [Member]	Paid-In-Surplus [Member]	Retained Earnings [Member]	Unrealized Appreciation of Investments Including Unrealized Other-Than-Temporary Impairment Losses [Member]	Foreign Currency Translation Gains [Member]	Postretirement Benefit Costs Not Yet Recognized in Net Income [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock, at Cost [Member]
In Millions
Balance, Beginning of Year at Dec. 31, 2011	'	$372	$190	$18,903	$1,736	$146	($687)	'	($5,359)
Net Income	1,443	'	'	1,443	'	'	'	'	'
Repurchase of Shares	'	'	'	'	'	'	'	'	-907
Changes Related to Stock-Based Employee Compensation (includes tax benefit of $28 and $24)	'	'	-28	'	'	'	'	'	'
Change During Period, Net of Tax	375	'	'	'	352	-17	40	'	'
Dividends Declared (per share $1.32 and $1.23)	'	'	'	-331	'	'	'	'	'
Shares Issued Under Stock-Based Employee Compensation Plans	'	'	'	'	'	'	'	'	121
Balance, End of Period at Sep. 30, 2012	15,974	372	162	20,015	2,088	129	-647	1,570	-6,145
Balance, Beginning of Year at Dec. 31, 2012	15,827	372	178	20,009	2,013	135	-717	'	-6,163
Net Income	1,776	'	'	1,776	'	'	'	'	'
Repurchase of Shares	'	'	'	'	'	'	'	'	-975
Changes Related to Stock-Based Employee Compensation (includes tax benefit of $28 and $24)	'	'	-28	'	'	'	'	'	'
Change During Period, Net of Tax	-716	'	'	'	-699	-63	46	'	'
Dividends Declared (per share $1.32 and $1.23)	'	'	'	-342	'	'	'	'	'
Shares Issued Under Stock-Based Employee Compensation Plans	'	'	'	'	'	'	'	'	79
Balance, End of Period at Sep. 30, 2013	$15,621	$372	$150	$21,443	$1,314	$72	($671)	$715	($7,059)

CONSOLIDATED_STATEMENTS_OF_SHA1

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) (USD $)	9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Dividends Declared Per Share	$1.32	$1.23
Paid-In-Surplus [Member]	'	'
Tax Benefit, Stock-Based Employee Compensation	$28	$24
Retained Earnings [Member]	'	'
Dividends Declared Per Share	$1.32	$1.23

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash Flows from Operating Activities	'	'
Net Income	$1,776	$1,443
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities	'	'
Increase (Decrease) in Unpaid Losses and Loss Expenses, Net	-303	237
Increase in Unearned Premiums, Net	160	51
Decrease in Premiums Receivable	40	82
Change in Income Tax Payable or Recoverable	26	-1
Amortization of Premiums and Discounts on Fixed Maturities	138	121
Depreciation	42	39
Realized Investment Gains, Net	-335	-103
Other, Net	-223	-29
Net Cash Provided by Operating Activities	1,321	1,840
Cash Flows from Investing Activities	'	'
Proceeds from Fixed Maturities - Sales	1,781	1,838
Proceeds from Fixed Maturities - Maturities, Calls and Redemptions	3,525	2,985
Proceeds from Sales of Equity Securities	399	128
Purchases of Fixed Maturities	-6,464	-5,505
Purchases of Equity Securities	-98	-88
Investments in Other Invested Assets, Net	394	248
Decrease (Increase) in Short Term Investments, Net	629	-384
Change in Receivable or Payable from Security Transactions Not Settled, Net	88	136
Purchases of Property and Equipment, Net	-38	-31
Net Cash Provided by (Used in) Investing Activities	216	-673
Cash Flows from Financing Activities	'	'
Repayment of Long Term Debt	-275	'
Decrease in Funds Held Under Deposit Contracts	-5	-8
Proceeds from Issuance of Common Stock Under Stock-Based Employee Compensation Plans	38	68
Repurchase of Shares	-962	-903
Dividends Paid to Shareholders	-337	-329
Net Cash Used in Financing Activities	-1,541	-1,172
Net Decrease in Cash	-4	-5
Cash at Beginning of Year	50	58
Cash at End of Period	$46	$53

General

General	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
General	'
	1) General
	The accompanying condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) and include the accounts of The Chubb Corporation (Chubb) and its subsidiaries (collectively, the Corporation). Significant intercompany transactions have been eliminated in consolidation.
	The amounts included in this report are unaudited but include those adjustments, consisting of normal recurring items, that management considers necessary for a fair presentation. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes in the Notes to Consolidated Financial Statements included in the Corporation’s Annual Report on Form 10-K for the year ended December 31, 2012.

