Cincinnati Financial (CINF) 10-Q 2 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Jul. 28, 2017
Document Documentand Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Trading Symbol	CINF
Entity Registrant Name	CINCINNATI FINANCIAL CORP
Entity Central Index Key	20,286
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		163,982,422

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Investments
Fixed maturities, at fair value (amortized cost: 2017—$10,106; 2016—$9,799)	$ 10,502	$ 10,085
Equity securities, at fair value (cost: 2017—$3,218; 2016—$2,995)	5,799	5,334
Other invested assets	93	81
Total investments	16,394	15,500
Cash and cash equivalents	606	777
Investment income receivable	130	134
Finance receivable	54	51
Premiums receivable	1,651	1,533
Reinsurance recoverable	532	545
Prepaid reinsurance premiums	48	62
Deferred policy acquisition costs	678	637
Land, building and equipment, net, for company use (accumulated depreciation: 2017—$245; 2016—$237)	184	183
Other assets	171	198
Separate accounts	790	766
Total assets	21,238	20,386
Insurance reserves
Loss and loss expense reserves	5,281	5,085
Life policy and investment contract reserves	2,702	2,671
Unearned premiums	2,461	2,307
Other liabilities	767	786
Deferred income tax	1,021	865
Note payable	17	20
Long-term debt and capital lease obligations	826	826
Separate accounts	790	766
Total liabilities	13,865	13,326
Commitments and contingent liabilities (Note 12)
Shareholders' Equity
Common stock, par value—$2 per share; (authorized: 2017 and 2016—500 million shares; issued: 2017 and 2016—198.3 million shares)	397	397
Paid-in capital	1,249	1,252
Retained earnings	5,174	5,037
Accumulated other comprehensive income	1,925	1,693
Treasury stock at cost (2017—34.4 million shares and 2016—33.9 million shares)	(1,372)	(1,319)
Total shareholders' equity	7,373	7,060
Total liabilities and shareholders' equity	$ 21,238	$ 20,386

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 10,106	$ 9,799
Equity securities, cost	3,218	2,995
Land, building and equipment, accumulated depreciation	$ 245	$ 237
Common stock, par value	$ 2	$ 2
Common stock, authorized	500	500
Common stock, issued	198.3	198.3
Common stock, outstanding	198.3	198.3
Treasury stock, shares	34.4	33.9

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues [Abstract]
Earned premiums	$ 1,241	$ 1,173	$ 2,449	$ 2,327
Investment income, net of expenses	151	149	300	294
Realized investment gains and losses, net	(11)	44	149	105
Fee revenues	4	3	9	6
Other revenues	1	2	2	3
Total revenues	1,386	1,371	2,909	2,735
Benefits and Expenses
Insurance losses and contract holders' benefits	854	821	1,707	1,545
Underwriting, acquisition and insurance expenses	387	366	764	726
Interest expense	13	13	26	26
Other operating expenses	4	5	8	7
Total benefits and expenses	1,258	1,205	2,505	2,304
Income Before Income Taxes	128	166	404	431
Provision (Benefit) for Income Taxes
Current	31	48	71	113
Deferred	(3)	(5)	32	7
Total provision for income taxes	28	43	103	120
Net Income	$ 100	$ 123	$ 301	$ 311
Per Common Share
Net income-basic (in USD per share)	$ 0.61	$ 0.75	$ 1.83	$ 1.89
Net income-diluted (in USD per share)	$ 0.60	$ 0.74	$ 1.81	$ 1.87

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net Income	$ 100	$ 123	$ 301	$ 311
Change in unrealized gains and losses on investments, net of tax of $77, $103, $123 and $203, respectively	144	186	229	376
Amortization of pension actuarial gains and losses and prior service cost, net of tax of $0, $0, $0 and $1, respectively	0	1	1	1
Change in life deferred acquisition costs, life policy reserves and other, net of tax of $0, $(3), $1 and $(4), respectively	1	(4)	2	(7)
Other comprehensive income	145	183	232	370
Comprehensive Income	$ 245	$ 306	$ 533	$ 681

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	$ 77	$ 103	$ 123	$ 203
Other Comprehensive Income Loss, Pension And Other Postretirement Benefit Plans, Net Actuarial Loss And Prior Service Cost Arising During Period, Tax	0	0	0	1
Other Comprehensive Income, Change in Life Deferred Acquisition Costs, Life Policy Reserves and Other, Tax	$ 0	$ (3)	$ 1	$ (4)

Condensed Consolidated Stateme7

Condensed Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common equities	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income	Treasury Stock
Beginning Balance at Dec. 31, 2015		$ 397	$ 1,232	$ 4,762	$ 1,344	$ (1,308)
Share-based awards		0	(10)			23
Share-based compensation			13
Other			2			2
Net Income	$ 311			311
Dividends declared				(158)
Other comprehensive income	370				370
Shares acquired - share repurchase authorization						(2)
Shares acquired - share-based compensation plans						(7)
Ending Balance at Jun. 30, 2016	6,971	$ 397	1,237	4,915	1,714	(1,292)
Beginning Balance (in shares) at Dec. 31, 2015		163.9
Share-based awards (in shares)		0.7
Shares acquired - share repurchase authorization (in shares)		0
Shares acquired - share-based compensation plans (in shares)		(0.1)
Ending Balance (in shares) at Jun. 30, 2016		164.5
Beginning Balance at Dec. 31, 2016	7,060	$ 397	1,252	5,037	1,693	(1,319)
Share-based awards		0	(18)			19
Share-based compensation			14
Other			1			2
Net Income	301			301
Dividends declared				(164)
Other comprehensive income	232				232
Shares acquired - share repurchase authorization						(70)
Shares acquired - share-based compensation plans						(4)
Ending Balance at Jun. 30, 2017	$ 7,373	$ 397	$ 1,249	$ 5,174	$ 1,925	$ (1,372)
Beginning Balance (in shares) at Dec. 31, 2016	198.3	164.4
Share-based awards (in shares)		0.6
Shares acquired - share repurchase authorization (in shares)		(1)
Shares acquired - share-based compensation plans (in shares)		(0.1)
Ending Balance (in shares) at Jun. 30, 2017	198.3	163.9

Condensed Consolidated Stateme8

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash Flows From Operating Activities
Net Income	$ 301	$ 311
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	27	24
Realized investment gains, net	(149)	(105)
Share-based compensation	14	13
Interest credited to contract holders'	24	25
Deferred income tax expense	32	7
Changes in:
Investment income receivable	4	3
Premiums and reinsurance receivable	(91)	(132)
Deferred policy acquisition costs	(45)	(26)
Other assets	(37)	(39)
Loss and loss expense reserves	196	252
Life policy reserves	50	50
Unearned premiums	154	148
Other liabilities	(82)	(33)
Current income tax receivable/payable	47	1
Net cash provided by operating activities	445	499
Cash Flows From Investing Activities
Sale of fixed maturities	12	15
Call or maturity of fixed maturities	540	820
Sale of equity securities	288	208
Purchase of fixed maturities	(802)	(975)
Purchase of equity securities	(352)	(360)
Investment in finance receivables	(14)	(10)
Collection of finance receivables	11	15
Investment in buildings and equipment, net	(9)	(7)
Change in other invested assets, net	(7)	(13)
Net cash used in investing activities	(333)	(307)
Cash Flows From Financing Activities
Payment of cash dividends to shareholders	(158)	(151)
Shares acquired - share repurchase authorization	(70)	(2)
Payments of note payable	(3)	(7)
Proceeds from stock options exercised	8	13
Contract holders' funds deposited	42	50
Contract holders' funds withdrawn	(83)	(77)
Excess tax benefits on stock-based compensation	0	2
Other	(19)	(17)
Net cash used in financing activities	(283)	(189)
Net change in cash and cash equivalents	(171)	3
Cash and cash equivalents at beginning of year	777	544
Cash and cash equivalents at end of period	606	547
Supplemental Disclosures of Cash Flow Information:
Interest paid	26	26
Income taxes paid	23	110
Noncash Activities
Conversion of securities	5	3
Equipment acquired under capital lease obligations	6	12
Cashless exercise of stock options	4	7
Other assets and other liabilities	$ 70	$ 0

Accounting Policies

Accounting Policies	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Accounting Policies	NOTE 1 — 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. Certain financial information that is normally included in annual financial statements prepared in accordance with GAAP, but that is not required for interim reporting purposes, has been omitted. Our June 30, 2017 , 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 2016 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 2016-07, Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-07, Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting. ASU 2016-07 eliminates the requirement to retroactively adjust an investment, results of operations, and retained earnings once an investment qualifies for use of the equity method. It requires the equity method investor to add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting without retroactive adjustment. The effective date of ASU 2016-07 was for interim and annual reporting periods beginning after December 15, 2016, and was applied prospectively. The company adopted this ASU effective January 1, 2017, and it did not have a material impact on our company's consolidated financial position, cash flows or results of operations. ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting In March 2016, the FASB issued ASU 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. ASU 2016-09 simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The effective date of ASU 2016-09 was for interim and annual reporting periods beginning after December 15, 2016. The recognition and classification of the excess tax benefit provisions were applied prospectively in the results of operations and statement of cash flows. This adoption resulted in excess tax benefits of $6 million , which reduced our current provision for income taxes in our results of operations for both the three and six months ended June 30, 2017, respectively. The statutory tax withholding classification, which are cash payments made to taxing authorities for shares withheld, were applied retrospectively and reclassified the statutory tax withholding requirements in the statement of cash flows from Other liabilities in operating activities to Other in financing activities. This statutory tax withholding reclassification resulted in $12 million and $9 million being included in financing activities for the six months ended June 30, 2017 and 2016, respectively. There were no cumulative effect adjustments upon adoption of this ASU. Pending Accounting Updates ASU 2014-09 Revenue from Contracts with Customers In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers . ASU 2014-09 requires an entity to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. Insurance contracts do not fall within the scope of this ASU. The effective date of ASU 2014-09 is for interim and annual reporting periods beginning after December 15, 2017. The ASU has not yet been adopted and will not have a material impact on our company’s financial position, cash flows or results of operations. ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities. ASU 2016-01 revises the accounting related to the classification and measurement of investments in equity securities and the presentation of certain fair value changes for financial liabilities measured at fair value. Our results of operations will be impacted as changes in fair value of equity securities will be reported in net income instead of reported in other comprehensive income. The effective date of ASU 2016-01 is for interim and annual reporting periods beginning after December 15, 2017 and will be applied prospectively. The ASU has not yet been adopted. Had we adopted this ASU on June 30, 2017, $1.677 billion of after-tax unrealized gains on equity securities would have been reclassified from accumulated other comprehensive income to retained earnings. The actual amount reclassified upon adoption will vary depending on the future changes in fair value of our equity portfolio. ASU 2016-02, Leases (Topic 842) In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The main provision of ASU 2016-02 requires the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous GAAP. The effective date of ASU 2016-02 is for interim and annual reporting periods beginning after December 15, 2018. The ASU has not yet been adopted. Management is currently evaluating the impact on our company’s consolidated financial position, cash flows and results of operations. ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . ASU 2016-13 amends previous guidance on the impairment of financial instruments by adding an impairment model that allows an entity to recognize expected credit losses as an allowance rather than impairing as they are incurred. The new guidance is intended to reduce complexity of credit impairment models and result in a more timely recognition of expected credit losses. The effective date of ASU 2016-13 is for interim and annual reporting periods beginning after December 15, 2019. The ASU has not yet been adopted. Management is currently evaluating the impact on our company's consolidated financial position, cash flows or results of operations. ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . ASU 2016-15 addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. The effective date of ASU 2016-15 is for interim and annual reporting periods beginning after December 15, 2017. The ASU has not yet been adopted; however, it is not expected to have a material impact on our company's consolidated financial position, cash flows or results of operations. ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In March 2017, the FASB issued ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Postretirement Benefit Costs . ASU 2017-07 provides guidance on how to present the components of net periodic benefit costs in the income statement for pension plans and other post-retirement benefit plans. The effective date of ASU 2017-07 is for interim and annual reporting periods beginning after December 15, 2017. The ASU has not yet been adopted; however, it is not expected to have a material impact on our company's consolidated financial position, cash flows or results of operations. ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities In March 2017, the FASB issued ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. ASU 2017-08 amends guidance on the amortization period of premiums on certain purchased callable debt securities. The amendments shorten the amortization period of premiums on certain purchased callable debt securities to the earliest call date. The amendments should be applied on a modified retrospective basis through a cumulative-effect adjustment to beginning retained earnings. The effective date of ASU 2017-08 is for interim and annual reporting periods beginning after December 15, 2018. The ASU has not yet been adopted. Management is currently evaluating the impact on our company's consolidated financial position, cash flows or results of operations. ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting. ASU 2017-09 clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. The amendment should be applied on a prospective basis. The effective date of ASU 2017-09 is for interim and annual reporting periods, beginning after December 15, 2017. The ASU has not yet been adopted; however, it will not have a material impact on our company's consolidated financial position, cash flows or results of operations upon adoption.

