Cincinnati Financial (CINF) 10-Q 24 Oct 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 21, 2013
Document Documentand 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	CINF
Entity Registrant Name	CINCINNATI FINANCIAL CORP
Entity Central Index Key	20286
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		163,830,717

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Investments
Fixed maturities, at fair value (amortized cost: 2013—$8,502; 2012—$8,222)	$9,038	$9,093
Equity securities, at fair value (cost: 2013—$2,471; 2012—$2,369)	3,984	3,373
Other invested assets	68	68
Total investments	13,090	12,534
Cash and cash equivalents	511	487
Investment income receivable	115	115
Finance receivable	79	75
Premiums receivable	1,393	1,214
Reinsurance recoverable	584	615
Prepaid reinsurance premiums	26	26
Deferred policy acquisition costs	576	470
Land, building and equipment, net, for company use (accumulated depreciation: 2013—$412; 2012—$397)	211	217
Other assets	54	61
Separate accounts	700	734
Total assets	17,339	16,548
Insurance reserves
Loss and loss expense reserves	4,307	4,230
Life policy and investment contract reserves	2,373	2,295
Unearned premiums	2,026	1,792
Other liabilities	639	660
Deferred income tax	542	453
Note payable	104	104
Long-term debt and capital lease obligations	832	827
Separate accounts	700	734
Total liabilities	11,523	11,095
Commitments and contingent liabilities (Note 12)	0	0
SHAREHOLDERS' EQUITY
Common stock, par value—$2 per share; (authorized: 2013 and 2012—500 million shares; issued and outstanding: 2013—198 million shares and 2012—197 million shares)	396	394
Paid-in capital	1,177	1,134
Retained earnings	4,214	4,021
Accumulated other comprehensive income	1,267	1,129
Treasury stock at cost (2013 and 2012—34 million shares)	-1,238	-1,225
Total shareholders' equity	5,816	5,453
Total liabilities and shareholders' equity	$17,339	$16,548

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, except Per Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$8,502	$8,222
Equity securities, cost	2,471	2,369
Land, building and equipment, accumulated depreciation	$412	$397
Common stock, par value	$2	$2
Common stock, authorized	500	500
Common stock, issued	198	197
Common stock, outstanding	198	197
Treasury stock, shares	34	34

Condensed_Consolidated_Stateme

Condensed 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
Earned premiums	$992	$889	$2,877	$2,605
Investment income, net of expenses	133	132	392	395
Realized investment gains, net	22	10	77	29
Fee revenues	2	1	6	4
Other revenues	3	3	7	8
Total revenues	1,152	1,035	3,359	3,041
BENEFITS AND EXPENSES
Insurance losses and policyholder benefits	642	571	1,841	1,840
Underwriting, acquisition and insurance expenses	312	296	919	857
Interest expense	13	14	40	41
Other operating expenses	3	2	12	10
Total benefits and expenses	970	883	2,812	2,748
INCOME BEFORE INCOME TAXES	182	152	547	293
PROVISION FOR INCOME TAXES
Current	46	34	137	60
Deferred	5	7	15	4
Total provision for income taxes	51	41	152	64
NET INCOME	$131	$111	$395	$229
PER COMMON SHARE
Net income-basic (in USD per share)	$0.80	$0.69	$2.42	$1.41
Net income-diluted (in USD per share)	$0.79	$0.68	$2.39	$1.40

Condensed_Consolidated_Stateme1

Condensed 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
NET INCOME	$131	$111	$395	$229
Unrealized gains on investments available-for-sale, net of tax of $22, $89, $61 and $150, respectively	40	164	113	278
Amortization of pension actuarial loss and prior service cost, net of tax of $1, $1, $3 and $2, respectively	1	1	4	3
Change in life deferred acquisition costs, life policy reserves and other, net of tax of $2, $(2), $10 and $(5), respectively	5	-4	21	-11
Other comprehensive income, net of tax	46	161	138	270
COMPREHENSIVE INCOME	$177	$272	$533	$499

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) (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 Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	$22	$89	$61	$150
Other Comprehensive Income Loss, Pension And Other Postretirement Benefit Plans, Net Actuarial Loss And Prior Service Cost Arising During Period, Tax	1	1	3	2
Other Comprehensive Income, Change in Life Deferred Acquisition Costs, Life Policy Reserves and Other, Tax	$2	($2)	$10	($5)

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Shareholders' Equity (USD $)	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income	Treasury Stock
In Millions
Balance at Dec. 31, 2010
Cumulative effect of a change in accounting for deferred policy acquisition costs, net of tax	($22)			($22)
Balance (As Adjusted)	5,033	393	1,096	3,863	901	-1,220
Balance at Dec. 31, 2011	5,055	393	1,096	3,885	901	-1,220
Balance (in shares) (As Adjusted)		162
Balance (in shares) at Dec. 31, 2011		162
NET INCOME	229			229
Other comprehensive income, net	270				270
Dividends declared	-196			-196
Stock-based awards exercised and vested (in shares)		1
Stock-based awards exercised and vested	13	1	10			2
Stock-based compensation	12		12
Purchases	-7					-7
Other	5		1			4
Balance at Sep. 30, 2012	5,359	394	1,119	3,896	1,171	-1,221
Balance (in shares) at Sep. 30, 2012		163
Balance at Dec. 31, 2012	5,453	394	1,134	4,021	1,129	-1,225
Balance (in shares) at Dec. 31, 2012	197	163
NET INCOME	395			395
Other comprehensive income, net	138				138
Dividends declared	-202			-202
Stock-based awards exercised and vested (in shares)		1
Stock-based awards exercised and vested	34	2	27			5
Stock-based compensation	14		14
Purchases	-22					-22
Other	6		2			4
Balance (As Adjusted)	5,816
Balance at Sep. 30, 2013	$5,816	$396	$1,177	$4,214	$1,267	($1,238)
Balance (in shares) at Sep. 30, 2013	198	164

Condensed_Consolidated_Stateme4

Condensed 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	$395	$229
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	30	32
Realized gains on investments, net	-77	-29
Stock-based compensation	14	12
Interest credited to contract holders	31	25
Deferred income tax expense	15	4
Changes in:
Investment income receivable	0	3
Premiums and reinsurance receivable	-148	-129
Deferred policy acquisition costs	-60	-37
Other assets	-5	-4
Loss and loss expense reserves	77	5
Life policy reserves	53	53
Unearned premiums	234	185
Other liabilities	15	33
Current income tax receivable	-36	51
Net cash provided by operating activities	538	433
CASH FLOWS FROM INVESTING ACTIVITIES
Sale of fixed maturities	28	131
Call or maturity of fixed maturities	711	689
Sale of equity securities	178	165
Purchase of fixed maturities	-1,016	-914
Purchase of equity securities	-216	-325
Investment in buildings and equipment, net	-5	-5
Investment in finance receivables	-26	-24
Collection of finance receivables	22	24
Change in other invested assets, net	4	2
Net cash used in investing activities	-320	-257
CASH FLOWS FROM FINANCING ACTIVITIES
Payment of cash dividends to shareholders	-195	-191
Proceeds from stock options exercised	17	6
Contract holders' funds deposited	64	79
Contract holders' funds withdrawn	-78	-83
Excess tax benefits on stock-based compensation	10	1
Other	-12	-10
Net cash used in financing activities	-194	-198
Net change in cash and cash equivalents	24	-22
Cash and cash equivalents at beginning of year	487	438
Cash and cash equivalents at end of period	511	416
Supplemental disclosures of cash flow information:
Interest paid	27	28
Income taxes paid	169	8
Non-cash activities:
Conversion of securities	59	21
Equipment acquired under capital lease obligations	21	20
Cashless exercise of stock options	$22	$7

Accounting_Policies

Accounting Policies	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]
Accounting Policies	ACCOUNTING POLICIES
	The condensed consolidated financial statements include the accounts of Cincinnati Financial Corporation and its consolidated subsidiaries, each of which is wholly owned. These statements are presented in conformity with accounting principles generally accepted in the United States of America (GAAP). All intercompany balances and transactions have been eliminated in consolidation.
	The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect amounts reported in the financial statements and accompanying notes. Our actual results could differ from those estimates. Our December 31, 2012, condensed consolidated balance sheet amounts are derived from the audited financial statements but do not include all disclosures required by GAAP.
	Our September 30, 2013, condensed consolidated financial statements are unaudited. Certain financial information that is included in annual financial statements prepared in accordance with GAAP is not required for interim reporting and has been condensed or omitted. We believe that we have made all adjustments, consisting only of normal recurring accruals, that are necessary for fair presentation. These condensed consolidated financial statements should be read in conjunction with our consolidated financial statements included in our 2012 Annual Report on Form 10-K. The results of operations for interim periods do not necessarily indicate results to be expected for the full year.
	Adopted Accounting Updates
	ASU 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income
	In February 2013, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. ASU 2013-02 requires entities to present in either a single note or parenthetically on the face of the financial statements, the effect of significant amounts reclassified from each component of accumulated other comprehensive income based on its source and the income statement line items affected by the reclassification. The company adopted this ASU during the first quarter of 2013, and it did not have a material impact on our company’s financial position, cash flows or results of operations. See Note 7, Accumulated Other Comprehensive Income, for further details.