Invested_Assets

Invested Assets	9 Months Ended
	Sep. 30, 2013
Text Block [Abstract]	'
Invested Assets	'
	2) Invested Assets
	(a) The amortized cost and fair value of fixed maturities and equity securities were as follows:
		September 30, 2013
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Appreciation			Depreciation
		(in millions)
	Fixed maturities
	Tax exempt	$	18,210		$	905		$	164		$	18,951
	Taxable
	U.S. government and government agency and authority obligations		790			35			7			818
	Corporate bonds		8,838			399			77			9,160
	Foreign government and government agency obligations		6,773			238			24			6,987
	Residential mortgage-backed securities		302			23			1			324
	Commercial mortgage-backed securities		1,333			39			2			1,370
			18,036			734			111			18,659
	Total fixed maturities	$	36,246		$	1,639		$	275		$	37,610
	Equity securities	$	1,163		$	665		$	7		$	1,821
		December 31, 2012
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Appreciation			Depreciation
		(in millions)
	Fixed maturities
	Tax exempt	$	18,410		$	1,522		$	19		$	19,913
	Taxable
	U.S. government and government agency and authority obligations		973			66			—			1,039
	Corporate bonds		7,331			609			3			7,937
	Foreign government and government agency obligations		6,614			395			1			7,008
	Residential mortgage-backed securities		421			36			2			455
	Commercial mortgage-backed securities		1,649			76			1			1,724
			16,988			1,182			7			18,163
	Total fixed maturities	$	35,398		$	2,704		$	26		$	38,076
	Equity securities	$	1,244		$	453		$	34		$	1,663
	The fair value and amortized cost of fixed maturities at September 30, 2013 by contractual maturity were as follows:
		Fair			Amortized
		Value			Cost
		(in millions)
	Due in one year or less	$	2,180		$	2,149
	Due after one year through five years		14,165			13,581
	Due after five years through ten years		11,717			11,148
	Due after ten years		7,854			7,733
			35,916			34,611
	Residential mortgage-backed securities		324			302
	Commercial mortgage-backed securities		1,370			1,333
		$	37,610		$	36,246
	Actual maturities could differ from contractual maturities because borrowers may have the right to call or prepay obligations.
	The Corporation’s equity securities comprise a diversified portfolio of primarily U.S. publicly-traded common stocks.
	The Corporation is involved in the normal course of business with variable interest entities (VIEs) primarily as a passive investor in residential mortgage-backed securities, commercial mortgage-backed securities and private equity limited partnerships issued by third party VIEs. The Corporation is not the primary beneficiary of these VIEs. The Corporation’s maximum exposure to loss with respect to these investments is limited to the investment carrying values included in the Corporation’s consolidated balance sheet and any unfunded partnership commitments.
	(b) The components of unrealized appreciation or depreciation, including unrealized other-than-temporary impairment losses, of investments carried at fair value were as follows:
		September 30			December 31
		2013			2012
		(in millions)
	Fixed maturities
	Gross unrealized appreciation	$	1,639		$	2,704
	Gross unrealized depreciation		275			26
			1,364			2,678
	Equity securities
	Gross unrealized appreciation		665			453
	Gross unrealized depreciation		7			34
			658			419
			2,022			3,097
	Deferred income tax liability		708			1,084
	$	1,314		$	2,013
The following table summarizes, for all investment securities in an unrealized loss position at September 30, 2013, the aggregate fair value and gross unrealized depreciation, including unrealized other-than-temporary impairment losses, by investment category and length of time that individual securities have continuously been in an unrealized loss position.
	Less Than 12 Months						12 Months or More						Total
	Fair			Gross			Fair			Gross			Fair		Gross
	Value			Unrealized			Value			Unrealized			Value		Unrealized
				Depreciation						Depreciation					Depreciation
	(in millions)
Fixed maturities
Tax exempt	$	2,900		$	145		$	128		$	19		$	3,028	$	164
Taxable
U.S. government and government agency and authority obligations		139			3			34			4			173		7
Corporate bonds		2,512			75			42			2			2,554		77
Foreign government and government agency obligations		1,519			22			36			2			1,555		24
Residential mortgage-backed securities		3			—			15			1			18		1
Commercial mortgage-backed securities		94			2			16			—			110		2
		4,267			102			143			9			4,410		111
Total fixed maturities		7,167			247			271			28			7,438		275
Equity securities		45			4			11			3			56		7
	$	7,212		$	251		$	282		$	31		$	7,494	$	282
At September 30, 2013, approximately 1,090 individual fixed maturities and 10 individual equity securities were in an unrealized loss position. The Corporation does not have the intent to sell and it is not more likely than not that the Corporation will be required to sell these fixed maturities before the securities recover to their amortized cost value. In addition, the Corporation believes that none of the declines in the fair values of these fixed maturities relate to credit losses. The Corporation has the intent and ability to hold the equity securities in an unrealized loss position for a period of time sufficient to allow for the recovery of cost. The Corporation believes that none of the declines in the fair value of these fixed maturities and equity securities were other than temporary at September 30, 2013.
The following table summarizes, for all investment securities in an unrealized loss position at December 31, 2012, the aggregate fair value and gross unrealized depreciation, including unrealized other-than-temporary impairment losses, by investment category and length of time that individual securities have continuously been in an unrealized loss position.
	Less Than 12 Months						12 Months or More						Total
	Fair			Gross			Fair			Gross			Fair		Gross
	Value			Unrealized			Value			Unrealized			Value		Unrealized
				Depreciation						Depreciation					Depreciation
	(in millions)
Fixed maturities
Tax exempt	$	344		$	6		$	104		$	13		$	448	$	19
Taxable
U.S. government and government agency and authority obligations		28			—			20			—			48		—
Corporate bonds		289			2			14			1			303		3
Foreign government and government agency obligations		429			1			13			—			442		1
Residential mortgage-backed securities		1			—			19			2			20		2
Commercial mortgage-backed securities		105			1			3			—			108		1
		852			4			69			3			921		7
Total fixed maturities		1,196			10			173			16			1,369		26
Equity securities		182			21			63			13			245		34
	$	1,378		$	31		$	236		$	29		$	1,614	$	60
The change in unrealized appreciation or depreciation of investments carried at fair value, including the change in unrealized other-than-temporary impairment losses, was as follows:
	Periods Ended September 30
	Third Quarter						Nine Months
	2013			2012			2013			2012
	(in millions)
Change in unrealized appreciation of fixed maturities	$	(99	)	$	295		$	(1,314	)	$	411
Change in unrealized appreciation of equity securities		94			57			239			131
		(5	)		352			(1,075	)		542
Deferred income tax (credit)		(2	)		123			(376	)		190
	$	(3	)	$	229		$	(699	)	$	352
(c) Realized investment gains and losses were as follows:
	Periods Ended September 30
	Third Quarter						Nine Months
	2013			2012			2013			2012
	(in millions)
Fixed maturities
Gross realized gains	$	17		$	35		$	44		$	97
Gross realized losses		(22	)		(8	)		(32	)		(18	)
Other-than-temporary impairment losses		(2	)		(2	)		(2	)		(4	)
		(7	)		25			10			75
Equity securities
Gross realized gains		5			25			179			50
Gross realized losses		(1	)		—			(1	)		—
Other-than-temporary impairment losses		(2	)		(5	)		(9	)		(40	)
		2			20			169			10
Other invested assets		23			(45	)		156			18
	$	18		$	—		$	335		$	103
(d) As of September 30, 2013 and December 31, 2012, fixed maturities still held by the Corporation for which a portion of their other-than-temporary impairment losses were recognized in other comprehensive income had cumulative credit-related losses of $20 million and $22 million, respectively, recognized in net income.

Comprehensive_Income

Comprehensive Income	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]	'
Comprehensive Income	'
	3) Comprehensive Income
	Comprehensive income is defined as all changes in shareholders’ equity, except those arising from transactions with shareholders. Comprehensive income includes net income and other comprehensive income or loss, which for the Corporation consists of changes in unrealized appreciation or depreciation of investments carried at fair value, changes in unrealized other-than-temporary impairment losses of fixed maturities, changes in foreign currency translation gains or losses and changes in postretirement benefit costs not yet recognized in net income.
	The components of other comprehensive income or loss were as follows:
		Periods Ended September 30, 2013
		Third Quarter									Nine Months
		Before			Income			Net of			Before			Income			Net of
		Tax			Tax			Tax			Tax			Tax			Tax
		(in millions)
	Net unrealized holding losses arising during the period	$	(10	)	$	(3	)	$	(7	)	$	(896	)	$	(313	)	$	(583	)
	Reclassification adjustment for net realized gains (losses) included in net income		(5	)		(1	)		(4	)		179			63			116
	Net unrealized losses recognized in other comprehensive income or loss		(5	)		(2	)		(3	)		(1,075	)		(376	)		(699	)
	Postretirement benefit costs not yet recognized in net income arising during the period		1			1			—			2			1			1
	Reclassification adjustment for the amortization of net actuarial loss and prior service cost (a)		(23	)		(8	)		(15	)		(70	)		(25	)		(45	)
	Net change in postretirement benefit costs not yet recognized in net income		24			9			15			72			26			46
	Foreign currency translation losses		(64	)		(23	)		(41	)		(99	)		(36	)		(63	)
	Total other comprehensive loss	$	(45	)	$	(16	)	$	(29	)	$	(1,102	)	$	(386	)	$	(716	)
	(a) Postretirement benefit costs recognized in net income during the period are included among several of the loss and expense components presented in the Consolidated Statements of Income.