Investments

Investments	6 Months Ended
	Jun. 30, 2017
Investments [Abstract]
Investments	Investments The following table provides cost or amortized cost, gross unrealized gains, gross unrealized losses and fair value for our fixed-maturity and equity securities: (Dollars in millions) Cost or amortized cost Gross unrealized Fair value At June 30, 2017 gains losses Fixed maturity securities: Corporate $ 5,530 $ 281 $ 14 $ 5,797 States, municipalities and political subdivisions 4,029 142 17 4,154 Commercial mortgage-backed 282 8 1 289 Government-sponsored enterprises 235 — 3 232 United States government 15 — — 15 Foreign government 10 — — 10 Convertibles and bonds with warrants attached 5 — — 5 Subtotal 10,106 431 35 10,502 Equity securities: Common equities 3,038 2,559 16 5,581 Nonredeemable preferred equities 180 38 — 218 Subtotal 3,218 2,597 16 5,799 Total $ 13,324 $ 3,028 $ 51 $ 16,301 At December 31, 2016 Fixed maturity securities: Corporate $ 5,555 $ 252 $ 26 $ 5,781 States, municipalities and political subdivisions 3,770 100 42 3,828 Commercial mortgage-backed 282 7 2 287 Government-sponsored enterprises 167 — 3 164 United States government 10 — — 10 Foreign government 10 — — 10 Convertibles and bonds with warrants attached 5 — — 5 Subtotal 9,799 359 73 10,085 Equity securities: Common equities 2,812 2,320 9 5,123 Nonredeemable preferred equities 183 28 — 211 Subtotal 2,995 2,348 9 5,334 Total $ 12,794 $ 2,707 $ 82 $ 15,419 The net unrealized investment gains in our fixed-maturity portfolio at June 30, 2017 , are primarily the result of the continued low interest rate environment that increased the fair value of our fixed-maturity portfolio. Our commercial mortgage-backed securities had an average rating of Aa1/AA at June 30, 2017 and December 31, 2016 . At June 30, 2017, the seven largest unrealized investment gains in our common stock portfolio are from Honeywell International Incorporated (NYSE:HON), JP Morgan Chase & Co. (NYSE:JPM), Hasbro Inc. (Nasdaq:HAS), Blackrock Inc. (Nasdaq: BLK), Apple Inc. (Nasdaq:AAPL), Johnson & Johnson (NYSE:JNJ) and Microsoft Corporation (Nasdaq: MSFT), which had a combined gross unrealized gain of $829 million . At June 30, 2017 , JP Morgan Chase & Co. was our largest single equity holding with a fair value of $206 million , which was 3.7 percent of our publicly traded common equities portfolio and 1.3 percent of the total investment portfolio. The table below provides fair values and gross unrealized losses by investment category and by the duration of the securities’ continuous unrealized loss positions: (Dollars in millions) Less than 12 months 12 months or more Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses At June 30, 2017 Fixed maturity securities: Corporate $ 290 $ 8 $ 136 $ 6 $ 426 $ 14 States, municipalities and political subdivisions 665 17 2 — 667 17 Commercial mortgage-backed securities 53 1 3 — 56 1 Government-sponsored enterprises 190 3 — — 190 3 United States government 7 — — — 7 — Subtotal 1,205 29 141 6 1,346 35 Equity securities: Common equities 354 16 — — 354 16 Subtotal 354 16 — — 354 16 Total $ 1,559 $ 45 $ 141 $ 6 $ 1,700 $ 51 At December 31, 2016 Fixed maturity securities: Corporate $ 733 $ 15 $ 189 $ 11 $ 922 $ 26 States, municipalities and political subdivisions 989 42 — — 989 42 Commercial mortgage-backed 89 2 2 — 91 2 Government-sponsored enterprises 155 3 — — 155 3 United States government 6 — — — 6 — Subtotal 1,972 62 191 11 2,163 73 Equity securities: Common equities 103 9 — — 103 9 Nonredeemable preferred equities 4 — — — 4 — Subtotal 107 9 — — 107 9 Total $ 2,079 $ 71 $ 191 $ 11 $ 2,270 $ 82 Contractual maturity dates for fixed-maturity investments were: (Dollars in millions) Amortized cost Fair value % of fair value At June 30, 2017 Maturity dates: Due in one year or less $ 699 $ 714 6.8 % Due after one year through five years 2,690 2,830 26.9 Due after five years through ten years 3,822 3,970 37.8 Due after ten years 2,895 2,988 28.5 Total $ 10,106 $ 10,502 100.0 % Actual maturities may differ from contractual maturities when there is a right to call or prepay obligations with or without call or prepayment penalties. The following table provides investment income, realized investment gains and losses, the change in unrealized investment gains and losses: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Investment income: Interest $ 111 $ 110 $ 222 $ 219 Dividends 42 41 81 78 Other 1 — 2 1 Total 154 151 305 298 Less investment expenses 3 2 5 4 Total $ 151 $ 149 $ 300 $ 294 Realized investment gains and losses: Fixed maturities: Gross realized gains $ 3 $ 4 $ 13 $ 7 Gross realized losses — — — (1 ) Other-than-temporary impairments (6 ) — (6 ) (2 ) Equity securities: Gross realized gains 6 38 159 100 Gross realized losses (10 ) — (14 ) (1 ) Other-than-temporary impairments (3 ) — (3 ) — Other (1 ) 2 — 2 Total $ (11 ) $ 44 $ 149 $ 105 Change in unrealized investment gains and losses: Fixed maturities $ 76 $ 178 $ 110 $ 294 Equity securities 145 111 242 285 Income tax (provision) benefit (77 ) (103 ) (123 ) (203 ) Total $ 144 $ 186 $ 229 $ 376 During the three and six months ended June 30, 2017 , there were five equity securities and one fixed-maturity security other-than-temporarily impaired. 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 for the three and six months ended June 30, 2017 and 2016 . At June 30, 2017 , 23 fixed-maturity investments with a total unrealized loss of $6 million had been in an unrealized loss position for 12 months or more. Of that total, no fixed-maturity investment had a fair value below 70 percent of amortized cost. At June 30, 2017 , no equity investment had been in an unrealized loss position for 12 months or more. There were no equity investments with a fair value below 70 percent of amortized cost. At December 31, 2016 , 32 fixed-maturity investments with a total unrealized loss of $11 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 security investments in an unrealized loss position for 12 months or more as of December 31, 2016 . There were no equity investments with a fair value below 70 percent of amortized cost at December 31, 2016.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements 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, 2016 , and ultimately management determines fair value. See our 2016 Annual Report on Form 10-K, Item 8, Note 3, Fair Value Measurements, Page 132, 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 June 30, 2017 , and December 31, 2016 . We do not have any material liabilities carried at fair value. There were no transfers between Level 1 and Level 2. (Dollars in millions) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Total At June 30, 2017 Fixed maturities, available for sale: Corporate $ — $ 5,796 $ 1 $ 5,797 States, municipalities and political subdivisions — 4,149 5 4,154 Commercial mortgage-backed — 289 — 289 Government-sponsored enterprises — 232 — 232 United States government 15 — — 15 Foreign government — 10 — 10 Convertibles and bonds with warrants attached — 5 — 5 Subtotal 15 10,481 6 10,502 Common equities, available for sale 5,581 — — 5,581 Nonredeemable preferred equities, available for sale — 218 — 218 Separate accounts taxable fixed maturities — 770 — 770 Top Hat savings plan mutual funds and common 28 — — 28 Total $ 5,624 $ 11,469 $ 6 $ 17,099 At December 31, 2016 Fixed maturities, available for sale: Corporate $ — $ 5,703 $ 78 $ 5,781 States, municipalities and political subdivisions — 3,828 — 3,828 Commercial mortgage-backed — 287 — 287 Government-sponsored enterprises — 164 — 164 United States government 10 — — 10 Foreign government — 10 — 10 Convertibles and bonds with warrants attached — 5 — 5 Subtotal 10 9,997 78 10,085 Common equities, available for sale 5,123 — — 5,123 Nonredeemable preferred equities, available for sale — 211 — 211 Separate accounts taxable fixed maturities — 750 — 750 Top Hat savings plan mutual funds and common equity (included in Other assets) 24 — — 24 Total $ 5,157 $ 10,958 $ 78 $ 16,193 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 June 30, 2017 . 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. Transfers out of Level 3 included situations where a broker quote was used without observable inputs or data that could be corroborated by our pricing vendors in the prior period and significant other observable inputs were identified in the current period. The quantitative detail of these unobservable inputs is neither provided nor reasonably available to us. The following table provides the change in Level 3 assets for the three months ended June 30: (Dollars in millions) Asset fair value measurements using significant unobservable inputs (Level 3) Corporate Taxable fixed maturities - separate accounts States, Nonredeemable preferred Total Beginning balance, April 1, 2017 $ 1 $ — $ — $ — $ 1 Total gains or losses (realized/unrealized): Included in net income — — — — — Included in other comprehensive income — — — — — Purchases — — — — — Sales — — — — — Transfers into Level 3 — — 5 — 5 Transfers out of Level 3 — — — — — Ending balance, June 30, 2017 $ 1 $ — $ 5 $ — $ 6 Beginning balance, April 1, 2016 $ 51 $ 1 $ — $ 2 $ 54 Total gains or losses (realized/unrealized): Included in net income — — — — — Included in other comprehensive income — — — — — Purchases 17 — — — 17 Sales — — — (2 ) (2 ) Transfers into Level 3 — — — — — Transfers out of Level 3 (16 ) — — — (16 ) Ending balance, June 30, 2016 $ 52 $ 1 $ — $ — $ 53 The following table provides the change in Level 3 assets for the six months ended June 30 : (Dollars in millions) Asset fair value measurements using significant unobservable inputs Corporate fixed maturities Taxable fixed maturities - separate accounts States, municipalities and political subdivisions fixed maturities Nonredeemable preferred equities Total Beginning balance, January 1, 2017 $ 78 $ — $ — $ — $ 78 Total gains or losses (realized/unrealized): Included in net income — — — — — Included in other comprehensive income — — — — — Purchases — — 5 — 5 Sales — — — — — Transfers into Level 3 — — — — — Transfers out of Level 3 (77 ) — — — (77 ) Ending balance, June 30, 2017 $ 1 $ — $ 5 $ — $ 6 Beginning balance, January 1, 2016 $ 51 $ 1 $ — $ 3 $ 55 Total gains or losses (realized/unrealized): Included in net income — — — — — Included in other comprehensive income — — — (1 ) (1 ) Purchases 22 — — — 22 Sales — — — (2 ) (2 ) Transfers into Level 3 — — — — — Transfers out of Level 3 (21 ) — — — (21 ) Ending balance, June 30, 2016 $ 52 $ 1 $ — $ — $ 53 Additional disclosures for the Level 3 category are not material. Fair Value Disclosures for Assets and Liabilities Not Carried at Fair Value The disclosures below are presented to provide 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: (Dollars in millions) Book value Principal amount Interest rate Year of issue June 30, December 31, June 30, December 31, 2017 2016 2017 2016 6.900 % 1998 Senior debentures, due 2028 $ 26 $ 26 $ 28 $ 28 6.920 % 2005 Senior debentures, due 2028 391 391 391 391 6.125 % 2004 Senior notes, due 2034 370 370 374 374 Total $ 787 $ 787 $ 793 $ 793 The following table shows fair values of our note payable and long-term debt: (Dollars in millions) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Total At June 30, 2017 Note payable $ — $ 17 $ — $ 17 6.900% senior debentures, due 2028 — 34 — 34 6.920% senior debentures, due 2028 — 506 — 506 6.125% senior notes, due 2034 — 458 — 458 Total $ — $ 1,015 $ — $ 1,015 At December 31, 2016 Note payable $ — $ 20 $ — $ 20 6.900% senior debentures, due 2028 — 33 — 33 6.920% senior debentures, due 2028 — 488 — 488 6.125% senior notes, due 2034 — 435 — 435 Total $ — $ 976 $ — $ 976 The following table shows the fair value of our life policy loans included in other invested assets: (Dollars in millions) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Total At June 30, 2017 Life policy loans $ — $ — $ 41 $ 41 At December 31, 2016 Life policy loans $ — $ — $ 40 $ 40 Outstanding principal and interest for these life policy loans totaled $31 million at June 30, 2017 and December 31, 2016 . The following table shows fair values of our deferred annuities and structured settlements included in life policy and investment contract reserves: (Dollars in millions) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Total At June 30, 2017 Deferred annuities $ — $ — $ 846 $ 846 Structured settlements — 206 — 206 Total $ — $ 206 $ 846 $ 1,052 At December 31, 2016 Deferred annuities $ — $ — $ 839 $ 839 Structured settlements — 206 — 206 Total $ — $ 206 $ 839 $ 1,045 Recorded reserves for the deferred annuities were $851 million and $861 million at June 30, 2017 , and December 31, 2016, respectively. Recorded reserves for the structured settlements were $164 million and $170 million at June 30, 2017 , and December 31, 2016 , respectively.

