Loews (L) 10-K 16 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 03, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Trading Symbol	L
Entity Registrant Name	LOEWS CORP
Entity Central Index Key	60,086
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		336,632,474
Entity Public Float			$ 11,399,000,000

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Assets:
Fixed maturities, amortized cost of $38,947 and $37,407	$ 41,494	$ 39,701
Equity securities, cost of $571 and $824	549	752
Limited partnership investments	3,220	3,313
Other invested assets, primarily mortgage loans	683	824
Short term investments	4,765	4,810
Total investments	50,711	49,400
Cash	327	440
Receivables	7,644	8,041
Property, plant and equipment	15,230	15,477
Goodwill	346	351
Other assets	1,736	1,699
Deferred acquisition costs of insurance subsidiaries	600	598
Total assets	76,594	76,006
Liabilities and Equity:
Claim and claim adjustment expense	22,343	22,663
Future policy benefits	10,326	10,152
Unearned premiums	3,762	3,671
Total insurance reserves	36,431	36,486
Payable to brokers	150	567
Short term debt	110	1,040
Long term debt	10,668	9,520
Deferred income taxes	636	382
Other liabilities	5,238	5,201
Total liabilities	53,233	53,196
Commitments and contingent liabilities
Shareholders' equity:
Preferred stock, $0.10 par value: Authorized - 100,000,000 shares
Common stock, $0.01 par value: Authorized - 1,800,000,000 shares Issued and outstanding - 336,621,358 and 339,897,547 shares	3	3
Additional paid-in capital	3,187	3,184
Retained earnings	15,196	14,731
Accumulated other comprehensive loss	(223)	(357)
Total shareholders' equity	18,163	17,561
Noncontrolling interests	5,198	5,249
Total equity	23,361	22,810
Total liabilities and equity	$ 76,594	$ 76,006

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 38,947	$ 37,407
Equity securities, cost	$ 571	$ 824
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,800,000,000	1,800,000,000
Common stock, shares issued	336,621,358	339,897,547
Common stock, shares outstanding	336,621,358	339,897,547

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Insurance premiums	$ 6,924	$ 6,921	$ 7,212
Net investment income	2,135	1,866	2,163
Investment gains (losses):
Other-than-temporary impairment losses	(81)	(156)	(77)
Other net investment gains	131	85	131
Total investment gains (losses)	50	(71)	54
Contract drilling revenues	1,525	2,360	2,737
Other revenues	2,471	2,339	2,159
Total	13,105	13,415	14,325
Expenses:
Insurance claims and policyholders' benefits	5,283	5,384	5,591
Amortization of deferred acquisition costs	1,235	1,540	1,317
Contract drilling expenses	772	1,228	1,524
Other operating expenses	4,343	4,499	3,585
Interest	536	520	498
Total	12,169	13,171	12,515
Income before income tax	936	244	1,810
Income tax (expense) benefit	(220)	43	(457)
Income from continuing operations	716	287	1,353
Discontinued operations, net			(391)
Net income	716	287	962
Amounts attributable to noncontrolling interests	(62)	(27)	(371)
Net income	654	260	591
Net income attributable to Loews Corporation:
Income from continuing operations	654	260	962
Discontinued operations, net			(371)
Net income	$ 654	$ 260	$ 591
Basic and diluted net income per common share:
Income from continuing operations	$ 1.93	$ 0.72	$ 2.52
Discontinued operations, net			(0.97)
Net income	1.93	0.72	1.55
Dividends per share	$ 0.25	$ 0.25	$ 0.25
Basic weighted average number of shares outstanding	337,950	362,430	381,920
Diluted weighted average number of shares outstanding	338,310	362,690	382,550

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 716	$ 287	$ 962
Other comprehensive income (loss), after tax Changes in:
Net unrealized gains (losses) on investments with other-than-temporary impairments	3	(9)	15
Net other unrealized gains (losses) on investments	257	(557)	267
Total unrealized gains (losses) on available-for-sale investments	260	(566)	282
Discontinued operations			(19)
Unrealized gains (losses) on cash flow hedges	2	5	(3)
Pension liability	5	(18)	(235)
Foreign currency translation	(114)	(139)	(94)
Other comprehensive income (loss)	153	(718)	(69)
Comprehensive income (loss)	869	(431)	893
Amounts attributable to noncontrolling interests	(81)	53	(361)
Total comprehensive income (loss) attributable to Loews Corporation	$ 788	$ (378)	$ 532

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Common Stock Held in Treasury [Member]	Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2013	$ 24,906	$ 4	$ 3,607	$ 15,508	$ 339		$ 5,448
Net income	962			591			371
Other comprehensive income (loss)	(69)				(59)		(10)
Dividends paid	(433)			(95)
Dividends paid							(338)
Purchases of subsidiary stock from noncontrolling interests	(144)		(9)				(135)
Purchases of Loews treasury stock	(622)					$ (622)
Retirement of treasury stock			(136)	(486)		622
Issuance of Loews common stock	6		6
Stock-based compensation	26		13				13
Other	18			(3)			21
Ending Balance at Dec. 31, 2014	24,650	4	3,481	15,515	280		5,370
Net income	287			260			27
Other comprehensive income (loss)	(718)				(638)		(80)
Dividends paid	(255)			(90)
Dividends paid							(165)
Issuance of equity securities by subsidiary	115		(2)		1		116
Purchases of subsidiary stock from noncontrolling interests	(31)		5				(36)
Purchases of Loews treasury stock	(1,265)					(1,265)
Retirement of treasury stock		(1)	(311)	(953)		1,265
Issuance of Loews common stock	7		7
Stock-based compensation	26		23				3
Other	(6)		(19)	(1)			14
Ending Balance at Dec. 31, 2015	22,810	3	3,184	14,731	(357)		5,249
Net income	716			654			62
Other comprehensive income (loss)	153				134		19
Dividends paid	(218)			(84)
Dividends paid							(134)
Purchases of subsidiary stock from noncontrolling interests	(9)		3				(12)
Purchases of Loews treasury stock	(134)					(134)
Retirement of treasury stock			(32)	(102)		$ 134
Stock-based compensation	47		45				2
Other	(4)		(13)	(3)			12
Ending Balance at Dec. 31, 2016	$ 23,361	$ 3	$ 3,187	$ 15,196	$ (223)		$ 5,198

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities:
Net income	$ 716	$ 287	$ 962
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Loss on sale of subsidiaries			451
Investment (gains) losses	(50)	71	(47)
Equity method investees	221	182	64
Amortization of investments	(27)	17	3
Depreciation	841	955	899
Impairment of goodwill		20
Asset impairments	697	865	228
Provision for deferred income taxes	102	(225)	11
Other non-cash items	73	105	134
Changes in operating assets and liabilities, net:
Receivables	24	120	738
Deferred acquisition costs	(8)	311	44
Insurance reserves	237	241	(363)
Other assets	(71)	(43)	(128)
Other liabilities	26	(33)	123
Trading securities	(528)	674	(129)
Net cash flow operating activities	2,253	3,547	2,990
Investing Activities:
Purchases of fixed maturities	(9,827)	(8,675)	(9,381)
Proceeds from sales of fixed maturities	5,332	4,390	4,914
Proceeds from maturities of fixed maturities	3,219	4,095	3,983
Purchases of limited partnership investments	(355)	(188)	(271)
Proceeds from sales of limited partnership investments	327	174	167
Purchases of property, plant and equipment	(1,450)	(1,555)	(2,753)
Acquisitions	(79)	(157)	(448)
Dispositions	330	33	1,031
Change in short term investments	158	120	1,396
Other, net	158	(172)	(108)
Net cash flow investing activities	(2,187)	(1,935)	(1,470)
Financing Activities:
Dividends paid	(84)	(90)	(95)
Dividends paid to noncontrolling interests	(134)	(165)	(338)
Purchases of subsidiary stock from noncontrolling interests	(8)	(29)	(149)
Purchases of Loews treasury stock	(134)	(1,265)	(622)
Issuance of Loews common stock		7	6
Proceeds from sale of subsidiary stock		114	5
Principal payments on debt	(3,418)	(1,929)	(2,269)
Issuance of debt	3,614	1,828	2,004
Other, net	(2)	4	16
Net cash flow financing activities	(166)	(1,525)	(1,442)
Effect of foreign exchange rate on cash	(13)	(11)	(8)
Net change in cash	(113)	76	70
Cash, beginning of year	440	364	294
Cash, end of year	$ 327	$ 440	$ 364