Segments_Information

Segments Information	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Segments Information	'
	4) Segments Information
	The principal business of the Corporation is the sale of property and casualty insurance. The profitability of the property and casualty insurance business depends on the results of both underwriting operations and investments, which are viewed as two distinct operations. The underwriting operations are managed and evaluated separately from the investment function.
	The property and casualty insurance subsidiaries underwrite most lines of property and casualty insurance. Underwriting operations consist of four separate business units: personal insurance, commercial insurance, specialty insurance and reinsurance assumed. The personal segment targets the personal insurance market. The personal classes include automobile, homeowners and other personal coverages. The commercial segment includes those classes of business that are generally available in broad markets and are of a more commodity nature. Commercial classes include multiple peril, casualty, workers’ compensation and property and marine. The specialty segment includes those classes of business that are available in more limited markets since they require specialized underwriting and claim settlement. Specialty classes include professional liability coverages and surety. The reinsurance assumed business is in runoff following the transfer of the ongoing business to a reinsurance company in 2005.
	Corporate and other includes investment income earned on corporate invested assets, corporate expenses and the results of the Corporation’s non-insurance subsidiaries.
	Revenues and income before income tax of each operating segment were as follows:
		Periods Ended
		September 30
		Third Quarter						Nine Months
		2013			2012			2013			2012
		(in millions)
	Revenues
	Property and casualty insurance
	Premiums earned
	Personal insurance	$	1,060		$	1,009		$	3,141		$	3,013
	Commercial insurance		1,321			1,299			3,928			3,890
	Specialty insurance		648			669			1,959			2,005
	Total insurance		3,029			2,977			9,028			8,908
	Reinsurance assumed		(2	)		—			(2	)		3
			3,027			2,977			9,026			8,911
	Investment income		352			373			1,076			1,145
	Total property and casualty insurance		3,379			3,350			10,102			10,056
	Corporate and other		6			12			34			36
	Realized investment gains, net		18			—			335			103
	Total revenues	$	3,403		$	3,362		$	10,471		$	10,195
	Income (loss) before income tax
	Property and casualty insurance
	Underwriting
	Personal insurance	$	108		$	155		$	333		$	374
	Commercial insurance		215			194			534			263
	Specialty insurance		108			63			299			194
	Total insurance		431			412			1,166			831
	Reinsurance assumed		—			15			10			34
			431			427			1,176			865
	Increase (decrease) in deferred policy acquisition costs		12			(9	)		69			15
	Underwriting income		443			418			1,245			880
	Investment income		342			364			1,042			1,117
	Other income (charges)		(3	)		1			11			6
	Total property and casualty insurance		782			783			2,298			2,003
	Corporate and other loss		(61	)		(56	)		(182	)		(173	)
	Realized investment gains, net		18			—			335			103
	Total income before income tax	$	739		$	727		$	2,451		$	1,933

Fair_Values_of_Financial_Instr

Fair Values of Financial Instruments	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Values of Financial Instruments	'
	5) Fair Values of Financial Instruments
	Fair values of financial instruments are determined by management using valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. Fair values are generally measured using quoted prices in active markets for identical assets or liabilities or other inputs, such as quoted prices for similar assets or liabilities, that are observable either directly or indirectly. In those instances where observable inputs are not available, fair values are measured using unobservable inputs for the asset or liability. Unobservable inputs reflect the Corporation’s own assumptions about the assumptions that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. Fair value estimates derived from unobservable inputs are affected by the assumptions used, including the discount rates and the estimated amounts and timing of future cash flows. The derived fair value estimates cannot be substantiated by comparison to independent markets and are not necessarily indicative of the amounts that would be realized in a current market exchange. Certain financial instruments, particularly insurance contracts, are excluded from fair value disclosure requirements.
	The methods and assumptions used to estimate the fair values of financial instruments are as follows:
		(i)	The carrying value of short term investments approximates fair value due to the short maturities of these investments.
		(ii)	Fair values for fixed maturities are determined by management, utilizing prices obtained from a third party, nationally recognized pricing service or, in the case of securities for which prices are not provided by a pricing service, from third party brokers. For fixed maturities that have quoted prices in active markets, market quotations are provided. For fixed maturities that do not trade on a daily basis, the pricing service and brokers provide fair value estimates using a variety of inputs including, but not limited to, benchmark yields, reported trades, broker/dealer quotes, issuer spreads, bids, offers, reference data, prepayment rates and measures of volatility. Management reviews on an ongoing basis the reasonableness of the methodologies used by the relevant pricing service and brokers. In addition, management, using the prices received for the securities from the pricing service and brokers, determines the aggregate portfolio price performance and reviews it against applicable indices. If management believes that significant discrepancies exist, it will discuss these with the relevant pricing service or broker to resolve the discrepancies.
		(iii)	Fair values of equity securities are determined by management, utilizing quoted market prices.
		(iv)	Fair values of warrants included in other invested assets are determined by management, utilizing an option pricing model.
		(v)	Fair values of long term debt issued by Chubb are determined by management, utilizing prices obtained from a third party, nationally recognized pricing service.
	The carrying values and fair values of financial instruments were as follows:
			September 30, 2013				December 31, 2012
			Carrying		Fair		Carrying		Fair
			Value		Value		Value		Value
			(in millions)
	Assets
	Invested assets
	Short term investments		$	1,881	$	1,881	$	2,528	$	2,528
	Fixed maturities			37,610		37,610		38,076		38,076
	Equity securities			1,821		1,821		1,663		1,663
	Other invested assets			—		—		46		46
	Liabilities
	Long term debt			3,300		3,834		3,575		4,372
	A pricing service provides fair value amounts for approximately 99% of the Corporation’s fixed maturities. The prices obtained from a pricing service and brokers generally are non-binding, but are reflective of current market transactions in the applicable financial instruments.
	At September 30, 2013 and December 31, 2012, the Corporation held an insignificant amount of financial instruments in its investment portfolio for which a lack of market liquidity impacted the determination of fair value.
	The fair value hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three broad levels as follows:
	Level 1 – Unadjusted quoted prices in active markets for identical financial instruments.
	Level 2 – Other inputs that are observable for the financial instrument, either directly or indirectly.
	Level 3 – Significant unobservable inputs.
	The fair value of financial instruments categorized based upon the lowest level of input that was significant to the fair value measurement was as follows:
			September 30, 2013
			Level 1		Level 2		Level 3		Total
			(in millions)
	Assets
	Short term investments		$	209	$	1,672	$	—	$	1,881
	Fixed maturities
	Tax exempt			—		18,946		5		18,951
	Taxable
	U.S. government and government agency and authority obligations			—		818		—		818
	Corporate bonds			—		9,031		129		9,160
	Foreign government and government agency obligations			—		6,977		10		6,987
	Residential mortgage-backed securities			—		318		6		324
	Commercial mortgage-backed securities			—		1,327		43		1,370
				—		18,471		188		18,659
	Total fixed maturities			—		37,417		193		37,610
	Equity securities			1,814		—		7		1,821
			$	2,023	$	39,089	$	200	$	41,312
	Liabilities
	Long term debt		$	—	$	3,834	$	—	$	3,834
			December 31, 2012
			Level 1		Level 2		Level 3		Total
			(in millions)
	Assets
	Short term investments		$	182	$	2,346	$	—	$	2,528
	Fixed maturities
	Tax exempt			—		19,907		6		19,913
	Taxable
	U.S. government and government agency and authority obligations			—		1,039		—		1,039
	Corporate bonds			—		7,779		158		7,937
	Foreign government and government agency obligations			—		7,008		—		7,008
	Residential mortgage-backed securities			—		446		9		455
	Commercial mortgage-backed securities			—		1,724		—		1,724
				—		17,996		167		18,163
	Total fixed maturities			—		37,903		173		38,076
	Equity securities			1,655		—		8		1,663
Other invested assets			—		—		46		46
		$	1,837	$	40,249	$	227	$	42,313
Liabilities
Long term debt		$	—	$	4,372	$	—	$	4,372