Investments

Investments	9 Months Ended
	Sep. 30, 2013
Investments [Abstract]
Investments	INVESTMENTS
	The following table provides cost or amortized cost, gross unrealized gains, gross unrealized losses and fair value for our invested assets:
	(In millions)	Cost or
		amortized			Gross unrealized						Fair
	At September 30, 2013	cost			gains			losses			value
	Fixed maturities:
	States, municipalities and political subdivisions	$	3,046		$	146		$	17		$	3,175
	Convertibles and bonds with warrants attached	16			—			—			16
	United States government	7			—			—			7
	Government-sponsored enterprises	209			—			19			190
	Foreign government	10			—			—			10
	Commercial mortgage-backed securities	79			—			3			76
	Corporate securities	5,135			454			25			5,564
	Subtotal	8,502			600			64			9,038
	Equity securities:
	Common equities	2,394			1,482			3			3,873
	Preferred equities	77			34			—			111
	Subtotal	2,471			1,516			3			3,984
	Total	$	10,973		$	2,116		$	67		$	13,022
	At December 31, 2012
	Fixed maturities:
	States, municipalities and political subdivisions	$	3,040		$	250		$	1		$	3,289
	Convertibles and bonds with warrants attached	31			—			—			31
	United States government	7			1			—			8
	Government-sponsored enterprises	164			—			—			164
	Foreign government	3			—			—			3
	Commercial mortgage-backed securities	27			1			—			28
	Corporate securities	4,950			622			2			5,570
	Subtotal	8,222			874			3			9,093
	Equity securities:
	Common equities	2,270			977			9			3,238
	Preferred equities	99			37			1			135
	Subtotal	2,369			1,014			10			3,373
	Total	$	10,591		$	1,888		$	13		$	12,466
	The net unrealized investment gains in our fixed-maturity portfolio are primarily the result of the current low interest rate environment that increased the fair value of our fixed-maturity portfolio. The three largest net unrealized investment gains in our common stock portfolio are from Exxon Mobil Corporation (NYSE:XOM), Chevron Corporation (NYSE:CVX) and The Procter & Gamble Company (NYSE:PG), which had a combined net gain position of $264 million. At At September 30, 2013, we had $16 million fair value of hybrid securities included in fixed maturities that follow Accounting Standards Codification (ASC) 815-15-25, Accounting for Certain Hybrid Financial Instruments, compared with $31 million fair value of hybrid securities at December 31, 2012. The hybrid securities are carried at fair value, and the changes in fair value are included in realized investment gains and losses.
	The table below provides fair values and unrealized losses by investment category and by the duration of the securities’ continuous unrealized loss position:
	(In millions)	Less than 12 months						12 months or more						Total		Total
		Fair			Unrealized			Fair			Unrealized			fair		unrealized
	At September 30, 2013	value			losses			value			losses			value		losses
	Fixed maturities:
	States, municipalities and political	$	371		$	17		$	8		$	—		$	379	$	17
	subdivisions
	United States government	1			—			—			—			1		—
	Government-sponsored enterprises	190			19			—			—			190		19
	Foreign government	9			—			—			—			9		—
	Commercial mortgage-backed securities	62			3			—			—			62		3
	Corporate securities	526			22			35			3			561		25
	Subtotal	1,159			61			43			3			1,202		64
	Equity securities:
	Common equities	74			3			—			—			74		3
	Preferred equities	4			—			—			—			4		—
	Subtotal	78			3			—			—			78		3
	Total	$	1,237		$	64		$	43		$	3		$	1,280	$	67
	At December 31, 2012
	Fixed maturities:
	States, municipalities and political	$	53		$	1		$	—		$	—		$	53	$	1
	subdivisions
	Government-sponsored enterprises	1			—			—			—			1		—
	Corporate securities	58			1			17			1			75		2
	Subtotal	112			2			17			1			129		3
	Equity securities:
	Common equities	107			9			—			—			107		9
	Preferred equities	4			1			—			—			4		1
	Subtotal	111			10			—			—			111		10
Total	$	223		$	12		$	17		$	1		$	240	$	13
The following table provides investment income, realized investment gains and losses, the change in unrealized investment gains and losses, and other items:
(In millions)	Three months ended September 30,						Nine months ended September 30,
	2013			2012			2013			2012
Investment income summary:
Interest on fixed maturities	$	104		$	105		$	309		$	317
Dividends on equity securities	30			28			87			81
Other investment income	1			1			2			3
Total	135			134			398			401
Less investment expenses	2			2			6			6
Total	$	133		$	132		$	392		$	395
Realized investment gains and losses summary:
Fixed maturities:
Gross realized gains	$	5		$	14		$	9		$	30
Gross realized losses	—			—			—			—
Other-than-temporary impairments	—			—			(2		)	—
Equity securities:
Gross realized gains	15			1			64			30
Gross realized losses	—			—			—			(1		)
Other-than-temporary impairments	—			(2		)	—			(32		)
Securities with embedded derivatives	—			(4		)	1			1
Other	2			1			5			1
Total	$	22		$	10		$	77		$	29
Change in unrealized gains and losses summary:
Fixed maturities	$	(28	)	$	110		$	(335	)	$	188
Equity securities	90			143			509			240
Amortization of pension actuarial loss and	2			2			7			5
prior service cost
Adjustment to deferred acquisition costs and	9			(6		)	38			(21		)
life policy reserves
Other	(2		)	—			(7		)	5
Income taxes on above	(25		)	(88		)	(74		)	(147		)
Total	$	46		$	161		$	138		$	270
During the three and nine months ended September 30, 2013 and 2012, there were no credit losses on fixed-maturity securities for which a portion of other-than-temporary impairment (OTTI) has been recognized in other comprehensive income.
During the quarter ended September 30, 2013, there were no other-than-temporarily impaired securities. At September 30, 2013, nine fixed-maturity investments with a total unrealized loss of $3 million had been in an unrealized loss position for 12 months or more. Of that total, no fixed-maturity investments had fair values below
70 percent of amortized cost. There were no equity investments in an unrealized loss position for 12 months or more as of September 30, 2013.
At December 31, 2012, four fixed-maturity investments with a total unrealized loss of $1 million had been in an unrealized loss position for 12 months or more. Of that total, no fixed-maturity investments had fair values below
70 percent of amortized cost. There were no equity investments in an unrealized loss position for 12 months or more as of December 31, 2012.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS
	Fair Value Hierarchy
	In accordance with accounting guidance for fair value measurements and disclosures, we categorized our financial instruments, based on the priority of the observable and market-based data for the valuation technique used, into a three-level fair value hierarchy. The fair value hierarchy gives the highest priority to quoted prices with readily available independent data in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable market inputs (Level 3). When various inputs for measurement fall within different levels of the fair value hierarchy, the lowest observable input that has a significant impact on fair value measurement is used. Our valuation techniques have not changed from those used at December 31, 2012, and ultimately management determines fair value. See our 2012 Annual Report on Form 10-K, Item 8, Note 3, Fair Value Measurements, Page 121, for information on characteristics and valuation techniques used in determining fair value.
	Fair Value Disclosures for Assets
	The following tables illustrate the fair value hierarchy for those assets measured at fair value on a recurring basis at September 30, 2013, and December 31, 2012. We do not have any material liabilities carried at fair value. There were no transfers between Level 1 and Level 2.
	(In millions)		Quoted prices in				Significant other			Significant			Total
			active markets for				observable inputs			unobservable
			identical assets				(Level 2)			inputs
	At September 30, 2013		(Level 1)							(Level 3)
	Fixed maturities, available for sale:
	States, municipalities and political subdivisions		$	—			$	3,175		$	—		$	3,175
	Convertibles and bonds with warrants attached		—				16			—			16
	United States government		7				—			—			7
	Government-sponsored enterprises		—				190			—			190
	Foreign government		—				10			—			10
	Commercial mortgage-backed securities		—				76			—			76
	Corporate securities		—				5,561			3			5,564
	Subtotal		7				9,028			3			9,038
	Common equities, available for sale		3,873				—			—			3,873
	Preferred equities, available for sale		—				109			2			111
	Taxable fixed maturities separate accounts		—				689			—			689
	Top Hat Savings Plan (included in Other assets)		12				—			—			12
	Total		$	3,892			$	9,826		$	5		$	13,723
	At December 31, 2012
	Fixed maturities, available for sale:
	States, municipalities and political subdivisions		$	—			$	3,288		$	1		$	3,289
	Convertibles and bonds with warrants attached		—				31			—			31
	United States government		8				—			—			8
	Government-sponsored enterprises		—				164			—			164
	Foreign government		—				3			—			3
	Commercial mortgage-backed securities		—				28			—			28
	Corporate securities		—				5,567			3			5,570
	Subtotal		8				9,081			4			9,093
	Common equities, available for sale		3,238				—			—			3,238
	Preferred equities, available for sale		—				134			1			135
	Taxable fixed-maturities separate accounts		—				689			—			689
	Top Hat Savings Plan (included in Other assets)		9				—			—			9
	Total		$	3,255			$	9,904		$	5		$	13,164
	Each financial instrument that was deemed to have significant unobservable inputs when determining valuation is identified in the following tables by security type with a summary of changes in fair value as of September 30, 2013. Total Level 3 assets continue to be less than 1 percent of financial assets measured at fair value in the condensed consolidated balance sheets. Assets presented in the table below were valued based primarily on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of these unobservable inputs is neither provided nor reasonably available to us.
	The following tables provide the change in Level 3 assets for the three months ended September 30:
	(In millions)		Corporate fixed				States,			Preferred  equities			Total
			maturities				municipalities
							and political
							subdivisions
							fixed maturities
	Beginning balance, June 30, 2013		$	3			$	1		$	2		$	6
	Total gains or losses (realized/unrealized):
	Included in earnings		—				—			—			—
	Included in other comprehensive income		—				—			—			—
	Purchases		—				—			—			—
	Sales		—				(1		)	—			(1		)
	Transfers into Level 3		—				—			—			—
	Transfers out of Level 3		—				—			—			—
	Ending balance, September 30, 2013		$	3			$	—		$	2		$	5
	Beginning balance, June 30, 2012		$	4			$	2		$	7		$	13
	Total gains or losses (realized/unrealized):
	Included in earnings		—				—			—			—
	Included in other comprehensive income		—				—			—			—
	Purchases		—				—			—			—
	Sales		—				(1		)	—			(1		)
	Transfers into Level 3		—				—			—			—
	Transfers out of Level 3		—				—			—			—
	Ending balance, September 30, 2012		$	4			$	1		$	7		$	12
	The following tables provide the change in Level 3 assets for the nine months ended September 30:
(In millions)		Corporate fixed				States,			Preferred			Total
		maturities				municipalities			equities
						and political
						subdivisions
						fixed maturities
Beginning balance, December 31, 2012		$	3			$	1		$	1		$	5
Total gains or losses (realized/unrealized):
Included in earnings		—				—			—			—
Included in other comprehensive income		—				—			—			—
Purchases		—				—			1			1
Sales		—				(1		)	—			(1		)
Transfers into Level 3		—				—			—			—
Transfers out of Level 3		—				—			—			—
Ending balance, September 30, 2013		$	3			$	—		$	2		$	5
Beginning balance, December 31, 2011		$	18			$	3		$	4		$	25
Total gains or losses (realized/unrealized):
Included in earnings		—				—			—			—
Included in other comprehensive income		3				—			2			5
Purchases		—				—			1			1
Sales		(4		)		(2		)	—			(6		)
Transfers into Level 3		1				—			—			1
Transfers out of Level 3		(14		)		—			—			(14		)
Ending balance, September 30, 2012		$	4			$	1		$	7		$	12
Additional disclosures for the Level 3 category are not material.
Fair Value Disclosure for Assets and Liabilities Not Carried at Fair Value
The disclosures below are presented to provide timely information about the effects of current market conditions on financial instruments that are not reported at fair value in our condensed consolidated financial statements.
This table summarizes the book value and principal amounts of our long-term debt:
(In millions)							Book value						Principal amount
							September 30,			December 31,			September 30,		December 31,
Interest rate			Year of issue				2013			2012			2013		2012
6.9	%		1998		Senior debentures, due 2028		$	28		$	28		$	28	$	28
6.92	%		2005		Senior debentures, due 2028		391			391			391		391
6.125	%		2004		Senior notes, due 2034		371			371			374		374
					Total		$	790		$	790		$	793	$	793
The following table shows fair values of our note payable and long-term debt subject to fair value disclosure requirements:
(In millions)		Quoted prices in				Significant other			Significant			Total
		active markets for				observable inputs			unobservable
		identical assets				(Level 2)			inputs
At September 30, 2013		(Level 1)							(Level 3)
Note payable		$	—			$	104		$	—		$	104
6.900% senior debentures, due 2028		—				32			—			32
6.920% senior debentures, due 2028		—				470			—			470
6.125% senior notes, due 2034		—				398			—			398
Total		$	—			$	1,004		$	—		$	1,004
At December 31, 2012
Note payable		$	—			$	104		$	—		$	104
6.900% senior debentures, due 2028		—				31			—			31
6.920% senior debentures, due 2028		—				479			—			479
6.125% senior notes, due 2034		—				431			—			431
Total		$	—			$	1,045		$	—		$	1,045
The following table shows the fair value of our life policy loans, included in other invested assets, subject to fair value disclosure requirements:
(In millions)		Quoted prices in				Significant other			Significant			Total
		active markets for				observable inputs			unobservable
		identical assets				(Level 2)			inputs
At September 30, 2013		(Level 1)							(Level 3)
Life policy loans		$	—			$	—		$	44		$	44
At December 31, 2012
Life policy loans		$	—			$	—		$	50		$	50
Outstanding principal and interest for these life policy loans was $35 million and $37 million at September 30, 2013, and December 31, 2012, respectively.
The following table shows fair values of our deferred annuities and structured settlements, included in life policy and investment contract reserves, subject to fair value disclosure requirements:
(In millions)		Quoted prices in				Significant other			Significant			Total
		active markets for				observable inputs			unobservable
		identical assets				(Level 2)			inputs
At September 30, 2013		(Level 1)							(Level 3)
Deferred annuities		$	—			$	—		$	881		$	881
Structured settlements		—				218			—			218
Total		$	—			$	218		$	881		$	1,099
At December 31, 2012
Deferred annuities		$	—			$	—		$	898		$	898
Structured settlements		—				240			—			240
Total		$	—			$	240		$	898		$	1,138
Recorded reserves for the deferred annuities and structured settlements were $1.049 billion and $1.043 billion at September 30, 2013, and December 31, 2012, respectively.

Property_Casualty_Loss_and_Los

Property Casualty Loss and Loss Expenses	9 Months Ended
	Sep. 30, 2013
Premiums Written, Net [Abstract]
Property Casualty Loss And Loss Expenses	PROPERTY CASUALTY LOSS AND LOSS EXPENSES
	This table summarizes activity for our consolidated property casualty loss and loss expense reserves:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Gross loss and loss expense reserves,	$	4,219		$	4,337		$	4,169		$	4,280
	beginning of period
	Less reinsurance receivable	333			332			356			375
	Net loss and loss expense reserves,	3,886			4,005			3,813			3,905
	beginning of period
	Net incurred loss and loss expenses related to:
	Current accident year	631			611			1,840			1,991
	Prior accident years	(38		)	(86		)	(140		)	(287		)
	Total incurred	593			525			1,700			1,704
	Net paid loss and loss expenses related to:
	Current accident year	329			364			699			778
	Prior accident years	233			229			897			894
	Total paid	562			593			1,596			1,672
	Net loss and loss expense reserves,	3,917			3,937			3,917			3,937
	end of period
	Plus reinsurance receivable	321			343			321			343
	Gross loss and loss expense reserves,	$	4,238		$	4,280		$	4,238		$	4,280
	end of period
	We use actuarial methods, models and judgment to estimate, as of a financial statement date, the property casualty loss and loss expense reserves required to pay for and settle all outstanding insured claims, including incurred but not reported (IBNR) claims, as of that date. The actuarial estimate is subject to review and adjustment by an
	inter-departmental committee that includes actuarial management that is familiar with relevant company and industry business, claims and underwriting trends, as well as general economic and legal trends that could affect future loss and loss expense payments. The amount we will actually have to pay for claims can be highly uncertain. This uncertainty, together with the size of our reserves, makes the loss and loss expense reserves our most significant estimate. The reserve for loss and loss expenses in the condensed consolidated balance sheets also included $69 million at September 30, 2013, and $64 million at September 30, 2012, for certain life and health loss and loss expense reserves.
	For the three months ended September 30, 2013, we experienced $38 million of favorable development on prior accident years, including $13 million of favorable development in commercial lines, $21 million of favorable development in personal lines and $4 million favorable development in excess and surplus lines. This included
	$9 million from favorable development of catastrophe losses for the three months ended September 30, 2013, compared with $12 million of favorable development of catastrophe losses for the three months ended September 30, 2012.
	For the nine months ended September 30, 2013, we experienced $140 million of favorable development on prior accident years, including $91 million of favorable development in commercial lines, $43 million of favorable development in personal lines and $6 million favorable development in excess and surplus lines. This included
	$24 million from favorable development of catastrophe losses for the nine months ended September 30, 2013, compared with $39 million of favorable development of catastrophe losses for the nine months ended September 30, 2012.