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Basis of presentation Principles of consolidation Accounting estimates Investments available-for-sale available-for-sale The cost of fixed maturity securities classified as available-for-sale To the extent that unrealized gains on fixed income securities supporting long term care products and structured settlements not funded by annuities would result in a premium deficiency if those gains were realized, a related increase in Insurance reserves is recorded, net of tax and noncontrolling interests, as a reduction of net unrealized gains through Other comprehensive income (“Shadow Adjustments”). Shadow Adjustments decreased $87 million (after tax and noncontrolling interests) and $159 million (after tax and noncontrolling interests) for the years ended December 31, 2016 and 2015. As of December 31, 2016 and 2015, net unrealized gains on investments included in Accumulated other comprehensive income (“AOCI”) were correspondingly reduced by Shadow Adjustments of $909 million and $996 million (after tax and noncontrolling interests). For asset-backed securities included in fixed maturity securities, the Company recognizes income using an effective yield based on anticipated prepayments and the estimated economic life of the securities. When estimates of prepayments change, the effective yield is recalculated to reflect actual payments to date and anticipated future payments. The amortized cost of high credit quality fixed rate securities is adjusted to the amount that would have existed had the new effective yield been applied since the acquisition of the securities. Such adjustments are reflected in Net investment income on the Consolidated Statements of Income. Interest income on lower rated and variable rate securities is determined using the prospective yield method. The Company’s carrying value of investments in limited partnerships is its share of the net asset value of each partnership, as determined by the general partner. Certain partnerships for which results are not available on a timely basis are reported on a lag, primarily three months or less. These investments are accounted for under the equity method and changes in net asset values are recorded within Net investment income on the Consolidated Statements of Income. Investments in derivative securities are carried at fair value with changes in fair value reported as a component of Investment gains (losses), Income (loss) from trading portfolio, or Other comprehensive income (loss), depending on their hedge designation. A derivative is typically defined as an instrument whose value is “derived” from an underlying instrument, index or rate, has a notional amount, requires little or no initial investment and can be net settled. Derivatives include, but are not limited to, the following types of investments: interest rate swaps, interest rate caps and floors, put and call options, warrants, futures, forwards, commitments to purchase securities, credit default swaps and combinations of the foregoing. Derivatives embedded within non-derivative A security is impaired if the fair value of the security is less than its cost adjusted for accretion, amortization and previously recorded other-than-temporary impairment (“OTTI”) losses, otherwise defined as an unrealized loss. When a security is impaired, the impairment is evaluated to determine whether it is temporary or other-than-temporary. Significant judgment is required in the determination of whether an OTTI loss has occurred for a security. CNA follows a consistent and systematic process for determining and recording an OTTI loss. CNA has established a committee responsible for the OTTI process referred to as the Impairment Committee. The Impairment Committee is responsible for evaluating all securities in an unrealized loss position on at least a quarterly basis. The Impairment Committee’s assessment of whether an OTTI loss has occurred incorporates both quantitative and qualitative information. Fixed maturity securities that CNA intends to sell, or it more likely than not will be required to sell before recovery of amortized cost, are considered to be other-than-temporarily impaired and the entire difference between the amortized cost basis and fair value of the security is recognized as an OTTI loss in earnings. The remaining fixed maturity securities in an unrealized loss position are evaluated to determine if a credit loss exists. The factors considered by the Impairment Committee include: (i) the financial condition and near term and long term prospects of the issuer, (ii) whether the debtor is current on interest and principal payments, (iii) credit ratings of the securities and (iv) general market conditions and industry or sector specific outlook. CNA also considers results and analysis of cash flow modeling for asset-backed securities, and when appropriate, other fixed maturity securities. The focus of the analysis for asset-backed securities is on assessing the sufficiency and quality of underlying collateral and timing of cash flows based on scenario tests. If the present value of the modeled expected cash flows equals or exceeds the amortized cost of a security, no credit loss is judged to exist and the asset-backed security is deemed to be temporarily impaired. If the present value of the expected cash flows is significantly less than amortized cost, the security is judged to be other-than-temporarily impaired for credit reasons and that shortfall, referred to as the credit component, is recognized as an OTTI loss in earnings. The difference between the adjusted amortized cost basis and fair value, referred to as the non-credit non-credit CNA performs the discounted cash flow analysis using stressed scenarios to determine future expectations regarding recoverability. Significant assumptions enter into these cash flow projections including delinquency rates, probable risk of default, loss severity upon a default, over collateralization and interest coverage triggers and credit support from lower level tranches. CNA applies the same impairment model as described above for the majority of its non-redeemable Joint venture investments The following tables present summarized financial information for these joint ventures: Year Ended December 31 2016 2015 (In millions) Total assets $ 1,749 $ 1,577 Total liabilities 1,444 1,231 Year Ended December 31 2016 2015 2014 Revenues $ 693 $ 606 $ 491 Net income 80 71 32 Hedging Securities lending activities Securities lending is typically done on a matched-book basis where the collateral is invested to substantially match the term of the loan. This matching of terms tends to limit risk. In accordance with the Company’s lending agreements, securities on loan are returned immediately to the Company upon notice. Collateral is not reflected as an asset of the Company. There was no collateral held at December 31, 2016 and 2015. Revenue recognition Insurance receivables include balances due currently or in the future, including amounts due from insureds related to losses under high deductible policies, and are presented at unpaid balances, net of an allowance for doubtful accounts. Amounts are considered past due based on policy payment terms. The allowance is determined based on periodic evaluations of aged receivables, management’s experience and current economic conditions. Insurance receivables and any related allowance are written off after collection efforts are exhausted or a negotiated settlement is reached. Property and casualty contracts that are retrospectively rated contain provisions that result in an adjustment to the initial policy premium depending on the contract provisions and loss experience of the insured during the experience period. For such contracts, CNA estimates the amount of ultimate premiums that it may earn upon completion of the experience period and recognizes either an asset or a liability for the difference between the initial policy premium and the estimated ultimate premium. CNA adjusts such estimated ultimate premium amounts during the course of the experience period based on actual results to date. The resulting adjustment is recorded as either a reduction of or an increase to the earned premiums for the period. Contract drilling revenue from dayrate drilling contracts is recognized as services are performed. In connection with such drilling contracts, Diamond Offshore may receive fees (either lump-sum Revenues from transportation and storage services are recognized in the period the service is provided based on contractual terms and the related transported and stored volumes. The majority of Boardwalk Pipeline’s operating subsidiaries are subject to Federal Energy Regulatory Commission (“FERC”) regulations and, accordingly, certain revenues collected may be subject to possible refunds to its customers. An estimated refund liability is recorded considering regulatory proceedings, advice of counsel and estimated total exposure. Claim and claim adjustment expense reserves Claim and claim adjustment expense reserves are presented net of anticipated amounts due from insureds related to losses under deductible policies of $1.2 billion as of December 31, 2016 and 2015. A significant portion of these amounts are supported by collateral. CNA also has an allowance for uncollectible deductible amounts, which is presented as a component of the allowance for doubtful accounts included in Receivables on the Consolidated Balance Sheets. Structured settlements have been negotiated for certain property and casualty insurance claims. Structured settlements are agreements to provide fixed periodic payments to claimants. CNA’s obligations for structured settlements not funded by annuities are included in claim and claim adjustment expense reserves and carried at present values determined using interest rates ranging from 5.5% to 8.0% at December 31, 2016 and 2015. At December 31, 2016 and 2015, the discounted reserves for unfunded structured settlements were $544 million and $560 million, net of discount of $841 million and $880 million. For the years ended December 31, 2016, 2015 and 2014, the amount of interest recognized on the discounted reserves of unfunded structured settlements was $42 million, $42 million and $43 million. This interest accretion is presented as a component of Insurance claims and policyholders’ benefits on the Consolidated Statements of Income but is excluded from the disclosure of prior year development. Workers’ compensation lifetime claim reserves are calculated using mortality assumptions determined through statutory regulation and economic factors. At December 31, 2016 and 2015, workers’ compensation lifetime claim reserves are discounted at a 3.5% interest rate. As of December 31, 2016 and 2015, the discounted reserves for workers’ compensation lifetime claim reserves were $371 million and $396 million, net of discount of $202 million and $218 million. For the years ended December 31, 2016, 2015 and 2014, the amount of interest accretion recognized on the discounted reserves of workers’ compensation lifetime claim reserves was $17 million, $20 million and $22 million. Long term care claim reserves are calculated using mortality and morbidity assumptions based on CNA and industry experience. Long term care claim reserves are discounted at interest rates ranging from 4.5% to 6.8% at December 31, 2016 and 2015. At December 31, 2016 and 2015, such discounted reserves totaled $2.2 billion, net of discount of $529 million and $435 million. Future policy benefits reserves Guaranty fund and other insurance-related assessments Reinsurance Reinsurance receivables related to paid losses are presented at unpaid balances. Reinsurance receivables related to unpaid losses are estimated in a manner consistent with claim and claim adjustment expense reserves or future policy benefits reserves. Reinsurance receivables are reported net of an allowance for doubtful accounts on the Consolidated Balance Sheets. The cost of reinsurance is primarily accounted for over the life of the underlying reinsured policies using assumptions consistent with those used to account for the underlying policies or over the reinsurance contract period. The ceding of insurance does not discharge the primary liability of CNA. CNA has established an allowance for doubtful accounts on reinsurance receivables which relates to both amounts already billed on ceded paid losses as well as ceded reserves that will be billed when losses are paid in the future. The allowance for doubtful accounts on reinsurance receivables is estimated on the basis of periodic evaluations of balances due from reinsurers, reinsurer solvency, management’s experience and current economic conditions. Reinsurer financial strength ratings are updated and reviewed on an annual basis or sooner if CNA becomes aware of significant changes related to a reinsurer. Because billed receivables generally approximate 3% or less of total reinsurance receivables, the age of the reinsurance receivables related to paid losses is not a significant input into the allowance analysis. Changes in the allowance for doubtful accounts on reinsurance receivables are presented as a component of Insurance claims and policyholders’ benefits on the Consolidated Statements of Income. Amounts are considered past due based on the reinsurance contract terms. Reinsurance receivables related to paid losses and any related allowance are written off after collection efforts have been exhausted or a negotiated settlement is reached with the reinsurer. Reinsurance receivables related to paid losses from insolvent insurers are written off when the settlement due from the estate can be reasonably estimated. At the time reinsurance receivables related to paid losses are written off, any required adjustment to reinsurance receivables related to unpaid losses is recorded as a component of Insurance claims and policyholders’ benefits on the Consolidated Statements of Income. Reinsurance contracts that do not effectively transfer the economic risk of loss on the underlying policies are recorded using the deposit method of accounting, which requires that premium paid or received by the ceding company or assuming company be accounted for as a deposit asset or liability. CNA had $3 million recorded as deposit assets at December 31, 2016 and 2015, and $6 million and $8 million recorded as deposit liabilities as of December 31, 2016 and 2015. Income on reinsurance contracts accounted for under the deposit method is recognized using an effective yield based on the anticipated timing of payments and the remaining life of the contract. When the anticipated timing of payments changes, the effective yield is recalculated to reflect actual payments to date and the estimated timing of future payments. The deposit asset or liability is adjusted to the amount that would have existed had the new effective yield been applied since the inception of the contract. A loss portfolio transfer is a retroactive reinsurance contract. If the cumulative claim and allocated claim adjustment expenses ceded under a loss portfolio transfer exceed the consideration paid, the resulting gain from such excess is deferred and amortized into earnings in future periods in proportion to actual recoveries under the loss portfolio transfer. In any period in which there is a gain position and a revised estimate of claim and allocated claim adjustment expenses, a portion of the deferred gain is cumulatively recognized in earnings as if the revised estimate was available at the inception date of the loss portfolio transfer. Deferred acquisition costs CNA evaluates deferred acquisition costs for recoverability. Anticipated investment income is considered in the determination of the recoverability of deferred acquisition costs. Adjustments, if necessary, are recorded in current period results of operations. Deferred acquisition costs related to long term care contracts issued prior to January 1, 2004 include costs which vary with and are primarily related to the acquisition of business. As noted under Future policy benefits reserves, all of the long term care deferred acquisition costs of $289 million were written off as of December 31, 2015 in recognition of a premium deficiency. Investments in life settlement contracts and related revenue recognition CNA accounts for its investments in life settlement contracts using the fair value method. Under the fair value method, each life settlement contract is carried at its fair value at the end of each reporting period. The change in fair value estimated through CNA’s internal valuation process, life insurance proceeds received and periodic maintenance costs, such as premiums, necessary to keep the underlying policy in force, are recorded in Other revenues on the Consolidated Statements of Income. The increase in fair value recognized in Other revenues for the years ended December 31, 2016, 2015 and 2014 on contracts still held was $7 million, $1 million and $8 million. The gains recognized during the years ended December 31, 2016, 2015 and 2014 on contracts that settled were $8 million, $24 million and $25 million. In December of 2016, CNA reached agreement on terms to sell the entire portfolio of life settlement contracts to a third party. CNA expects to consummate this transaction in 2017. As a result, the portfolio was determined to be held for sale as of December 31, 2016. Therefore, the contracts were measured at the lower of the carrying amount or the fair value per the agreed terms, resulting in a $10 million loss recognized within Other operating expenses. As of December 31, 2016, there were 526 life settlement contracts with a total fair value of $58 million, included in Other assets on the Consolidated Balance Sheets, and a face value of $285 million. Goodwill Property, plant and equipment The principal service lives used in computing provisions for depreciation are as follows: Years Pipeline equipment 30 to 50 Offshore drilling equipment 15 to 30 Other 3 to 40 Impairment of long-lived assets Income taxes The Company recognizes uncertain tax positions that it has taken or expects to take on a tax return. The tax benefit of a qualifying position is the largest amount of tax benefit that is greater than 50% likely of being realized upon ultimate settlement with a taxing authority having full knowledge of all relevant information. See Note 10 for additional information on the provision for income taxes. Pension and postretirement benefits Stock-based compensation Net income per share For each of the years ended December 31, 2016, 2015 and 2014, approximately 0.4 million, 0.3 million and 0.6 million potential shares attributable to issuances and exercises under the Loews Corporation 2016 Incentive Compensation Plan and the prior plan were included in the calculation of diluted net income per share. For those same periods, approximately 3.7 million, 4.8 million and 2.3 million shares attributable to employee stock-based compensation awards were not included in the calculation of diluted net income per share because the effect would have been antidilutive. Foreign currency Regulatory accounting Supplementary cash flow information Accounting changes – 2015-03, 835-30): Simplifying In May of 2015, the FASB issued ASU 2015-09, – Recently issued ASUs – 2014-09, In January of 2016, the FASB issued ASU 2016-01, – 825-10): In February of 2016, the FASB issued ASU 2016-02, 2014-09. In June of 2016, the FASB issued ASU 2016-13, available-for-sale available-for-sale

Acquisitions and Divestitures

Acquisitions and Divestitures	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisitions and Divestitures	CNA Financial On August 1, 2014, CNA completed the sale of Continental Assurance Company (“CAC”), its former life insurance subsidiary, which is reported as discontinued operations in the Consolidated Statements of Income for year ended December 31, 2014. See Note 19 for further discussion of discontinued operations. In connection with the sale of CAC, CNA entered into a 100% coinsurance agreement on a separate small block of annuity business outside of CAC. The coinsurance agreement required the transfer of assets with a book value equal to the ceded reserves on the inception date of the contract. Because a substantial portion of the assets supporting these liabilities are held in trust for the benefit of the original cedant, those assets were transferred on a funds withheld basis. Under this approach CNA maintains legal ownership of the assets, but the investment income and realized gains and losses on those assets inure to the reinsurer. As a result, the $31 million (after tax and noncontrolling interests) difference between market value and book value of the funds withheld assets at the coinsurance contract’s inception was recognized in Other operating expenses in 2014. HighMount On September 30, 2014, the Company sold HighMount Exploration & Production LLC (“HighMount”), its former natural gas and oil exploration and production subsidiary. As of December 31, 2014, the Company had no remaining natural gas and oil exploration and production properties. The results of this sold business are reported as discontinued operations in the Consolidated Statements of Income for year ended December 31, 2014. See Note 19 for further discussion of discontinued operations. Boardwalk Pipeline In October of 2014, Boardwalk Pipeline acquired Boardwalk Petrochemical, which owns and operates the Evangeline ethylene pipeline system, from Chevron Pipe Line Company, for $295 million in cash. In 2013, Boardwalk Pipeline executed a series of agreements with the Williams Companies, Inc. (“Williams”) to develop the Bluegrass Project. In 2014, the Company expensed the previously capitalized project costs related to the development process due to cost escalations, construction delays and the lack of customer commitments, resulting in a charge of $94 million ($55 million after tax and noncontrolling interests), inclusive of a $10 million charge recorded by Boardwalk Pipeline Partners, LP. This charge was recorded within Other operating expenses on the Consolidated Statements of Income. In the fourth quarter of 2014, Boardwalk Pipeline and Williams dissolved the Bluegrass project entities. Loews Hotels Loews Hotels paid a total of approximately $84 million to acquire a hotel in 2016, approximately $330 million to acquire two hotels in 2015 and approximately $230 million to acquire three hotels in 2014. These acquisitions were funded with a combination of cash and property-level debt.