Property Casualty Loss and Loss

Property Casualty Loss and Loss Expenses	6 Months Ended
	Jun. 30, 2017
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: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Gross loss and loss expense reserves, beginning of period $ 5,128 $ 4,750 $ 5,035 $ 4,660 Less reinsurance recoverable 297 272 298 281 Net loss and loss expense reserves, beginning of period 4,831 4,478 4,737 4,379 Net incurred loss and loss expenses related to: Current accident year 832 808 1,658 1,531 Prior accident years (38 ) (49 ) (76 ) (111 ) Total incurred 794 759 1,582 1,420 Net paid loss and loss expenses related to: Current accident year 373 328 558 474 Prior accident years 322 301 831 717 Total paid 695 629 1,389 1,191 Net loss and loss expense reserves, end of period 4,930 4,608 4,930 4,608 Plus reinsurance recoverable 283 310 283 310 Gross loss and loss expense reserves, end of period $ 5,213 $ 4,918 $ 5,213 $ 4,918 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, claims, underwriting, loss prevention and accounting management. This committee 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 $68 million at June 30, 2017 , and $52 million at June 30, 2016 , for certain life and health loss and loss expense reserves. For the three months ended June 30, 2017, we experienced $38 million of favorable development on prior accident years, including $26 million of favorable development in commercial lines, $3 million of favorable development in personal lines and $9 million of favorable development in excess and surplus lines. This included $3 million from favorable development of catastrophe losses for the three months ended June 30, 2017 . For the three months ended June 30, 2017, we recognized favorable reserve development of $12 million for the workers' compensation line, $7 million for the commercial casualty line, $5 million for the commercial property line and $11 million for the other commercial lines due to reduced uncertainty of prior accident year loss and loss adjustment expense for these lines. For the three months ended June 30, 2017, we recognized unfavorable reserve development of $9 million for the commercial auto line. For the six months ended June 30, 2017 , we experienced $76 million of favorable development on prior accident years, including $37 million of favorable development in commercial lines, $13 million of favorable development in personal lines, $22 million of favorable development in excess and surplus lines and $4 million of favorable development in our reinsurance assumed operations. This included $14 million from favorable development of catastrophe losses for the six months ended June 30, 2017 . For the six months ended June 30, 2017, we recognized favorable reserve development of $31 million for the workers' compensation line, $15 million for the commercial property line and $19 million for the other commercial lines due to reduced uncertainty of prior accident year loss and loss adjustment expense for these lines. For the six months ended June 30, 2017, we recognized unfavorable reserve development of $20 million for the commercial auto line and $8 million for the commercial casualty line. Commercial auto developed unfavorably due to higher loss cost effects in recent accident years, resulting in an increase of our reserve estimate for claims that have not yet been settled. The unfavorable reserve development for commercial casualty reflected higher than usual large loss activity. For the three months ended June 30, 2016, we experienced $49 million of favorable development on prior accident years, including $58 million of favorable development in commercial lines, $10 million of adverse development in personal lines and $1 million of favorable development in excess and surplus lines. We recognized favorable reserve development during the three months ended June 30, 2016 , of $23 million for the workers' compensation line, $20 million for commercial casualty line, $15 million for the other commercial lines and $14 million for the commercial property line due to reduced uncertainty of prior accident year loss and loss adjustment expenses for these lines. Our personal auto line developed unfavorably by $14 million for the three months ended June 30, 2016, largely due to $8 million of adverse development for accident year 2015. Our commercial auto line developed unfavorably by $13 million for the three months ended June 30, 2016, due to higher loss cost effects in recent accident years, resulting in an increase of our reserve estimate for claims that have not yet been settled. For the six months ended June 30, 2016 , we experienced $111 million of favorable development on prior accident years, including $87 million of favorable development in commercial lines, $8 million of favorable development in personal lines, $15 million of favorable development in excess and surplus lines, and $1 million of favorable development in our reinsurance assumed operations. This included $7 million from favorable development of catastrophe losses for the six months ended June 30, 2016 . We recognized favorable reserve development during the six months ended June 30, 2016 , of $35 million for the workers' compensation line, $23 million for the commercial casualty line, $22 million for the commercial property line and $28 million for the other commercial lines due to reduced uncertainty of prior accident year loss and loss adjustment expenses for these lines. Our commercial auto line developed unfavorably by $21 million for the six months ended June 30, 2016 , due to higher loss cost effects in recent accident years, resulting in an increase of our reserve estimate for claims that have not yet been settled. Our personal auto line developed unfavorably by $6 million for the six months ended June 30, 2016 for accident years prior to 2015.

Life Policy and Investment Cont

Life Policy and Investment Contract Reserves	6 Months Ended
	Jun. 30, 2017
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 deferred annuity, universal life 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: (Dollars in millions) June 30, December 31, 2016 Life policy reserves: Ordinary/traditional life $ 1,045 $ 1,011 Other 46 45 Subtotal 1,091 1,056 Investment contract reserves: Deferred annuities 851 861 Universal life 590 578 Structured settlements 164 170 Other 6 6 Subtotal 1,611 1,615 Total life policy and investment contract reserves $ 2,702 $ 2,671

Deferred Acquisition Costs

Deferred Acquisition Costs	6 Months Ended
	Jun. 30, 2017
Deferred Costs [Abstract]
Deferred Acquisition Costs	Deferred Policy Acquisition Costs Expenses directly related to successfully acquired 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. (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Property casualty: Deferred policy acquisition costs asset, beginning of period $ 428 $ 397 $ 408 $ 388 Capitalized deferred policy acquisition costs 237 218 463 428 Amortized deferred policy acquisition costs (217 ) (203 ) (423 ) (404 ) Deferred policy acquisition costs asset, end of period $ 448 $ 412 $ 448 $ 412 Life: Deferred policy acquisition costs asset, beginning of period $ 232 $ 221 $ 229 $ 228 Capitalized deferred policy acquisition costs 12 12 25 24 Amortized deferred policy acquisition costs (12 ) (11 ) (20 ) (22 ) Amortized shadow deferred policy acquisition costs (2 ) (10 ) (4 ) (18 ) Deferred policy acquisition costs asset, end of period $ 230 $ 212 $ 230 $ 212 Consolidated: Deferred policy acquisition costs asset, beginning of period $ 660 $ 618 $ 637 $ 616 Capitalized deferred policy acquisition costs 249 230 488 452 Amortized deferred policy acquisition costs (229 ) (214 ) (443 ) (426 ) Amortized shadow deferred policy acquisition costs (2 ) (10 ) (4 ) (18 ) Deferred policy acquisition costs asset, end of period $ 678 $ 624 $ 678 $ 624 No premium deficiencies were recorded in the condensed consolidated statements of income, as the sum of the anticipated loss and loss expenses, policyholder dividends and unamortized deferred acquisition expenses did not exceed the related unearned premiums and anticipated investment income.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	6 Months Ended
	Jun. 30, 2017
Accumulated Other Comprehensive Income [Abstract]
Comprehensive Income (Loss) Note	Accumulated Other Comprehensive Income Accumulated other comprehensive income (AOCI) includes changes in unrealized gains and losses on investments, changes in pension obligations and changes in life deferred acquisition costs, life policy reserves and other as follows: (Dollars in millions) Three months ended June 30, 2017 2016 Before tax Income tax Net Before tax Income tax Net Investments: AOCI, beginning of period $ 2,756 $ 954 $ 1,802 $ 2,384 $ 822 $ 1,562 OCI before realized gains recognized in net income 211 74 137 331 118 213 Realized gains and losses recognized in net income 10 3 7 (42 ) (15 ) (27 ) OCI 221 77 144 289 103 186 AOCI, end of period $ 2,977 $ 1,031 $ 1,946 $ 2,673 $ 925 $ 1,748 Pension obligations: AOCI, beginning of period $ (25 ) $ (8 ) $ (17 ) $ (41 ) $ (13 ) $ (28 ) OCI excluding amortization recognized in net income — — — — — — Amortization recognized in net income — — — 1 — 1 OCI — — — 1 — 1 AOCI, end of period $ (25 ) $ (8 ) $ (17 ) $ (40 ) $ (13 ) $ (27 ) Life deferred acquisition costs, life policy reserves and other: AOCI, beginning of period $ (7 ) $ (2 ) $ (5 ) $ (3 ) $ — $ (3 ) OCI before realized gains recognized in net income — (1 ) 1 (5 ) (2 ) (3 ) Realized gains and losses recognized in net income 1 1 — (2 ) (1 ) (1 ) OCI 1 — 1 (7 ) (3 ) (4 ) AOCI, end of period $ (6 ) $ (2 ) $ (4 ) $ (10 ) $ (3 ) $ (7 ) Summary of AOCI: AOCI, beginning of period $ 2,724 $ 944 $ 1,780 $ 2,340 $ 809 $ 1,531 Investments OCI 221 77 144 289 103 186 Pension obligations OCI — — — 1 — 1 Life deferred acquisition costs, life policy reserves and other OCI 1 — 1 (7 ) (3 ) (4 ) Total OCI 222 77 145 283 100 183 AOCI, end of period $ 2,946 $ 1,021 $ 1,925 $ 2,623 $ 909 $ 1,714 (Dollars in millions) Six months ended June 30, 2017 2016 Before tax Income tax Net Before tax Income tax Net Investments: AOCI, beginning of period $ 2,625 $ 908 $ 1,717 $ 2,094 $ 722 $ 1,372 OCI before realized gains recognized in net income 501 176 325 682 239 443 Realized gains recognized in net income (149 ) (53 ) (96 ) (103 ) (36 ) (67 ) OCI 352 123 229 579 203 376 AOCI, end of period $ 2,977 $ 1,031 $ 1,946 $ 2,673 $ 925 $ 1,748 Pension obligations: AOCI, beginning of period $ (26 ) $ (8 ) $ (18 ) $ (42 ) $ (14 ) $ (28 ) OCI excluding amortization recognized in net income — — — — — — Amortization recognized in net income 1 — 1 2 1 1 OCI 1 — 1 2 1 1 AOCI, end of period $ (25 ) $ (8 ) $ (17 ) $ (40 ) $ (13 ) $ (27 ) Life deferred acquisition costs, life policy reserves and other: AOCI, beginning of period $ (9 ) $ (3 ) $ (6 ) $ 1 $ 1 $ — OCI before realized gains recognized in net income 3 1 2 (9 ) (3 ) (6 ) Realized gains recognized in net income — — — (2 ) (1 ) (1 ) OCI 3 1 2 (11 ) (4 ) (7 ) AOCI, end of period $ (6 ) $ (2 ) $ (4 ) $ (10 ) $ (3 ) $ (7 ) Summary of AOCI: AOCI, beginning of period $ 2,590 $ 897 $ 1,693 $ 2,053 $ 709 $ 1,344 Investments OCI 352 123 229 579 203 376 Pension obligations OCI 1 — 1 2 1 1 Life deferred acquisition costs, life policy reserves and other OCI 3 1 2 (11 ) (4 ) (7 ) Total OCI 356 124 232 570 200 370 AOCI, end of period $ 2,946 $ 1,021 $ 1,925 $ 2,623 $ 909 $ 1,714 Investments realized gains and life deferred acquisition costs, life policy reserves and other realized gains are recorded in the realized investment gains, net, line item in the condensed consolidated statements of income. Amortization on pension obligations is recorded in the insurance losses and contract holders' benefits and underwriting, acquisition and insurance expenses in the condensed consolidated statements of income.

Reinsurance

Reinsurance	6 Months Ended
	Jun. 30, 2017
Reinsurance Disclosures [Abstract]
Reinsurance	Reinsurance Primary components of our property casualty reinsurance assumed operations include involuntary and voluntary assumed as well as contracts from our reinsurance assumed operations, known as Cincinnati Re. Primary components of our ceded reinsurance include a property per risk treaty, property excess treaty, casualty per occurrence treaty, casualty excess treaty, property catastrophe treaty and catastrophe bonds and retrocessions on our reinsurance assumed operations. 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. The table below includes our net written consolidated property casualty insurance premiums on assumed and ceded business: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct written premiums $ 1,265 $ 1,211 $ 2,491 $ 2,372 Assumed written premiums 42 42 75 63 Ceded written premiums (36 ) (59 ) (64 ) (94 ) Net written premiums $ 1,271 $ 1,194 $ 2,502 $ 2,341 Our condensed consolidated statements of income include earned consolidated property casualty insurance premiums on assumed and ceded business: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct earned premiums $ 1,189 $ 1,137 $ 2,352 $ 2,256 Assumed earned premiums 33 16 60 31 Ceded earned premiums (41 ) (39 ) (80 ) (77 ) Earned premiums $ 1,181 $ 1,114 $ 2,332 $ 2,210 Our condensed consolidated statements of income include incurred consolidated property casualty insurance loss and loss expenses on assumed and ceded business: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct incurred loss and loss expenses $ 770 $ 792 $ 1,558 $ 1,440 Assumed incurred loss and loss expenses 20 11 35 21 Ceded incurred loss and loss expenses 4 (44 ) (11 ) (41 ) Incurred loss and loss expenses $ 794 $ 759 $ 1,582 $ 1,420 Our life insurance company purchases reinsurance for protection of a portion of the risks that are written. Primary components of our life reinsurance program include individual mortality coverage, 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: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct earned premiums $ 77 $ 75 $ 151 $ 146 Ceded earned premiums (17 ) (16 ) (34 ) (29 ) Earned premiums $ 60 $ 59 $ 117 $ 117 Our condensed consolidated statements of income include life insurance contract holders' benefits incurred on ceded business: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct contract holders' benefits incurred $ 87 $ 80 $ 163 $ 156 Ceded contract holders' benefits incurred (27 ) (18 ) (38 ) (31 ) Contract holders' benefits incurred $ 60 $ 62 $ 125 $ 125 The ceded benefits incurred can vary depending on the type of life insurance policy held and the year the policy was issued.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes As of June 30, 2017 , and December 31, 2016 , we had no liability for unrecognized tax benefits. The differences between the 35 percent statutory federal income tax rate and our effective income tax rate were as follows: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Tax at statutory rate: $ 44 35.0 % $ 58 35.0 % $ 141 35.0 % $ 151 35.0 % Increase (decrease) resulting from: Tax-exempt income from municipal bonds (9 ) (7.0 ) (8 ) (4.8 ) (18 ) (4.5 ) (17 ) (3.9 ) Dividend received exclusion (9 ) (7.0 ) (8 ) (4.8 ) (17 ) (4.2 ) (16 ) (3.7 ) Other 2 0.9 1 0.5 (3 ) (0.8 ) 2 0.4 Provision for income taxes $ 28 21.9 % $ 43 25.9 % $ 103 25.5 % $ 120 27.8 % The provision for federal income taxes is based upon filing a consolidated income tax return for the company and its subsidiaries. Included in Other above is the adoption of ASU 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting , which decreased both the provision for income taxes and the effective income tax rate by an immaterial amount during the three months ended June 30, 2017 and $6 million and 1.5 percent , during the six months ended June 30, 2017. As of June 30, 2017 , we had no operating or capital loss carry forwards.