Life_Policy_and_Investment_Con

Life Policy and Investment Contract Reserves	9 Months Ended
	Sep. 30, 2013
Liability for Future Policy Benefits [Abstract]
Life Policy And Investment Contract Reserves	LIFE POLICY AND INVESTMENT CONTRACT RESERVES
	We establish the reserves for traditional life insurance policies based on expected expenses, mortality, morbidity, withdrawal rates, timing of claim presentation and investment yields, including a provision for uncertainty. Once these assumptions are established, they generally are maintained throughout the lives of the contracts. We use both our own experience and industry experience, adjusted for historical trends, in arriving at our assumptions for expected mortality, morbidity and withdrawal rates as well as for expected expenses. We base our assumptions for expected investment income on our own experience adjusted for current economic conditions.
	We establish reserves for the company’s universal life, deferred annuity and structured settlement policies equal to the cumulative account balances, which include premium deposits plus credited interest less charges and withdrawals. Some of our universal life policies contain no-lapse guarantee provisions. For these policies, we establish a reserve in addition to the account balance, based on expected no-lapse guarantee benefits and expected policy assessments.
	This table summarizes our life policy and investment contract reserves:
	(In millions)	September 30,		December 31, 2012
		2013
	Ordinary/traditional life	$	796	$	752
	Universal life	512		483
	Deferred annuities	860		850
	Structured settlements	189		193
	Other	16		17
	Total life policy and investment contract reserves	$	2,373	$	2,295

Deferred_Acquisition_Costs

Deferred Acquisition Costs	9 Months Ended
	Sep. 30, 2013
Deferred Costs [Abstract]
Deferred Acquisition Costs	DEFERRED ACQUISITION COSTS
	Expenses directly related to successfully acquiring insurance policies – primarily commissions, premium taxes and underwriting costs – are deferred and amortized over the terms of the policies. We update our acquisition cost assumptions periodically to reflect actual experience, and we evaluate the costs for recoverability. The table below shows the deferred policy acquisition costs and asset reconciliation.
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Deferred policy acquisition costs asset at beginning of period	$	546		$	484		$	470		$	477
	Capitalized deferred policy acquisition costs	211			192			612			554
	Amortized deferred policy acquisition costs	(190		)	(180		)	(552		)	(517		)
	Amortized shadow deferred policy acquisition costs	9			(5		)	46			(23		)
	Deferred policy acquisition costs asset at end of period	$	576		$	491		$	576		$	491
	No premium deficiencies were recorded in the condensed consolidated statements of income, as the sum of the anticipated loss and loss adjustment expenses, policyholder dividends and unamortized deferred acquisition expenses did not exceed the related unearned premiums and anticipated investment income.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	9 Months Ended
	Sep. 30, 2013
Accumulated Other Comprehensive Income [Abstract]
Comprehensive Income (Loss) Note	ACCUMULATED OTHER COMPREHENSIVE INCOME
	Accumulated other comprehensive income includes changes in unrealized gains and losses on available for sale investments and other invested assets, changes in pension obligations and changes in life deferred acquisition costs, life policy reserves and other as follows:
	(In millions)	Three months ended September 30,
		2013									2012
		Before tax			Income tax			Net			Before tax			Income tax			Net
	Accumulated unrealized gains, net, on investments available for sale,	$	1,987		$	686		$	1,301		$	1,664		$	573		$	1,091
	beginning of period
	Other comprehensive income before reclassification	82			29			53			262			93			169
	Reclassification adjustment for realized investment gains, net,	(20		)	(7		)	(13		)	(9		)	(4		)	(5		)
	included in net income
	Effect on other comprehensive income	62			22			40			253			89			164
	Accumulated unrealized gains, net, on investments available for sale,	$	2,049		$	708		$	1,341		$	1,917		$	662		$	1,255
	end of period
	Accumulated unrealized losses, net, for pension obligations,	$	(96	)	$	(33	)	$	(63	)	$	(85	)	$	(30	)	$	(55	)
	beginning of period
	Other comprehensive income before reclassification	—			—			—			—			—			—
	Reclassification adjustment for amortization of actuarial loss	2			1			1			2			1			1
	and prior service cost, net, included in net income
	Effect on other comprehensive income	2			1			1			2			1			1
	Accumulated unrealized losses, net, for pension obligations,	$	(94	)	$	(32	)	$	(62	)	$	(83	)	$	(29	)	$	(54	)
	end of period
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(26	)	$	(9	)	$	(17	)	$	(39	)	$	(13	)	$	(26	)
	life policy reserves and other, beginning of period
	Other comprehensive income before reclassification	9			2			7			(5		)	(2		)	(3		)
	Reclassification adjustment for life deferred acquisition costs,	(2		)	—			(2		)	(1		)	—			(1		)
	life policy reserves and other, net, included in net income
	Effect on other comprehensive income	7			2			5			(6		)	(2		)	(4		)
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(19	)	$	(7	)	$	(12	)	$	(45	)	$	(15	)	$	(30	)
	life policy reserves and other, end of period
	Accumulated other comprehensive income, beginning of period	$	1,865		$	644		$	1,221		$	1,540		$	530		$	1,010
	Change in unrealized gains, net, on investments available for sale	62			22			40			253			89			164
	Change in pension obligations	2			1			1			2			1			1
	Change in life deferred acquisition costs, life policy reserves	7			2			5			(6		)	(2		)	(4		)
	and other
	Effect on other comprehensive income	71			25			46			249			88			161
	Accumulated other comprehensive income, end of period	$	1,936		$	669		$	1,267		$	1,789		$	618		$	1,171
	(In millions)	Nine months ended September 30,
		2013									2012
		Before tax			Income tax			Net			Before tax			Income tax			Net
	Accumulated unrealized gains, net, on investments available for sale,	$	1,875		$	647		$	1,228		$	1,489		$	512		$	977
	beginning of period
	Other comprehensive income before reclassification	246			85			161			456			160			296
	Reclassification adjustment for realized investment gains, net,	(72		)	(24		)	(48		)	(28		)	(10		)	(18		)
	included in net income
	Effect on other comprehensive income	174			61			113			428			150			278
	Accumulated unrealized gains, net, on investments available for sale,	$	2,049		$	708		$	1,341		$	1,917		$	662		$	1,255
	end of period
	Accumulated unrealized losses, net, for pension obligations,	$	(101	)	$	(35	)	$	(66	)	$	(88	)	$	(31	)	$	(57	)
	beginning of period
	Effect on other comprehensive income	7			3			4			5			2			3
	Accumulated unrealized losses, net, for pension obligations,	$	(94	)	$	(32	)	$	(62	)	$	(83	)	$	(29	)	$	(54	)
	end of period
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(50	)	$	(17	)	$	(33	)	$	(29	)	$	(10	)	$	(19	)
	life policy reserves and other, beginning of period
	Other comprehensive income before reclassification	36			12			24			(15		)	(5		)	(10		)
	Reclassification adjustment for life deferred acquisition costs,	(5		)	(2		)	(3		)	(1		)	—			(1		)
	life policy reserves and other, net, included in net income
	Effect on other comprehensive income	31			10			21			(16		)	(5		)	(11		)
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(19	)	$	(7	)	$	(12	)	$	(45	)	$	(15	)	$	(30	)
	life policy reserves and other, end of period
	Accumulated other comprehensive income, beginning of period	$	1,724		$	595		$	1,129		$	1,372		$	471		$	901
	Change in unrealized gains, net, on investments available for sale	174			61			113			428			150			278
	Change in pension obligations	7			3			4			5			2			3
	Change in life deferred acquisition costs, life policy reserves	31			10			21			(16		)	(5		)	(11		)
and other
Effect on other comprehensive income	212			74			138			417			147			270
Accumulated other comprehensive income, end of period	$	1,936		$	669		$	1,267		$	1,789		$	618		$	1,171
The reclassification adjustment for realized gains on investments available for sale are recorded in the total realized investment gains, net, line item of the condensed consolidated statements of income. The reclassification adjustment for amortization of actuarial loss and prior service cost, net, are recorded in the insurance losses and policyholder benefits, underwriting, acquisition and insurance expenses and the other operating expenses line items of the condensed consolidated statements of income.

Reinsurance

Reinsurance	9 Months Ended
	Sep. 30, 2013
Reinsurance Disclosures [Abstract]
Reinsurance	REINSURANCE
	Reinsurance mitigates the risk of highly uncertain exposures and limits the maximum net loss that can arise from large risks or risks concentrated in areas of exposure. Management's decisions about the appropriate level of risk retention are affected by various factors, including changes in our underwriting practices, capacity to retain risks and reinsurance market conditions.
	Primary components of our property casualty reinsurance program include a property per risk treaty, property excess treaty, casualty per occurrence treaty, casualty excess treaty, property catastrophe treaty and catastrophe bonds.
	Our condensed consolidated statements of income include earned consolidated property casualty insurance premiums on assumed and ceded business:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Direct earned premiums	$	1,002		$	898		$	2,895		$	2,605
	Assumed earned premiums	3			1			8			7
	Ceded earned premiums	(51		)	(48		)	(150		)	(137		)
	Net earned premiums	$	954		$	851		$	2,753		$	2,475
	Our condensed consolidated statements of income include incurred consolidated property casualty insurance loss and loss expenses on assumed and ceded business:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Direct incurred loss and loss expenses	$	597		$	562		$	1,725		$	1,745
	Assumed incurred loss and loss expenses	1			(3		)	8			3
	Ceded incurred loss and loss expenses	(5		)	(34		)	(33		)	(44		)
	Net incurred loss and loss expenses	$	593		$	525		$	1,700		$	1,704
	Our life insurance company purchases reinsurance for protection of a portion of the risk that is written. Primary components of our life reinsurance program include individual mortality coverage and aggregate catastrophe and accidental death coverage in excess of certain deductibles.
	Our condensed consolidated statements of income include earned life insurance premiums on ceded business:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Direct earned premiums	$	52		$	52		$	166		$	170
	Assumed earned premiums	—			—			—			—
	Ceded earned premiums	(14		)	(14		)	(42		)	(40		)
	Net earned premiums	$	38		$	38		$	124		$	130
	Our condensed consolidated statements of income include life insurance policyholders’ benefits incurred on ceded business:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Direct policyholders' benefits incurred	$	64		$	62		$	190		$	172
	Assumed policyholders' benefits incurred	—			—			—			—
	Ceded policyholders' benefits incurred	(15		)	(16		)	(49		)	(36		)
	Net policyholders' benefits incurred	$	49		$	46		$	141		$	136
	The ceded benefits incurred can vary depending on the type of life insurance policy held and the year the policy was sold.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES
	As of September 30, 2013, and December 31, 2012, we had no liability for unrecognized tax benefits. Details about our liability for unrecognized tax benefits are found in our 2012 Annual Report on Form 10-K, Item 8, Note 11, Income Taxes, Page 129.
	During the third quarter of 2013, we were advised that the congressional Joint Committee on Taxation had completed its review of tax years 2009 and 2010 and agreed with the Internal Revenue Service examination report, which resulted in no material changes to the returns as filed.
	On September 13, 2013, the Internal Revenue Service released final tangible property regulations under Sections 162(a) and 263(a) of the Internal Revenue Code of 1986 (Code), regarding the deduction and capitalization of expenditures related to tangible property. The final regulations replace temporary regulations that were issued in December 2011.  Also released were proposed regulations under Section 168 of the Code regarding dispositions of tangible property.  These regulations generally apply to taxable years beginning on or after January 1, 2014.  Although the final regulations will affect all taxpayers that acquire, produce, or improve tangible property, we do not expect them to have a material impact on our consolidated financial statements.
	The differences between the 35 percent statutory income tax rate and our effective income tax rate were as follows:
	(Dollars in millions)	Three months ended September 30,										Nine months ended September 30,
		2013					2012					2013					2012
	Tax at statutory rate	$	64		35	%	$	53		35	%	$	191		35	%	$	103		35	%
	Increase (decrease) resulting from:
	Tax-exempt income from municipal bonds	(8		)	(4.4	)	(8		)	(5.3	)	(24		)	(4.4	)	(25		)	(8.5	)
	Dividend received exclusion	(6		)	(3.3	)	(6		)	(4.0	)	(18		)	(3.3	)	(17		)	(5.8	)
	Other	1			0.7		2			1.3		3			0.5		3			1.1
	Provision for income taxes	$	51		28	%	$	41		27	%	$	152		27.8	%	$	64		21.8	%
	The change in our effective tax rate was primarily due to changes in pretax income from underwriting results and realized investment gains and losses, compared with unchanged levels of permanent book-tax differences.