Investments

Investments	12 Months Ended
	Dec. 31, 2016
Text Block [Abstract]
Investments	Net investment income is as follows: Year Ended December 31 2016 2015 2014 (In millions) Fixed maturity securities $ 1,819 $ 1,751 $ 1,803 Limited partnership investments 199 119 304 Short term investments 9 11 4 Equity securities 10 12 12 Income from trading portfolio (a) 112 2 64 Other 45 34 34 Total investment income 2,194 1,929 2,221 Investment expenses (59) (63) (58) Net investment income $ 2,135 $ 1,866 $ 2,163 (a) Includes net unrealized gains (losses) related to changes in fair value on trading securities still held of $44, $(46) and $42 for the years ended December 31, 2016, 2015 and 2014. As of December 31, 2016, the Company held no non-income non-income Investment gains (losses) are as follows: Year Ended December 31 2016 2015 2014 (In millions) Fixed maturity securities $ 54 $ (66 ) $ 41 Equity securities (5 ) (23 ) 1 Derivative instruments (2 ) 10 (1) Short term investments and other 3 8 13 Investment gains (losses) (a) $ 50 $ (71 ) $ 54 (a) Includes gross realized gains of $209, $133 and $178 and gross realized losses of $160, $222 and $136 on available-for-sale Net change in unrealized gains (losses) on available-for-sale Year Ended December 31 2016 2015 2014 (In millions) Fixed maturity securities $ 225 $ (1,114 ) $ 1,511 Equity securities (2 ) (6 ) 6 Other 1 1 Total net change in unrealized gains (losses) on available-for-sale $ 224 $ (1,119 ) $ 1,517 The components of OTTI losses recognized in earnings by asset type are as follows: Year Ended December 31 2016 2015 2014 (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 59 $ 104 $ 18 States, municipalities and political subdivisions 18 46 Asset-backed: Residential mortgage-backed 10 8 5 Other asset-backed 3 1 1 Total asset-backed 13 9 6 Total fixed maturities available-for-sale 72 131 70 Equity securities available-for-sale 9 25 7 Net OTTI losses recognized in earnings $ 81 $ 156 $ 77 The amortized cost and fair values of securities are as follows: Cost or Gross Gross Unrealized Amortized Unrealized Unrealized Estimated OTTI Losses December 31, 2016 Cost Gains Losses Fair Value (Gains) (In millions) Fixed maturity securities: Corporate and other bonds $ 17,711 $ 1,323 $ 76 $ 18,958 $ (1) States, municipalities and political subdivisions 12,060 1,213 33 13,240 (16) Asset-backed: Residential mortgage-backed 5,004 120 51 5,073 (28) Commercial mortgage-backed 2,016 48 24 2,040 Other asset-backed 1,022 8 5 1,025 Total asset-backed 8,042 176 80 8,138 (28) U.S. Treasury and obligations of government-sponsored enterprises 83 10 93 Foreign government 435 13 3 445 Redeemable preferred stock 18 1 19 Fixed maturities available-for-sale 38,349 2,736 192 40,893 (45) Fixed maturities, trading 598 3 601 Total fixed maturities 38,947 2,739 192 41,494 (45) Equity securities: Common stock 13 6 19 Preferred stock 93 2 4 91 Equity securities available-for-sale 106 8 4 110 - Equity securities, trading 465 60 86 439 Total equity securities 571 68 90 549 - Total $ 39,518 $ 2,807 $ 282 $ 42,043 $ (45) December 31, 2015 (In millions) Fixed maturity securities: Corporate and other bonds $ 17,097 $ 1,019 $ 347 $ 17,769 States, municipalities and political subdivisions 11,729 1,453 8 13,174 $ (4) Asset-backed: Residential mortgage-backed 4,935 154 17 5,072 (37) Commercial mortgage-backed 2,154 55 12 2,197 Other asset-backed 923 6 8 921 Total asset-backed 8,012 215 37 8,190 (37) U.S. Treasury and obligations of government-sponsored enterprises 62 5 67 Foreign government 334 13 1 346 Redeemable preferred stock 33 2 35 Fixed maturities available-for-sale 37,267 2,707 393 39,581 (41) Fixed maturities, trading 140 20 120 Total fixed maturities 37,407 2,707 413 39,701 (41) Equity securities: Common stock 46 3 1 48 Preferred stock 145 7 3 149 Equity securities available-for-sale 191 10 4 197 - Equity securities, trading 633 56 134 555 Total equity securities 824 66 138 752 - Total $ 38,231 $ 2,773 $ 551 $ 40,453 $ (41) The available-for-sale Less than 12 Months 12 Months or Longer Total Gross Gross Gross Estimated Unrealized Estimated Unrealized Estimated Unrealized December 31, 2016 Fair Value Losses Fair Value Losses Fair Value Losses (In millions) Fixed maturity securities: Corporate and other bonds $ 2,615 $ 61 $ 254 $ 15 $ 2,869 $ 76 States, municipalities and political subdivisions 959 32 23 1 982 33 Asset-backed: Residential mortgage-backed 2,136 44 201 7 2,337 51 Commercial mortgage-backed 756 22 69 2 825 24 Other asset-backed 398 5 24 422 5 Total asset-backed 3,290 71 294 9 3,584 80 U.S. Treasury and obligations of government-sponsored enterprises 5 5 Foreign government 108 3 108 3 Total fixed maturity securities 6,977 167 571 25 7,548 192 Equity securities 12 13 4 25 4 Total $ 6,989 $ 167 $ 584 $ 29 $ 7,573 $ 196 December 31, 2015 (In millions) Fixed maturity securities: Corporate and other bonds $ 4,882 $ 302 $ 174 $ 45 $ 5,056 $ 347 States, municipalities and political subdivisions 338 8 75 413 8 Asset-backed: Residential mortgage-backed 963 9 164 8 1,127 17 Commercial mortgage-backed 652 10 96 2 748 12 Other asset-backed 552 8 5 557 8 Total asset-backed 2,167 27 265 10 2,432 37 U.S. Treasury and obligations of government-sponsored enterprises 4 4 Foreign government 54 1 54 1 Redeemable preferred stock 3 3 Total fixed maturity securities 7,448 338 514 55 7,962 393 Equity securities: Common stock 3 1 3 1 Preferred stock 13 3 13 3 Total equity securities 16 4 16 4 Total $ 7,464 $ 342 $ 514 $ 55 $ 7,978 $ 397 Based on current facts and circumstances, the Company believes the unrealized losses presented in the table above are not indicative of the ultimate collectibility of the current amortized cost of the securities, but rather are attributable to changes in interest rates, credit spreads and other factors. The Company has no current intent to sell securities with unrealized losses, nor is it more likely than not that it will be required to sell prior to recovery of amortized cost; accordingly, the Company has determined that there are no additional OTTI losses to be recorded at December 31, 2016. The following table presents the activity related to the pretax credit loss component reflected in Retained earnings on fixed maturity securities still held at December 31, 2016, 2015 and 2014 for which a portion of an OTTI loss was recognized in Other comprehensive income. Year Ended December 31 2016 2015 2014 (In millions) Beginning balance of credit losses on fixed maturity securities $ 53 $ 62 $ 74 Reductions for securities sold during the period (16 ) (9 ) (9 ) Reductions for securities the Company intends to sell or more likely than not will be required to sell (1 ) (3 ) Ending balance of credit losses on fixed maturity securities $ 36 $ 53 $ 62 Contractual Maturity The following table presents available-for-sale December 31 2016 2015 Cost or Cost or Amortized Estimated Amortized Estimated Cost Fair Value Cost Fair Value (In millions) Due in one year or less $ 1,779 $ 1,828 $ 1,574 $ 1,595 Due after one year through five years 7,566 7,955 7,738 8,082 Due after five years through ten years 15,892 16,332 14,652 14,915 Due after ten years 13,112 14,778 13,303 14,989 Total $ 38,349 $ 40,893 $ 37,267 $ 39,581 Actual maturities may differ from contractual maturities because certain securities may be called or prepaid. Securities not due at a single date are allocated based on weighted average life. Limited Partnerships The carrying value of limited partnerships as of December 31, 2016 and 2015 was approximately $3.2 billion and $3.3 billion, which includes undistributed earnings of $820 million and $952 million. Limited partnerships comprising 70.4% of the total carrying value are reported on a current basis through December 31, 2016 with no reporting lag, 13.4% of the total carrying value are reported on a one month lag and the remainder are reported on more than a one month lag. The number of limited partnerships held and the strategies employed provide diversification to the limited partnership portfolio and the overall invested asset portfolio. Limited partnerships comprising 76.6% of the carrying value as of December 31, 2016 and 2015 employ hedge fund strategies. Limited partnerships comprising 19.8% and 23.4% of the carrying value at December 31, 2016 and 2015 were invested in private debt and equity and the remainder were primarily invested in real estate strategies. Hedge fund strategies include both long and short positions in fixed income, equity and derivative instruments. These hedge fund strategies may seek to generate gains from mispriced or undervalued securities, price differentials between securities, distressed investments, sector rotation or various arbitrage disciplines. Within hedge fund strategies, approximately 59.8% were equity related, 25.5% pursued a multi-strategy approach, 11.1% were focused on distressed investments and 3.6% were fixed income related as of December 31, 2016. The ten largest limited partnership positions held totaled $1.5 billion as of December 31, 2016 and 2015. Based on the most recent information available regarding the Company’s percentage ownership of the individual limited partnerships, the carrying value reflected on the Consolidated Balance Sheets represents approximately 3.5% and 2.8% of the aggregate partnership equity at December 31, 2016 and 2015, and the related income reflected on the Consolidated Statements of Income represents approximately 4.0%, 2.8% and 4.3% of the changes in aggregate partnership equity for the years ended December 31, 2016, 2015 and 2014. While the Company generally does not invest in highly leveraged partnerships, there are risks inherent in limited partnership investments which may result in losses due to short-selling, derivatives or other speculative investment practices. The use of leverage increases volatility generated by the underlying investment strategies. The Company’s limited partnership investments contain withdrawal provisions that generally limit liquidity for a period of thirty days up to one year and in some cases do not permit withdrawals until the termination of the partnership. Typically, withdrawals require advance written notice of up to 90 days. Derivative Financial Instruments The Company may use derivatives in the normal course of business, primarily in an attempt to reduce exposure to market risk (principally interest rate risk, credit risk, equity price risk, commodity price risk and foreign currency risk) stemming from various assets and liabilities. The principal objective under such strategies is to achieve the desired reduction in economic risk, even if the position does not receive hedge accounting treatment. The Company may enter into interest rate swaps, futures and forward commitments to purchase securities to manage interest rate risk. Credit derivatives such as credit default swaps may be entered into to modify the credit risk inherent in certain investments. Forward contracts, futures, swaps and options may be used to manage foreign currency and commodity price risk. In addition to the derivatives used for risk management purposes described above, the Company may also use derivatives for purposes of income enhancement. Income enhancement transactions include but are not limited to interest rate swaps, call options, put options, credit default swaps, index futures and foreign currency forwards. See Note 4 for information regarding the fair value of derivative instruments. The following tables present the aggregate contractual or notional amount and estimated fair value related to derivative financial instruments. December 31 2016 2015 Contractual/ Contractual/ Notional Estimated Fair Value Notional Estimated Fair Value Amount Asset (Liability) Amount Asset (Liability) (In millions) Without hedge designation: Equity markets: Options – purchased $ 223 $ 14 $ 501 $ 16 – written 267 $ (8) 614 $ (28) Futures – long 312 (1) Futures – short 225 1 Interest rate risk: Futures – long 63 Foreign exchange: Currency forwards – long 133 2 – short 152 Currency options – long 550 7 Commodities: Futures – long 42 Embedded derivative on funds withheld liability 174 3 179 5 Investment Commitments As of December 31, 2016, the Company had committed approximately $380 million to future capital calls from various third party limited partnership investments in exchange for an ownership interest in the related partnerships. The Company invests in various privately placed debt securities, including bank loans, as part of its overall investment strategy and has committed to additional future purchases, sales and funding. Purchases and sales of privately placed debt securities are recorded once funded. As of December 31, 2016, the Company had commitments to purchase or fund additional amounts of $130 million and sell $121 million under the terms of such securities. Investments on Deposit Securities with carrying values of approximately $2.3 billion and $2.8 billion were deposited by CNA’s insurance subsidiaries under requirements of regulatory authorities and others as of December 31, 2016 and 2015. Cash and securities with carrying values of approximately $514 million and $364 million were deposited with financial institutions as collateral for letters of credit as of December 31, 2016 and 2015. In addition, cash and securities were deposited in trusts with financial institutions to secure reinsurance and other obligations with various third parties. The carrying values of these deposits were approximately $261 million and $263 million as of December 31, 2016 and 2015.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value	Fair value is the price that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The following fair value hierarchy is used in selecting inputs, with the highest priority given to Level 1, as these are the most transparent or reliable: ● Level 1 – Quoted prices for identical instruments in active markets. ● Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets. ● Level 3 – Valuations derived from valuation techniques in which one or more significant inputs are not observable. Prices may fall within Level 1, 2 or 3 depending upon the methodology and inputs used to estimate fair value for each specific security. In general, the Company seeks to price securities using third party pricing services. Securities not priced by pricing services are submitted to independent brokers for valuation and, if those are not available, internally developed pricing models are used to value assets using a methodology and inputs the Company believes market participants would use to value the assets. Prices obtained from third-party pricing services or brokers are not adjusted by the Company. The Company performs control procedures over information obtained from pricing services and brokers to ensure prices received represent a reasonable estimate of fair value and to confirm representations regarding whether inputs are observable or unobservable. Procedures may include: (i) the review of pricing service methodologies or broker pricing qualifications, (ii) back-testing, where past fair value estimates are compared to actual transactions executed in the market on similar dates, (iii) exception reporting, where period-over-period changes in price are reviewed and challenged with the pricing service or broker based on exception criteria, (iv) detailed analysis, where the Company performs an independent analysis of the inputs and assumptions used to price individual securities and (v) pricing validation, where prices received are compared to prices independently estimated by the Company. The fair values of CNA’s life settlement contracts are included in Other assets on the Consolidated Balance Sheets. Equity options purchased are included in Equity securities, and all other derivative assets are included in Receivables. Derivative liabilities are included in Payable to brokers. Assets and liabilities measured at fair value on a recurring basis are summarized in the tables below: December 31, 2016 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 18,828 $ 130 $ 18,958 States, municipalities and political subdivisions 13,239 1 13,240 Asset-backed: Residential mortgage-backed 4,944 129 5,073 Commercial mortgage-backed 2,027 13 2,040 Other asset-backed 968 57 1,025 Total asset-backed 7,939 199 8,138 U.S. Treasury and obligations of government-sponsored enterprises $ 93 93 Foreign government 445 445 Redeemable preferred stock 19 19 Fixed maturities available-for-sale 112 40,451 330 40,893 Fixed maturities trading 595 6 601 Total fixed maturities $ 112 $ 41,046 $ 336 $ 41,494 Equity securities available-for-sale $ 91 $ 19 $ 110 Equity securities trading 438 1 439 Total equity securities $ 529 $ - $ 20 $ 549 Short term investments $ 3,833 $ 853 $ 4,686 Other invested assets 55 5 60 Receivables 1 1 Life settlement contracts $ 58 58 Payable to brokers (44 ) (44) December 31, 2015 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 17,601 $ 168 $ 17,769 States, municipalities and political subdivisions 13,172 2 13,174 Asset-backed: Residential mortgage-backed 4,938 134 5,072 Commercial mortgage-backed 2,175 22 2,197 Other asset-backed 868 53 921 Total asset-backed 7,981 209 8,190 U.S. Treasury and obligations of government-sponsored enterprises $ 66 1 67 Foreign government 346 346 Redeemable preferred stock 35 35 Fixed maturities available-for-sale 101 39,101 379 39,581 Fixed maturities trading 35 85 120 Total fixed maturities $ 101 $ 39,136 $ 464 $ 39,701 Equity securities available-for-sale $ 177 $ 20 $ 197 Equity securities trading 554 1 555 Total equity securities $ 731 $ - $ 21 $ 752 Short term investments $ 3,600 $ 1,134 $ 4,734 Other invested assets 102 44 146 Receivables 9 $ 3 12 Life settlement contracts 74 74 Payable to brokers (196 ) (196) The tables below present reconciliations for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2016 and 2015: Purchases Sales Settlements Transfers into Transfers out of Balance, Unrealized Held at Net Realized Gains 2016 Balance, Included in Included (In millions) Fixed maturity securities: Corporate and other bonds $ 168 $ 1 $ 1 $ 163 $ (36 ) $ (103 ) $ (64 ) $ 130 States, municipalities and 2 (1 ) 1 Asset-backed: Residential mortgage-backed 134 3 (5 ) 15 (14 ) $ 56 (60 ) 129 Commercial mortgage-backed 22 (1 ) (1 ) 32 (17 ) 3 (25 ) 13 Other asset-backed 53 (2 ) 1 86 (25 ) (1 ) 2 (57 ) 57 Total asset-backed 209 - (5 ) 133 (25 ) (32 ) 61 (142 ) 199 $ - Fixed maturities available-for-sale 379 1 (4 ) 296 (61 ) (136 ) 61 (206 ) 330 Fixed maturities trading 85 5 2 (86 ) 6 3 Total fixed maturities $ 464 $ 6 $ (4 ) $ 298 $ (147 ) $ (136 ) $ 61 $ (206 ) $ 336 $ 3 Equity securities available-for-sale $ 20 $ (1 ) $ 19 $ (2 ) Equity securities trading 1 1 $ (1 ) 1 Total equity securities $ 21 $ - $ - $ - $ (1 ) $ - $ - $ - $ 20 $ (2 ) Life settlement contracts $ 74 $ 5 $ (21 ) $ 58 $ (3 ) Derivative financial instruments, net 3 (1 ) $ (2 ) - 2015 Balance, Purchases Sales Settlements Transfers into Transfers out of Balance, Unrealized Net Realized Gains Included in Included in (In millions) Fixed maturity securities: Corporate and other bonds $ 162 $ (2 ) $ (3 ) $ 65 $ (13 ) $ (35 ) $ 40 $ (46 ) $ 168 $ (2 ) States, municipalities and political subdivisions 94 1 (10 ) (83 ) 2 Asset-backed: Residential mortgage-backed 189 5 (3 ) 81 (35 ) 14 (117 ) 134 Commercial mortgage-backed 83 7 (4 ) 23 (17 ) 17 (87 ) 22 Other asset-backed 655 3 3 130 (263 ) (52 ) 7 (430 ) 53 Total asset-backed 927 15 (4 ) 234 (263 ) (104 ) 38 (634 ) 209 - Fixed maturities available-for-sale 1,183 14 (7 ) 299 (276 ) (149 ) 78 (763 ) 379 (2 ) Fixed maturities trading 90 (3 ) (2 ) 85 (3 ) Total fixed maturities $ 1,273 $ 11 $ (7 ) $ 299 $ (278 ) $ (149 ) $ 78 $ (763 ) $ 464 $ (5 ) Equity securities available-for-sale $ 16 $ (1 ) $ 4 $ 1 $ 20 Equity securities trading 1 $ 1 1 $ (2 ) 1 $ 1 Total equity securities $ 17 $ 1 $ (1 ) $ 5 $ (2 ) $ - $ 1 $ - $ 21 $ 1 Life settlement contracts $ 82 $ 25 $ (33 ) $ 74 $ 1 Derivative financial instruments, net $ 3 3 Net realized and unrealized gains and losses are reported in Net income as follows: Major Category of Assets and Liabilities Consolidated Statements of Income Line Items Fixed maturity securities available-for-sale Investment gains (losses) Fixed maturity securities, trading Net investment income Equity securities available-for-sale Investment gains (losses) Equity securities, trading Net investment income Other invested assets Investment gains (losses) and Net investment income Derivative financial instruments held in a trading portfolio Net investment income Derivative financial instruments, other Investment gains (losses) and Other revenues Life settlement contracts Other revenues Securities may be transferred in or out of levels within the fair value hierarchy based on the availability of observable market information and quoted prices used to determine the fair value of the security. The availability of observable market information and quoted prices varies based on market conditions and trading volume. During the year ended December 31, 2016 there were no transfers between Level 1 and Level 2. There were $63 million of transfers from Level 2 to Level 1 and $52 million of transfers from Level 1 to Level 2 during the year ended December 31, 2015. The Company’s policy is to recognize transfers between levels at the beginning of quarterly reporting periods. Valuation Methodologies and Inputs The following section describes the valuation methodologies and relevant inputs used to measure different financial instruments at fair value, including an indication of the level in the fair value hierarchy in which the instruments are generally classified. Fixed Maturity Securities Level 1 securities include highly liquid and exchange traded bonds and redeemable preferred stock, valued using quoted market prices. Level 2 securities include most other fixed maturity securities as the significant inputs are observable in the marketplace. All classes of Level 2 fixed maturity securities are valued using a methodology based on information generated by market transactions involving identical or comparable assets, a discounted cash flow methodology or a combination of both when necessary. Common inputs for all classes of fixed maturity securities include prices from recently executed transactions of similar securities, marketplace quotes, benchmark yields, spreads off benchmark yields, interest rates and U.S. Treasury or swap curves. Specifically for asset-backed securities, key inputs include prepayment and default projections based on past performance of the underlying collateral and current market data. Fixed maturity securities are primarily assigned to Level 3 in cases where broker/dealer quotes are significant inputs to the valuation and there is a lack of transparency as to whether these quotes are based on information that is observable in the marketplace. Level 3 securities also include private placement debt securities whose fair value is determined using internal models with inputs that are not market observable. Equity Securities Level 1 equity securities include publicly traded securities valued using quoted market prices. Level 2 securities are primarily non-redeemable Derivative Financial Instruments Exchange traded derivatives are valued using quoted market prices and are classified within Level 1 of the fair value hierarchy. Level 2 derivatives primarily include currency forwards valued using observable market forward rates. Over-the-counter Short Term Investments Securities that are actively traded or have quoted prices are classified as Level 1. These securities include money market funds and treasury bills. Level 2 primarily includes commercial paper, for which all inputs are market observable. Fixed maturity securities purchased within one year of maturity are classified consistent with fixed maturity securities discussed above. Short term investments as presented in the tables above differ from the amounts presented in the Consolidated Balance Sheets because certain short term investments, such as time deposits, are not measured at fair value. Other Invested Assets Level 1 securities include exchange traded open-end Life Settlement Contracts Historically, the fair values of life settlement contracts were determined as the present value of the anticipated death benefits less anticipated premium payments based on contract terms that are distinct for each insured, as well as CNA’s own assumptions for mortality, premium expense, and the rate of return that a buyer would require on the contracts. As discussed in Note 1, because CNA has reached agreement on terms to sell the portfolio of life settlement contracts to a third party, the fair value was written down to reflect the value determined per the agreed terms of sale. Despite the pending sale, as there is not an active market for life settlement contracts, they have been classified as Level 3. Significant Unobservable Inputs The following tables present quantitative information about the significant unobservable inputs utilized by the Company in the fair value measurements of Level 3 assets. Valuations for assets and liabilities not presented in the tables below are primarily based on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of unobservable inputs from these broker quotes is neither provided nor reasonably available to the Company. The valuation of life settlement contracts as of December 31, 2016 was based on the terms of the pending sale of the contracts to a third party, therefore the contracts are not included in the table below. December 31, 2016 Estimated Valuation Techniques Unobservable Inputs Range (Weighted Average) (In millions) Fixed maturity securities $ 106 Discounted cash flow Credit spread 2% – 40% (4%) December 31, 2015 Fixed maturity securities $ 138 Discounted cash flow Credit spread 3% – 184% (6%) Life settlement contracts 74 Discounted cash flow Discount rate risk premium 9% Mortality assumption 55% – 1,676% (164%) For fixed maturity securities, an increase to the credit spread assumptions would result in a lower fair value measurement. For life settlement contracts, an increase in the discount rate risk premium or decrease in the mortality assumption would result in a lower fair value measurement. Financial Assets and Liabilities Not Measured at Fair Value The carrying amount, estimated fair value and the level of the fair value hierarchy of the Company’s financial assets and liabilities which are not measured at fair value on the Consolidated Balance Sheets are presented in the following tables. The carrying amounts and estimated fair values of short term debt and long term debt exclude capital lease obligations. The carrying amounts reported on the Consolidated Balance Sheets for cash and short term investments not carried at fair value and certain other assets and liabilities approximate fair value due to the short term nature of these items. Carrying Amount Estimated Fair Value December 31, 2016 Level 1 Level 2 Level 3 Total (In millions) Assets: Other invested assets, primarily mortgage loans $ 591 $ 594 $ 594 Liabilities: Short term debt 107 $ 104 3 107 Long term debt 10,655 10,150 646 10,796 December 31, 2015 Assets: Other invested assets, primarily mortgage loans $ 678 $ 688 $ 688 Liabilities: Short term debt 1,038 $ 1,050 2 1,052 Long term debt 9,507 8,538 595 9,133 The following methods and assumptions were used in estimating the fair value of these financial assets and liabilities. The fair values of mortgage loans, included in Other invested assets, were based on the present value of the expected future cash flows discounted at the current interest rate for similar financial instruments, adjusted for specific loan risk. Fair value of debt was based on observable market prices when available. When observable market prices were not available, the fair value of debt was based on observable market prices of comparable instruments adjusted for differences between the observed instruments and the instruments being valued or is estimated using discounted cash flow analyses, based on current incremental borrowing rates for similar types of borrowing arrangements.