Net Income Per Common Share

Net Income Per Common Share	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Net Income Per Common Share	Basic earnings per share are computed based on the weighted average number of common 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: (In millions except per share data) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Numerator: Net income—basic and diluted $ 100 $ 123 $ 301 $ 311 Denominator: Basic weighted-average common shares outstanding 164.3 164.5 164.4 164.4 Effect of share-based awards: Stock options 1.0 1.1 1.1 1.1 Nonvested shares 0.7 0.9 0.7 0.8 Diluted weighted-average shares 166.0 166.5 166.2 166.3 Earnings per share: Basic $ 0.61 $ 0.75 $ 1.83 $ 1.89 Diluted 0.60 0.74 1.81 1.87 Number of anti-dilutive share-based awards 0.6 0.3 0.7 0.4 The sources of dilution of our common shares are certain equity-based awards. See our 2016 Annual Report on Form 10-K, Item 8, Note 17, Share-Based Associate Compensation Plans, Page 160, for information about equity-based awards. The above table shows the number of anti-dilutive share-based awards for the three and six months ended June 30, 2017 and 2016 . We did not include these share-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	6 Months Ended
	Jun. 30, 2017
Compensation and Retirement Disclosure [Abstract]
Employee Retirement Benefits	Employee Retirement Benefits The following summarizes the components of net periodic benefit cost for our qualified and supplemental pension plans: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Service cost $ 2 $ 2 $ 5 $ 5 Interest cost 4 4 7 7 Expected return on plan assets (5 ) (4 ) (10 ) (9 ) Amortization of actuarial loss and prior service cost — 1 1 2 Net periodic benefit cost $ 1 $ 3 $ 3 $ 5 See our 2016 Annual Report on Form 10-K, Item 8, Note 13, Employee Retirement Benefits, Page 155, for information on our retirement benefits. We made matching contributions totaling $3 million and $4 million to our 401(k) and Top Hat savings plans during the second quarter of 2017 and 2016 and contributions of $9 million and $8 million for the first half of 2017 and 2016, respectively. We contributed $5 million to our qualified pension plan during the first six months of 2017.

Commitments and Contingent Liab

Commitments and Contingent Liabilities	6 Months Ended
	Jun. 30, 2017
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 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 databases 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 or current 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 of losses for any other matters for which the risk of loss is not probable, but more than remote, is immaterial.

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information We operate primarily in two industries, property casualty insurance and life insurance. Our chief operating decision maker regularly reviews our reporting segments to make decisions about allocating resources and assessing performance. Our reporting segments are: • Commercial lines insurance • Personal lines insurance • Excess and surplus lines insurance • Life insurance • Investments We report as Other the noninvestment operations of the parent company and its noninsurer subsidiary, CFC Investment Company and Cincinnati Re, our reinsurance assumed operations. See our 2016 Annual Report on Form 10-K, Item 8, Note 18, Segment Information, Page 163, 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: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Revenues: Commercial lines insurance Commercial casualty $ 271 $ 263 $ 536 $ 520 Commercial property 226 215 449 429 Commercial auto 158 147 313 291 Workers' compensation 86 89 170 178 Other commercial 55 57 109 113 Commercial lines insurance premiums 796 771 1,577 1,531 Fee revenues 1 1 2 2 Total commercial lines insurance 797 772 1,579 1,533 Personal lines insurance Personal auto 144 135 285 266 Homeowner 128 121 253 240 Other personal 35 32 69 65 Personal lines insurance premiums 307 288 607 571 Fee revenues 1 1 3 2 Total personal lines insurance 308 289 610 573 Excess and surplus lines insurance 52 45 100 88 Fee revenues 1 — 1 — Total excess and surplus lines insurance 53 45 101 88 Life insurance premiums 60 59 117 117 Fee revenues 1 1 3 2 Total life insurance 61 60 120 119 Investments Investment income, net of expenses 151 149 300 294 Realized investment gains and losses, net (11 ) 44 149 105 Total investment revenue 140 193 449 399 Other Cincinnati Re insurance premiums 26 10 48 20 Other 1 2 2 3 Total other revenues 27 12 50 23 Total revenues $ 1,386 $ 1,371 $ 2,909 $ 2,735 Income (loss) before income taxes: Insurance underwriting results Commercial lines insurance $ 24 $ 26 $ 22 $ 76 Personal lines insurance (24 ) (20 ) (39 ) 8 Excess and surplus lines insurance 19 5 37 22 Life insurance 4 1 4 — Investments 117 171 403 355 Other (12 ) (17 ) (23 ) (30 ) Total income before income taxes $ 128 $ 166 $ 404 $ 431 Identifiable assets: June 30, December 31, 2016 Property casualty insurance $ 3,042 $ 2,967 Life insurance 1,427 1,366 Investments 16,431 15,569 Other 338 484 Total $ 21,238 $ 20,386

Accounting Policies Pending Acc

Accounting Policies Pending Accounting Updates (Policies)	6 Months Ended
	Jun. 30, 2017
Accounting Policies [Abstract]
Adopted Accounting Updates and Pending Accounting Updates	Adopted Accounting Updates ASU 2016-07, Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting In March 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-07, Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting. ASU 2016-07 eliminates the requirement to retroactively adjust an investment, results of operations, and retained earnings once an investment qualifies for use of the equity method. It requires the equity method investor to add the cost of acquiring the additional interest in the investee to the current basis of the investor's previously held interest and adopt the equity method of accounting as of the date the investment becomes qualified for equity method accounting without retroactive adjustment. The effective date of ASU 2016-07 was for interim and annual reporting periods beginning after December 15, 2016, and was applied prospectively. The company adopted this ASU effective January 1, 2017, and it did not have a material impact on our company's consolidated financial position, cash flows or results of operations. ASU 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting In March 2016, the FASB issued ASU 2016-09, Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. ASU 2016-09 simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The effective date of ASU 2016-09 was for interim and annual reporting periods beginning after December 15, 2016. The recognition and classification of the excess tax benefit provisions were applied prospectively in the results of operations and statement of cash flows. This adoption resulted in excess tax benefits of $6 million , which reduced our current provision for income taxes in our results of operations for both the three and six months ended June 30, 2017, respectively. The statutory tax withholding classification, which are cash payments made to taxing authorities for shares withheld, were applied retrospectively and reclassified the statutory tax withholding requirements in the statement of cash flows from Other liabilities in operating activities to Other in financing activities. This statutory tax withholding reclassification resulted in $12 million and $9 million being included in financing activities for the six months ended June 30, 2017 and 2016, respectively. There were no cumulative effect adjustments upon adoption of this ASU. Pending Accounting Updates ASU 2014-09 Revenue from Contracts with Customers In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers . ASU 2014-09 requires an entity to recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. Insurance contracts do not fall within the scope of this ASU. The effective date of ASU 2014-09 is for interim and annual reporting periods beginning after December 15, 2017. The ASU has not yet been adopted and will not have a material impact on our company’s financial position, cash flows or results of operations. ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, the FASB issued ASU 2016-01, Financial Instruments - Overall (Subtopic 825-10) - Recognition and Measurement of Financial Assets and Financial Liabilities. ASU 2016-01 revises the accounting related to the classification and measurement of investments in equity securities and the presentation of certain fair value changes for financial liabilities measured at fair value. Our results of operations will be impacted as changes in fair value of equity securities will be reported in net income instead of reported in other comprehensive income. The effective date of ASU 2016-01 is for interim and annual reporting periods beginning after December 15, 2017 and will be applied prospectively. The ASU has not yet been adopted. Had we adopted this ASU on June 30, 2017, $1.677 billion of after-tax unrealized gains on equity securities would have been reclassified from accumulated other comprehensive income to retained earnings. The actual amount reclassified upon adoption will vary depending on the future changes in fair value of our equity portfolio. ASU 2016-02, Leases (Topic 842) In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). The main provision of ASU 2016-02 requires the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous GAAP. The effective date of ASU 2016-02 is for interim and annual reporting periods beginning after December 15, 2018. The ASU has not yet been adopted. Management is currently evaluating the impact on our company’s consolidated financial position, cash flows and results of operations. ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments In June 2016, the FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments . ASU 2016-13 amends previous guidance on the impairment of financial instruments by adding an impairment model that allows an entity to recognize expected credit losses as an allowance rather than impairing as they are incurred. The new guidance is intended to reduce complexity of credit impairment models and result in a more timely recognition of expected credit losses. The effective date of ASU 2016-13 is for interim and annual reporting periods beginning after December 15, 2019. The ASU has not yet been adopted. Management is currently evaluating the impact on our company's consolidated financial position, cash flows or results of operations. ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments . ASU 2016-15 addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. The effective date of ASU 2016-15 is for interim and annual reporting periods beginning after December 15, 2017. The ASU has not yet been adopted; however, it is not expected to have a material impact on our company's consolidated financial position, cash flows or results of operations. ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost In March 2017, the FASB issued ASU 2017-07, Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Postretirement Benefit Costs . ASU 2017-07 provides guidance on how to present the components of net periodic benefit costs in the income statement for pension plans and other post-retirement benefit plans. The effective date of ASU 2017-07 is for interim and annual reporting periods beginning after December 15, 2017. The ASU has not yet been adopted; however, it is not expected to have a material impact on our company's consolidated financial position, cash flows or results of operations. ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities In March 2017, the FASB issued ASU 2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities. ASU 2017-08 amends guidance on the amortization period of premiums on certain purchased callable debt securities. The amendments shorten the amortization period of premiums on certain purchased callable debt securities to the earliest call date. The amendments should be applied on a modified retrospective basis through a cumulative-effect adjustment to beginning retained earnings. The effective date of ASU 2017-08 is for interim and annual reporting periods beginning after December 15, 2018. The ASU has not yet been adopted. Management is currently evaluating the impact on our company's consolidated financial position, cash flows or results of operations. ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting In May 2017, the FASB issued ASU 2017-09, Compensation - Stock Compensation (Topic 718): Scope of Modification Accounting. ASU 2017-09 clarifies when to account for a change to the terms or conditions of a share-based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. The amendment should be applied on a prospective basis. The effective date of ASU 2017-09 is for interim and annual reporting periods, beginning after December 15, 2017. The ASU has not yet been adopted; however, it will not have a material impact on our company's consolidated financial position, cash flows or results of operations upon adoption.

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2017
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 fixed-maturity and equity securities: (Dollars in millions) Cost or amortized cost Gross unrealized Fair value At June 30, 2017 gains losses Fixed maturity securities: Corporate $ 5,530 $ 281 $ 14 $ 5,797 States, municipalities and political subdivisions 4,029 142 17 4,154 Commercial mortgage-backed 282 8 1 289 Government-sponsored enterprises 235 — 3 232 United States government 15 — — 15 Foreign government 10 — — 10 Convertibles and bonds with warrants attached 5 — — 5 Subtotal 10,106 431 35 10,502 Equity securities: Common equities 3,038 2,559 16 5,581 Nonredeemable preferred equities 180 38 — 218 Subtotal 3,218 2,597 16 5,799 Total $ 13,324 $ 3,028 $ 51 $ 16,301 At December 31, 2016 Fixed maturity securities: Corporate $ 5,555 $ 252 $ 26 $ 5,781 States, municipalities and political subdivisions 3,770 100 42 3,828 Commercial mortgage-backed 282 7 2 287 Government-sponsored enterprises 167 — 3 164 United States government 10 — — 10 Foreign government 10 — — 10 Convertibles and bonds with warrants attached 5 — — 5 Subtotal 9,799 359 73 10,085 Equity securities: Common equities 2,812 2,320 9 5,123 Nonredeemable preferred equities 183 28 — 211 Subtotal 2,995 2,348 9 5,334 Total $ 12,794 $ 2,707 $ 82 $ 15,419
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 gross unrealized losses by investment category and by the duration of the securities’ continuous unrealized loss positions: (Dollars in millions) Less than 12 months 12 months or more Total Fair value Unrealized losses Fair value Unrealized losses Fair value Unrealized losses At June 30, 2017 Fixed maturity securities: Corporate $ 290 $ 8 $ 136 $ 6 $ 426 $ 14 States, municipalities and political subdivisions 665 17 2 — 667 17 Commercial mortgage-backed securities 53 1 3 — 56 1 Government-sponsored enterprises 190 3 — — 190 3 United States government 7 — — — 7 — Subtotal 1,205 29 141 6 1,346 35 Equity securities: Common equities 354 16 — — 354 16 Subtotal 354 16 — — 354 16 Total $ 1,559 $ 45 $ 141 $ 6 $ 1,700 $ 51 At December 31, 2016 Fixed maturity securities: Corporate $ 733 $ 15 $ 189 $ 11 $ 922 $ 26 States, municipalities and political subdivisions 989 42 — — 989 42 Commercial mortgage-backed 89 2 2 — 91 2 Government-sponsored enterprises 155 3 — — 155 3 United States government 6 — — — 6 — Subtotal 1,972 62 191 11 2,163 73 Equity securities: Common equities 103 9 — — 103 9 Nonredeemable preferred equities 4 — — — 4 — Subtotal 107 9 — — 107 9 Total $ 2,079 $ 71 $ 191 $ 11 $ 2,270 $ 82
Investments Classified by Contractual Maturity Date [Table Text Block]	Contractual maturity dates for fixed-maturity investments were: (Dollars in millions) Amortized cost Fair value % of fair value At June 30, 2017 Maturity dates: Due in one year or less $ 699 $ 714 6.8 % Due after one year through five years 2,690 2,830 26.9 Due after five years through ten years 3,822 3,970 37.8 Due after ten years 2,895 2,988 28.5 Total $ 10,106 $ 10,502 100.0 %
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: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Investment income: Interest $ 111 $ 110 $ 222 $ 219 Dividends 42 41 81 78 Other 1 — 2 1 Total 154 151 305 298 Less investment expenses 3 2 5 4 Total $ 151 $ 149 $ 300 $ 294 Realized investment gains and losses: Fixed maturities: Gross realized gains $ 3 $ 4 $ 13 $ 7 Gross realized losses — — — (1 ) Other-than-temporary impairments (6 ) — (6 ) (2 ) Equity securities: Gross realized gains 6 38 159 100 Gross realized losses (10 ) — (14 ) (1 ) Other-than-temporary impairments (3 ) — (3 ) — Other (1 ) 2 — 2 Total $ (11 ) $ 44 $ 149 $ 105 Change in unrealized investment gains and losses: Fixed maturities $ 76 $ 178 $ 110 $ 294 Equity securities 145 111 242 285 Income tax (provision) benefit (77 ) (103 ) (123 ) (203 ) Total $ 144 $ 186 $ 229 $ 376