Net_Income_Per_Common_Share

Net Income Per Common Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Net Income Per Common Share	NET INCOME PER COMMON SHARE
	Basic earnings per share are computed based on the weighted average number of shares outstanding. Diluted earnings per share are computed based on the weighted average number of common and dilutive potential common shares outstanding using the treasury stock method.
	The table shows calculations for basic and diluted earnings per share:
	(Dollars in millions except share data in thousands)	Three months ended September 30,				Nine months ended September 30,
		2013		2012		2013		2012
	Numerator:
	Net income—basic and diluted	$	131	$	111	$	395	$	229
	Denominator:
	Weighted-average common shares outstanding	163,710		162,555		163,454		162,419
	Effect of stock-based awards:
	Stock options	1,184		563		1,131		441
	Nonvested shares	707		739		719		647
	Adjusted weighted-average shares	165,601		163,857		165,304		163,507
	Earnings per share:
	Basic	$	0.8	$	0.69	$	2.42	$	1.41
	Diluted	0.79		0.68		2.39		1.4
	Number of anti-dilutive stock-based awards	335		5,045		390		6,000
	The current sources of dilution of our common shares are certain equity-based awards as discussed in our 2012 Annual Report on Form 10-K, Item 8, Note 17, Stock-Based Associate Compensation Plans, Page 135. The above table shows the number of anti-dilutive stock-based awards for the three and nine months ended September 30, 2013 and 2012. We did not include these stock-based awards in the computation of net income per common share (diluted) because their exercise would have anti-dilutive effects.

Employee_Retirement_Benefits

Employee Retirement Benefits	9 Months Ended
	Sep. 30, 2013
Compensation and Retirement Disclosure [Abstract]
Employee Retirement Benefits	EMPLOYEE RETIREMENT BENEFITS
	The following summarizes the components of net periodic costs for our qualified and supplemental pension plans:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Service cost	$	4		$	3		$	10		$	9
	Interest cost	4			4			10			11
	Expected return on plan assets	(5		)	(4		)	(13		)	(12		)
	Amortization of actuarial loss and prior service	2			2			7			5
	cost
	Net periodic benefit cost	$	5		$	5		$	14		$	13
	See our 2012 Annual Report on Form 10-K, Item 8, Note 13, Employee Retirement Benefits, Page 130, for information on our retirement benefits. We made matching contributions of $2 million to our 401(k) and Top Hat savings plans during both the third quarter of 2013 and 2012 and contributions of $7 million for both the first nine months of 2013 and 2012.
	We contributed $15 million to our qualified pension plan during the first quarter of 2013. We do not anticipate further contributions to our qualified pension plan during the remainder of 2013.

Segment_Information

Segment Information	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Segment Information	SEGMENT INFORMATION
	We operate primarily in two industries, property casualty insurance and life insurance. We regularly review our reporting segments to make decisions about allocating resources and assessing performance:
	•	Commercial lines property casualty insurance
	•	Personal lines property casualty insurance
	•	Excess and surplus lines property casualty insurance
	•	Life insurance
	•	Investments
	We report as Other the noninvestment operations of the parent company and its noninsurer subsidiary, CFC Investment Company. See our 2012 Annual Report on Form 10-K, Item 8, Note 18, Segment Information, Page 137, for a description of revenue, income or loss before income taxes and identifiable assets for each of the five segments.
	Segment information is summarized in the following table:
	(In millions)		Three months ended September 30,						Nine months ended September 30,
			2013			2012			2013			2012
	Revenues:
	Commercial lines insurance
	Commercial casualty		$	221		$	197		$	636		$	569
	Commercial property		161			138			460			403
	Commercial auto		124			108			355			315
	Workers' compensation		95			89			270			255
	Specialty packages		38			37			114			112
	Surety and executive risk		30			28			89			82
	Machinery and equipment		11			10			32			29
	Commercial lines insurance premiums		680			607			1,956			1,765
	Fee revenue		1			—			2			2
	Total commercial lines insurance		681			607			1,958			1,767
	Personal lines insurance
	Personal auto		112			101			328			299
	Homeowner		103			90			298			261
	Other personal lines		29			28			86			82
	Personal lines insurance premiums		244			219			712			642
	Fee revenue		—			1			1			2
	Total personal lines insurance		244			220			713			644
	Excess and surplus lines insurance		30			25			85			68
	Life insurance		38			38			124			130
	Separate account investment management fees		1			1			3			1
	Total life insurance		39			39			127			131
	Investment operations
	Investment income, net of expenses		133			132			392			395
	Realized investment gains, net		22			10			77			29
	Total investment revenue		155			142			469			424
	Other		3			2			7			7
	Total revenues		$	1,152		$	1,035		$	3,359		$	3,041
	Income (loss) before income taxes:
	Insurance underwriting results
	Commercial lines insurance		$	43		$	60		$	135		$	74
	Personal lines insurance		14			(12		)	33			(89		)
	Excess and surplus lines insurance		4			(3		)	5			(8		)
	Life insurance		—			—			10			(2		)
	Investment operations		134			121			409			362
	Other		(13		)	(14		)	(45		)	(44		)
	Total		$	182		$	152		$	547		$	293
	Identifiable assets:		September 30,			December 31, 2012
			2013
	Property casualty insurance		$	2,479		$	2,395
	Life insurance		1,263			1,201
	Investment operations		13,137			12,599
	Other		460			353
	Total		$	17,339		$	16,548

Commitments_and_Contingent_Lia

Commitments and Contingent Liabilities	9 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingent Liabilities	COMMITMENTS AND CONTINGENT LIABILITIES
	In the ordinary course of conducting business, the company and its subsidiaries are named as defendants in various legal proceedings. Most of these proceedings are claims litigation involving the company's insurance subsidiaries in which the company is either defending or providing indemnity for third-party claims brought against insureds or litigating first-party coverage claims. The company accounts for such activity through the establishment of unpaid loss and loss adjustment expense reserves. We believe that the ultimate liability, if any, with respect to such ordinary-course claims litigation, after consideration of provisions made for potential losses and costs of defense, is immaterial to our consolidated financial condition, results of operations and cash flows.
	The company and its subsidiaries also are occasionally involved in other legal and regulatory proceedings, some of which assert claims for substantial amounts. These actions include, among others, putative class actions seeking certification of a state or national class. Such proceedings have alleged, for example, breach of an alleged duty to search national data bases to ascertain unreported deaths of insureds under life insurance policies. The company's insurance subsidiaries also are occasionally parties to individual actions in which extra-contractual damages, punitive damages or penalties are sought, such as claims alleging bad faith handling of insurance claims or writing unauthorized coverage or claims alleging discrimination by former associates.
	On a quarterly basis, we review these outstanding matters. Under current accounting guidance, we establish accruals when it is probable that a loss has been incurred and we can reasonably estimate its potential exposure. The company accounts for such probable and estimable losses, if any, through the establishment of legal expense reserves. Based on our quarterly review, we believe that our accruals for probable and estimable losses are reasonable and that the amounts accrued do not have a material effect on our consolidated financial condition or results of operations. However, if any one or more of these matters results in a judgment against us or settlement for an amount that is significantly greater than the amount accrued, the resulting liability could have a material effect on the company's consolidated results of operations or cash flows. Based on our most recent review, our estimate for any other matters for which the risk of loss is not probable, but more than remote, is less than $1 million.

Accounting_Policies_Policies

Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]
Adopted Accounting Updates, Policy	ASU 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income
	In February 2013, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income. ASU 2013-02 requires entities to present in either a single note or parenthetically on the face of the financial statements, the effect of significant amounts reclassified from each component of accumulated other comprehensive income based on its source and the income statement line items affected by the reclassification. The company adopted this ASU during the first quarter of 2013, and it did not have a material impact on our company’s financial position, cash flows or results of operations. See Note 7, Accumulated Other Comprehensive Income, for further details.

Investments_Tables

Investments (Tables)	9 Months Ended
	Sep. 30, 2013
Investments [Abstract]
Analysis Of Cost Or Amortized Cost, Gross Unrealized Gains And Losses And Fair Value for Investments	The following table provides cost or amortized cost, gross unrealized gains, gross unrealized losses and fair value for our invested assets:
	(In millions)	Cost or
		amortized			Gross unrealized						Fair
	At September 30, 2013	cost			gains			losses			value
	Fixed maturities:
	States, municipalities and political subdivisions	$	3,046		$	146		$	17		$	3,175
	Convertibles and bonds with warrants attached	16			—			—			16
	United States government	7			—			—			7
	Government-sponsored enterprises	209			—			19			190
	Foreign government	10			—			—			10
	Commercial mortgage-backed securities	79			—			3			76
	Corporate securities	5,135			454			25			5,564
	Subtotal	8,502			600			64			9,038
	Equity securities:
	Common equities	2,394			1,482			3			3,873
	Preferred equities	77			34			—			111
	Subtotal	2,471			1,516			3			3,984
	Total	$	10,973		$	2,116		$	67		$	13,022
	At December 31, 2012
	Fixed maturities:
	States, municipalities and political subdivisions	$	3,040		$	250		$	1		$	3,289
	Convertibles and bonds with warrants attached	31			—			—			31
	United States government	7			1			—			8
	Government-sponsored enterprises	164			—			—			164
	Foreign government	3			—			—			3
	Commercial mortgage-backed securities	27			1			—			28
	Corporate securities	4,950			622			2			5,570
	Subtotal	8,222			874			3			9,093
	Equity securities:
	Common equities	2,270			977			9			3,238
	Preferred equities	99			37			1			135
	Subtotal	2,369			1,014			10			3,373
	Total	$	10,591		$	1,888		$	13		$	12,466
Fair Values And Unrealized Losses by Investment Category And By The Duration Of The Securities' Continuous Unrealized Loss Position	The table below provides fair values and unrealized losses by investment category and by the duration of the securities’ continuous unrealized loss position:
	(In millions)	Less than 12 months						12 months or more						Total		Total
		Fair			Unrealized			Fair			Unrealized			fair		unrealized
	At September 30, 2013	value			losses			value			losses			value		losses
	Fixed maturities:
	States, municipalities and political	$	371		$	17		$	8		$	—		$	379	$	17
	subdivisions
	United States government	1			—			—			—			1		—
	Government-sponsored enterprises	190			19			—			—			190		19
	Foreign government	9			—			—			—			9		—
	Commercial mortgage-backed securities	62			3			—			—			62		3
	Corporate securities	526			22			35			3			561		25
	Subtotal	1,159			61			43			3			1,202		64
	Equity securities:
	Common equities	74			3			—			—			74		3
	Preferred equities	4			—			—			—			4		—
	Subtotal	78			3			—			—			78		3
	Total	$	1,237		$	64		$	43		$	3		$	1,280	$	67
	At December 31, 2012
	Fixed maturities:
	States, municipalities and political	$	53		$	1		$	—		$	—		$	53	$	1
	subdivisions
	Government-sponsored enterprises	1			—			—			—			1		—
	Corporate securities	58			1			17			1			75		2
	Subtotal	112			2			17			1			129		3
	Equity securities:
	Common equities	107			9			—			—			107		9
	Preferred equities	4			1			—			—			4		1
	Subtotal	111			10			—			—			111		10
	Total	$	223		$	12		$	17		$	1		$	240	$	13
Investment Income, Realized Investment Gains And Losses And Change In Unrealized Investment Gains And Losses	The following table provides investment income, realized investment gains and losses, the change in unrealized investment gains and losses, and other items:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Investment income summary:
	Interest on fixed maturities	$	104		$	105		$	309		$	317
	Dividends on equity securities	30			28			87			81
	Other investment income	1			1			2			3
	Total	135			134			398			401
	Less investment expenses	2			2			6			6
	Total	$	133		$	132		$	392		$	395
	Realized investment gains and losses summary:
	Fixed maturities:
	Gross realized gains	$	5		$	14		$	9		$	30
	Gross realized losses	—			—			—			—
	Other-than-temporary impairments	—			—			(2		)	—
	Equity securities:
	Gross realized gains	15			1			64			30
	Gross realized losses	—			—			—			(1		)
	Other-than-temporary impairments	—			(2		)	—			(32		)
	Securities with embedded derivatives	—			(4		)	1			1
	Other	2			1			5			1
	Total	$	22		$	10		$	77		$	29
	Change in unrealized gains and losses summary:
	Fixed maturities	$	(28	)	$	110		$	(335	)	$	188
	Equity securities	90			143			509			240
	Amortization of pension actuarial loss and	2			2			7			5
	prior service cost
	Adjustment to deferred acquisition costs and	9			(6		)	38			(21		)
	life policy reserves
	Other	(2		)	—			(7		)	5
	Income taxes on above	(25		)	(88		)	(74		)	(147		)
	Total	$	46		$	161		$	138		$	270