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	6) Earnings Per Share
	The following table sets forth the computation of basic and diluted earnings per share:
		Periods Ended
		September 30
		Third Quarter				Nine Months
		2013		2012		2013		2012
		(in millions, except for
		per share amounts)
	Basic earnings per share:
	Net income	$	541	$	533	$	1,776	$	1,443
	Weighted average shares outstanding		256		267.3		259.9		271
	Basic earnings per share	$	2.11	$	1.99	$	6.83	$	5.32
	Diluted earnings per share:
	Net income	$	541	$	533	$	1,776	$	1,443
	Weighted average shares outstanding		256		267.3		259.9		271
	Additional shares from assumed issuance of shares under stock- based compensation awards		1.1		1.9		1.2		1.9
	Weighted average shares and potential shares assumed outstanding for computing diluted earnings per share		257.1		269.2		261.1		272.9
	Diluted earnings per share	$	2.1	$	1.98	$	6.8	$	5.29

Invested_Assets_Tables

Invested Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Text Block [Abstract]	'
Amortized Cost and Fair Value of Fixed Maturities and Equity Securities	'
	(a) The amortized cost and fair value of fixed maturities and equity securities were as follows:
		September 30, 2013
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Appreciation			Depreciation
		(in millions)
	Fixed maturities
	Tax exempt	$	18,210		$	905		$	164		$	18,951
	Taxable
	U.S. government and government agency and authority obligations		790			35			7			818
	Corporate bonds		8,838			399			77			9,160
	Foreign government and government agency obligations		6,773			238			24			6,987
	Residential mortgage-backed securities		302			23			1			324
	Commercial mortgage-backed securities		1,333			39			2			1,370
			18,036			734			111			18,659
	Total fixed maturities	$	36,246		$	1,639		$	275		$	37,610
	Equity securities	$	1,163		$	665		$	7		$	1,821
		December 31, 2012
		Amortized			Gross			Gross			Fair
		Cost			Unrealized			Unrealized			Value
					Appreciation			Depreciation
		(in millions)
	Fixed maturities
	Tax exempt	$	18,410		$	1,522		$	19		$	19,913
	Taxable
	U.S. government and government agency and authority obligations		973			66			—			1,039
	Corporate bonds		7,331			609			3			7,937
	Foreign government and government agency obligations		6,614			395			1			7,008
	Residential mortgage-backed securities		421			36			2			455
	Commercial mortgage-backed securities		1,649			76			1			1,724
			16,988			1,182			7			18,163
	Total fixed maturities	$	35,398		$	2,704		$	26		$	38,076
	Equity securities	$	1,244		$	453		$	34		$	1,663
Fair Value and Amortized Cost of Fixed Maturities by Contractual Maturity	'
	The fair value and amortized cost of fixed maturities at September 30, 2013 by contractual maturity were as follows:
		Fair			Amortized
		Value			Cost
		(in millions)
	Due in one year or less	$	2,180		$	2,149
	Due after one year through five years		14,165			13,581
	Due after five years through ten years		11,717			11,148
	Due after ten years		7,854			7,733
			35,916			34,611
	Residential mortgage-backed securities		324			302
	Commercial mortgage-backed securities		1,370			1,333
		$	37,610		$	36,246
Components of Unrealized Appreciation or Depreciation of Investments	'
	(b) The components of unrealized appreciation or depreciation, including unrealized other-than-temporary impairment losses, of investments carried at fair value were as follows:
		September 30			December 31
		2013			2012
		(in millions)
	Fixed maturities
	Gross unrealized appreciation	$	1,639		$	2,704
	Gross unrealized depreciation		275			26
			1,364			2,678
	Equity securities
	Gross unrealized appreciation		665			453
	Gross unrealized depreciation		7			34
			658			419
			2,022			3,097
	Deferred income tax liability		708			1,084
		$	1,314		$	2,013
Fair Value and Gross Unrealized Depreciation of Investments in Unrealized Loss Position	'
	The following table summarizes, for all investment securities in an unrealized loss position at September 30, 2013, the aggregate fair value and gross unrealized depreciation, including unrealized other-than-temporary impairment losses, by investment category and length of time that individual securities have continuously been in an unrealized loss position.
		Less Than 12 Months						12 Months or More						Total
		Fair			Gross			Fair			Gross			Fair		Gross
		Value			Unrealized			Value			Unrealized			Value		Unrealized
					Depreciation						Depreciation					Depreciation
		(in millions)
	Fixed maturities
	Tax exempt	$	2,900		$	145		$	128		$	19		$	3,028	$	164
	Taxable
	U.S. government and government agency and authority obligations		139			3			34			4			173		7
	Corporate bonds		2,512			75			42			2			2,554		77
	Foreign government and government agency obligations		1,519			22			36			2			1,555		24
	Residential mortgage-backed securities		3			—			15			1			18		1
	Commercial mortgage-backed securities		94			2			16			—			110		2
			4,267			102			143			9			4,410		111
	Total fixed maturities		7,167			247			271			28			7,438		275
	Equity securities		45			4			11			3			56		7
		$	7,212		$	251		$	282		$	31		$	7,494	$	282
	The following table summarizes, for all investment securities in an unrealized loss position at December 31, 2012, the aggregate fair value and gross unrealized depreciation, including unrealized other-than-temporary impairment losses, by investment category and length of time that individual securities have continuously been in an unrealized loss position.
		Less Than 12 Months						12 Months or More						Total
		Fair			Gross			Fair			Gross			Fair		Gross
		Value			Unrealized			Value			Unrealized			Value		Unrealized
					Depreciation						Depreciation					Depreciation
		(in millions)
	Fixed maturities
	Tax exempt	$	344		$	6		$	104		$	13		$	448	$	19
	Taxable
	U.S. government and government agency and authority obligations		28			—			20			—			48		—
	Corporate bonds		289			2			14			1			303		3
	Foreign government and government agency obligations		429			1			13			—			442		1
	Residential mortgage-backed securities		1			—			19			2			20		2
	Commercial mortgage-backed securities		105			1			3			—			108		1
			852			4			69			3			921		7
	Total fixed maturities		1,196			10			173			16			1,369		26
	Equity securities		182			21			63			13			245		34
		$	1,378		$	31		$	236		$	29		$	1,614	$	60
Change in Unrealized Appreciation or Depreciation of Investments Carried at Fair Value	'
	The change in unrealized appreciation or depreciation of investments carried at fair value, including the change in unrealized other-than-temporary impairment losses, was as follows:
		Periods Ended September 30
		Third Quarter						Nine Months
		2013			2012			2013			2012
		(in millions)
	Change in unrealized appreciation of fixed maturities	$	(99	)	$	295		$	(1,314	)	$	411
	Change in unrealized appreciation of equity securities		94			57			239			131
			(5	)		352			(1,075	)		542
	Deferred income tax (credit)		(2	)		123			(376	)		190
		$	(3	)	$	229		$	(699	)	$	352
Realized Investment Gains and Losses	'
	(c) Realized investment gains and losses were as follows:
		Periods Ended September 30
		Third Quarter						Nine Months
		2013			2012			2013			2012
		(in millions)
	Fixed maturities
	Gross realized gains	$	17		$	35		$	44		$	97
	Gross realized losses		(22	)		(8	)		(32	)		(18	)
	Other-than-temporary impairment losses		(2	)		(2	)		(2	)		(4	)
			(7	)		25			10			75
	Equity securities
	Gross realized gains		5			25			179			50
	Gross realized losses		(1	)		—			(1	)		—
	Other-than-temporary impairment losses		(2	)		(5	)		(9	)		(40	)
			2			20			169			10
	Other invested assets		23			(45	)		156			18
		$	18		$	—		$	335		$	103