Receivables

Receivables	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Receivables	December 31 2016 2015 (In millions) Reinsurance (Note 15) $ 4,453 $ 4,491 Insurance 2,255 2,129 Receivable from brokers 178 471 Accrued investment income 410 408 Federal income taxes 7 45 Other, primarily customer accounts 431 593 Total 7,734 8,137 Less:allowance for doubtful accounts on reinsurance receivables 37 38 allowance for other doubtful accounts 53 58 Receivables $ 7,644 $ 8,041

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	December 31 2016 2015 (In millions) Pipeline equipment (net of accumulated depreciation of $2,174 and $1,887) $ 7,631 $ 7,462 Offshore drilling equipment (net of accumulated depreciation of $3,310 and $3,335) 5,693 6,071 Other (net of accumulated depreciation of $873 and $811) 1,527 1,450 Construction in process 379 494 Property, plant and equipment $ 15,230 $ 15,477 Depreciation expense and capital expenditures are as follows: Year Ended December 31 2016 2015 2014 Depre- Capital Depre- Capital Depre- Capital (In millions) CNA Financial $ 67 $ 128 $ 74 $ 123 $ 69 $ 72 Diamond Offshore 384 629 494 812 457 2,050 Boardwalk Pipeline 321 648 327 390 292 378 Loews Hotels 63 164 54 389 37 289 Corporate 6 3 6 4 6 24 Total $ 841 $ 1,572 $ 955 $ 1,718 $ 861 $ 2,813 Capitalized interest related to the construction and upgrade of qualifying assets amounted to approximately $51 million, $36 million and $80 million for the years ended December 31, 2016, 2015 and 2014. Offshore Drilling Equipment Purchase of Assets In 2016, Diamond Offshore took delivery of one ultra-deepwater semisubmersible rig. The net book value of this newly constructed rig was $774 million at December 31, 2016, of which $270 million was reported in Construction in process at December 31, 2015. In 2015, Diamond Offshore took delivery of one ultra-deepwater drillship. The net book value of this newly constructed rig was $655 million at December 31, 2015, of which $225 million was reported in Construction in process at December 31, 2014. Sale of Assets In February of 2016, Diamond Offshore entered into a ten-year ten-year During 2016, Diamond Offshore recognized $34 million in aggregate expense related to the well control equipment leases and contractual services agreement. Asset Impairments During 2016, in response to the continuing industry-wide decline in utilization for semisubmersible rigs, further exacerbated by additional and more frequent contract cancelations by customers, declining dayrates, as well as the results of a third-party strategic review of Diamond Offshore’s long-term business plan completed in the second quarter of 2016, Diamond Offshore reassessed its projections for a recovery in the offshore drilling market. As a result, Diamond Offshore concluded that an expected market recovery is now likely further in the future than had previously been estimated. Consequently, Diamond Offshore believes its cold-stacked rigs, as well as those rigs expected to be cold-stacked in the near term after they come off contract, will likely remain cold-stacked for an extended period of time. Diamond Offshore also believes that the re-entry mid-water Diamond Offshore estimated the fair value of the eight impaired rigs using an income approach. The fair value of each rig was estimated based on a calculation of the rig’s discounted future net cash flows over its remaining economic life, which utilized significant unobservable inputs, including, but not limited to, assumptions related to estimated dayrate revenue, rig utilization, estimated reactivation and regulatory survey costs, as well as estimated proceeds that may be received on ultimate disposition of the rig. The fair value estimates were representative of Level 3 fair value measurements due to the significant level of estimation involved and the lack of transparency as to the inputs used. During the second quarter of 2016, Diamond Offshore recognized an impairment loss of $672 million ($263 million after tax and noncontrolling interests). During 2015, Diamond Offshore evaluated 25 of its drilling rigs with indications that their carrying amounts may not be recoverable. Based on this analysis, Diamond Offshore determined that the carrying value of 17 of these rigs, consisting of two ultra-deepwater, one deepwater and nine mid-water jack-up During 2014, Diamond Offshore initiated a plan to retire and scrap six mid-water Of the rigs impaired during the three-year period ended December 31, 2016, 20 rigs have been sold and eight rigs are currently cold-stacked. Two other previously impaired rigs are currently operating under contract. The impairment losses recorded during the years ended December 31, 2016, 2015 and 2014 are reported within Other operating expenses on the Consolidated Statements of Income. If market fundamentals in the offshore oil and gas industry deteriorate further or if Diamond Offshore is unable to secure new or extend existing contracts for its current, actively-marketed drilling fleet or reactivate any of its cold stacked rigs or if Diamond Offshore experiences unfavorable changes to actual dayrates and rig utilization, additional impairment losses may be required to be recognized in future periods if the carrying value of any of the drilling rigs is not recoverable.

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Total CNA Diamond Boardwalk Loews Corporate (In millions) Balance, December 31, 2014 $ 374 $ 117 $ 20 $ 237 $ - $ - Impairments (20 ) (20 ) Other adjustments (3 ) (3 ) Balance, December 31, 2015 351 114 - 237 - - Other adjustments (5 ) (5 ) Balance, December 31, 2016 $ 346 $ 109 $ - $ 237 $ - $ - An impairment charge of $20 million was recorded in Other operating expenses in 2015 to write off all goodwill attributable to Diamond Offshore.