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2017
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 June 30, 2017 , and December 31, 2016 . We do not have any material liabilities carried at fair value. There were no transfers between Level 1 and Level 2. (Dollars in millions) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Total At June 30, 2017 Fixed maturities, available for sale: Corporate $ — $ 5,796 $ 1 $ 5,797 States, municipalities and political subdivisions — 4,149 5 4,154 Commercial mortgage-backed — 289 — 289 Government-sponsored enterprises — 232 — 232 United States government 15 — — 15 Foreign government — 10 — 10 Convertibles and bonds with warrants attached — 5 — 5 Subtotal 15 10,481 6 10,502 Common equities, available for sale 5,581 — — 5,581 Nonredeemable preferred equities, available for sale — 218 — 218 Separate accounts taxable fixed maturities — 770 — 770 Top Hat savings plan mutual funds and common 28 — — 28 Total $ 5,624 $ 11,469 $ 6 $ 17,099 At December 31, 2016 Fixed maturities, available for sale: Corporate $ — $ 5,703 $ 78 $ 5,781 States, municipalities and political subdivisions — 3,828 — 3,828 Commercial mortgage-backed — 287 — 287 Government-sponsored enterprises — 164 — 164 United States government 10 — — 10 Foreign government — 10 — 10 Convertibles and bonds with warrants attached — 5 — 5 Subtotal 10 9,997 78 10,085 Common equities, available for sale 5,123 — — 5,123 Nonredeemable preferred equities, available for sale — 211 — 211 Separate accounts taxable fixed maturities — 750 — 750 Top Hat savings plan mutual funds and common equity (included in Other assets) 24 — — 24 Total $ 5,157 $ 10,958 $ 78 $ 16,193
Asset Fair Value Measurements Using Significant Unobservable Inputs (Level 3)	(Dollars in millions) Asset fair value measurements using significant unobservable inputs (Level 3) Corporate Taxable fixed maturities - separate accounts States, Nonredeemable preferred Total Beginning balance, April 1, 2017 $ 1 $ — $ — $ — $ 1 Total gains or losses (realized/unrealized): Included in net income — — — — — Included in other comprehensive income — — — — — Purchases — — — — — Sales — — — — — Transfers into Level 3 — — 5 — 5 Transfers out of Level 3 — — — — — Ending balance, June 30, 2017 $ 1 $ — $ 5 $ — $ 6 Beginning balance, April 1, 2016 $ 51 $ 1 $ — $ 2 $ 54 Total gains or losses (realized/unrealized): Included in net income — — — — — Included in other comprehensive income — — — — — Purchases 17 — — — 17 Sales — — — (2 ) (2 ) Transfers into Level 3 — — — — — Transfers out of Level 3 (16 ) — — — (16 ) Ending balance, June 30, 2016 $ 52 $ 1 $ — $ — $ 53 The following table provides the change in Level 3 assets for the six months ended June 30 : (Dollars in millions) Asset fair value measurements using significant unobservable inputs Corporate fixed maturities Taxable fixed maturities - separate accounts States, municipalities and political subdivisions fixed maturities Nonredeemable preferred equities Total Beginning balance, January 1, 2017 $ 78 $ — $ — $ — $ 78 Total gains or losses (realized/unrealized): Included in net income — — — — — Included in other comprehensive income — — — — — Purchases — — 5 — 5 Sales — — — — — Transfers into Level 3 — — — — — Transfers out of Level 3 (77 ) — — — (77 ) Ending balance, June 30, 2017 $ 1 $ — $ 5 $ — $ 6 Beginning balance, January 1, 2016 $ 51 $ 1 $ — $ 3 $ 55 Total gains or losses (realized/unrealized): Included in net income — — — — — Included in other comprehensive income — — — (1 ) (1 ) Purchases 22 — — — 22 Sales — — — (2 ) (2 ) Transfers into Level 3 — — — — — Transfers out of Level 3 (21 ) — — — (21 ) Ending balance, June 30, 2016 $ 52 $ 1 $ — $ — $ 53
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: (Dollars in millions) Book value Principal amount Interest rate Year of issue June 30, December 31, June 30, December 31, 2017 2016 2017 2016 6.900 % 1998 Senior debentures, due 2028 $ 26 $ 26 $ 28 $ 28 6.920 % 2005 Senior debentures, due 2028 391 391 391 391 6.125 % 2004 Senior notes, due 2034 370 370 374 374 Total $ 787 $ 787 $ 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: (Dollars in millions) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Total At June 30, 2017 Life policy loans $ — $ — $ 41 $ 41 At December 31, 2016 Life policy loans $ — $ — $ 40 $ 40
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: (Dollars in millions) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Total At June 30, 2017 Note payable $ — $ 17 $ — $ 17 6.900% senior debentures, due 2028 — 34 — 34 6.920% senior debentures, due 2028 — 506 — 506 6.125% senior notes, due 2034 — 458 — 458 Total $ — $ 1,015 $ — $ 1,015 At December 31, 2016 Note payable $ — $ 20 $ — $ 20 6.900% senior debentures, due 2028 — 33 — 33 6.920% senior debentures, due 2028 — 488 — 488 6.125% senior notes, due 2034 — 435 — 435 Total $ — $ 976 $ — $ 976
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: (Dollars in millions) Quoted prices in active markets for identical assets (Level 1) Significant other observable inputs (Level 2) Significant unobservable inputs (Level 3) Total At June 30, 2017 Deferred annuities $ — $ — $ 846 $ 846 Structured settlements — 206 — 206 Total $ — $ 206 $ 846 $ 1,052 At December 31, 2016 Deferred annuities $ — $ — $ 839 $ 839 Structured settlements — 206 — 206 Total $ — $ 206 $ 839 $ 1,045

Property Casualty Loss and Lo25

Property Casualty Loss and Loss Expenses (Tables)	6 Months Ended
	Jun. 30, 2017
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: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Gross loss and loss expense reserves, beginning of period $ 5,128 $ 4,750 $ 5,035 $ 4,660 Less reinsurance recoverable 297 272 298 281 Net loss and loss expense reserves, beginning of period 4,831 4,478 4,737 4,379 Net incurred loss and loss expenses related to: Current accident year 832 808 1,658 1,531 Prior accident years (38 ) (49 ) (76 ) (111 ) Total incurred 794 759 1,582 1,420 Net paid loss and loss expenses related to: Current accident year 373 328 558 474 Prior accident years 322 301 831 717 Total paid 695 629 1,389 1,191 Net loss and loss expense reserves, end of period 4,930 4,608 4,930 4,608 Plus reinsurance recoverable 283 310 283 310 Gross loss and loss expense reserves, end of period $ 5,213 $ 4,918 $ 5,213 $ 4,918

Life Policy and Investment Co26

Life Policy and Investment Contract Reserves (Tables)	6 Months Ended
	Jun. 30, 2017
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: (Dollars in millions) June 30, December 31, 2016 Life policy reserves: Ordinary/traditional life $ 1,045 $ 1,011 Other 46 45 Subtotal 1,091 1,056 Investment contract reserves: Deferred annuities 851 861 Universal life 590 578 Structured settlements 164 170 Other 6 6 Subtotal 1,611 1,615 Total life policy and investment contract reserves $ 2,702 $ 2,671

Deferred Acquisition Costs (Ta

Deferred Acquisition Costs (Tables)	6 Months Ended
	Jun. 30, 2017
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. (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Property casualty: Deferred policy acquisition costs asset, beginning of period $ 428 $ 397 $ 408 $ 388 Capitalized deferred policy acquisition costs 237 218 463 428 Amortized deferred policy acquisition costs (217 ) (203 ) (423 ) (404 ) Deferred policy acquisition costs asset, end of period $ 448 $ 412 $ 448 $ 412 Life: Deferred policy acquisition costs asset, beginning of period $ 232 $ 221 $ 229 $ 228 Capitalized deferred policy acquisition costs 12 12 25 24 Amortized deferred policy acquisition costs (12 ) (11 ) (20 ) (22 ) Amortized shadow deferred policy acquisition costs (2 ) (10 ) (4 ) (18 ) Deferred policy acquisition costs asset, end of period $ 230 $ 212 $ 230 $ 212 Consolidated: Deferred policy acquisition costs asset, beginning of period $ 660 $ 618 $ 637 $ 616 Capitalized deferred policy acquisition costs 249 230 488 452 Amortized deferred policy acquisition costs (229 ) (214 ) (443 ) (426 ) Amortized shadow deferred policy acquisition costs (2 ) (10 ) (4 ) (18 ) Deferred policy acquisition costs asset, end of period $ 678 $ 624 $ 678 $ 624

Accumulated Other Comprehensi28

Accumulated Other Comprehensive Income (Tables)	6 Months Ended
	Jun. 30, 2017
Accumulated Other Comprehensive Income [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	(Dollars in millions) Three months ended June 30, 2017 2016 Before tax Income tax Net Before tax Income tax Net Investments: AOCI, beginning of period $ 2,756 $ 954 $ 1,802 $ 2,384 $ 822 $ 1,562 OCI before realized gains recognized in net income 211 74 137 331 118 213 Realized gains and losses recognized in net income 10 3 7 (42 ) (15 ) (27 ) OCI 221 77 144 289 103 186 AOCI, end of period $ 2,977 $ 1,031 $ 1,946 $ 2,673 $ 925 $ 1,748 Pension obligations: AOCI, beginning of period $ (25 ) $ (8 ) $ (17 ) $ (41 ) $ (13 ) $ (28 ) OCI excluding amortization recognized in net income — — — — — — Amortization recognized in net income — — — 1 — 1 OCI — — — 1 — 1 AOCI, end of period $ (25 ) $ (8 ) $ (17 ) $ (40 ) $ (13 ) $ (27 ) Life deferred acquisition costs, life policy reserves and other: AOCI, beginning of period $ (7 ) $ (2 ) $ (5 ) $ (3 ) $ — $ (3 ) OCI before realized gains recognized in net income — (1 ) 1 (5 ) (2 ) (3 ) Realized gains and losses recognized in net income 1 1 — (2 ) (1 ) (1 ) OCI 1 — 1 (7 ) (3 ) (4 ) AOCI, end of period $ (6 ) $ (2 ) $ (4 ) $ (10 ) $ (3 ) $ (7 ) Summary of AOCI: AOCI, beginning of period $ 2,724 $ 944 $ 1,780 $ 2,340 $ 809 $ 1,531 Investments OCI 221 77 144 289 103 186 Pension obligations OCI — — — 1 — 1 Life deferred acquisition costs, life policy reserves and other OCI 1 — 1 (7 ) (3 ) (4 ) Total OCI 222 77 145 283 100 183 AOCI, end of period $ 2,946 $ 1,021 $ 1,925 $ 2,623 $ 909 $ 1,714 (Dollars in millions) Six months ended June 30, 2017 2016 Before tax Income tax Net Before tax Income tax Net Investments: AOCI, beginning of period $ 2,625 $ 908 $ 1,717 $ 2,094 $ 722 $ 1,372 OCI before realized gains recognized in net income 501 176 325 682 239 443 Realized gains recognized in net income (149 ) (53 ) (96 ) (103 ) (36 ) (67 ) OCI 352 123 229 579 203 376 AOCI, end of period $ 2,977 $ 1,031 $ 1,946 $ 2,673 $ 925 $ 1,748 Pension obligations: AOCI, beginning of period $ (26 ) $ (8 ) $ (18 ) $ (42 ) $ (14 ) $ (28 ) OCI excluding amortization recognized in net income — — — — — — Amortization recognized in net income 1 — 1 2 1 1 OCI 1 — 1 2 1 1 AOCI, end of period $ (25 ) $ (8 ) $ (17 ) $ (40 ) $ (13 ) $ (27 ) Life deferred acquisition costs, life policy reserves and other: AOCI, beginning of period $ (9 ) $ (3 ) $ (6 ) $ 1 $ 1 $ — OCI before realized gains recognized in net income 3 1 2 (9 ) (3 ) (6 ) Realized gains recognized in net income — — — (2 ) (1 ) (1 ) OCI 3 1 2 (11 ) (4 ) (7 ) AOCI, end of period $ (6 ) $ (2 ) $ (4 ) $ (10 ) $ (3 ) $ (7 ) Summary of AOCI: AOCI, beginning of period $ 2,590 $ 897 $ 1,693 $ 2,053 $ 709 $ 1,344 Investments OCI 352 123 229 579 203 376 Pension obligations OCI 1 — 1 2 1 1 Life deferred acquisition costs, life policy reserves and other OCI 3 1 2 (11 ) (4 ) (7 ) Total OCI 356 124 232 570 200 370 AOCI, end of period $ 2,946 $ 1,021 $ 1,925 $ 2,623 $ 909 $ 1,714