Comprehensive_Income_Tables

Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]	'
Components of Other Comprehensive Income or Loss	'
	The components of other comprehensive income or loss were as follows:
		Periods Ended September 30, 2013
		Third Quarter									Nine Months
		Before			Income			Net of			Before			Income			Net of
		Tax			Tax			Tax			Tax			Tax			Tax
		(in millions)
	Net unrealized holding losses arising during the period	$	(10	)	$	(3	)	$	(7	)	$	(896	)	$	(313	)	$	(583	)
	Reclassification adjustment for net realized gains (losses) included in net income		(5	)		(1	)		(4	)		179			63			116
	Net unrealized losses recognized in other comprehensive income or loss		(5	)		(2	)		(3	)		(1,075	)		(376	)		(699	)
	Postretirement benefit costs not yet recognized in net income arising during the period		1			1			—			2			1			1
	Reclassification adjustment for the amortization of net actuarial loss and prior service cost (a)		(23	)		(8	)		(15	)		(70	)		(25	)		(45	)
	Net change in postretirement benefit costs not yet recognized in net income		24			9			15			72			26			46
	Foreign currency translation losses		(64	)		(23	)		(41	)		(99	)		(36	)		(63	)
	Total other comprehensive loss	$	(45	)	$	(16	)	$	(29	)	$	(1,102	)	$	(386	)	$	(716	)
	(a) Postretirement benefit costs recognized in net income during the period are included among several of the loss and expense components presented in the Consolidated Statements of Income.

Segments_Information_Tables

Segments Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Revenues and Income Before Income Tax of Each Operating Segment	'
	Revenues and income before income tax of each operating segment were as follows:
		Periods Ended
		September 30
		Third Quarter						Nine Months
		2013			2012			2013			2012
		(in millions)
	Revenues
	Property and casualty insurance
	Premiums earned
	Personal insurance	$	1,060		$	1,009		$	3,141		$	3,013
	Commercial insurance		1,321			1,299			3,928			3,890
	Specialty insurance		648			669			1,959			2,005
	Total insurance		3,029			2,977			9,028			8,908
	Reinsurance assumed		(2	)		—			(2	)		3
			3,027			2,977			9,026			8,911
	Investment income		352			373			1,076			1,145
	Total property and casualty insurance		3,379			3,350			10,102			10,056
	Corporate and other		6			12			34			36
	Realized investment gains, net		18			—			335			103
	Total revenues	$	3,403		$	3,362		$	10,471		$	10,195
	Income (loss) before income tax
	Property and casualty insurance
	Underwriting
	Personal insurance	$	108		$	155		$	333		$	374
	Commercial insurance		215			194			534			263
	Specialty insurance		108			63			299			194
	Total insurance		431			412			1,166			831
	Reinsurance assumed		—			15			10			34
			431			427			1,176			865
	Increase (decrease) in deferred policy acquisition costs		12			(9	)		69			15
	Underwriting income		443			418			1,245			880
	Investment income		342			364			1,042			1,117
	Other income (charges)		(3	)		1			11			6
	Total property and casualty insurance		782			783			2,298			2,003
	Corporate and other loss		(61	)		(56	)		(182	)		(173	)
	Realized investment gains, net		18			—			335			103
	Total income before income tax	$	739		$	727		$	2,451		$	1,933