Claim and Claim Adjustment Expe

Claim and Claim Adjustment Expense Reserves	12 Months Ended
	Dec. 31, 2016
Insurance [Abstract]
Claim and Claim Adjustment Expense Reserves	CNA’s property and casualty insurance claim and claim adjustment expense reserves represent the estimated amounts necessary to resolve all outstanding claims, including claims that are incurred but not reported (“IBNR”) as of the reporting date. CNA’s reserve projections are based primarily on detailed analysis of the facts in each case, CNA’s experience with similar cases and various historical development patterns. Consideration is given to such historical patterns as claim reserving trends and settlement practices, loss payments, pending levels of unpaid claims and product mix, as well as court decisions, economic conditions including inflation and public attitudes. All of these factors can affect the estimation of claim and claim adjustment expense reserves. Establishing claim and claim adjustment expense reserves, including claim and claim adjustment expense reserves for catastrophic events that have occurred, is an estimation process. Many factors can ultimately affect the final settlement of a claim and, therefore, the necessary reserve. Changes in the law, results of litigation, medical costs, the cost of repair materials and labor rates can all affect ultimate claim costs. In addition, time can be a critical part of reserving determinations since the longer the span between the incidence of a loss and the payment or settlement of the claim, the more variable the ultimate settlement amount can be. Accordingly, short-tail claims, such as property damage claims, tend to be more reasonably estimable than long-tail claims, such as workers’ compensation, general liability and professional liability claims. Adjustments to prior year reserve estimates, if necessary, are reflected in the results of operations in the period that the need for such adjustments is determined. There can be no assurance that CNA’s ultimate cost for insurance losses will not exceed current estimates. Catastrophes are an inherent risk of the property and casualty insurance business and have contributed to material period-to-period In developing claim and claim adjustment expense (“loss” or “losses”) reserve estimates, CNA’s actuaries perform detailed reserve analyses that are staggered throughout the year. Every reserve group is reviewed at least once during the year. The analyses generally review losses gross of ceded reinsurance and apply the ceded reinsurance terms to the gross estimates to establish estimates net of reinsurance. In addition to the detailed analyses, CNA reviews actual loss emergence for all products each quarter. In developing the loss reserve estimates for property and casualty contracts, CNA generally projects ultimate losses using several common actuarial methods as listed below. CNA reviews the various indications from the various methods and applies judgment to select an actuarial point estimate. The indicated required reserve is the difference between the selected ultimate loss and the inception-to-date • paid development; • incurred development; • loss ratio; • Bornhuetter-Ferguson using premiums and paid loss; • Bornhuetter-Ferguson using premiums and incurred loss; • frequency times severity; and • stochastic modeling. The paid development method estimates ultimate losses by reviewing paid loss patterns and applying them to accident years with further expected changes in paid losses. The incurred development method is similar to the paid development method, but it uses case incurred losses instead of paid losses. The loss ratio method multiplies premiums by an expected loss ratio to produce ultimate loss estimates for each accident year. The Bornhuetter-Ferguson using premiums and paid loss method is a combination of the paid development approach and the loss ratio approach. This method normally determines expected loss ratios similar to the approach used to estimate the expected loss ratio for the loss ratio method. The Bornhuetter-Ferguson using premiums and incurred loss method is similar to the Bornhuetter-Ferguson using premiums and paid loss method except that it uses case incurred losses. The frequency times severity method multiplies a projected number of ultimate claims by an estimated ultimate average loss for each accident year to produce ultimate loss estimates. Stochastic modeling produces a range of possible outcomes based on varying assumptions related to the particular product being modeled. For many exposures, especially those that can be considered long-tail, a particular accident or policy year may not have a sufficient volume of paid losses to produce a statistically reliable estimate of ultimate losses. In such a case, CNA’s actuaries typically assign more weight to the incurred development method than to the paid development method. As claims continue to settle and the volume of paid loss increases, the actuaries may assign additional weight to the paid development method. For most of CNA’s products, even the incurred losses for accident or policy years that are early in the claim settlement process will not be of sufficient volume to produce a reliable estimate of ultimate losses. In these cases, CNA may not assign any weight to the paid and incurred development methods. CNA will use the loss ratio, Bornhuetter-Ferguson and frequency times severity methods. For short-tail exposures, the paid and incurred development methods can often be relied on sooner, primarily because CNA’s history includes a sufficient number of years to cover the entire period over which paid and incurred losses are expected to change. However, CNA may also use the loss ratio, Bornhuetter-Ferguson and frequency times severity methods for short-tail exposures. For other more complex reserve groups where the above methods may not produce reliable indications, CNA uses additional methods tailored to the characteristics of the specific situation. Reserves for policyholder benefits for non-core locked-in locked-in Certain claim liabilities are more difficult to estimate and have differing methodologies and considerations which are described below. CNA’s mass tort and A&EP reserving methodologies are similar as both are based on detailed account reviews of all large accounts with estimates based on ultimate payments considering the applicable law and coverage litigation. These reserves are subject to greater inherent variability than is typical of the remainder of CNA’s reserves due to, among other things, a general lack of sufficiently detailed data, expansion of the population being held responsible for these exposures and significant unresolved legal issues such as the existence of coverage and the definition of an occurrence. CNA’s actuarial reserve analyses result in point estimates. Each quarter, the results of detailed reserve reviews are summarized and discussed with CNA’s senior management to determine management’s best estimate of reserves. CNA’s senior management considers many factors in making this decision. The factors include, but are not limited to, the historical pattern and volatility of the actuarial indications, the sensitivity of the actuarial indications to changes in paid and incurred loss patterns, the consistency of claims handling processes, the consistency of case reserving practices, changes in CNA’s pricing and underwriting, pricing and underwriting trends in the insurance market and legal, judicial, social and economic trends. CNA’s recorded reserves reflect its best estimate as of a particular point in time based upon known facts, consideration of the factors cited above and its judgment. The carried reserve may differ from the actuarial point estimate as the result of CNA’s consideration of the factors noted above as well as the potential volatility of the projections associated with the specific product being analyzed and other factors affecting claims costs that may not be quantifiable through traditional actuarial analysis. The loss reserve development tables presented herein illustrate the change over time of reserves established for claim and allocated claim adjustment expenses arising from short duration insurance contracts for certain lines of business within CNA’s property and casualty operations. Not all lines of business are presented based on their context to CNA’s overall loss reserves, calendar year reserve development, or calendar year net earned premiums. Insurance contracts are considered to be short duration contracts when the contracts are not expected to remain in force for an extended period of time. The Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses tables, reading across, show the cumulative net incurred claim and allocated claim adjustment expenses relating to each accident year at the end of the stated calendar year. Changes in the cumulative amount across time are the result of CNA’s expanded awareness of additional facts and circumstances that pertain to the unsettled claims. The Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses tables, reading across, show the cumulative amount paid for claims in each accident year as of the end of the stated calendar year. The Net Strengthening or (Releases) of Prior Accident Year Reserves tables, reading across, show the net increase or decrease in the cumulative net incurred accident year claim and allocated claim adjustment expenses during each stated calendar year and indicates whether the reserves for that accident year were strengthened or released. The information in the tables is reported on a net basis after reinsurance and does not include unallocated claim and claim adjustment expenses or the effects of discounting. The information contained in the years preceding the current calendar year is unaudited. To the extent CNA enters into a commutation, the transaction is reported on a prospective basis. To the extent that CNA enters into a disposition, the effects of the disposition are reported on a retrospective basis by removing the balances associated with it. The amounts reported for the cumulative number of reported claims include direct and assumed open and closed claims by accident year at the claimant level. The number excludes claim counts for claims within a policy deductible where the insured is responsible for payment of losses in the deductible layer. Claim count data for certain assumed reinsurance contracts is unavailable. In the loss reserve development tables, IBNR includes reserves for incurred but not reported losses and expected development on case reserves. Liability for Unpaid Claim and Claim Adjustment Expenses Rollforward The following table presents a reconciliation between beginning and ending claim and claim adjustment expense reserves, including claim and claim adjustment expense reserves of non-core Year Ended December 31 2016 2015 2014 (In millions) Reserves, beginning of year: Gross $ 22,663 $ 23,271 $ 24,089 Ceded 4,087 4,344 4,972 Net reserves, beginning of year 18,576 18,927 19,117 Change in net reserves due to disposition of subsidiaries (13 ) Net incurred claim and claim adjustment expenses: Provision for insured events of current year 5,025 4,934 5,043 Decrease in provision for insured events of prior years (342 ) (255 ) (36 ) Amortization of discount 175 166 161 Total net incurred (a) 4,858 4,845 5,168 Net payments attributable to: Current year events (967 ) (856 ) (945 ) Prior year events (4,167 ) (4,089 ) (4,355 ) Total net payments (5,134 ) (4,945 ) (5,300 ) Foreign currency translation adjustment and other (51 ) (251 ) (45 ) Net reserves, end of year 18,249 18,576 18,927 Ceded reserves, end of year 4,094 4,087 4,344 Gross reserves, end of year $ 22,343 $ 22,663 $ 23,271 (a) Total net incurred above does not agree to Insurance claims and policyholders’ benefits as reflected in the Consolidated Statements of Income due to amounts related to retroactive reinsurance deferred gain accounting, uncollectible reinsurance and loss deductible receivables and benefit expenses related to future policy benefits, which are not reflected in the table above. The following tables present the gross and net carried reserves: December 31, 2016 Property Non-Core Total (In millions) Gross Case Reserves $ 7,164 $ 4,696 $ 11,860 Gross IBNR Reserves 9,207 1,276 10,483 Total Gross Carried Claim and Claim Adjustment Expense Reserves $ 16,371 $ 5,972 $ 22,343 Net Case Reserves $ 6,582 $ 3,045 $ 9,627 Net IBNR Reserves 8,328 294 8,622 Total Net Carried Claim and Claim Adjustment Expense Reserves $ 14,910 $ 3,339 $ 18,249 December 31, 2015 Gross Case Reserves $ 7,608 $ 4,494 $ 12,102 Gross IBNR Reserves 9,191 1,370 10,561 Total Gross Carried Claim and Claim Adjustment Expense Reserves $ 16,799 $ 5,864 $ 22,663 Net Case Reserves $ 6,992 $ 2,844 $ 9,836 Net IBNR Reserves 8,371 369 8,740 Total Net Carried Claim and Claim Adjustment Expense Reserves $ 15,363 $ 3,213 $ 18,576 Net Prior Year Development Changes in estimates of claim and allocated claim adjustment expense reserves and premium accruals, net of reinsurance, for prior years are defined as net prior year development. These changes can be favorable or unfavorable. Favorable net prior year development of $316 million, $218 million and $50 million was recorded for property and casualty operations for the years ended December 31, 2016, 2015 and 2014. Favorable net prior year development of $43 million, $50 million and $17 million was recorded for non-core Premium development can occur in the property and casualty business when there is a change in exposure on auditable policies or when premium accruals differ from processed premium. Audits on policies usually occur in a period after the expiration date of the policy. The following table and discussion presents detail of the net prior year claim and allocated claim adjustment expense reserve development (“development”): Year Ended December 31 2016 2015 2014 (In millions) Medical professional liability $ (37 ) $ (43 ) $ 39 Other professional liability and management liability (130 ) (87 ) Surety (63 ) (69 ) (82 ) Commercial auto (46 ) (22 ) 31 General liability (28 ) (33 ) 45 Workers’ compensation 150 80 139 Other (134 ) (123 ) (106 ) Total pretax (favorable) unfavorable development $ (288 ) $ (210 ) $ (21 ) 2016 Favorable development for medical professional liability was primarily due to lower than expected severities for individual health care professionals, allied facilities and hospitals in accident years 2011 and prior and better than expected severity in medical products liability in accident years 2010 through 2015. This was partially offset by unfavorable development in accident years 2012 and 2013 related to higher than expected large loss emergence in hospitals and higher than expected frequency and severity in accident years 2014 and 2015 in the aging services business. Favorable development in other professional liability and management liability was primarily due to favorable settlements on closed claims and lower than expected frequency of claims in accident years 2010 through 2014 related to professional services and financial institutions. This was partially offset by unfavorable development related to a specific financial institutions claim in accident year 2014, higher management liability severities in accident year 2015 and deterioration on credit crises-related claims in accident year 2009. Favorable development in surety coverages was primarily due to lower than expected frequency of large losses in accident years 2014 and prior. Favorable development for commercial auto was primarily due to favorable settlements on claims in accident years 2010 through 2014 and lower than expected severities in accident years 2012 through 2015. Favorable development for general liability was primarily due to better than expected claim settlements in accident years 2012 through 2014 and better than expected severity on umbrella claims in accident years 2010 through 2013. This was partially offset by unfavorable development related to an increase in reported claims prior to the closing of the three year window set forth by the Minnesota Child Victims Act in accident years 2006 and prior. Unfavorable development for workers’ compensation was primarily due to higher than expected severity for Defense Base Act contractors that largely resulted from a reduction of expected future recoveries from the U.S. Department of Labor under the War Hazard Act. Further unfavorable development was due to the impact of recent Florida court rulings for accident years 2008 through 2015. These were partially offset by favorable development related to lower than expected frequencies related to the ongoing Middle Market and Small Business results for accident years 2009 through 2014. 