Reinsurance (Tables)

Reinsurance (Tables)	6 Months Ended
	Jun. 30, 2017
Reinsurance Disclosures [Abstract]
Property Casualty Insurance Premiums Written On Assumed And Ceded Business	The table below includes our net written consolidated property casualty insurance premiums on assumed and ceded business: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct written premiums $ 1,265 $ 1,211 $ 2,491 $ 2,372 Assumed written premiums 42 42 75 63 Ceded written premiums (36 ) (59 ) (64 ) (94 ) Net written premiums $ 1,271 $ 1,194 $ 2,502 $ 2,341
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: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct earned premiums $ 1,189 $ 1,137 $ 2,352 $ 2,256 Assumed earned premiums 33 16 60 31 Ceded earned premiums (41 ) (39 ) (80 ) (77 ) Earned premiums $ 1,181 $ 1,114 $ 2,332 $ 2,210
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: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct incurred loss and loss expenses $ 770 $ 792 $ 1,558 $ 1,440 Assumed incurred loss and loss expenses 20 11 35 21 Ceded incurred loss and loss expenses 4 (44 ) (11 ) (41 ) Incurred loss and loss expenses $ 794 $ 759 $ 1,582 $ 1,420
Earned Life Insurance Premiums On Ceded Business	Our condensed consolidated statements of income include earned life insurance premiums on ceded business: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct earned premiums $ 77 $ 75 $ 151 $ 146 Ceded earned premiums (17 ) (16 ) (34 ) (29 ) Earned premiums $ 60 $ 59 $ 117 $ 117
Life Insurance Contract Holders' Benefits Incurred On Ceded Business	Our condensed consolidated statements of income include life insurance contract holders' benefits incurred on ceded business: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Direct contract holders' benefits incurred $ 87 $ 80 $ 163 $ 156 Ceded contract holders' benefits incurred (27 ) (18 ) (38 ) (31 ) Contract holders' benefits incurred $ 60 $ 62 $ 125 $ 125

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2017
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 federal income tax rate and our effective income tax rate were as follows: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Tax at statutory rate: $ 44 35.0 % $ 58 35.0 % $ 141 35.0 % $ 151 35.0 % Increase (decrease) resulting from: Tax-exempt income from municipal bonds (9 ) (7.0 ) (8 ) (4.8 ) (18 ) (4.5 ) (17 ) (3.9 ) Dividend received exclusion (9 ) (7.0 ) (8 ) (4.8 ) (17 ) (4.2 ) (16 ) (3.7 ) Other 2 0.9 1 0.5 (3 ) (0.8 ) 2 0.4 Provision for income taxes $ 28 21.9 % $ 43 25.9 % $ 103 25.5 % $ 120 27.8 %

Net Income Per Common Share (Ta

Net Income Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2017
Earnings Per Share [Abstract]
Calculations For Basic And Diluted Earnings Per Share	The table shows calculations for basic and diluted earnings per share: (In millions except per share data) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Numerator: Net income—basic and diluted $ 100 $ 123 $ 301 $ 311 Denominator: Basic weighted-average common shares outstanding 164.3 164.5 164.4 164.4 Effect of share-based awards: Stock options 1.0 1.1 1.1 1.1 Nonvested shares 0.7 0.9 0.7 0.8 Diluted weighted-average shares 166.0 166.5 166.2 166.3 Earnings per share: Basic $ 0.61 $ 0.75 $ 1.83 $ 1.89 Diluted 0.60 0.74 1.81 1.87 Number of anti-dilutive share-based awards 0.6 0.3 0.7 0.4

Employee Retirement Benefits (T

Employee Retirement Benefits (Tables)	6 Months Ended
	Jun. 30, 2017
Compensation and Retirement Disclosure [Abstract]
Schedule of Defined Benefit Plans Disclosures	The following summarizes the components of net periodic benefit cost for our qualified and supplemental pension plans: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Service cost $ 2 $ 2 $ 5 $ 5 Interest cost 4 4 7 7 Expected return on plan assets (5 ) (4 ) (10 ) (9 ) Amortization of actuarial loss and prior service cost — 1 1 2 Net periodic benefit cost $ 1 $ 3 $ 3 $ 5

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2017
Segment Reporting [Abstract]
Segment Information	Segment information is summarized in the following table: (Dollars in millions) Three months ended June 30, Six months ended June 30, 2017 2016 2017 2016 Revenues: Commercial lines insurance Commercial casualty $ 271 $ 263 $ 536 $ 520 Commercial property 226 215 449 429 Commercial auto 158 147 313 291 Workers' compensation 86 89 170 178 Other commercial 55 57 109 113 Commercial lines insurance premiums 796 771 1,577 1,531 Fee revenues 1 1 2 2 Total commercial lines insurance 797 772 1,579 1,533 Personal lines insurance Personal auto 144 135 285 266 Homeowner 128 121 253 240 Other personal 35 32 69 65 Personal lines insurance premiums 307 288 607 571 Fee revenues 1 1 3 2 Total personal lines insurance 308 289 610 573 Excess and surplus lines insurance 52 45 100 88 Fee revenues 1 — 1 — Total excess and surplus lines insurance 53 45 101 88 Life insurance premiums 60 59 117 117 Fee revenues 1 1 3 2 Total life insurance 61 60 120 119 Investments Investment income, net of expenses 151 149 300 294 Realized investment gains and losses, net (11 ) 44 149 105 Total investment revenue 140 193 449 399 Other Cincinnati Re insurance premiums 26 10 48 20 Other 1 2 2 3 Total other revenues 27 12 50 23 Total revenues $ 1,386 $ 1,371 $ 2,909 $ 2,735 Income (loss) before income taxes: Insurance underwriting results Commercial lines insurance $ 24 $ 26 $ 22 $ 76 Personal lines insurance (24 ) (20 ) (39 ) 8 Excess and surplus lines insurance 19 5 37 22 Life insurance 4 1 4 — Investments 117 171 403 355 Other (12 ) (17 ) (23 ) (30 ) Total income before income taxes $ 128 $ 166 $ 404 $ 431 Identifiable assets: June 30, December 31, 2016 Property casualty insurance $ 3,042 $ 2,967 Life insurance 1,427 1,366 Investments 16,431 15,569 Other 338 484 Total $ 21,238 $ 20,386

Accounting Policies (Details)

Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification included in financing activities		$ (283)	$ (189)
Excess tax benefit	$ 6	6
Available-for-sale Equity Securities, Unrealized Gain, After Tax	1,677	1,677
Accounting Standards Update 2016-09, Excess Tax Benefit Component [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification included in financing activities		12	$ 9
Cumulative effect adjustment	$ 0	$ 0

Investments - Analysis of Cost

Investments - Analysis of Cost or Amortized Cost, Gross Unrealized Gains and Losses and Fair Value for Investments (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	$ 10,106	$ 9,799
Gross Unrealized Gains	431	359
Gross Unrealized Losses	35	73
Fair Value	10,502	10,085
Debt Securities | Corporate
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	5,530	5,555
Gross Unrealized Gains	281	252
Gross Unrealized Losses	14	26
Fair Value	5,797	5,781
Debt Securities | States, municipalities and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	4,029	3,770
Gross Unrealized Gains	142	100
Gross Unrealized Losses	17	42
Fair Value	4,154	3,828
Debt Securities | Commercial mortgage-backed
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	282	282
Gross Unrealized Gains	8	7
Gross Unrealized Losses	1	2
Fair Value	289	287
Debt Securities | Government-sponsored enterprises
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	235	167
Gross Unrealized Gains	0	0
Gross Unrealized Losses	3	3
Fair Value	232	164
Debt Securities | United States government
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	15	10
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	15	10
Debt Securities | Foreign government
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	10	10
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	10	10
Debt Securities | Convertibles and bonds with warrants attached
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	5	5
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	5	5
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	3,218	2,995
Gross Unrealized Gains	2,597	2,348
Gross Unrealized Losses	16	9
Fair Value	5,799	5,334
Equity Securities | Common equities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	3,038	2,812
Gross Unrealized Gains	2,559	2,320
Gross Unrealized Losses	16	9
Fair Value	5,581	5,123
Equity Securities | Nonredeemable preferred equities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	180	183
Gross Unrealized Gains	38	28
Gross Unrealized Losses	0	0
Fair Value	218	211
Fixed Maturities And Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	13,324	12,794
Gross Unrealized Gains	3,028	2,707
Gross Unrealized Losses	51	82
Fair Value	$ 16,301	$ 15,419

Investments - Fair Values and U

Investments - Fair Values and Unrealized Losses by Investment Category and by Duration of Securities' Continuous Unrealized Loss Position (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	$ 1,559	$ 2,079
Less than 12 months Unrealized Losses	45	71
12 months or more Fair Value	141	191
12 months or more Unrealized Losses	6	11
Total Fair Value	1,700	2,270
Total Unrealized Losses	51	82
Fixed Maturities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	1,205	1,972
Less than 12 months Unrealized Losses	29	62
12 months or more Fair Value	141	191
12 months or more Unrealized Losses	6	11
Total Fair Value	1,346	2,163
Total Unrealized Losses	35	73
Fixed Maturities | Corporate
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	290	733
Less than 12 months Unrealized Losses	8	15
12 months or more Fair Value	136	189
12 months or more Unrealized Losses	6	11
Total Fair Value	426	922
Total Unrealized Losses	14	26
Fixed Maturities | States, municipalities and political subdivisions
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	665	989
Less than 12 months Unrealized Losses	17	42
12 months or more Fair Value	2	0
12 months or more Unrealized Losses	0	0
Total Fair Value	667	989
Total Unrealized Losses	17	42
Fixed Maturities | Commercial mortgage-backed
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	53	89
Less than 12 months Unrealized Losses	1	2
12 months or more Fair Value	3	2
12 months or more Unrealized Losses	0	0
Total Fair Value	56	91
Total Unrealized Losses	1	2
Fixed Maturities | Government-sponsored enterprises
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	190	155
Less than 12 months Unrealized Losses	3	3
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	0	0
Total Fair Value	190	155
Total Unrealized Losses	3	3
Fixed Maturities | United States government
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	7	6
Less than 12 months Unrealized Losses	0	0
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	0	0
Total Fair Value	7	6
Total Unrealized Losses	0	0
Equity Securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	354	107
Less than 12 months Unrealized Losses	16	9
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	0	0
Total Fair Value	354	107
Total Unrealized Losses	16	9
Equity Securities | Common equities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	354	103
Less than 12 months Unrealized Losses	16	9
12 months or more Fair Value	0	0
12 months or more Unrealized Losses	0	0
Total Fair Value	354	103
Total Unrealized Losses	$ 16	9
Equity Securities | Nonredeemable preferred equities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value		4
Less than 12 months Unrealized Losses		0
12 months or more Fair Value		0
12 months or more Unrealized Losses		0
Total Fair Value		4
Total Unrealized Losses		$ 0

Investments - Schedule of Contr

Investments - Schedule of Contractual Maturities of Investments (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Amortized cost
Due in one year or less	$ 699
Due after one year through five years	2,690
Due after five years through ten years	3,822
Due after ten years	2,895
Total	10,106	$ 9,799
Fair value
Due in one year or less	714
Due after one year through five years	2,830
Due after five years through ten years	3,970
Due after ten years	2,988
Total	$ 10,502	$ 10,085
% of fair value
Due in one year or less	6.80%
Due after one year through five years	26.90%
Due after five years through ten years	37.80%
Due after ten years	28.50%
Total	100.00%

Investments - Realized Investme

Investments - Realized Investment Gains and Losses and Change in Unrealized Investment Gains and Losses and Other Items (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Investment income summary:
Interest	$ 111	$ 110	$ 222	$ 219
Dividends	42	41	81	78
Other	1	0	2	1
Total	154	151	305	298
Less investment expenses	3	2	5	4
Total	151	149	300	294
Realized investment gains and losses summary:
Realized investment gains and losses, net	(11)	44	149	105
Change in unrealized gains and losses summary:
Fixed maturities	144	186	229	376
Income tax (provision) benefit	(77)	(103)	(123)	(203)
Fixed Maturities
Realized investment gains and losses summary:
Gross realized gains	3	4	13	7
Gross realized losses	0	0	0	(1)
Other-than-temporary impairments	(6)	0	(6)	(2)
Change in unrealized gains and losses summary:
Fixed maturities	76	178	110	294
Equity Securities
Realized investment gains and losses summary:
Gross realized gains	6	38	159	100
Gross realized losses	(10)	0	(14)	(1)
Other-than-temporary impairments	(3)	0	(3)	0
Other	(1)	2	0	2
Change in unrealized gains and losses summary:
Fixed maturities	$ 145	$ 111	$ 242	$ 285