Fair_Values_of_Financial_Instr1

Fair Values of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Carrying Values and Fair Values of Financial Instruments	'
	The carrying values and fair values of financial instruments were as follows:
		September 30, 2013				December 31, 2012
		Carrying		Fair		Carrying		Fair
		Value		Value		Value		Value
		(in millions)
	Assets
	Invested assets
	Short term investments	$	1,881	$	1,881	$	2,528	$	2,528
	Fixed maturities		37,610		37,610		38,076		38,076
	Equity securities		1,821		1,821		1,663		1,663
	Other invested assets		—		—		46		46
	Liabilities
	Long term debt		3,300		3,834		3,575		4,372
Fair Value of Financial Instruments Categorized Based Upon Lowest Level of Input	'
	The fair value of financial instruments categorized based upon the lowest level of input that was significant to the fair value measurement was as follows:
		September 30, 2013
		Level 1		Level 2		Level 3		Total
		(in millions)
	Assets
	Short term investments	$	209	$	1,672	$	—	$	1,881
	Fixed maturities
	Tax exempt		—		18,946		5		18,951
	Taxable
	U.S. government and government agency and authority obligations		—		818		—		818
	Corporate bonds		—		9,031		129		9,160
	Foreign government and government agency obligations		—		6,977		10		6,987
	Residential mortgage-backed securities		—		318		6		324
	Commercial mortgage-backed securities		—		1,327		43		1,370
			—		18,471		188		18,659
	Total fixed maturities		—		37,417		193		37,610
	Equity securities		1,814		—		7		1,821
		$	2,023	$	39,089	$	200	$	41,312
	Liabilities
	Long term debt	$	—	$	3,834	$	—	$	3,834
		December 31, 2012
		Level 1		Level 2		Level 3		Total
		(in millions)
	Assets
	Short term investments	$	182	$	2,346	$	—	$	2,528
	Fixed maturities
	Tax exempt		—		19,907		6		19,913
	Taxable
	U.S. government and government agency and authority obligations		—		1,039		—		1,039
	Corporate bonds		—		7,779		158		7,937
	Foreign government and government agency obligations		—		7,008		—		7,008
	Residential mortgage-backed securities		—		446		9		455
	Commercial mortgage-backed securities		—		1,724		—		1,724
			—		17,996		167		18,163
	Total fixed maturities		—		37,903		173		38,076
	Equity securities		1,655		—		8		1,663
	Other invested assets		—		—		46		46
		$	1,837	$	40,249	$	227	$	42,313
	Liabilities
	Long term debt	$	—	$	4,372	$	—	$	4,372

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Computation of Basic and Diluted Earnings Per Share	'
	The following table sets forth the computation of basic and diluted earnings per share:
		Periods Ended
		September 30
		Third Quarter				Nine Months
		2013		2012		2013		2012
		(in millions, except for
		per share amounts)
	Basic earnings per share:
	Net income	$	541	$	533	$	1,776	$	1,443
	Weighted average shares outstanding		256		267.3		259.9		271
	Basic earnings per share	$	2.11	$	1.99	$	6.83	$	5.32
	Diluted earnings per share:
	Net income	$	541	$	533	$	1,776	$	1,443
	Weighted average shares outstanding		256		267.3		259.9		271
	Additional shares from assumed issuance of shares under stock- based compensation awards		1.1		1.9		1.2		1.9
	Weighted average shares and potential shares assumed outstanding for computing diluted earnings per share		257.1		269.2		261.1		272.9
	Diluted earnings per share	$	2.1	$	1.98	$	6.8	$	5.29

Invested_Assets_Amortized_Cost

Invested Assets - Amortized Cost and Fair Value of Fixed Maturities and Equity Securities (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Schedule of Available-For-Sale Securities [Line Items]	'	'
Tax exempt, Amortized Cost	$18,210	$18,410
Taxable, Amortized Cost	18,036	16,988
Tax exempt, Gross Unrealized Appreciation	905	1,522
Taxable, Gross Unrealized Appreciation	734	1,182
Tax exempt, Gross Unrealized Depreciation	164	19
Taxable, Gross Unrealized Depreciation	111	7
Tax exempt, Fair Value	18,951	19,913
Taxable, Fair Value	18,659	18,163
Total fixed maturities, Amortized Cost	36,246	35,398
Total fixed maturities, Gross Unrealized Appreciation	1,639	2,704
Total fixed maturities, Gross Unrealized Depreciation	275	26
Total fixed maturities, Fair Value	37,610	38,076
Equity securities, Amortized Cost	1,163	1,244
Equity securities, Gross Unrealized Appreciation	665	453
Equity securities, Gross Unrealized Depreciation	7	34
Equity securities, Fair Value	1,821	1,663
U.S. government and government agency and authority obligations [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Taxable, Amortized Cost	790	973
Taxable, Gross Unrealized Appreciation	35	66
Taxable, Gross Unrealized Depreciation	7	'
Taxable, Fair Value	818	1,039
Corporate bonds [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Taxable, Amortized Cost	8,838	7,331
Taxable, Gross Unrealized Appreciation	399	609
Taxable, Gross Unrealized Depreciation	77	3
Taxable, Fair Value	9,160	7,937
Foreign government and government agency obligations [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Taxable, Amortized Cost	6,773	6,614
Taxable, Gross Unrealized Appreciation	238	395
Taxable, Gross Unrealized Depreciation	24	1
Taxable, Fair Value	6,987	7,008
Residential mortgage-backed securities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Taxable, Amortized Cost	302	421
Taxable, Gross Unrealized Appreciation	23	36
Taxable, Gross Unrealized Depreciation	1	2
Taxable, Fair Value	324	455
Commercial mortgage-backed securities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Taxable, Amortized Cost	1,333	1,649
Taxable, Gross Unrealized Appreciation	39	76
Taxable, Gross Unrealized Depreciation	2	1
Taxable, Fair Value	$1,370	$1,724

Invested_Assets_Fair_Value_and

Invested Assets - Fair Value and Amortized Cost of Fixed Maturities by Contractual Maturity (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Schedule of Available-For-Sale Securities [Line Items]	'	'
Due in one year or less, Fair Value	$2,180	'
Due after one year through five years, Fair Value	14,165	'
Due after five years through ten years, Fair Value	11,717	'
Due after ten years, Fair Value	7,854	'
Subtotal fixed maturities, Fair Value	35,916	'
Total fixed maturities, Fair Value	37,610	38,076
Due in one year or less, Amortized Cost	2,149	'
Due after one year through five years, Amortized Cost	13,581	'
Due after five years through ten years, Amortized Cost	11,148	'
Due after ten years, Amortized Cost	7,733	'
Subtotal fixed maturities, Amortized Cost	34,611	'
Total fixed maturities, Amortized Cost	36,246	35,398
Residential mortgage-backed securities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Taxable, Fair Value	324	'
Taxable, Amortized Cost	302	'
Commercial mortgage-backed securities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Taxable, Fair Value	1,370	'
Taxable, Amortized Cost	$1,333	'

Invested_Assets_Components_of_

Invested Assets - Components of Unrealized Appreciation or Depreciation of Investments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Investments Debt And Equity Securities [Abstract]	'	'
Fixed maturities, Gross unrealized appreciation	$1,639	$2,704
Fixed maturities, Gross unrealized depreciation	275	26
Fixed maturities, Unrealized appreciation (depreciation), Net	1,364	2,678
Equity securities, Gross Unrealized Appreciation	665	453
Equity securities, Gross Unrealized Depreciation	7	34
Equity securities, Unrealized appreciation (depreciation), Net	658	419
Total fixed maturities and equity securities, Unrealized appreciation (depreciation), Net	2,022	3,097
Deferred income tax liability	708	1,084
Total fixed maturities and equity securities, Unrealized appreciation (depreciation), Net of tax	$1,314	$2,013