2015 Overall, favorable development for medical professional liability was related to lower than expected severity in accident years 2012 and prior. Unfavorable development was recorded related to increased claim frequency and severity in the aging services business in accident years 2013 and 2014. Favorable development in other professional liability and management liability related to better than expected large loss emergence in financial institutions primarily in accident years 2011 through 2014. Additional favorable development related to lower than expected severity for professional services in accident years 2011 and prior. Unfavorable development was recorded related to increased frequency of large claims on public company management liability in accident years 2012 through 2014. Favorable development for surety coverages was primarily due to lower than expected frequency of large losses in accident years 2013 and prior. Favorable development for commercial auto was primarily due to lower than expected severity in accident years 2009 through 2014. Favorable development for general liability was primarily due to favorable settlements on claims in accident years 2010 through 2013. Unfavorable development for workers’ compensation was primarily due to higher than expected severity related to Defense Base Act contractors in accident years 2008 through 2014. 2014 Unfavorable development for medical professional liability was primarily related to increased frequency of large medical products liability class action lawsuits in accident years 2012 and prior and increased frequency of other large medical professional liability losses in accident years 2011 through 2013. Overall, favorable development for other professional liability and management liability was related to better than expected severity in accident years 2008 through 2011, including favorable outcomes on individual large claims. Additional favorable development related to lower than expected frequency in accident years 2011 through 2013. Unfavorable development was recorded due to higher than expected severity in financial institution and professional service coverages in accident years 2009 through 2011. Favorable development for surety coverages was primarily due to better than expected large loss emergence in accident years 2012 and prior. Unfavorable development for commercial auto was primarily related to higher than expected frequency in accident years 2012 and 2013 and higher than expected severity for liability coverages in accident years 2010 through 2013. Favorable development was recorded related to fewer large claims than expected in accident years 2008 and 2009. Overall, unfavorable development for general liability was primarily related to higher than expected severity in accident years 2010 through 2013. Favorable development was recorded primarily related to lower than expected frequency of large losses in accident years 2005 through 2009. Overall, unfavorable development for workers’ compensation was primarily due to increased medical severity in accident years 2010 and prior, higher than expected severity related to Defense Base Act contractors in accident years 2010 through 2013 and the recognition of losses related to favorable premium development in accident year 2013. Favorable development of $26 million was recorded in accident years 1996 and prior related to the commutation of a workers’ compensation reinsurance pool. Property and Casualty Operations – Line of Business Composition The table below presents the net liability for unpaid claim and claim adjustment expenses, by line of business for property and casualty operations: December 31 2016 (In millions) Medical professional liability $ 1,779 Other professional liability and management liability 3,063 Surety 394 Commercial auto 424 General liability 3,248 Workers’ compensation 4,306 Other 1,696 Total net liability for unpaid claim and claim adjustment expenses $ 14,910 Medical Professional Liability December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative Number of December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Claims (In millions, except reported claims data) Accident Year 2007 $ 448 $ 452 $ 444 $ 427 $ 395 $ 391 $ 390 $ 401 $ 399 $ 385 $ 9 12,122 2008 426 451 496 480 468 468 467 455 442 9 14,094 2009 462 469 494 506 480 471 463 432 12 15,573 2010 483 478 478 486 470 446 403 16 15,206 2011 486 492 507 533 501 491 23 17,428 2012 526 529 575 567 559 47 18,375 2013 534 540 560 567 95 19,565 2014 511 548 585 165 19,286 2015 480 539 278 16,798 2016 469 400 11,600 Total $ 4,872 $ 1,054 Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 11 $ 68 $ 134 $ 201 $ 247 $ 296 $ 326 $ 352 $ 364 $ 365 2008 9 90 207 282 332 377 395 409 428 2009 9 75 180 278 328 353 377 396 2010 11 93 186 273 338 361 371 2011 18 121 225 315 379 407 2012 15 121 236 359 428 2013 18 121 259 364 2014 25 149 274 2015 22 105 2016 18 Total $ 3,156 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 1,716 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 30 Liability for unallocated claim adjustment expenses for accident years presented 33 Total net liability for unpaid claim and claim adjustment expenses $ 1,779 Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 4 $ (8) $ (17) $ (32) $ (4) $ (1) $ 11 $ (2) $ (14) $ (63) 2008 25 45 (16) (12) (1) (12) (13) 16 2009 7 25 12 (26) (9) (8) (31) (30) 2010 (5) 8 (16) (24) (43) (80) 2011 6 15 26 (32) (10) 5 2012 3 46 (8) (8) 33 2013 6 20 7 33 2014 37 37 74 2015 59 59 Total net development for the accident years presented above $ 63 $ (29) $ (16) Total net development for accident years prior to 2007 (24) (14) (21) Total $ 39 $ (43) $ (37) (a) Data presented for these calendar years is required supplemental information, which is unaudited. Other Professional Liability and Management Liability December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Number of (In millions, except reported claims data) Accident Year 2007 $ 804 $ 817 $ 806 $ 754 $ 734 $ 724 $ 704 $ 681 $ 662 $ 662 $ 13 16,011 2008 916 933 954 924 915 880 850 845 827 35 16,326 2009 829 873 903 898 891 900 895 903 50 17,263 2010 825 827 850 848 846 836 823 39 17,796 2011 876 904 933 948 944 910 107 18,620 2012 907 894 876 870 833 107 18,228 2013 844 841 879 840 137 17,324 2014 841 859 854 306 16,886 2015 847 851 478 16,391 2016 859 742 15,045 Total $ 8,362 $ 2,014 Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 32 $ 162 $ 307 $ 397 $ 472 $ 524 $ 564 $ 585 $ 593 $ 614 2008 39 181 376 515 600 641 678 719 741 2009 37 195 358 550 638 719 769 798 2010 31 203 404 541 630 670 721 2011 71 313 502 604 682 726 2012 57 248 398 570 648 2013 51 240 426 583 2014 51 212 375 2015 48 209 2016 60 Total $ 5,475 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 2,887 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 104 Liability for unallocated claim adjustment expenses for accident years presented 72 Total net liability for unpaid claim and claim adjustment expenses $ 3,063 Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 13 $ (11) $ (52) $ (20) $ (10) $ (20) $ (23) $ (19) $ (142) 2008 17 21 (30) (9) (35) (30) (5) $ (18) (89) 2009 44 30 (5) (7) 9 (5) 8 74 2010 2 23 (2) (2) (10) (13) (2) 2011 28 29 15 (4) (34) 34 2012 (13) (18) (6) (37) (74) 2013 (3) 38 (39) (4) 2014 18 (5) 13 2015 4 4 Total net development for the accident years presented above $ (52) $ 7 $ (134) Total net development for accident years prior to 2007 (35) (7) 4 Total $ (87) $ - $ (130) (a) Data presented for these calendar years is required supplemental information, which is unaudited. Surety December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Number of (In millions, except reported claims data) Accident Year 2007 $ 98 $ 107 $ 81 $ 57 $ 59 $ 56 $ 51 $ 49 $ 49 $ 50 6,270 2008 114 114 73 68 61 52 48 45 44 7,153 2009 114 114 103 85 68 59 52 53 $ 1 6,654 2010 112 112 111 84 76 66 63 8 5,943 2011 120 121 116 87 75 70 9 5,760 2012 120 122 98 70 52 16 5,473 2013 120 121 115 106 24 4,890 2014 123 124 94 51 4,737 2015 131 131 100 4,279 2016 124 110 2,902 Total $ 787 $ 319 Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 12 $ 30 $ 40 $ 45 $ 46 $ 46 $ 46 $ 48 $ 49 $ 50 2008 9 27 35 39 42 43 43 43 43 2009 13 24 34 41 43 45 46 47 2010 13 34 50 55 57 58 55 2011 19 42 55 58 60 60 2012 5 32 34 35 35 2013 16 40 69 78 2014 7 30 38 2015 7 26 2016 5 Total $ 437 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 350 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 16 Liability for unallocated claim adjustment expenses for accident years presented 28 Total net liability for unpaid claim and claim adjustment expenses $ 394 Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 9 $ (26) $ (24) $ 2 $ (3) $ (5) $ (2) $ 1 $ (48) 2008 (41) (5) (7) (9) (4) $ (3) (1) (70) 2009 (11) (18) (17) (9) (7) 1 (61) 2010 (1) (27) (8) (10) (3) (49) 2011 1 (5) (29) (12) (5) (50) 2012 2 (24) (28) (18) (68) 2013 1 (6) (9) (14) 2014 1 (30) (29) 2015 Total net development for the accident years presented above $ (75) $ (65) $ (64) Total net development for accident years prior to 2007 (7) (4) 1 Total $ (82) $ (69) $ (63) (a) Data presented for these calendar years is required supplemental information, which is unaudited. Commercial Auto December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative Number of December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Claims (In millions, except reported claims data) Accident Year 2007 $ 348 $ 367 $ 368 $ 360 $ 355 $ 358 $ 356 $ 355 $ 354 $ 352 67,473 2008 322 323 316 306 309 305 298 298 296 56,407 2009 287 272 274 278 281 277 275 272 47,325 2010 262 274 279 283 291 286 281 $ 1 46,324 2011 262 273 279 293 290 285 5 46,676 2012 270 282 292 296 300 11 45,279 2013 242 259 257 241 20 38,513 2014 231 221 210 40 32,958 2015 199 197 65 29,714 2016 196 105 25,196 Total $ 2,630 $ 247 Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 93 $ 185 $ 250 $ 295 $ 329 $ 340 $ 348 $ 349 $ 350 $ 351 2008 83 158 210 244 274 289 291 292 293 2009 72 128 188 229 257 269 270 270 2010 72 137 197 240 265 274 279 2011 78 141 193 241 264 275 2012 77 157 214 253 276 2013 73 132 164 195 2014 63 100 135 2015 52 95 2016 51 Total $ 2,220 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 410 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 4 Liability for unallocated claim adjustment expenses for accident years presented 10 Total net liability for unpaid claim and claim adjustment expenses $ 424 Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 19 $ 1 $ (8) $ (5) $ 3 $ (2) $ (1) $ (1) $ (2) $ 4 2008 1 (7) (10) 3 (4) (7) (2) (26) 2009 (15) 2 4 3 (4) (2) (3) (15) 2010 12 5 4 8 (5) (5) 19 2011 11 6 14 (3) (5) 23 2012 12 10 4 4 30 2013 17 (2) (16) (1) 2014 (10) (11) (21) 2015 (2) (2) Total net development for the accident years presented above $ 37 $ (19) $ (42) Total net development for accident years prior to 2007 (6) (3) (4) Total $ 31 $ (22) $ (46) (a) Data presented for these calendar years is required supplemental information, which is unaudited. General Liability December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative Number of December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Claims (In millions, except reported claims data) Accident Year 2007 $ 774 $ 673 $ 678 $ 639 $ 610 $ 600 $ 559 $ 545 $ 548 $ 540 $ 28 53,553 2008 611 604 630 647 633 632 613 600 591 18 44,586 2009 591 637 634 633 629 623 619 622 16 43,955 2010 566 597 599 649 695 675 659 25 43,378 2011 537 534 564 610 611 621 41 38,101 2012 539 563 579 570 558 63 34,037 2013 615 645 634 643 142 32,897 2014 627 634 635 224 26,744 2015 573 574 330 21,687 2016 622 495 16,720 Total $ 6,065 $ 1,382 Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 30 $ 130 $ 236 $ 328 $ 413 $ 458 $ 481 $ 492 $ 497 $ 504 2008 31 129 261 390 473 528 550 560 567 2009 33 112 270 392 486 532 557 584 2010 27 139 267 414 530 577 608 2011 27 135 253 389 484 534 2012 27 127 233 340 417 2013 33 135 257 377 2014 29 115 245 2015 31 132 2016 34 Total $ 4,002 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 2,063 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 1,130 Liability for unallocated claim adjustment expenses for accident years presented 55 Total net liability for unpaid claim and claim adjustment expenses $ 3,248 Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ (101) $ 5 $ (39) $ (29) $ (10) $ (41) $ (14) $ 3 $ (8) $ (234) 2008 (7) 26 17 (14) (1) (19) (13) (9) (20) 2009 46 (3) (1) (4) (6) (4) 3 31 2010 31 2 50 46 (20) (16) 93 2011 (3) 30 46 1 10 84 2012 24 16 (9) (12) 19 2013 30 (11) 9 28 2014 7 1 8 2015 1 1 Total net development for the accident years presented above $ 99 $ (46) $ (21) Total net development for accident years prior to 2007 (54) 13 (7) Total $ 45 $ (33) $ (28) (a) Data presented for these calendar years is required supplemental information, which is unaudited. Workers’ Compensation December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative Number of December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Claims (In millions, except reported claims data) Accident Year 2007 $ 568 $ 580 $ 596 $ 604 $ 603 $ 603 $ 604 $ 610 $ 608 $ 627 $ 32 71,049 2008 558 575 593 606 608 612 622 630 638 36 59,883 2009 583 587 594 596 600 611 617 625 46 51,111 2010 576 619 641 663 683 697 717 45 48,056 2011 593 628 637 648 642 666 52 44,571 2012 589 616 648 661 671 86 41,683 2013 528 563 584 610 121 38,102 2014 459 474 474 157 32,996 2015 416 426 206 31,296 2016 421 287 27,042 Total $ 5,875 $ 1,068 Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 100 $ 246 $ 337 $ 390 $ 429 $ 471 $ 502 $ 522 $ 533 $ 535 2008 92 233 323 381 425 461 489 505 520 2009 88 223 315 381 435 468 495 516 2010 94 245 352 433 500 531 565 2011 97 245 353 432 471 515 2012 86 229 338 411 465 2013 79 211 297 366 2014 60 157 213 2015 50 130 2016 52 Total $ 3,877 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 1,998 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 2,334 Other (b) (30) Liability for unallocated claim adjustment expenses for accident years presented 4 Total net liability for unpaid claim and claim adjustment expenses $ 4,306 (b) Other includes the effect of discounting lifetime claim reserves. Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 12 $ 16 $ 8 $ (1 ) $ 1