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Hierarchy for Assets Measured at Fair Value on a Recurring Basis	The following tables illustrate the fair value hierarchy for those assets measured at fair value on a recurring basis at September 30, 2013, and December 31, 2012. We do not have any material liabilities carried at fair value. There were no transfers between Level 1 and Level 2.
	(In millions)		Quoted prices in			Significant other			Significant			Total
			active markets for			observable inputs			unobservable
			identical assets			(Level 2)			inputs
	At September 30, 2013		(Level 1)						(Level 3)
	Fixed maturities, available for sale:
	States, municipalities and political subdivisions		$	—		$	3,175		$	—		$	3,175
	Convertibles and bonds with warrants attached		—			16			—			16
	United States government		7			—			—			7
	Government-sponsored enterprises		—			190			—			190
	Foreign government		—			10			—			10
	Commercial mortgage-backed securities		—			76			—			76
	Corporate securities		—			5,561			3			5,564
	Subtotal		7			9,028			3			9,038
	Common equities, available for sale		3,873			—			—			3,873
	Preferred equities, available for sale		—			109			2			111
	Taxable fixed maturities separate accounts		—			689			—			689
	Top Hat Savings Plan (included in Other assets)		12			—			—			12
	Total		$	3,892		$	9,826		$	5		$	13,723
	At December 31, 2012
	Fixed maturities, available for sale:
	States, municipalities and political subdivisions		$	—		$	3,288		$	1		$	3,289
	Convertibles and bonds with warrants attached		—			31			—			31
	United States government		8			—			—			8
	Government-sponsored enterprises		—			164			—			164
	Foreign government		—			3			—			3
	Commercial mortgage-backed securities		—			28			—			28
	Corporate securities		—			5,567			3			5,570
	Subtotal		8			9,081			4			9,093
	Common equities, available for sale		3,238			—			—			3,238
	Preferred equities, available for sale		—			134			1			135
	Taxable fixed-maturities separate accounts		—			689			—			689
	Top Hat Savings Plan (included in Other assets)		9			—			—			9
	Total		$	3,255		$	9,904		$	5		$	13,164
Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)	The following tables provide the change in Level 3 assets for the three months ended September 30:
	(In millions)		Corporate fixed			States,			Preferred  equities			Total
			maturities			municipalities
						and political
						subdivisions
						fixed maturities
	Beginning balance, June 30, 2013		$	3		$	1		$	2		$	6
	Total gains or losses (realized/unrealized):
	Included in earnings		—			—			—			—
	Included in other comprehensive income		—			—			—			—
	Purchases		—			—			—			—
	Sales		—			(1		)	—			(1		)
	Transfers into Level 3		—			—			—			—
	Transfers out of Level 3		—			—			—			—
	Ending balance, September 30, 2013		$	3		$	—		$	2		$	5
	Beginning balance, June 30, 2012		$	4		$	2		$	7		$	13
	Total gains or losses (realized/unrealized):
	Included in earnings		—			—			—			—
	Included in other comprehensive income		—			—			—			—
	Purchases		—			—			—			—
	Sales		—			(1		)	—			(1		)
	Transfers into Level 3		—			—			—			—
	Transfers out of Level 3		—			—			—			—
	Ending balance, September 30, 2012		$	4		$	1		$	7		$	12
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]	This table summarizes the book value and principal amounts of our long-term debt:
	(In millions)						Book value						Principal amount
							September 30,			December 31,			September 30,		December 31,
	Interest rate			Year of issue			2013			2012			2013		2012
	6.9	%		1998	Senior debentures, due 2028		$	28		$	28		$	28	$	28
	6.92	%		2005	Senior debentures, due 2028		391			391			391		391
	6.125	%		2004	Senior notes, due 2034		371			371			374		374
					Total		$	790		$	790		$	793	$	793
Fair Value of Life Policy Loans	The following table shows the fair value of our life policy loans, included in other invested assets, subject to fair value disclosure requirements:
	(In millions)		Quoted prices in			Significant other			Significant			Total
			active markets for			observable inputs			unobservable
			identical assets			(Level 2)			inputs
	At September 30, 2013		(Level 1)						(Level 3)
	Life policy loans		$	—		$	—		$	44		$	44
	At December 31, 2012
	Life policy loans		$	—		$	—		$	50		$	50
Debt
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Values of Deferred Annuities, Structured Settlements and Other Items	The following table shows fair values of our note payable and long-term debt subject to fair value disclosure requirements:
	(In millions)		Quoted prices in			Significant other			Significant			Total
			active markets for			observable inputs			unobservable
			identical assets			(Level 2)			inputs
	At September 30, 2013		(Level 1)						(Level 3)
	Note payable		$	—		$	104		$	—		$	104
	6.900% senior debentures, due 2028		—			32			—			32
	6.920% senior debentures, due 2028		—			470			—			470
	6.125% senior notes, due 2034		—			398			—			398
	Total		$	—		$	1,004		$	—		$	1,004
	At December 31, 2012
	Note payable		$	—		$	104		$	—		$	104
	6.900% senior debentures, due 2028		—			31			—			31
	6.920% senior debentures, due 2028		—			479			—			479
	6.125% senior notes, due 2034		—			431			—			431
	Total		$	—		$	1,045		$	—		$	1,045
Deferred Annuities, Structured Settlements, And Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Values of Deferred Annuities, Structured Settlements and Other Items	The following table shows fair values of our deferred annuities and structured settlements, included in life policy and investment contract reserves, subject to fair value disclosure requirements:
	(In millions)		Quoted prices in			Significant other			Significant			Total
			active markets for			observable inputs			unobservable
			identical assets			(Level 2)			inputs
	At September 30, 2013		(Level 1)						(Level 3)
	Deferred annuities		$	—		$	—		$	881		$	881
	Structured settlements		—			218			—			218
	Total		$	—		$	218		$	881		$	1,099
	At December 31, 2012
	Deferred annuities		$	—		$	—		$	898		$	898
	Structured settlements		—			240			—			240
	Total		$	—		$	240		$	898		$	1,138

Property_Casualty_Loss_and_Los1

Property Casualty Loss and Loss Expenses (Tables)	9 Months Ended
	Sep. 30, 2013
Premiums Written, Net [Abstract]
Consolidated Property Casualty Loss And Loss Expense Reserves	This table summarizes activity for our consolidated property casualty loss and loss expense reserves:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Gross loss and loss expense reserves,	$	4,219		$	4,337		$	4,169		$	4,280
	beginning of period
	Less reinsurance receivable	333			332			356			375
	Net loss and loss expense reserves,	3,886			4,005			3,813			3,905
	beginning of period
	Net incurred loss and loss expenses related to:
	Current accident year	631			611			1,840			1,991
	Prior accident years	(38		)	(86		)	(140		)	(287		)
	Total incurred	593			525			1,700			1,704
	Net paid loss and loss expenses related to:
	Current accident year	329			364			699			778
	Prior accident years	233			229			897			894
	Total paid	562			593			1,596			1,672
	Net loss and loss expense reserves,	3,917			3,937			3,917			3,937
	end of period
	Plus reinsurance receivable	321			343			321			343
	Gross loss and loss expense reserves,	$	4,238		$	4,280		$	4,238		$	4,280
	end of period

Life_Policy_and_Investment_Con1

Life Policy and Investment Contract Reserves (Tables)	9 Months Ended
	Sep. 30, 2013
Liability for Future Policy Benefits [Abstract]
Reserve For Losses Loss Adjustment Expenses Table [Text Block]	This table summarizes our life policy and investment contract reserves:
	(In millions)	September 30,		December 31, 2012
		2013
	Ordinary/traditional life	$	796	$	752
	Universal life	512		483
	Deferred annuities	860		850
	Structured settlements	189		193
	Other	16		17
	Total life policy and investment contract reserves	$	2,373	$	2,295

Deferred_Acquisition_Costs_Tab

Deferred Acquisition Costs (Tables)	9 Months Ended
	Sep. 30, 2013
Deferred Costs [Abstract]
Deferred Policy Acquisition Costs And Asset Reconciliation, Including the Amortized Deferred Policy Acquisition Costs	The table below shows the deferred policy acquisition costs and asset reconciliation.
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Deferred policy acquisition costs asset at beginning of period	$	546		$	484		$	470		$	477
	Capitalized deferred policy acquisition costs	211			192			612			554
	Amortized deferred policy acquisition costs	(190		)	(180		)	(552		)	(517		)
	Amortized shadow deferred policy acquisition costs	9			(5		)	46			(23		)
	Deferred policy acquisition costs asset at end of period	$	576		$	491		$	576		$	491

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	3 Months Ended																			9 Months Ended
	Sep. 30, 2013																			Sep. 30, 2013
Accumulated Other Comprehensive Income [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)
	(In millions)	Three months ended September 30,																		(In millions)	Nine months ended September 30,
		2013									2012										2013									2012
		Before tax			Income tax			Net			Before tax			Income tax			Net				Before tax			Income tax			Net			Before tax			Income tax			Net
	Accumulated unrealized gains, net, on investments available for sale,	$	1,987		$	686		$	1,301		$	1,664		$	573		$	1,091		Accumulated unrealized gains, net, on investments available for sale,	$	1,875		$	647		$	1,228		$	1,489		$	512		$	977
	beginning of period																			beginning of period
	Other comprehensive income before reclassification	82			29			53			262			93			169			Other comprehensive income before reclassification	246			85			161			456			160			296
	Reclassification adjustment for realized investment gains, net,	(20		)	(7		)	(13		)	(9		)	(4		)	(5		)	Reclassification adjustment for realized investment gains, net,	(72		)	(24		)	(48		)	(28		)	(10		)	(18		)
	included in net income																			included in net income
	Effect on other comprehensive income	62			22			40			253			89			164			Effect on other comprehensive income	174			61			113			428			150			278
	Accumulated unrealized gains, net, on investments available for sale,	$	2,049		$	708		$	1,341		$	1,917		$	662		$	1,255		Accumulated unrealized gains, net, on investments available for sale,	$	2,049		$	708		$	1,341		$	1,917		$	662		$	1,255
	end of period																			end of period
	Accumulated unrealized losses, net, for pension obligations,	$	(96	)	$	(33	)	$	(63	)	$	(85	)	$	(30	)	$	(55	)	Accumulated unrealized losses, net, for pension obligations,	$	(101	)	$	(35	)	$	(66	)	$	(88	)	$	(31	)	$	(57	)
	beginning of period																			beginning of period
	Other comprehensive income before reclassification	—			—			—			—			—			—			Effect on other comprehensive income	7			3			4			5			2			3
	Reclassification adjustment for amortization of actuarial loss	2			1			1			2			1			1			Accumulated unrealized losses, net, for pension obligations,	$	(94	)	$	(32	)	$	(62	)	$	(83	)	$	(29	)	$	(54	)
	and prior service cost, net, included in net income																			end of period
	Effect on other comprehensive income	2			1			1			2			1			1
																				Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(50	)	$	(17	)	$	(33	)	$	(29	)	$	(10	)	$	(19	)
	Accumulated unrealized losses, net, for pension obligations,	$	(94	)	$	(32	)	$	(62	)	$	(83	)	$	(29	)	$	(54	)	life policy reserves and other, beginning of period
	end of period																			Other comprehensive income before reclassification	36			12			24			(15		)	(5		)	(10		)
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(26	)	$	(9	)	$	(17	)	$	(39	)	$	(13	)	$	(26	)	Reclassification adjustment for life deferred acquisition costs,	(5		)	(2		)	(3		)	(1		)	—			(1		)
	life policy reserves and other, beginning of period																			life policy reserves and other, net, included in net income
	Other comprehensive income before reclassification	9			2			7			(5		)	(2		)	(3		)	Effect on other comprehensive income	31			10			21			(16		)	(5		)	(11		)
	Reclassification adjustment for life deferred acquisition costs,	(2		)	—			(2		)	(1		)	—			(1		)	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(19	)	$	(7	)	$	(12	)	$	(45	)	$	(15	)	$	(30	)
	life policy reserves and other, net, included in net income																			life policy reserves and other, end of period
	Effect on other comprehensive income	7			2			5			(6		)	(2		)	(4		)
																				Accumulated other comprehensive income, beginning of period	$	1,724		$	595		$	1,129		$	1,372		$	471		$	901
	Accumulated unrealized losses, net, on life deferred acquisition costs,	$	(19	)	$	(7	)	$	(12	)	$	(45	)	$	(15	)	$	(30	)
	life policy reserves and other, end of period																			Change in unrealized gains, net, on investments available for sale	174			61			113			428			150			278
	Accumulated other comprehensive income, beginning of period	$	1,865		$	644		$	1,221		$	1,540		$	530		$	1,010		Change in pension obligations	7			3			4			5			2			3
	Change in unrealized gains, net, on investments available for sale	62			22			40			253			89			164			Change in life deferred acquisition costs, life policy reserves	31			10			21			(16		)	(5		)	(11		)
																				and other
	Change in pension obligations	2			1			1			2			1			1			Effect on other comprehensive income	212			74			138			417			147			270
	Change in life deferred acquisition costs, life policy reserves	7			2			5			(6		)	(2		)	(4		)	Accumulated other comprehensive income, end of period	$	1,936		$	669		$	1,267		$	1,789		$	618		$	1,171
	and other
	Effect on other comprehensive income	71			25			46			249			88			161
	Accumulated other comprehensive income, end of period	$	1,936		$	669		$	1,267		$	1,789		$	618		$	1,171