Investments - Additional Inform

Investments - Additional Information (Detail)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017USD ($)security	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)security	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)security
Gain (Loss) on Investments [Line Items]
Largest Single Common Stock Holding	$ 206,000,000		$ 206,000,000
Largest equity holdings to total equity portfolio	3.70%		3.70%
Largest equity holdings to total portfolio	1.30%		1.30%
Unrealized losses 12 months or more (equity investment less than $500,000)	$ (6,000,000)		$ (6,000,000)		$ (11,000,000)
Fixed maturity investments, Percentage of amortized costs			70.00%		70.00%
Fixed Maturities
Gain (Loss) on Investments [Line Items]
Unrealized investment gains due to a net gain position	$ 431,000,000		$ 431,000,000		$ 359,000,000
Number Of Securities Other Than Temporary Impairment Losses1 | security	1		1
Provision for Other Credit Losses	$ 0	$ 0	$ 0	$ 0
Number Of Securities Continuous Unrealized Loss Position More Than Twelve Months | security	23		23		32
Unrealized losses 12 months or more (equity investment less than $500,000)	$ (6,000,000)		$ (6,000,000)		$ (11,000,000)
Number Of Securities Continuous Unrealized Loss Position More Than Twelve Months and Below 70 Percent of Amortized Cost	0		0		0
Equity Securities
Gain (Loss) on Investments [Line Items]
Unrealized investment gains due to a net gain position	$ 2,597,000,000		$ 2,597,000,000		$ 2,348,000,000
Number Of Securities Other Than Temporary Impairment Losses1 | security	5		5
Number Of Securities Continuous Unrealized Loss Position More Than Twelve Months	0		0		0
Unrealized losses 12 months or more (equity investment less than $500,000)	$ 0		$ 0		$ 0
Number Of Securities Continuous Unrealized Loss Position More Than Twelve Months and Below 70 Percent of Amortized Cost	0		0		0
Largest unrealized investment gains in common stock portfolio [Member]
Gain (Loss) on Investments [Line Items]
Unrealized investment gains due to a net gain position	$ 829,000,000		$ 829,000,000
Common equities
Gain (Loss) on Investments [Line Items]
Number of securities	7		7

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value Hierarchy for Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	$ 10,502	$ 10,085
Equity securities, at fair value	5,799	5,334
Separate accounts	790	766
Top Hat savings plan mutual funds and common equity (included in Other assets)	28	24
Fair value of asset	17,099	16,193
Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	10,502	10,085
Debt Securities | Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	5,797	5,781
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	4,154	3,828
Debt Securities | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	289	287
Debt Securities | Government-sponsored enterprises
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	232	164
Debt Securities | United States government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	15	10
Debt Securities | Foreign government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	10	10
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	5	5
Equity Securities | Common equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	5,581	5,123
Equity Securities | Nonredeemable preferred equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	218	211
Taxable Fixed Maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Separate accounts	770	750
Quoted prices in active markets for identical assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Top Hat savings plan mutual funds and common equity (included in Other assets)	28	24
Fair value of asset	5,624	5,157
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	15	10
Quoted prices in active markets for identical assets (Level 1) | Debt Securities | Corporate
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 | 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 | Commercial mortgage-backed
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 | 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 | United States government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	15	10
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 | 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) | Equity Securities | Common equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	5,581	5,123
Quoted prices in active markets for identical assets (Level 1) | Equity Securities | Nonredeemable preferred equities
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]
Top Hat savings plan mutual funds and common equity (included in Other assets)	0	0
Fair value of asset	11,469	10,958
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	10,481	9,997
Significant other observable inputs (Level 2) | Debt Securities | Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	5,796	5,703
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	4,149	3,828
Significant other observable inputs (Level 2) | Debt Securities | Commercial mortgage-backed
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	289	287
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	232	164
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 | Foreign government
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	10	10
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	5	5
Significant other observable inputs (Level 2) | Equity Securities | Common equities
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 | Nonredeemable preferred equities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities, at fair value	218	211
Significant other observable inputs (Level 2) | Taxable Fixed Maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Separate accounts	770	750
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Top Hat savings plan mutual funds and common equity (included in Other assets)	0	0
Fair value of asset	6	78
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	6	78
Significant unobservable inputs (Level 3) | Debt Securities | Corporate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed maturities, at fair value	1	78
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	5	0
Significant unobservable inputs (Level 3) | Debt Securities | Commercial mortgage-backed
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 | 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 | 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 | 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) | Equity Securities | Common equities
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 | Nonredeemable preferred equities
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) | Taxable Fixed Maturities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Separate accounts	$ 0	$ 0

Fair Value Measurements - Chang

Fair Value Measurements - Change in Level 3 Assets (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 1	$ 54	$ 78	$ 55
Total gains or losses (realized/unrealized):
Included in net income	0	0	0	0
Included in other comprehensive income	0	0	0	(1)
Purchases	0	17	5	22
Sales	0	(2)	0	(2)
Transfers into Level 3	5	0	0	0
Transfers out of Level 3	0	(16)	(77)	(21)
Ending balance	6	53	6	53
Corporate Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1	51	78	51
Total gains or losses (realized/unrealized):
Included in net income	0	0	0	0
Included in other comprehensive income	0	0	0	0
Purchases	0	17	0	22
Sales	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	(16)	(77)	(21)
Ending balance	1	52	1	52
Taxable Fixed Maturities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0	1	0	1
Total gains or losses (realized/unrealized):
Included in net income	0	0	0	0
Included in other comprehensive income	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	0	1	0	1
States, Municipalities And Political Subdivisions Fixed Maturities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0	0	0	0
Total gains or losses (realized/unrealized):
Included in net income	0	0	0	0
Included in other comprehensive income	0	0	0	0
Purchases	0	0	5	0
Sales	0	0	0	0
Transfers into Level 3	5	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	5	0	5	0
Preferred Equities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	0	2	0	3
Total gains or losses (realized/unrealized):
Included in net income	0	0	0	0
Included in other comprehensive income	0	0	0	(1)
Purchases	0	0	0	0
Sales	0	(2)	0	(2)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Ending balance	$ 0	$ 0	$ 0	$ 0

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Book Value and Principal Amounts of Long-Term Debt (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Book value	$ 787	$ 787
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	1,998	1,998
Book value	$ 26	$ 26
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	2,005	2,005
Book value	$ 391	$ 391
Principal amount of debt	$ 391	$ 391
Senior Notes 6.152% Due 2034
Debt Instrument [Line Items]
Interest rate	6.125%	6.125%
Debt issuance year	2,004	2,004
Book value	$ 370	$ 370
Principal amount of debt	$ 374	$ 374

Fair Value Measurements - Fai43

Fair Value Measurements - Fair Values of Note Payable and Long-Term Debt (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of note payable	$ 17	$ 20
Total	1,015	976
Finance receivable	$ 54	$ 51
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	2,028	2,028
Fair value of senior debt	$ 34	$ 33
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	2,028	2,028
Fair value of senior debt	$ 506	$ 488
Senior Notes 6.125 % Due 2034
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	6.125%	6.125%
Debt instrument, year of maturity	2,034	2,034
Fair value of senior debt	$ 458	$ 435
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	17	20
Total	1,015	976
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	34	33
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	506	488
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	458	435
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
Deferred Annuities And Structured Settlements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for Future Policy Benefits, Individual and Group Annuities and Supplementary Contracts	851	861
Policy Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finance receivable	$ 31	$ 31

Fair Value Measurements - Fai44

Fair Value Measurements - Fair Value of Life Policy Loans (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finance receivable	$ 54	$ 51
Fair value of life policy loans	41	40
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	41	40
Policy Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finance receivable	$ 31	$ 31

Fair Value Measurements - Fai45

Fair Value Measurements - Fair Values of Deferred Annuities, Structured Settlements and Other Items (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	$ 1,052	$ 1,045
Deferred annuities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	846	839
Structured Settlements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	206	206
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	206	206
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	206	206
Significant unobservable inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of life insurance liabilities	846	839
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	846	839
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 - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finance receivable	$ 54	$ 51
Loss and loss expense reserves	5,281	5,085
Life Policy Loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Finance receivable	31	31
Deferred Annuities And Structured Settlements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for Future Policy Benefits, Individual and Group Annuities and Supplementary Contracts	851	861
Loss and loss expense reserves	$ 164	$ 170
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Percentage Of Level 3 Assets To Total Financial Instruments Measured At Fair Value	1.00%

Property Casualty Loss and Lo47

Property Casualty Loss and Loss Expenses - Consolidated Property Casualty Loss and Loss Expense Reserves (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Summary of Consolidated Property Casualty Loss and Loss Expense Reserves [Roll Forward]
Gross loss and loss expense reserves, beginning of period	$ 5,128	$ 4,750	$ 5,035	$ 4,660
Less reinsurance recoverable	297	272	298	281
Net loss and loss expense reserves, beginning of period	4,831	4,478	4,737	4,379
Current accident year	832	808	1,658	1,531
Prior accident years	(38)	(49)	(76)	(111)
Total incurred	794	759	1,582	1,420
Current accident year	373	328	558	474
Prior accident years	322	301	831	717
Total paid	695	629	1,389	1,191
Net loss and loss expense reserves, end of period	4,930	4,608	4,930	4,608
Plus reinsurance recoverable	283	310	283	310
Gross loss and loss expense reserves, end of period	$ 5,213	$ 4,918	$ 5,213	$ 4,918

Property Casualty Loss and Lo48

Property Casualty Loss and Loss Expenses - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Reserve for loss and loss expenses	$ 5,213	$ 4,918	$ 5,213	$ 4,918	$ 5,128	$ 5,035	$ 4,750	$ 4,660
Prior accident years	(38)	(49)	(76)	(111)
Life and Health Loss Reserves
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Reserve for loss and loss expenses	68	52	68	52
Commercial Lines
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years	(26)	(58)	(37)	(87)
Commercial Lines | Workers' Compensation
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years	(12)	(23)	(31)	(35)
Commercial Lines | Commercial Casualty Segment [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years	(7)	(20)	8	(23)
Commercial Lines | Other Commercial Lines [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years	(11)	(15)	(19)	(28)
Commercial Lines | Commercial Auto
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years	9	13	20	21
Commercial Lines | Commercial Property Segment [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years	(5)	(14)	(15)	(22)
Personal Lines
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years	(3)	(10)	(13)	(8)
Personal Lines | Personal Auto [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years		14		6
Excess and Surplus Lines Insurance
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years	(9)	(1)	(22)	(15)
Reinsurance assumed and other non segment [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years			(4)	(1)
Consolidated Property and Casualty Insurance Entity | Catastrophe Development
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years	$ (3)		$ (14)	$ (7)
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Personal Lines | Personal Auto [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Prior accident years		$ 8

Reserves in Addition to Account

Reserves in Addition to Account Balance, Based on Expected No-Lapse Guarantee Benefits and Expected Policy Assessments (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	$ 2,702	$ 2,671
Life policy reserves:
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	1,091	1,056
Life policy reserves: | Ordinary/traditional life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	1,045	1,011
Life policy reserves: | Other
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	46	45
Investment contract reserves:
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	1,611	1,615
Investment contract reserves: | Deferred annuities
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	851	861
Investment contract reserves: | Universal life
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	590	578
Investment contract reserves: | Structured settlements
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	164	170
Investment contract reserves: | Other
Liability for Future Policy Benefit, by Product Segment [Line Items]
Life policy and investment contract reserves	$ 6	$ 6

Deferred Acquisition Costs - De

Deferred Acquisition Costs - Deferred Policy Acquisition Costs and Asset Reconciliation (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset, beginning of period	$ 660	$ 618	$ 637	$ 616
Capitalized deferred policy acquisition costs	249	230	488	452
Deferred Policy Acquisition Cost, Amortization Expense	(229)	(214)	(443)	(426)
Deferred Policy Acquisition Cost, Amortization Expense, Other	(2)	(10)	(4)	(18)
Deferred policy acquisition costs asset, end of period	678	624	678	624
Life Insurance Product Line [Member]
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset, beginning of period	232	221	229	228
Capitalized deferred policy acquisition costs	12	12	25	24
Deferred Policy Acquisition Cost, Amortization Expense	(12)	(11)	(20)	(22)
Deferred Policy Acquisition Cost, Amortization Expense, Other	(2)	(10)	(4)	(18)
Deferred policy acquisition costs asset, end of period	230	212	230	212
Consolidated Property and Casualty Insurance Entity
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Deferred policy acquisition costs asset, beginning of period	428	397	408	388
Capitalized deferred policy acquisition costs	237	218	463	428
Deferred Policy Acquisition Cost, Amortization Expense	(217)	(203)	(423)	(404)
Deferred policy acquisition costs asset, end of period	$ 448	$ 412	$ 448	$ 412