Invested_Assets_Fair_Value_and1

Invested Assets - Fair Value and Gross Unrealized Depreciation of Investments in Unrealized Loss Position (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	$7,212	$1,378
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	251	31
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	282	236
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	31	29
Investment securities, Continuous unrealized loss position, Fair Value, Total	7,494	1,614
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	282	60
Fixed maturities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	7,167	1,196
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	247	10
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	271	173
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	28	16
Investment securities, Continuous unrealized loss position, Fair Value, Total	7,438	1,369
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	275	26
Equity securities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	45	182
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	4	21
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	11	63
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	3	13
Investment securities, Continuous unrealized loss position, Fair Value, Total	56	245
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	7	34
Tax exempt [Member] | Fixed maturities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	2,900	344
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	145	6
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	128	104
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	19	13
Investment securities, Continuous unrealized loss position, Fair Value, Total	3,028	448
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	164	19
Taxable [Member] | Fixed maturities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	4,267	852
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	102	4
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	143	69
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	9	3
Investment securities, Continuous unrealized loss position, Fair Value, Total	4,410	921
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	111	7
U.S. government and government agency and authority obligations [Member] | Taxable [Member] | Fixed maturities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	139	28
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	3	'
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	34	20
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	4	'
Investment securities, Continuous unrealized loss position, Fair Value, Total	173	48
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	7	'
Corporate bonds [Member] | Taxable [Member] | Fixed maturities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	2,512	289
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	75	2
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	42	14
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	2	1
Investment securities, Continuous unrealized loss position, Fair Value, Total	2,554	303
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	77	3
Foreign government and government agency obligations [Member] | Taxable [Member] | Fixed maturities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	1,519	429
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	22	1
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	36	13
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	2	'
Investment securities, Continuous unrealized loss position, Fair Value, Total	1,555	442
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	24	1
Residential mortgage-backed securities [Member] | Taxable [Member] | Fixed maturities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	3	1
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	'	'
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	15	19
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	1	2
Investment securities, Continuous unrealized loss position, Fair Value, Total	18	20
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	1	2
Commercial mortgage-backed securities [Member] | Taxable [Member] | Fixed maturities [Member]	'	'
Schedule of Available-For-Sale Securities [Line Items]	'	'
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Fair Value	94	105
Investment securities, Continuous unrealized loss position, Less Than 12 Months, Gross Unrealized Depreciation	2	1
Investment securities, Continuous unrealized loss position, 12 Months or More, Fair Value	16	3
Investment securities, Continuous unrealized loss position, 12 Months or More, Gross Unrealized Depreciation	'	'
Investment securities, Continuous unrealized loss position, Fair Value, Total	110	108
Investment securities, Continuous unrealized loss position, Gross Unrealized Depreciation, Total	$2	$1

Invested_Assets_Additional_Inf

Invested Assets - Additional Information (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified	Investment
Investments Debt And Equity Securities [Abstract]	'	'
Approximate number of individual fixed maturities in unrealized loss position	1,090	'
Approximate number of individual equity securities in unrealized loss position	10	'
Cumulative credit-related losses recognized in net income	$20	$22

Invested_Assets_Change_in_Unre

Invested Assets - Change in Unrealized Appreciation or Depreciation of Investments Carried at Fair Value (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Investments Debt And Equity Securities [Abstract]	'	'	'	'
Change in unrealized appreciation of fixed maturities	($99)	$295	($1,314)	$411
Change in unrealized appreciation of equity securities	94	57	239	131
Change in unrealized appreciation of fixed maturities and equity securities	-5	352	-1,075	542
Deferred income tax (credit)	-2	123	-376	190
Total change in unrealized appreciation (depreciation) of fixed maturities and equity securities, Net of tax	($3)	$229	($699)	$352

Invested_Assets_Realized_Inves

Invested Assets - Realized Investment Gains and Losses (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Investments Debt And Equity Securities [Abstract]	'	'	'	'
Fixed maturities, Gross realized gains	$17	$35	$44	$97
Fixed maturities, Gross realized losses	-22	-8	-32	-18
Fixed maturities, Other-than-temporary impairment losses	-2	-2	-2	-4
Total fixed maturities	-7	25	10	75
Equity securities, Gross realized gains	5	25	179	50
Equity securities, Gross realized losses	-1	'	-1	'
Equity securities, Other-than-temporary impairment losses	-2	-5	-9	-40
Total equity securities	2	20	169	10
Other invested assets	23	-45	156	18
Total Realized Investment Gains, Net	$18	'	$335	$103

Comprehensive_Income_Component

Comprehensive Income - Components of Other Comprehensive Income or Loss (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]	'	'	'	'
Net unrealized holding losses arising during the period, Before Tax	($10)	'	($896)	'
Reclassification adjustment for net realized gains (losses) included in net income, Before Tax	-5	'	179	'
Net unrealized losses recognized in other comprehensive income or loss, Before Tax	-5	'	-1,075	'
Postretirement benefit costs not yet recognized in net income arising during the period, Before Tax	1	'	2	'
Reclassification adjustment for the amortization of net actuarial loss and prior service cost, Before Tax	-23	'	-70	'
Net change in postretirement benefit costs not yet recognized in net income, Before Tax	24	'	72	'
Foreign currency translation losses, Before Tax	-64	'	-99	'
Total other comprehensive loss, Before Tax	-45	'	-1,102	'
Net unrealized holding losses arising during the period, Income Tax	-3	'	-313	'
Reclassification adjustment for net realized gains (losses) included in net income, Income Tax	-1	'	63	'
Net unrealized losses recognized in other comprehensive income or loss, Income Tax	-2	'	-376	'
Postretirement benefit costs not yet recognized in net income arising during the period, Income Tax	1	'	1	'
Reclassification adjustment for the amortization of net actuarial loss and prior service cost, Income Tax	-8	'	-25	'
Net change in postretirement benefit costs not yet recognized in net income, Income Tax	9	'	26	'
Foreign currency translation losses, Income Tax	-23	'	-36	'
Total other comprehensive loss, Income Tax	-16	'	-386	'
Net unrealized holding losses arising during the period, Net of Tax	-7	'	-583	'
Reclassification adjustment for net realized gains (losses) included in net income, Net of Tax	-4	'	116	'
Net unrealized losses recognized in other comprehensive income or loss, Net of Tax	-3	229	-699	350
Postretirement benefit costs not yet recognized in net income arising during the period, Net of Tax	'	'	1	'
Reclassification adjustment for the amortization of net actuarial loss and prior service cost, Net of Tax	-15	'	-45	'
Net change in postretirement benefit costs not yet recognized in net income, Net of Tax	15	12	46	40
Foreign currency translation losses, Net of Tax	-41	20	-63	-17
Total Other Comprehensive Income (Loss) Net of Tax	($29)	$261	($716)	$375

Segments_Information_Additiona

Segments Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013
	Operations
	Business_Unit
Segment Reporting [Abstract]	'
Number of segment operations	2
Number of business units	4