Reinsurance_Tables

Reinsurance (Tables)	9 Months Ended
	Sep. 30, 2013
Reinsurance Disclosures [Abstract]
Earned Consolidated Property Casualty Insurance Premiums On Assumed And Ceded Business	Our condensed consolidated statements of income include earned consolidated property casualty insurance premiums on assumed and ceded business:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Direct earned premiums	$	1,002		$	898		$	2,895		$	2,605
	Assumed earned premiums	3			1			8			7
	Ceded earned premiums	(51		)	(48		)	(150		)	(137		)
	Net earned premiums	$	954		$	851		$	2,753		$	2,475
Incurred Consolidated Property Casualty Insurance Loss And Loss Expenses On Assumed And Ceded Business	Our condensed consolidated statements of income include incurred consolidated property casualty insurance loss and loss expenses on assumed and ceded business:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Direct incurred loss and loss expenses	$	597		$	562		$	1,725		$	1,745
	Assumed incurred loss and loss expenses	1			(3		)	8			3
	Ceded incurred loss and loss expenses	(5		)	(34		)	(33		)	(44		)
	Net incurred loss and loss expenses	$	593		$	525		$	1,700		$	1,704
Earned Life Insurance Premiums On Ceded Business	Our condensed consolidated statements of income include earned life insurance premiums on ceded business:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Direct earned premiums	$	52		$	52		$	166		$	170
	Assumed earned premiums	—			—			—			—
	Ceded earned premiums	(14		)	(14		)	(42		)	(40		)
	Net earned premiums	$	38		$	38		$	124		$	130
Life Insurance Contract Holders' Benefits Incurred On Ceded Business	Our condensed consolidated statements of income include life insurance policyholders’ benefits incurred on ceded business:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Direct policyholders' benefits incurred	$	64		$	62		$	190		$	172
	Assumed policyholders' benefits incurred	—			—			—			—
	Ceded policyholders' benefits incurred	(15		)	(16		)	(49		)	(36		)
	Net policyholders' benefits incurred	$	49		$	46		$	141		$	136

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Differences Between The 35 Percent Statutory Income Tax Rate And Effective Income Tax Rate	The differences between the 35 percent statutory income tax rate and our effective income tax rate were as follows:
	(Dollars in millions)	Three months ended September 30,										Nine months ended September 30,
		2013					2012					2013					2012
	Tax at statutory rate	$	64		35	%	$	53		35	%	$	191		35	%	$	103		35	%
	Increase (decrease) resulting from:
	Tax-exempt income from municipal bonds	(8		)	(4.4	)	(8		)	(5.3	)	(24		)	(4.4	)	(25		)	(8.5	)
	Dividend received exclusion	(6		)	(3.3	)	(6		)	(4.0	)	(18		)	(3.3	)	(17		)	(5.8	)
	Other	1			0.7		2			1.3		3			0.5		3			1.1
	Provision for income taxes	$	51		28	%	$	41		27	%	$	152		27.8	%	$	64		21.8	%

Net_Income_Per_Common_Share_Ta

Net Income Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]
Calculations For Basic And Diluted Earnings Per Share	The table shows calculations for basic and diluted earnings per share:
	(Dollars in millions except share data in thousands)	Three months ended September 30,				Nine months ended September 30,
		2013		2012		2013		2012
	Numerator:
	Net income—basic and diluted	$	131	$	111	$	395	$	229
	Denominator:
	Weighted-average common shares outstanding	163,710		162,555		163,454		162,419
	Effect of stock-based awards:
	Stock options	1,184		563		1,131		441
	Nonvested shares	707		739		719		647
	Adjusted weighted-average shares	165,601		163,857		165,304		163,507
	Earnings per share:
	Basic	$	0.8	$	0.69	$	2.42	$	1.41
	Diluted	0.79		0.68		2.39		1.4
	Number of anti-dilutive stock-based awards	335		5,045		390		6,000

Employee_Retirement_Benefits_T

Employee Retirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2013
Compensation and Retirement Disclosure [Abstract]
Schedule of Defined Benefit Plans Disclosures	The following summarizes the components of net periodic costs for our qualified and supplemental pension plans:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Service cost	$	4		$	3		$	10		$	9
	Interest cost	4			4			10			11
	Expected return on plan assets	(5		)	(4		)	(13		)	(12		)
	Amortization of actuarial loss and prior service	2			2			7			5
	cost
	Net periodic benefit cost	$	5		$	5		$	14		$	13

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]
Segment Information	Segment information is summarized in the following table:
	(In millions)	Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Revenues:
	Commercial lines insurance
	Commercial casualty	$	221		$	197		$	636		$	569
	Commercial property	161			138			460			403
	Commercial auto	124			108			355			315
	Workers' compensation	95			89			270			255
	Specialty packages	38			37			114			112
	Surety and executive risk	30			28			89			82
	Machinery and equipment	11			10			32			29
	Commercial lines insurance premiums	680			607			1,956			1,765
	Fee revenue	1			—			2			2
	Total commercial lines insurance	681			607			1,958			1,767
	Personal lines insurance
	Personal auto	112			101			328			299
	Homeowner	103			90			298			261
	Other personal lines	29			28			86			82
	Personal lines insurance premiums	244			219			712			642
	Fee revenue	—			1			1			2
	Total personal lines insurance	244			220			713			644
	Excess and surplus lines insurance	30			25			85			68
	Life insurance	38			38			124			130
	Separate account investment management fees	1			1			3			1
	Total life insurance	39			39			127			131
	Investment operations
	Investment income, net of expenses	133			132			392			395
	Realized investment gains, net	22			10			77			29
	Total investment revenue	155			142			469			424
	Other	3			2			7			7
	Total revenues	$	1,152		$	1,035		$	3,359		$	3,041
	Income (loss) before income taxes:
	Insurance underwriting results
	Commercial lines insurance	$	43		$	60		$	135		$	74
	Personal lines insurance	14			(12		)	33			(89		)
	Excess and surplus lines insurance	4			(3		)	5			(8		)
	Life insurance	—			—			10			(2		)
	Investment operations	134			121			409			362
	Other	(13		)	(14		)	(45		)	(44		)
	Total	$	182		$	152		$	547		$	293
	Identifiable assets:	September 30,			December 31, 2012
		2013
	Property casualty insurance	$	2,479		$	2,395
	Life insurance	1,263			1,201
	Investment operations	13,137			12,599
	Other	460			353
	Total	$	17,339		$	16,548

Investments_Analysis_of_Cost_o

Investments - Analysis of Cost or Amortized Cost, Gross Unrealized Gains and Losses and Fair Value for Investments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	$8,502	$8,222
Gross Unrealized Gains	600	874
Gross Unrealized Losses	64	3
Fair Value	9,038	9,093
Debt Securities | States, Municipalities And Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	3,046	3,040
Gross Unrealized Gains	146	250
Gross Unrealized Losses	17	1
Fair Value	3,175	3,289
Debt Securities | Convertibles And Bonds With Warrants Attached
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	16	31
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	16	31
Debt Securities | United States Government
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	7	7
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Fair Value	7	8
Debt Securities | Government-Sponsored Enterprises
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	209	164
Gross Unrealized Gains	0	0
Gross Unrealized Losses	19	0
Fair Value	190	164
Debt Securities | Foreign Government
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	10	3
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	10	3
Debt Securities | Commercial Mortgage Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	79	27
Gross Unrealized Gains	0	1
Gross Unrealized Losses	3	0
Fair Value	76	28
Debt Securities | Corporate Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	5,135	4,950
Gross Unrealized Gains	454	622
Gross Unrealized Losses	25	2
Fair Value	5,564	5,570
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	2,471	2,369
Gross Unrealized Gains	1,516	1,014
Gross Unrealized Losses	3	10
Fair Value	3,984	3,373
Equity Securities | Common Stock
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	2,394	2,270
Gross Unrealized Gains	1,482	977
Gross Unrealized Losses	3	9
Fair Value	3,873	3,238
Equity Securities | Preferred Stock
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	77	99
Gross Unrealized Gains	34	37
Gross Unrealized Losses	0	1
Fair Value	111	135
Fixed Maturities And Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	10,973	10,591
Gross Unrealized Gains	2,116	1,888
Gross Unrealized Losses	67	13
Fair Value	$13,022	$12,466

Investments_Fair_Values_and_Un

Investments - Fair Values and Unrealized Losses by Investment Category and by Duration of Securities' Continuous Unrealized Loss Position (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	$1,237	$223
Less than 12 months Unrealized Losses	64	12
12 months or more Fair Value	43	17
12 months or more Unrealized Losses	3	1
Total Fair Value	1,280	240
Total Unrealized Losses	67	13
Fixed Maturities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	1,159	112
Less than 12 months Unrealized Losses	61	2
12 months or more Fair Value	43	17
12 months or more Unrealized Losses	3	1
Total Fair Value	1,202	129
Total Unrealized Losses	64	3
Fixed Maturities | States, Municipalities And Political Subdivisions
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	371	53
Less than 12 months Unrealized Losses	17	1
12 months or more Fair Value	8	0
12 months or more Unrealized Losses	0	0
Total Fair Value	379	53
Total Unrealized Losses	17	1
Fixed Maturities | Foreign Government Debt Securities [Member]
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	9
Less than 12 months Unrealized Losses	0
12 months or more Fair Value	0
12 months or more Unrealized Losses	0
Total Fair Value	9
Total Unrealized Losses	0
Fixed Maturities | United States Government
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	1
Less than 12 months Unrealized Losses	0
12 months or more Fair Value	0
12 months or more Unrealized Losses	0
Total Fair Value	1
Total Unrealized Losses	0
Fixed Maturities | Government-Sponsored Enterprises
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	190	1
Less than 12 months Unrealized Losses	19	0
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	0	0
Total Fair Value	190	1
Total Unrealized Losses	19	0
Fixed Maturities | Commercial Mortgage Backed Securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	62
Less than 12 months Unrealized Losses	3
12 months or more Fair Value	0
12 months or more Unrealized Losses	0
Total Fair Value	62
Total Unrealized Losses	3
Fixed Maturities | Corporate Securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	526	58
Less than 12 months Unrealized Losses	22	1
12 months or more Fair Value	35	17
12 months or more Unrealized Losses	3	1
Total Fair Value	561	75
Total Unrealized Losses	25	2
Equity Securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	78	111
Less than 12 months Unrealized Losses	3	10
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	0	0
Total Fair Value	78	111
Total Unrealized Losses	3	10
Equity Securities | Common Stock
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	74	107
Less than 12 months Unrealized Losses	3	9
12 months or more Fair Value	0
12 months or more Unrealized Losses	0
Total Fair Value	74	107
Total Unrealized Losses	3	9
Equity Securities | Preferred Stock
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	4	4
Less than 12 months Unrealized Losses	0	1
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	0	0
Total Fair Value	4	4
Total Unrealized Losses	$0	$1

Investments_Realized_Investmen

Investments - Realized Investment Gains and Losses and Change in Unrealized Investment Gains and Losses and Other Items (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
Investment income summary:
Interest on fixed maturities	$104	$105	$309	$317
Dividends on equity securities	30	28	87	81
Other investment income	1	1	2	3
Total	135	134	398	401
Less investment expenses	2	2	6	6
Total	133	132	392	395
Realized investment gains and losses summary:
Other	-2	0	-7	5
Realized gains on investments	22	10	77	29
Change in unrealized gains and losses summary:
Unrealized gains (losses) on investments available-for-sale	40	164	113	278
Adjustment to deferred acquisition costs and life policy reserves	9	-6	38	-21
Amortization of pension actuarial loss and prior service cost	2	2	7	5
Other	-2	0	-7	5
Income taxes on above	-25	-88	74	147
Other comprehensive income (loss), net of tax	46	161	138	270
Fixed Maturities
Realized investment gains and losses summary:
Gross realized gains	5	14	9	30
Gross realized losses	0	0	0	0
Other-than-temporary impairments	0	0	-2	0
Change in unrealized gains and losses summary:
Unrealized gains (losses) on investments available-for-sale	-28	110	-335	188
Equity Securities
Realized investment gains and losses summary:
Gross realized gains	15	1	64	30
Gross realized losses	0	0	0	-1
Other-than-temporary impairments	0	-2	0	-32
Securities with embedded derivatives	0	-4	1	1
Other	2	1	5	1
Realized gains on investments	22	10
Change in unrealized gains and losses summary:
Unrealized gains (losses) on investments available-for-sale	90	143	509	240
Other	$2	$1	$5	$1