Accumulated Other Comprehensi51

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	$ 1,925		$ 1,925			$ 1,693
Accumulated other comprehensive income, net of tax, end of period	1,925		1,925
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated other comprehensive income, before tax, beginning of period	2,756	$ 2,384	2,625	$ 2,094
Other comprehensive income before reclassification, before tax	211	331	501	682
Reclassification adjustment, before tax	10	(42)	(149)	(103)
Effect on other comprehensive income, before tax	221	289	352	579
Accumulated other comprehensive income, before tax, end of period	2,977	2,673	2,977	2,673
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated other comprehensive income, tax, beginning of period	954	822	908	722
Other comprehensive income before reclassification, tax	74	118	176	239
Reclassification adjustment, tax	3	(15)	(53)	(36)
Effect on other comprehensive income, tax	77	103	123	203
Accumulated other comprehensive income, tax, end of period	1,031	925	1,031	925
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	1,946	1,748	1,946	1,748	$ 1,802	1,717	$ 1,562	$ 1,372
Other comprehensive income before reclassification, net of tax	137	213	325	443
Reclassification adjustment, net of tax	7	(27)	(96)	(67)
Effect on other comprehensive income, net of tax	144	186	229	376
Accumulated other comprehensive income, net of tax, end of period	1,946	1,748	1,946	1,748
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated other comprehensive income, before tax, beginning of period	(25)	(41)	(26)	(42)
Other comprehensive income before reclassification, before tax	0	0	0	0
Reclassification adjustment, before tax	0	1	1	2
Effect on other comprehensive income, before tax	0	1	1	2
Accumulated other comprehensive income, before tax, end of period	(25)	(40)	(25)	(40)
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated other comprehensive income, tax, beginning of period	(8)	(13)	(8)	(14)
Other comprehensive income before reclassification, tax	0	0	0	0
Reclassification adjustment, tax	0	0	0	1
Effect on other comprehensive income, tax	0	0	0	1
Accumulated other comprehensive income, tax, end of period	(8)	(13)	(8)	(13)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	(17)	(27)	(17)	(27)	(17)	(18)	(28)	(28)
Other comprehensive income before reclassification, net of tax	0	0	0	0
Reclassification adjustment, net of tax	0	1	1	1
Effect on other comprehensive income, net of tax	0	1	1	1
Accumulated other comprehensive income, net of tax, end of period	(17)	(27)	(17)	(27)
Accumulated Net Unrealized Gain (Loss) on Deferred Costs, Reserves And Other
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated other comprehensive income, before tax, beginning of period	(7)	(3)	(9)	1
Other comprehensive income before reclassification, before tax	0	(5)	3	(9)
Reclassification adjustment, before tax	1	(2)	0	(2)
Effect on other comprehensive income, before tax	1	(7)	3	(11)
Accumulated other comprehensive income, before tax, end of period	(6)	(10)	(6)	(10)
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated other comprehensive income, tax, beginning of period	(2)	0	(3)	1
Other comprehensive income before reclassification, tax	(1)	(2)	1	(3)
Reclassification adjustment, tax	1	(1)	0	(1)
Effect on other comprehensive income, tax	0	(3)	1	(4)
Accumulated other comprehensive income, tax, end of period	(2)	(3)	(2)	(3)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	(4)	(7)	(4)	(7)	(5)	(6)	(3)	0
Other comprehensive income before reclassification, net of tax	1	(3)	2	(6)
Reclassification adjustment, net of tax	0	(1)	0	(1)
Effect on other comprehensive income, net of tax	1	(4)	2	(7)
Accumulated other comprehensive income, net of tax, end of period	(4)	(7)	(4)	(7)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss Before Tax [Abstract]
Accumulated other comprehensive income, before tax, beginning of period	2,724	2,340	2,590	2,053
Change in unrealized gains, net, on investments available for sale, before tax	221	289	352	579
Change in pension obligations, before tax	0	1	1	2
Change in life deferred acquisition costs, life policy reserves and other, before tax	1	(7)	3	(11)
Effect on other comprehensive income, before tax	222	283	356	570
Accumulated other comprehensive income, before tax, end of period	2,946	2,623	2,946	2,623
Accumulated Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated other comprehensive income, tax, beginning of period	944	809	897	709
Change in unrealized gains, net, on investments available for sale, tax	77	103	123	203
Change in pension obligations, tax	0	0	0	1
Change in life deferred acquisition costs, life policy reserves and other, tax	0	(3)	1	(4)
Effect on other comprehensive income, tax	77	100	124	200
Accumulated other comprehensive income, tax, end of period	1,021	909	1,021	909
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income, net of tax, beginning of period	1,925	1,714	1,925	1,714	$ 1,780	$ 1,693	$ 1,531	$ 1,344
Change in unrealized gains, net, on investments available for sale, net of tax	144	186	229	376
Change in pension obligations, net of tax	0	1	1	1
Change in life deferred acquisition costs, life policy reserves and other, net of tax	1	(4)	2	(7)
Effect on other comprehensive income, net of tax	145	183	232	370
Accumulated other comprehensive income, net of tax, end of period	$ 1,925	$ 1,714	$ 1,925	$ 1,714

Reinsurance - Written Consolida

Reinsurance - Written Consolidated Property Casualty Insurance Premium on Assumed and Ceded Business (Details) - Consolidated Property and Casualty Insurance Entity - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Property Casualty Insurance Premiums Written On Assumed And Ceded Business [Line Items]
Direct written premiums	$ 1,265	$ 1,211	$ 2,491	$ 2,372
Assumed written premiums	42	42	75	63
Ceded written premiums	(36)	(59)	(64)	(94)
Net written premiums	$ 1,271	$ 1,194	$ 2,502	$ 2,341

Reinsurance - Earned Consolidat

Reinsurance - Earned Consolidated Property Casualty Insurance Premiums on Assumed and Ceded Business (Detail) - Consolidated Property and Casualty Insurance Entity - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct earned premiums	$ 1,189	$ 1,137	$ 2,352	$ 2,256
Assumed earned premiums	33	16	60	31
Ceded earned premiums	(41)	(39)	(80)	(77)
Earned premiums	$ 1,181	$ 1,114	$ 2,332	$ 2,210

Reinsurance - Incurred Consolid

Reinsurance - Incurred Consolidated Property Casualty Insurance Loss and Loss Expenses on Assumed and Ceded Business (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Incurred loss and loss expenses	$ 854	$ 821	$ 1,707	$ 1,545
Consolidated Property and Casualty Insurance Entity
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct incurred loss and loss expenses	770	792	1,558	1,440
Assumed incurred loss and loss expenses	20	11	35	21
Ceded incurred loss and loss expenses	4	(44)	(11)	(41)
Incurred loss and loss expenses	$ 794	$ 759	$ 1,582	$ 1,420

Reinsurance - Earned Life Insur

Reinsurance - Earned Life Insurance Premiums on Ceded Business (Detail) - Life Insurance Segment - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct earned premiums	$ 77	$ 75	$ 151	$ 146
Ceded earned premiums	(17)	(16)	(34)	(29)
Earned premiums	$ 60	$ 59	$ 117	$ 117

Reinsurance - Life Insurance Co

Reinsurance - Life Insurance Contract Holders' Benefits Incurred on Ceded Business (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Insurance losses and contract holders' benefits	$ 854	$ 821	$ 1,707	$ 1,545
Life Insurance Segment
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct contract holders' benefits incurred	87	80	163	156
Ceded contract holders' benefits incurred	(27)	(18)	(38)	(31)
Insurance losses and contract holders' benefits	$ 60	$ 62	$ 125	$ 125

Income Taxes - Differences Betw

Income Taxes - Differences Between 35 Percent Statutory Income Tax Rate and Effective Income Tax Rate (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Tax at statutory rate	$ 44	$ 58	$ 141	$ 151
Increase (decrease) resulting from:
Tax-exempt income from municipal bonds	(9)	(8)	(18)	(17)
Dividend received exclusion	(9)	(8)	(17)	(16)
Other	2	1	(3)	2
Total provision for income taxes	$ 28	$ 43	$ 103	$ 120
Tax at statutory rate	35.00%	35.00%	35.00%	35.00%
Increase (decrease) resulting from:
Tax-exempt income from municipal bonds	(7.00%)	(4.80%)	(4.50%)	(3.90%)
Dividend received exclusion	(7.00%)	(4.80%)	(4.20%)	(3.70%)
Other	0.90%	0.50%	(0.80%)	0.40%
Provision for income taxes	21.90%	25.90%	25.50%	27.80%

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Tax at statutory rate, percentage	35.00%	35.00%	35.00%	35.00%
Excess tax benefit, ASU 2016-09	$ 6		$ 6
Effect of excess tax benefit, ASU 2016-09, percent			1.50%

Net Income Per Common Share - C

Net Income Per Common Share - Calculations for Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net income-basic and diluted	$ 100	$ 123	$ 301	$ 311
Denominator:
Basic weighted-average common shares outstanding (in shares)	164.3	164.5	164.4	164.4
Diluted weighted-average shares	166	166.5	166.2	166.3
Earnings per share:
Basic (in USD per share)	$ 0.61	$ 0.75	$ 1.83	$ 1.89
Diluted (in USD per share)	$ 0.60	$ 0.74	$ 1.81	$ 1.87
Number of anti-dilutive stock-based awards (in shares)	0.6	0.3	0.7	0.4
Stock Options
Denominator:
Effect of stock-based awards (in shares)	1	1.1	1.1	1.1
Nonvested shares
Denominator:
Effect of stock-based awards (in shares)	0.7	0.9	0.7	0.8

Employee Retirement Benefits -

Employee Retirement Benefits - Components of Net Periodic Costs for Qualified and Supplemental Pension Plans (Detail) - Qualified Pension Plans [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 2	$ 5	$ 5
Interest cost	4	4	7	7
Expected return on plan assets	(5)	(4)	(10)	(9)
Amortization of actuarial loss and prior service cost	0	1	1	2
Net periodic benefit cost	$ 1	$ 3	$ 3	$ 5

Employee Retirement Benefits 61

Employee Retirement Benefits - Defined Contribution Plan (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Matching contributions to 401(k) and Top Hat plans	$ 3	$ 4	$ 9	$ 8
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contributions by employer in the remainder of year	$ 0		0
Pension contributions			$ 5

Segment Information (Detail)

Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Earned premiums	$ 1,241	$ 1,173	$ 2,449	$ 2,327
Fee revenues	4	3	9	6
Investment income, net of expenses	151	149	300	294
Realized investment gains and losses, net	(11)	44	149	105
Other	1	2	2	3
Total revenues	1,386	1,371	2,909	2,735
Income (loss) before income taxes	128	166	404	431
Identifiable assets	21,238		21,238		$ 20,386
Consolidated Property and Casualty Insurance Entity
Segment Reporting Information [Line Items]
Identifiable assets	3,042		3,042		2,967
Life Insurance Segment
Segment Reporting Information [Line Items]
Identifiable assets	1,427		1,427		1,366
Investments Segment
Segment Reporting Information [Line Items]
Identifiable assets	16,431		16,431		15,569
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Other	1	2	2	3
Total revenues	27	12	50	23
Income (loss) before income taxes	(12)	(17)	(23)	(30)
Identifiable assets	338		338		$ 484
Corporate, Non-Segment [Member] | Reinsurance assumed and other non segment [Member]
Segment Reporting Information [Line Items]
Earned premiums	26	10	48	20
Operating Segments | Commercial Lines
Segment Reporting Information [Line Items]
Earned premiums	796	771	1,577	1,531
Fee revenues	1	1	2	2
Total revenues	797	772	1,579	1,533
Income (loss) before income taxes	24	26	22	76
Operating Segments | Personal Lines
Segment Reporting Information [Line Items]
Earned premiums	307	288	607	571
Fee revenues	1	1	3	2
Total revenues	308	289	610	573
Income (loss) before income taxes	(24)	(20)	(39)	8
Operating Segments | Excess and Surplus Lines Insurance
Segment Reporting Information [Line Items]
Earned premiums	52	45	100	88
Fee revenues	1	0	1	0
Total revenues	53	45	101	88
Income (loss) before income taxes	19	5	37	22
Operating Segments | Life Insurance Segment
Segment Reporting Information [Line Items]
Earned premiums	60	59	117	117
Fee revenues	1	1	3	2
Total revenues	61	60	120	119
Income (loss) before income taxes	4	1	4	0
Operating Segments | Investments Segment
Segment Reporting Information [Line Items]
Investment income, net of expenses	151	149	300	294
Realized investment gains and losses, net	(11)	44	149	105
Total revenues	140	193	449	399
Income (loss) before income taxes	117	171	403	355
Commercial Casualty | Operating Segments | Commercial Lines
Segment Reporting Information [Line Items]
Earned premiums	271	263	536	520
Commercial Property | Operating Segments | Commercial Lines
Segment Reporting Information [Line Items]
Earned premiums	226	215	449	429
Commercial Auto | Operating Segments | Commercial Lines
Segment Reporting Information [Line Items]
Earned premiums	158	147	313	291
Workers' Compensation | Operating Segments | Commercial Lines
Segment Reporting Information [Line Items]
Earned premiums	86	89	170	178
Other Commercial Lines | Operating Segments | Commercial Lines
Segment Reporting Information [Line Items]
Earned premiums	55	57	109	113
Personal Auto | Operating Segments | Personal Lines
Segment Reporting Information [Line Items]
Earned premiums	144	135	285	266
Home Owner Segment | Operating Segments | Personal Lines
Segment Reporting Information [Line Items]
Earned premiums	128	121	253	240
Other Personal Lines | Operating Segments | Personal Lines
Segment Reporting Information [Line Items]
Earned premiums	$ 35	$ 32	$ 69	$ 65

Segment Information - Narrative

Segment Information - Narrative (Details)	6 Months Ended
	Jun. 30, 2017segmentindustry
Segment Reporting [Abstract]
Number of Industries Operating In | industry	2
Number of Reportable Segments | segment	5