Leases

Leases	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Leases	Leases primarily cover office facilities, machinery and computer equipment. Hotel properties, in some instances, are constructed on leased land. Rent expense amounted to $97 million, $85 million and $94 million for the years ended December 31, 2016, 2015 and 2014. The table below presents the future minimum lease payments to be made under non-cancelable Future Minimum Lease Year Ended December 31 Payments Receipts (In millions) 2017 $ 72 $ 5 2018 59 5 2019 51 4 2020 54 4 2021 53 4 Thereafter 349 19 Total $ 638 $ 41 In connection with the planned relocation of CNA’s global headquarters, in 2016, CNA sold the building in which it maintains its current principal executive offices. Concurrently, CNA leased back the current office space until the relocation of the global headquarters, which is expected to occur in 2018. The sale-leaseback arrangement includes expected future minimum lease payments of $10 million in 2017 and $4 million in 2018.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	The Company and its eligible subsidiaries file a consolidated federal income tax return. The Company has entered into a separate tax allocation agreement with CNA, a majority-owned subsidiary in which its ownership exceeds 80%. The agreement provides that the Company will: (i) pay to CNA the amount, if any, by which the Company’s consolidated federal income tax is reduced by virtue of inclusion of CNA in the Company’s return or (ii) be paid by CNA an amount, if any, equal to the federal income tax that would have been payable by CNA if it had filed a separate consolidated return. The agreement may be canceled by either of the parties upon thirty days written notice. For 2014 through 2016, the Internal Revenue Service (“IRS”) has accepted the Company into the Compliance Assurance Process (“CAP”), which is a voluntary program for large corporations. Under CAP, the IRS conducts a real-time audit and works contemporaneously with the Company to resolve any issues prior to the filing of the tax return. The Company believes this approach should reduce tax-related Diamond Offshore, which is not included in the Company’s consolidated federal income tax return, files income tax returns in the U.S. federal and various state and foreign jurisdictions. Tax years that remain subject to examination by these jurisdictions include years 2009 to 2016. The 2013 federal income tax return is under examination. The current and deferred components of income tax expense (benefit) are as follows: Year Ended December 31 2016 2015 2014 (In millions) Income tax expense (benefit): Federal: Current $ 71 $ 79 $ 370 Deferred 102 (234 ) (23 ) State and city: Current 13 21 12 Deferred 13 5 6 Foreign 21 86 92 Total $ 220 $ (43 ) $ 457 The components of U.S. and foreign income before income tax and a reconciliation between the federal income tax expense at statutory rates and the actual income tax expense (benefit) is as follows: Year Ended December 31 2016 2015 2014 (In millions) Income before income tax: U.S. $ 1,207 $ 543 $ 1,499 Foreign (271 ) (299 ) 311 Total $ 936 $ 244 $ 1,810 Income tax expense at statutory rate $ 328 $ 86 $ 633 Increase (decrease) in income tax expense resulting from: Exempt investment income (126 ) (126 ) (121 ) Foreign related tax differential 40 (18 ) (48 ) Amortization of deferred charges associated with intercompany rig sales to other tax jurisdictions 38 44 Taxes related to domestic affiliate (14 ) (10 ) 14 Partnership earnings not subject to taxes (52 ) (38 ) (39 ) Allowance for foreign tax credits 62 Unrecognized tax positions, including foreign currency revaluation (42 ) 1 (42 ) Other (a) 24 24 16 Income tax expense (benefit) $ 220 $ (43 ) $ 457 (a) Includes state and local taxes, adjustments to prior year estimates and other non-deductible Provision has been made for the expected U.S. federal income tax liabilities applicable to undistributed earnings of subsidiaries, except for certain subsidiaries for which the Company intends to invest the undistributed earnings indefinitely to finance foreign activities, or recover such undistributed earnings tax-free. A reconciliation of the beginning and ending amount of unrecognized tax benefits, excluding tax carryforwards and interest and penalties, is as follows: Year Ended December 31 2016 2015 2014 (In millions) Balance at January 1 $ 54 $ 57 $ 91 Additions for tax positions related to the current year 4 7 6 Additions for tax positions related to a prior year 1 Reductions for tax positions related to a prior year (20 ) (3 ) (35 ) Lapse of statute of limitations (4 ) (7 ) (5 ) Balance at December 31 $ 35 $ 54 $ 57 The $20 million in reductions for tax positions related to a prior year is primarily from the devaluation of the Egyptian pound. At December 31, 2016, 2015 and 2014, $36 million, $49 million and $51 million of unrecognized tax benefits related to Diamond Offshore would affect the effective tax rate if recognized. The Company recognizes interest accrued related to: (i) unrecognized tax benefits in Interest expense and (ii) tax refund claims in Other revenues on the Consolidated Statements of Income. The Company recognizes penalties in Income tax expense on the Consolidated Statements of Income. Interest amounts recorded by the Company were insignificant for the years ended December 31, 2016, 2015 and 2014. The Company recorded income tax benefit of $23 million and $22 million for the years ended December 31, 2016 and 2014 and income tax expense of $2 million for the year ended December 31, 2015 related to penalties. The $23 million reduction in penalties related to uncertain tax positions results primarily from the devaluation of the Egyptian pound. During 2014, Diamond Offshore settled certain disputes for the years 2006 through 2008 with the Egyptian tax authorities, resulting in a net reduction to income tax expense of $17 million. One issue for the 2006 through 2008 period remains open, which Diamond Offshore appealed. The court case is currently pending. Diamond Offshore has sought assistance from an agency of the U.S. Treasury Department, pursuant to international tax treaties and continues to believe that its position will, more likely than not, be sustained. However, if Diamond Offshore’s position is not sustained, tax expense and related penalties would increase by approximately $22 million related to this issue for the 2006 through 2008 tax years as of December 31, 2016. The following table summarizes deferred tax assets and liabilities: December 31 2016 2015 (In millions) Deferred tax assets: Insurance reserves: Property and casualty claim and claim adjustment expense reserves $ 125 $ 178 Unearned premium reserves 206 230 Receivables 26 30 Employee benefits 407 419 Life settlement contracts 56 48 Deferred retroactive reinsurance benefit 117 84 Net operating loss carryforwards 178 245 Tax credit carryforwards 289 131 Basis differential in investment in subsidiary 17 19 Other 246 282 Total deferred tax assets 1,667 1,666 Valuation allowance (210 ) (147 ) Net deferred tax assets 1,457 1,519 Deferred tax liabilities: Deferred acquisition costs (120 ) (117 ) Net unrealized gains (295 ) (166 ) Property, plant and equipment (1,019 ) (998 ) Basis differential in investment in subsidiary (409 ) (428 ) Other liabilities (235 ) (173 ) Total deferred tax liabilities (2,078 ) (1,882 ) Net deferred tax liabilities (a) $ (621 ) $ (363 ) (a) Includes $15 and $19 of deferred tax assets reflected in Other assets in the Consolidated Balance Sheets at December 31, 2016 and 2015. Federal net operating loss carryforwards of $76 million expire in 2034 and 2036. Net operating loss carryforwards in foreign tax jurisdictions of $59 million expire between 2020 and 2025 and $36 million can be carried forward indefinitely. Federal tax credit carryforwards of $157 million have indefinite lives and $98 million of foreign tax credit carryforwards expire between 2024 and 2026. Diamond Offshore intends to carryback foreign tax credits of $33 million to prior years, which otherwise will expire between 2021 and 2023. Although realization of deferred tax assets is not assured, management believes it is more likely than not that the recognized deferred tax assets will be realized through recoupment of ordinary and capital taxes paid in prior carryback years and through future earnings, reversal of existing temporary differences and available tax planning strategies. As of December 31, 2016, Diamond Offshore recorded a valuation allowance of $210 million related to net operating losses of $91 million, foreign tax credits of $62 million, and other deferred tax assets of $57 million.