Investments_Additional_Informa

Investments - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Gain (Loss) on Investments [Line Items]
Fixed maturities, fair value of hybrid securities	$16	$31
Impaired securities	0
12 months or more Unrealized Losses	3	1
Fixed maturity investments, Percentage of amortized costs	70.00%	70.00%
Investments in fair value, deposit with various states	13,723	13,164
Fixed Maturities
Gain (Loss) on Investments [Line Items]
Unrealized investment gains due to a net gain position	600	874
Number of securities total unrealized loss in an unrealized loss position for 12 months or more	9	4
12 months or more Unrealized Losses	3	1
Equity Securities
Gain (Loss) on Investments [Line Items]
Unrealized investment gains due to a net gain position	1,516	1,014
12 months or more Unrealized Losses	0	0
Procter And Gamble Company, Exxon Mobile Corporation And Chevron Corporation [Member]
Gain (Loss) on Investments [Line Items]
Unrealized investment gains due to a net gain position	$264
Common Stock
Gain (Loss) on Investments [Line Items]
Number of securities	3

Fair_Value_Measurements_Fair_V

Fair Value Measurements - Fair Value Hierarchy for Assets Measured at Fair Value on Recurring Basis (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]
Fixed maturities, at fair value	$9,038	$9,093
Equity securities, at fair value	3,984	3,373
Separate accounts	700	734
Fair value of asset	13,723	13,164
Top Hat Savings Plan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	12	9
Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	9,038	9,093
Debt Securities | States, Municipalities And Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	3,175	3,289
Debt Securities | Convertibles And Bonds With Warrants Attached
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	16	31
Debt Securities | United States Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	7	8
Debt Securities | Government-Sponsored Enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	190	164
Debt Securities | Foreign Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	10	3
Debt Securities | Commercial Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	76	28
Debt Securities | Corporate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	5,564	5,570
Equity Securities | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	3,873	3,238
Equity Securities | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	111	135
Taxable Fixed Maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Separate accounts	689	689
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of asset	3,892	3,255
Quoted prices in active markets for identical assets (Level 1) | Top Hat Savings Plan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	12	9
Quoted prices in active markets for identical assets (Level 1) | Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	7	8
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | States, Municipalities And Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Convertibles And Bonds With Warrants Attached
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | United States Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	7	8
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Government-Sponsored Enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Foreign Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Commercial Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Corporate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Equity Securities | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	3,873	3,238
Quoted prices in active markets for identical assets (Level 1) | Equity Securities | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	0	0
Quoted prices in active markets for identical assets (Level 1) | Taxable Fixed Maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Separate accounts	0	0
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of asset	9,826	9,904
Significant other observable inputs (Level 2) | Top Hat Savings Plan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Significant other observable inputs (Level 2) | Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	9,028	9,081
Significant other observable inputs (Level 2) | Debt Securities | States, Municipalities And Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	3,175	3,288
Significant other observable inputs (Level 2) | Debt Securities | Convertibles And Bonds With Warrants Attached
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	16	31
Significant other observable inputs (Level 2) | Debt Securities | United States Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Significant other observable inputs (Level 2) | Debt Securities | Government-Sponsored Enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	190	164
Significant other observable inputs (Level 2) | Debt Securities | Foreign Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	10	3
Significant other observable inputs (Level 2) | Debt Securities | Commercial Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	76	28
Significant other observable inputs (Level 2) | Debt Securities | Corporate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	5,561	5,567
Significant other observable inputs (Level 2) | Equity Securities | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	0	0
Significant other observable inputs (Level 2) | Equity Securities | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	109	134
Significant other observable inputs (Level 2) | Taxable Fixed Maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Separate accounts	689	689
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of asset	5	5
Significant unobservable inputs (Level 3) | Top Hat Savings Plan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	0	0
Significant unobservable inputs (Level 3) | Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	3	4
Significant unobservable inputs (Level 3) | Debt Securities | States, Municipalities And Political Subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	1
Significant unobservable inputs (Level 3) | Debt Securities | Convertibles And Bonds With Warrants Attached
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | United States Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | Government-Sponsored Enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | Foreign Government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | Commercial Mortgage Backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	0	0
Significant unobservable inputs (Level 3) | Debt Securities | Corporate Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	3	3
Significant unobservable inputs (Level 3) | Equity Securities | Common Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	0	0
Significant unobservable inputs (Level 3) | Equity Securities | Preferred Stock
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	2	1
Significant unobservable inputs (Level 3) | Taxable Fixed Maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Separate accounts	$0	$0

Fair_Value_Measurements_Change

Fair Value Measurements - Change in Level 3 Assets (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
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$6	$13	$5	$25
Total gains or losses (realized/unrealized):
Included in earnings	0	0	0	0
Included in other comprehensive income	0	0	0	5
Purchases	0	0	1	1
Sales	-1	-1	-1	-6
Transfers into Level 3	0	0	0	1
Transfers out of Level 3	0	0	0	-14
Ending balance	5	12	5	12
Corporate Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	3	4	3	18
Total gains or losses (realized/unrealized):
Included in earnings	0	0	0	0
Included in other comprehensive income	0	0	0	3
Purchases	0	0	0	0
Sales	0	0	0	-4
Transfers into Level 3	0	0	0	1
Transfers out of Level 3	0	0	0	-14
Ending balance	3	4	3	4
States, Municipalities And Political Subdivisions Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1	2	1	3
Total gains or losses (realized/unrealized):
Included in earnings	0	0	0	0
Included in other comprehensive income	0	0	0	0
Purchases	0	0	0	0
Sales	-1	-1	-1	-2
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	0	1	0	1
Preferred Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	2	7	1	4
Total gains or losses (realized/unrealized):
Included in earnings	0	0	0	0
Included in other comprehensive income	0	0	0	2
Purchases	0	0	1	1
Sales	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	$2	$7	$2	$7

Fair_Value_Measurements_Summar

Fair Value Measurements - Summary of Book Value and Principal Amounts of Long-Term Debt (Detail) (USD $)	9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Book value	$790	$790
Principal amount of debt	793	793
Senior Debentures 6.900% Due 2028
Debt Instrument [Line Items]
Interest rate	6.90%	6.90%
Debt issuance year	1998	1998
Book value	28	28
Principal amount of debt	28	28
Senior Debentures 6.920% Due 2028
Debt Instrument [Line Items]
Interest rate	6.92%	6.92%
Debt issuance year	2005	2005
Book value	391	391
Principal amount of debt	391	391
Senior Notes 6.152% Due 2034
Debt Instrument [Line Items]
Interest rate	6.13%	6.13%
Debt issuance year	2004	2004
Book value	371	371
Principal amount of debt	$374	$374

Fair_Value_Measurements_Fair_V1

Fair Value Measurements - Fair Values of Note Payable and Long-Term Debt (Detail) (USD $)	9 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of note payable	$104	$104
Total	1,004	1,045
Senior Debentures 6.900 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	6.90%	6.90%
Debt instrument, year of maturity	2028	2028
Fair value of senior debt	32	31
Senior Debentures 6.920 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	6.92%	6.92%
Debt instrument, year of maturity	2028	2028
Fair value of senior debt	470	479
Senior Notes 6.125 % Due 2034
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	6.13%	6.13%
Debt instrument, year of maturity	2034	2034
Fair value of senior debt	398	431
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of note payable	0	0
Total	0	0
Quoted prices in active markets for identical assets (Level 1) | Senior Debentures 6.900 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Quoted prices in active markets for identical assets (Level 1) | Senior Debentures 6.920 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Quoted prices in active markets for identical assets (Level 1) | Senior Notes 6.125 % Due 2034
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of note payable	104	104
Total	1,004	1,045
Significant other observable inputs (Level 2) | Senior Debentures 6.900 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	32	31
Significant other observable inputs (Level 2) | Senior Debentures 6.920 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	470	479
Significant other observable inputs (Level 2) | Senior Notes 6.125 % Due 2034
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	398	431
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of note payable	0	0
Total	0	0
Significant unobservable inputs (Level 3) | Senior Debentures 6.900 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Significant unobservable inputs (Level 3) | Senior Debentures 6.920 % Due 2028
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	0	0
Significant unobservable inputs (Level 3) | Senior Notes 6.125 % Due 2034
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of senior debt	$0	$0

Fair_Value_Measurements_Fair_V2

Fair Value Measurements - Fair Value of Life Policy Loans (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]
Fair value of life policy loans	$44	$50
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life policy loans	0	0
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life policy loans	0	0
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of life policy loans	$44	$50

Fair_Value_Measurements_Fair_V3

Fair Value Measurements - Fair Values of Deferred Annuities, Structured Settlements and Other Items (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]
Fair Value of life insurance liabilities	$1,099	$1,138
Deferred Annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	881	898
Structured Settlements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	218	240
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	0	0
Quoted prices in active markets for identical assets (Level 1) | Deferred Annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	0	0
Quoted prices in active markets for identical assets (Level 1) | Structured Settlements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	0	0
Significant other observable inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	218	240
Significant other observable inputs (Level 2) | Deferred Annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	0	0
Significant other observable inputs (Level 2) | Structured Settlements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	218	240
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	881	898
Significant unobservable inputs (Level 3) | Deferred Annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	881	898
Significant unobservable inputs (Level 3) | Structured Settlements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	$0	$0

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (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]
Finance receivable	$79	$75
Loss and loss expense reserves	4,307	4,230
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage of Level 3 assets measured at fair value	1.00%
Life Policy Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finance receivable	35	37
Deferred Annuities And Structured Settlements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loss and loss expense reserves	$1,049	$1,043

Property_Casualty_Loss_and_Los2

Property Casualty Loss and Loss Expenses - Consolidated Property Casualty Loss and Loss Expense Reserves (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
Summary of Consolidated Property Casualty Loss and Loss Expense Reserves [Roll Forward]
Gross loss and loss expense reserves, beginning of period	$4,219	$4,337	$4,169	$4,280
Less reinsurance receivable	333	332	356	375
Net loss and loss expense reserves, beginning of period	3,886	4,005	3,813	3,905
Current accident year	631	611	1,840	1,991
Prior accident years	-38	-86	-140	-287
Total incurred	593	525	1,700	1,704
Current accident year	329	364	699	778
Prior accident years	233	229	897	894
Total paid	562	593	1,596	1,672
Net loss and loss expense reserves, end of period	3,917	3,937	3,917	3,937
Plus reinsurance receivable	321	343	321	343
Gross loss and loss expense reserves, end of period	$4,238	$4,280	$4,238	$4,280

Property_Casualty_Loss_and_Los3

Property Casualty Loss and Loss Expenses - Additional Information (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
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Favorable reserve development on prior accident years	$38	$86	$140	$287
Life and Health Loss Reserves
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Reserve for loss and loss expenses	69	64	69	64
Commercial Lines
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Favorable reserve development on prior accident years	13		91
Commercial Lines | Catastrophe Development
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Favorable reserve development on prior accident years	9	12	24	39
Personal Lines
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Favorable reserve development on prior accident years	21		43
Excess And Surplus Lines Insurance
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Favorable reserve development on prior accident years	$4		$6

Reserves_in_Addition_to_Accoun

Reserves in Addition to Account Balance, Based on Expected No-Lapse Guarantee Benefits and Expected Policy Assessments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	$2,373	$2,295
Ordinary/Traditional Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	796	752
Universal Life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	512	483
Deferred Annuities
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	860	850
Structured Settlements
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	189	193
Other
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	$16	$17

Deferred_Acquisition_Costs_Def

Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (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
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset at beginning of period	$546	$484	$470	$477
Capitalized deferred policy acquisition costs	211	192	612	554
Amortized deferred policy acquisition costs	-190	-180	-552	-517
Amortized shadow deferred policy acquisition costs	9	-5	46	-23
Deferred policy acquisition costs asset at end of period	$576	$491	$576	$491