Segments_Information_Revenues_

Segments Information - Revenues and Income Before Income Tax of Each Operating Segment (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues	'	'	'	'
Premiums earned related to insurance business	$3,029	$2,977	$9,028	$8,908
Investment Income	358	383	1,098	1,174
Premiums earned related to reinsurance assumed	-2	'	-2	3
Net Premiums earned	3,027	2,977	9,026	8,911
Corporate and other	6	12	34	36
Realized investment gains, net	18	'	335	103
Total revenues	3,403	3,362	10,471	10,195
Insurance underwriting income (loss)	431	412	1,166	831
Reinsurance assumed underwriting income	'	15	10	34
Underwriting income before deferred policy acquisition costs	431	427	1,176	865
Increase (decrease) in deferred policy acquisition costs	12	-9	69	15
Underwriting income	443	418	1,245	880
Total property and casualty insurance	782	783	2,298	2,003
Corporate and other loss	-61	-56	-182	-173
Realized investment gains, net	18	'	335	103
Income Before Federal and Foreign Income Tax	739	727	2,451	1,933
Personal insurance [Member]	'	'	'	'
Revenues	'	'	'	'
Premiums earned related to insurance business	1,060	1,009	3,141	3,013
Insurance underwriting income (loss)	108	155	333	374
Commercial insurance [Member]	'	'	'	'
Revenues	'	'	'	'
Premiums earned related to insurance business	1,321	1,299	3,928	3,890
Insurance underwriting income (loss)	215	194	534	263
Specialty insurance [Member]	'	'	'	'
Revenues	'	'	'	'
Premiums earned related to insurance business	648	669	1,959	2,005
Insurance underwriting income (loss)	108	63	299	194
Property and casualty insurance [Member]	'	'	'	'
Revenues	'	'	'	'
Investment Income	352	373	1,076	1,145
Total revenues	3,379	3,350	10,102	10,056
Investment income	342	364	1,042	1,117
Other income (charges)	($3)	$1	$11	$6

Fair_Values_of_Financial_Instr2

Fair Values of Financial Instruments - Carrying Values and Fair Values of Financial Instruments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Short term investments	$1,881	$2,528
Fixed maturities	37,610	38,076
Equity securities	1,821	1,663
Other invested assets	1,665	1,954
Long Term Debt	3,300	3,575
Carrying Value [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Short term investments	1,881	2,528
Fixed maturities	37,610	38,076
Equity securities	1,821	1,663
Other invested assets	'	46
Long Term Debt	3,300	3,575
Fair Value [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Short term investments	1,881	2,528
Fixed maturities	37,610	38,076
Equity securities	1,821	1,663
Other invested assets	'	46
Long Term Debt	$3,834	$4,372

Fair_Values_of_Financial_Instr3

Fair Values of Financial Instruments - Additional Information (Detail)	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Percentage of fair value amounts for fixed maturities provided by a pricing service	99.00%

Fair_Values_of_Financial_Instr4

Fair Values of Financial Instruments - Fair Value of Financial Instruments Categorized Based Upon Lowest Level of Input (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short term investments	$1,881	$2,528
Tax exempt, Fair Value	18,951	19,913
Taxable, Fair Value	18,659	18,163
Total fixed maturities, Fair Value	37,610	38,076
Equity securities	1,821	1,663
Other invested assets	1,665	1,954
Long Term Debt	3,300	3,575
Fair value [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short term investments	1,881	2,528
Tax exempt, Fair Value	18,951	19,913
Taxable, Fair Value	18,659	18,163
Total fixed maturities, Fair Value	37,610	38,076
Equity securities	1,821	1,663
Other invested assets	'	46
Total fixed maturities, equity securities and other invested assets, Fair value	41,312	42,313
Long Term Debt	3,834	4,372
U.S. government and government agency and authority obligations [Member] | Fair value [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	818	1,039
Corporate bonds [Member] | Fair value [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	9,160	7,937
Foreign government and government agency obligations [Member] | Fair value [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	6,987	7,008
Residential mortgage-backed securities [Member] | Fair value [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	324	455
Commercial mortgage-backed securities [Member] | Fair value [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	1,370	1,724
Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short term investments	209	182
Tax exempt, Fair Value	'	'
Taxable, Fair Value	'	'
Total fixed maturities, Fair Value	'	'
Equity securities	1,814	1,655
Other invested assets	'	'
Total fixed maturities, equity securities and other invested assets, Fair value	2,023	1,837
Long Term Debt	'	'
Level 1 [Member] | U.S. government and government agency and authority obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	'	'
Level 1 [Member] | Corporate bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	'	'
Level 1 [Member] | Foreign government and government agency obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	'	'
Level 1 [Member] | Residential mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	'	'
Level 1 [Member] | Commercial mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	'	'
Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short term investments	1,672	2,346
Tax exempt, Fair Value	18,946	19,907
Taxable, Fair Value	18,471	17,996
Total fixed maturities, Fair Value	37,417	37,903
Equity securities	'	'
Other invested assets	'	'
Total fixed maturities, equity securities and other invested assets, Fair value	39,089	40,249
Long Term Debt	3,834	4,372
Level 2 [Member] | U.S. government and government agency and authority obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	818	1,039
Level 2 [Member] | Corporate bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	9,031	7,779
Level 2 [Member] | Foreign government and government agency obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	6,977	7,008
Level 2 [Member] | Residential mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	318	446
Level 2 [Member] | Commercial mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	1,327	1,724
Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Short term investments	'	'
Tax exempt, Fair Value	5	6
Taxable, Fair Value	188	167
Total fixed maturities, Fair Value	193	173
Equity securities	7	8
Other invested assets	'	46
Total fixed maturities, equity securities and other invested assets, Fair value	200	227
Long Term Debt	'	'
Level 3 [Member] | U.S. government and government agency and authority obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	'	'
Level 3 [Member] | Corporate bonds [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	129	158
Level 3 [Member] | Foreign government and government agency obligations [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	10	'
Level 3 [Member] | Residential mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	6	9
Level 3 [Member] | Commercial mortgage-backed securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Taxable, Fair Value	$43	'

Earnings_Per_Share_Computation

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Basic earnings per share:	'	'	'	'
Net Income	$541	$533	$1,776	$1,443
Weighted average shares outstanding	256	267.3	259.9	271
Basic earnings per share	$2.11	$1.99	$6.83	$5.32
Diluted earnings per share:	'	'	'	'
Net Income	$541	$533	$1,776	$1,443
Weighted average shares outstanding	256	267.3	259.9	271
Additional shares from assumed issuance of shares under stock-based compensation awards	1.1	1.9	1.2	1.9
Weighted average shares and potential shares assumed outstanding for computing diluted earnings per share	257.1	269.2	261.1	272.9
Diluted earnings per share	$2.10	$1.98	$6.80	$5.29