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Details) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	$1,267		$1,267			$1,129
Accumulated other comprehensive income, net of tax, end of period	1,267		1,267			1,129
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated unrealized gains, net, on investments available for sale, before tax, beginning of period	1,987	1,664	1,875	1,489
Other comprehensive income before reclassification, before tax	82	262	246	456
Reclassification adjustment for realized gains, net, included in net income, before tax	-20	-9	-72	-28
Effect on other comprehensive income, before tax	62	253	174	428
Accumulated unrealized gains, net, on investments available for sale, before tax, end of period	2,049	1,917	2,049	1,917
Accumulated Other Comprehensive Income Loss Tax [Abstract]
Accumulated unrealized gains, net, on investments available for sale and other invested assets, tax, beginning of period	708	662	708	662
Other comprehensive income before reclassification, tax	29	93	85	160
Reclassification adjustment for realized gains, net, included in net income, tax	-7	-4	-24	-10
Effect on other comprehensive income, tax	22	89	61	150
Accumulated unrealized gains, net, on investments available for sale and other invested assets, tax, end of period	686	573	647	512
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated unrealized gains, net, on investments available for sale and other invested assets, net of tax, beginning of period	1,301	1,091	1,228	977
Other comprehensive income before reclassification , net of tax	53	169	161	296
Reclassification adjustment for realized gains, net, included in net income, net of tax	-13	-5	-48	-18
Effect on other comprehensive income, net of tax	40	164	113	278
Accumulated unrealized gains, net, on investments available for sale and other invested assets, net of tax, end of period	1,341	1,255	1,341	1,255
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Other comprehensive income before reclassification, before tax	0	0
Accumulated unrealized losses, net, for pension obligations, before Tax, beginning of period	-96	-85	-101	-88
Reclassification adjustment for amortization of actuarial loss and prior service cost, net, included in net income, before tax	2	2
Effect on other comprehensive income, before tax	2	2	7	5
Accumulated unrealized losses, net, for pension obligations, before Tax, end of period	-94	-83	-94	-83
Accumulated Other Comprehensive Income Loss Tax [Abstract]
Other comprehensive income before reclassification, tax	0	0
Accumulated unrealized losses, net, for pension obligations, tax, beginning of period	-33	-30	-35	-31
Reclassification adjustment for amortization of actuarial loss and prior service cost, net, included in net income, tax	1	1
Effect on other comprehensive income, tax	1	1	3	2
Accumulated unrealized losses, net, for pension obligations, tax, end of period	-32	-29	-32	-29
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other comprehensive income before reclassification , net of tax	0	0
Accumulated unrealized losses, net, for pension obligations, net of tax, beginning of period	-63	-55	-66	-57
Reclassification adjustment for amortization of actuarial loss and prior service cost,net, included in net income, net of tax	1	1
Effect on other comprehensive income, net of tax	1	1	4	3
Accumulated unrealized losses, net, for pension obligations, net of tax, end of period	-62	-54	-62	-54
Accumulated Net Unrealized Gain (Loss) on Deferred Costs, Reserves And Other
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Other comprehensive income before reclassification, before tax	9	-5	36	-15
Other Comprehensive Income (Loss), Reclassification Adjustment for Life Deferred Acquisition Costs, Life Policy Reserves and Other, Before Tax	-2	-1	-5	-1
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, before tax, beginning of period	-26	-39	-50	-29
Effect on other comprehensive income, before tax	7	-6	31	-16
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, before tax, end of period	-19	-45	-19	-45
Accumulated Other Comprehensive Income Loss Tax [Abstract]
Other comprehensive income before reclassification, tax	2	-2	12	-5
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, tax, beginning of period	-9	-13	-17	-10
Other Comprehensive Income (Loss), Reclassification Adjustment for Life Deferred Acquisition Costs, Life Policy Reserves and Other, Tax	0	0	-2	0
Effect on other comprehensive income, tax	2	-2	10	-5
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, tax, end of period	-7	-15	-7	-15
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Other comprehensive income before reclassification , net of tax	7	-3	24	-10
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, beginning of period, net of tax	-17	-26	-33	-19
Other Comprehensive Income (Loss), Reclassification Adjustment for Life Deferred Acquisition Costs, Life Policy Reserves and Other, Net of Tax	-2	-1	-3	-1
Effect on other comprehensive income, net of tax	5	-4	21	-11
Accumulated unrealized losses, net, on life deferred acquisition costs, life policy reserves and other, end of period, net of tax	-12	-30	-12	-30
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated other comprehensive income, before taxes, beginning of period	1,865	1,540	1,724	1,372
Change in unrealized gains, net, on investments available for sale, before Tax	62	253	174	428
Change in pension obligations, before tax	2	2	7	5
Change in life deferred acquisition costs, life policy reserves and other, before Tax	7	-6	31	-16
Effect on other comprehensive income, before Tax	71	249	212	417
Accumulated other comprehensive income, before taxes, end of period	1,936	1,789	1,936	1,789
Accumulated Other Comprehensive Income Loss Tax [Abstract]
Accumulated other comprehensive income, tax, beginning of period	644	530	595	471
Change in unrealized gains, net, on investments available for sale and other invested assets, tax	22	89	61	150
Change in pension obligations, tax	1	1	3	2
Change in life deferred acquisition costs, life policy reserves and other, tax	2	-2	10	-5
Effect on other comprehensive income, tax	25	88	74	147
Accumulated other comprehensive income, tax, end of period	669	618	669	618
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	1,267	1,171	1,267	1,171	1,221	1,129	1,010	901
Change in unrealized gains, net, on investments available for sale, net of tax	40	164	113	278
Change in pension obligations, net of tax	1	1	4	3
Change in life deferred acquisition costs, life policy reserves and other, net of tax	5	-4	21	-11
Effect on other comprehensive income, net of tax	46	161	138	270
Accumulated other comprehensive income, net of tax, end of period	$1,267	$1,171	$1,267	$1,171	$1,221	$1,129	$1,010	$901

Reinsurance_Earned_Consolidate

Reinsurance - Earned Consolidated Property Casualty Insurance Premiums on Assumed and Ceded Business (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
Reinsurance Disclosures [Abstract]
Direct earned premiums	$1,002	$898	$2,895	$2,605
Assumed earned premiums	3	1	8	7
Ceded earned premiums	-51	-48	-150	-137
Net earned premiums	$954	$851	$2,753	$2,475

Reinsurance_Incurred_Consolida

Reinsurance - Incurred Consolidated Property Casualty Insurance Loss and Loss Expenses on Assumed and Ceded Business (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
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Net incurred loss and loss expenses	$642	$571	$1,841	$1,840
Property, Liability And Casualty Insurance Segment
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct incurred loss and loss expenses	597	562	1,725	1,745
Assumed incurred loss and loss expenses	1	-3	8	3
Ceded incurred loss and loss expenses	-5	-34	-33	-44
Net incurred loss and loss expenses	$593	$525	$1,700	$1,704

Reinsurance_Earned_Life_Insura

Reinsurance - Earned Life Insurance Premiums on Ceded Business (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
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct earned premiums	$1,002	$898	$2,895	$2,605
Assumed earned premiums	3	1	8	7
Ceded earned premiums	-51	-48	-150	-137
Life Insurance Segment
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct earned premiums	52	52	166	170
Assumed earned premiums	0	0	0	0
Ceded earned premiums	-14	-14	-42	-40
Net earned premiums	$38	$38	$124	$130

Reinsurance_Life_Insurance_Con

Reinsurance - Life Insurance Contract Holders' Benefits Incurred on Ceded Business (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
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Assumed earned premiums	$3	$1	$8	$7
Net incurred loss and loss expenses	642	571	1,841	1,840
Life Insurance Segment
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct policyholders' benefits incurred	64	62	190	172
Assumed policyholders' benefits incurred	0	0	0
Assumed earned premiums	0	0	0	0
Ceded policyholders' benefits incurred	-15	-16	-49	-36
Net incurred loss and loss expenses	$49	$46	$141	$136

Income_Taxes_Differences_Betwe

Income Taxes - Differences Between 35 Percent Statutory Income Tax Rate and Effective Income Tax Rate (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
Income Tax Disclosure [Abstract]
Tax at statutory rate	$64	$53	$191	$103
Increase (decrease) resulting from:
Tax-exempt income from municipal bonds	-8	-8	-24	-25
Dividend received exclusion	-6	-6	-18	-17
Other	1	2	3	3
Total provision for income taxes	$51	$41	$152	$64
Tax at statutory rate	35.00%	35.00%	35.00%	35.00%
Increase (decrease) resulting from:
Tax-exempt income from municipal bonds	-4.40%	-5.30%	-4.40%	-8.50%
Dividend received exclusion	-3.30%	-4.00%	-3.30%	-5.80%
Other	0.70%	1.30%	0.50%	1.10%
Provision (benefit) for income taxes	28.00%	27.00%	27.80%	21.80%

Income_Taxes_Narrative_Details

Income Taxes (Narrative) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]
Tax at statutory rate, percentage	35.00%	35.00%	35.00%	35.00%

Net_Income_Per_Common_Share_Ca

Net Income Per Common Share - Calculations for Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator:
Net income-basic and diluted	$131	$111	$395	$229
Denominator:
Weighted-average common shares outstanding (in shares)	163,710	162,555	163,454	162,419
Adjusted diluted weighted-average shares (in shares)	165,601	163,857	165,304	163,507
Earnings per share:
Basic (in USD per share)	$0.80	$0.69	$2.42	$1.41
Diluted (in USD per share)	$0.79	$0.68	$2.39	$1.40
Number of anti-dilutive stock-based awards (in shares)	335	5,045	390	6,000
Nonvested shares
Denominator:
Effect of stock-based awards (in shares)	1,184	563	1,131	441
Stock Options
Denominator:
Effect of stock-based awards (in shares)	707	739	719	647

Employee_Retirement_Benefits_C

Employee Retirement Benefits - Components of Net Periodic Costs for Qualified and Supplemental Pension Plans (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
Compensation and Retirement Disclosure [Abstract]
Service cost	$4	$3	$10	$9
Interest cost	4	4	10	11
Expected return on plan assets	-5	-4	-13	-12
Amortization of actuarial loss and prior service cost	2	2	7	5
Net periodic benefit cost	$5	$5	$14	$13

Employee_Retirement_Benefits_A

Employee Retirement Benefits - Additional Information (Detail) (USD $)	3 Months Ended			9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Mar. 31, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Matching contributions for 401(k) plan and Top Hat savings plan	$2		$2	$7	$7
Pension Contributions		15
Qualified Pension Plans [Member] | Future Period [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected contribution by employer for the remainder of the year	$0		$0	$0	$0

Segment_Information_Detail

Segment Information (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	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$1,152	$1,035	$3,359	$3,041
Net Investment Income	133	132	392	395
Realized gains on investments	22	10	77	29
Income (loss) before income taxes	182	152	547	293
Identifiable assets	17,339		17,339		16,548
Property Casualty Insurance Segment
Segment Reporting Information [Line Items]
Identifiable assets	2,479		2,479		2,395
Commercial Lines
Segment Reporting Information [Line Items]
Revenues	681	607	1,958	1,767
Income (loss) before income taxes	43	60	135	74
Commercial Lines | Commercial Casualty Segment
Segment Reporting Information [Line Items]
Revenues	221	197	636	569
Commercial Lines | Commercial Property Segment
Segment Reporting Information [Line Items]
Revenues	161	138	460	403
Commercial Lines | Commercial Auto Segment
Segment Reporting Information [Line Items]
Revenues	124	108	355	315
Commercial Lines | Workers' Compensation
Segment Reporting Information [Line Items]
Revenues	95	89	270	255
Commercial Lines | Specialty Packages
Segment Reporting Information [Line Items]
Revenues	38	37	114	112
Commercial Lines | Surety and Executive Risk
Segment Reporting Information [Line Items]
Revenues	30	28	89	82
Commercial Lines | Machinery and Equipment
Segment Reporting Information [Line Items]
Revenues	11	10	32	29
Commercial Lines | Commercial Lines Insurance Premiums
Segment Reporting Information [Line Items]
Revenues	680	607	1,956	1,765
Commercial Lines | Other Fee Revenue
Segment Reporting Information [Line Items]
Revenues	1	0	2	2
Personal Lines
Segment Reporting Information [Line Items]
Revenues	244	220	713	644
Income (loss) before income taxes	14	-12	33	-89
Personal Lines | Personal Auto
Segment Reporting Information [Line Items]
Revenues	112	101	328	299
Personal Lines | Home Owner Segment
Segment Reporting Information [Line Items]
Revenues	103	90	298	261
Personal Lines | Other Personal Lines
Segment Reporting Information [Line Items]
Revenues	29	28	86	82
Personal Lines | Commercial Lines Insurance Premiums
Segment Reporting Information [Line Items]
Revenues	244	219	712	642
Personal Lines | Other Fee Revenue
Segment Reporting Information [Line Items]
Revenues	0	1	1	2
Excess And Surplus Lines Insurance
Segment Reporting Information [Line Items]
Revenues	30	25	85	68
Income (loss) before income taxes	4	-3	5	-8
Life Insurance Segment
Segment Reporting Information [Line Items]
Revenues	39	39	127	131
Income (loss) before income taxes	0	0	10	-2
Identifiable assets	1,263		1,263		1,201
Life Insurance Segment | Life Insurance Excluding Account Investment Fees
Segment Reporting Information [Line Items]
Revenues	38	38	124	130
Life Insurance Segment | Seperate Account Investment Management Fees
Segment Reporting Information [Line Items]
Revenues	1	1	3	1
Investments Segment
Segment Reporting Information [Line Items]
Revenues	155	142	469	424
Income (loss) before income taxes	134	121	409	362
Identifiable assets	13,137		13,137		12,599
Investments Segment | Investment Income, Net
Segment Reporting Information [Line Items]
Net Investment Income	133	132	392	395
Investments Segment | Realized Investment Gains, Net
Segment Reporting Information [Line Items]
Realized gains on investments	22	10	77	29
Other
Segment Reporting Information [Line Items]
Revenues	3	2	7	7
Income (loss) before income taxes	-13	-14	-45	-44
Identifiable assets	$460		$460		$353

Segment_Information_Narrative_

Segment Information - Narrative (Details)	9 Months Ended
	Sep. 30, 2013
	segment
	industry
Segment Reporting [Abstract]
Number of Industries Operating In	2
Number of Reportable Segments	5

Commitments_and_Contingent_Lia1

Commitments and Contingent Liabilities (Narrative) (Details) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Loss Contingencies [Line Items]
Estimate for which the risk of loss is more than remote but not probable	$1