Debt

Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt	December 31 2016 2015 (In millions) Loews Corporation (Parent Company): Senior: 5.3% notes due 2016 (effective interest rate of 5.4%) (authorized, $400) $ 400 2.6% notes due 2023 (effective interest rate of 2.8%) (authorized, $500) $ 500 500 3.8% notes due 2026 (effective interest rate of 3.9%) (authorized, $500) 500 6.0% notes due 2035 (effective interest rate of 6.2%) (authorized, $300) 300 300 4.1% notes due 2043 (effective interest rate of 4.3%) (authorized, $500) 500 500 CNA Financial: Senior: 6.5% notes due 2016 (effective interest rate of 6.6%) (authorized, $350) 350 7.0% notes due 2018 (effective interest rate of 7.1%) (authorized, $150) 150 150 7.4% notes due 2019 (effective interest rate of 7.5%) (authorized, $350) 350 350 5.9% notes due 2020 (effective interest rate of 6.0%) (authorized, $500) 500 500 5.8% notes due 2021 (effective interest rate of 5.9%) (authorized, $400) 400 400 7.3% debentures due 2023 (effective interest rate of 7.3%) (authorized, $250) 243 243 4.0% notes due 2024 (effective interest rate of 4.0%) (authorized, $550) 550 550 4.5% notes due 2026 (effective interest rate of 4.5%) (authorized, $500) 500 Variable rate note due 2036 (effective interest rate of 4.3% and 3.8%) 30 30 Capital lease obligation 5 4 Diamond Offshore: Senior: Commercial paper (weighted average interest rate of 0.9%) 287 Variable rate revolving credit facility due 2020 (effective interest rate of 1.9%) 104 5.9% notes due 2019 (effective interest rate of 6.0%) (authorized, $500) 500 500 3.5% notes due 2023 (effective interest rate of 3.6%) (authorized, $250) 250 250 5.7% notes due 2039 (effective interest rate of 5.8%) (authorized, $500) 500 500 4.9% notes due 2043 (effective interest rate of 5.0%) (authorized, $750) 750 750 Boardwalk Pipeline: Senior: Variable rate revolving credit facility due 2021 (effective interest rate of 2.0% and 1.7%) 180 375 5.9% notes due 2016 (effective interest rate of 6.0%) (authorized, $250) 250 5.5% notes due 2017 (effective interest rate of 5.6%) (authorized, $300) 300 300 6.3% notes due 2017 (effective interest rate of 6.4%) (authorized, $275) 275 275 5.2% notes due 2018 (effective interest rate of 5.4%) (authorized, $185) 185 185 5.8% notes due 2019 (effective interest rate of 5.9%) (authorized, $350) 350 350 4.5% notes due 2021 (effective interest rate of 5.0%) (authorized, $440) 440 440 4.0% notes due 2022 (effective interest rate of 4.4%) (authorized, $300) 300 300 3.4% notes due 2023 (effective interest rate of 3.5%) (authorized, $300) 300 300 5.0% notes due 2024 (effective interest rate of 5.2%) (authorized, $600 and $350) 600 600 6.0% notes due 2026 (effective interest rate of 6.2%) (authorized, $550) 550 7.3% debentures due 2027 (effective interest rate of 8.1%) (authorized, $100) 100 100 Capital lease obligation 9 10 Loews Hotels: Senior debt, principally mortgages (effective interest rates approximate 4.1%) 650 598 10,871 10,647 Less unamortized discount and issuance costs 93 87 Debt $ 10,778 $ 10,560 December 31, 2016 Principal Unamortized Net Short Term Long Term (In millions) Loews Corporation $ 1,800 $ 25 $ 1,775 $ 1,775 CNA Financial 2,728 13 2,715 $ 2 2,713 Diamond Offshore 2,104 19 2,085 104 1,981 Boardwalk Pipeline 3,589 31 3,558 1 3,557 Loews Hotels 650 5 645 3 642 Total $ 10,871 $ 93 $ 10,778 $ 110 $ 10,668 At December 31, 2016, the aggregate long term debt maturing in each of the next five years is approximately as follows: $110 million in 2017, $534 million in 2018, $1.3 billion in 2019, $550 million in 2020, $1.6 billion in 2021, and $6.8 billion thereafter. Long term debt is generally redeemable in whole or in part at the greater of the principal amount or the net present value of remaining scheduled payments discounted at the specified treasury rate plus a margin. CNA Financial CNA is a member of the Federal Home Loan Bank of Chicago (“FHLBC”). FHLBC membership provides participants with access to additional sources of liquidity through various programs and services. As a requirement of membership in the FHLBC, CNA held $5 million of FHLBC stock as of December 31, 2016, giving it access to approximately $111 million of additional liquidity. As of December 31, 2016 and 2015, CNA had no outstanding borrowings from the FHLBC. In the first quarter of 2016, CNA completed a public offering of $500 million aggregate principal amount of 4.5% senior notes due March 1, 2026 and used the net proceeds to repay the entire $350 million outstanding principal amount of its 6.5% senior notes due August 15, 2016. CNA has a five-year $250 million senior unsecured revolving credit facility with a syndicate of banks which may be used for general corporate purposes. At CNA’s election, the commitments under the credit agreement may be increased from time to time up to an additional aggregate amount of $100 million and the credit agreement includes two optional one-year Diamond Offshore In the first quarter of 2016, Diamond Offshore cancelled its commercial paper program and repaid $287 million in commercial paper outstanding at December 31, 2015 with proceeds from borrowings under its revolving credit agreement. Diamond Offshore has a $1.5 billion senior unsecured revolving credit facility that matures in October of 2020, except for $40 million of commitments that mature in March of 2019 and $60 million of commitments that mature in October of 2019. In addition, Diamond Offshore also has the option to increase the revolving commitments under the revolving credit facility by up to an additional $500 million from time to time, upon receipt of additional commitments from new or existing lenders, and to request one additional one-year Boardwalk Pipeline In May of 2016, Boardwalk Pipeline completed a public offering of $550 million aggregate principal amount of 6.0% senior notes due June 1, 2026 and used the proceeds to reduce borrowings under its revolving credit facility. In November of 2016, the outstanding aggregate principal amount of the 5.9% senior notes was retired with borrowings under its revolving credit facility. In January of 2017, Boardwalk Pipeline completed a public offering of $500 million aggregate principal amount of 4.5% senior notes due July 15, 2027 and will use the proceeds to refinance future maturities of debt and to fund growth capital expenditures. Initially, the proceeds were used to reduce outstanding borrowings under its revolving credit facility. Boardwalk Pipeline has a revolving credit facility having aggregate lending commitments of $1.5 billion. During the third quarter of 2016, Boardwalk Pipeline extended the maturity date of the revolving credit facility by one year to May 26, 2021. Boardwalk Pipeline has in place a subordinated loan agreement with a subsidiary of the Company under which it can borrow up to $300 million until December 31, 2018. Boardwalk Pipeline had no outstanding borrowings under the subordinated loan agreement. Loews Corporation In March of 2016, the Company completed a public offering of $500 million aggregate principal amount of 3.8% senior notes due April 1, 2026 and repaid in full the entire $400 million aggregate principal amount of its 5.3% senior notes at maturity.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Shareholders' Equity	Accumulated other comprehensive income The tables below display the changes in AOCI by component for the years ended December 31, 2014, 2015 and 2016: OTTI Gains (Losses) Unrealized Discontinued Cash Flow Pension Foreign Translation Total (In millions) Balance, January 1, 2014 $ 23 $ 622 $ (3) $ (4) $ (432 ) $ 133 $ 339 Sale of subsidiaries (5 ) (15) 20 Other comprehensive income (loss) before reclassifications, after tax of $(8), $(132), $(3), $1, $132 and $0 15 295 2 (2) (244 ) (94 ) (28) Reclassification of (gains) losses from accumulated other comprehensive income, after tax of $0, $10, $16, $0, $(7) and $0 (28) (21) (1) 9 (41) Other comprehensive income (loss) 15 267 (19) (3) (235 ) (94 ) (69) Amounts attributable to noncontrolling interests (1 ) (28) 2 1 26 10 10 Balance, December 31, 2014 32 846 - (6) (641 ) 49 280 Other comprehensive loss before reclassifications, after tax of $13, $313, $0, $1, $16 and $0 (23 ) (600) (2) (31 ) (139 ) (795) Reclassification of losses from accumulated other comprehensive income, after tax of $(8), $(31), $0, $(2), $(11) and $0 14 43 7 13 77 Other comprehensive income (loss) (9 ) (557) - 5 (18 ) (139 ) (718) Issuance of equity securities by subsidiary 1 1 Amounts attributable to noncontrolling interests 1 58 (2) 9 14 80 Balance, December 31, 2015 24 347 - (3) (649 ) (76 ) (357) Other comprehensive income (loss) before reclassifications, after tax of $(4), $(133), $0, $0, $9 and $0 9 283 (22 ) (114 ) 156 Reclassification of (gains) losses from accumulated other comprehensive income, after tax of $3, $16, $0, $0, $(15) and $0 (6 ) (26) 2 27 (3) Other comprehensive income (loss) 3 257 - 2 5 (114 ) 153 Amounts attributable to noncontrolling interests (28) (1) (2 ) 12 (19) Balance, December 31, 2016 $ 27 $ 576 $ - $ (2) $ (646 ) $ (178 ) $ (223) Amounts reclassified from AOCI shown above are reported in Net income as follows: Major Category of AOCI Affected Line Item OTTI gains (losses) Investment gains (losses) Unrealized gains (losses) on investments Investment gains (losses) Unrealized gains (losses) and cash flow hedges related to discontinued operations Discontinued operations, net Cash flow hedges Other revenues and Contract drilling expenses Pension liability Other operating expenses Common Stock Dividends Dividends of $0.25 per share on the Company’s common stock were declared and paid in 2016, 2015 and 2014. There are no restrictions on the Company’s retained earnings or net income with regard to payment of dividends. However, as a holding company, Loews relies upon invested cash balances and distributions from its subsidiaries to generate the funds necessary to declare and pay any dividends to holders of its common stock. The ability of the Company’s subsidiaries to pay dividends is subject to, among other things, the availability of sufficient earnings and funds in such subsidiaries, compliance with covenants in their respective credit agreements and applicable state laws, including in the case of the insurance subsidiaries of CNA, laws and rules governing the payment of dividends by regulated insurance companies. See Note 13 for a discussion of the regulatory restrictions on CNA’s availability to pay dividends. Subsidiary Equity Transactions The Company purchased 0.3 million shares of CNA common stock at an aggregate cost of $8 million during 2016. The Company’s percentage ownership interest in CNA remained unchanged as a result of these transactions, at 90%. The Company’s purchase price of the shares was lower than the carrying value of its investment in CNA, resulting in an increase to Additional paid-in Treasury Stock The Company repurchased 3.4 million, 33.3 million and 14.6 million shares of its common stock at aggregate costs of $134 million, $1.3 billion and $622 million during the years ended December 31, 2016, 2015 and 2014. As of December 31, 2016 all outstanding treasury stock was retired. Upon retirement, treasury stock was eliminated through a reduction to common stock, APIC and retained earnings.

Statutory Accounting Practices

Statutory Accounting Practices	12 Months Ended
	Dec. 31, 2016
Text Block [Abstract]
Statutory Accounting Practices	CNA’s insurance subsidiaries are domiciled in various jurisdictions. These subsidiaries prepare statutory financial statements in accordance with accounting practices prescribed or permitted by the respective jurisdictions’ insurance regulators. Domestic prescribed statutory accounting practices are set forth in a variety of publications of the National Association of Insurance Commissioners (“NAIC”) as well as state laws, regulations and general administrative rules. These statutory accounting principles vary in certain respects from GAAP. In converting from statutory accounting principles to GAAP, the more significant adjustments include deferral of policy acquisition costs and the inclusion of net unrealized holding gains or losses in shareholders’ equity relating to certain fixed maturity securities. CNA has a prescribed practice as it relates to the accounting under Statement of Statutory Accounting Principles No. 62R (“SSAP No. 62R”), Property and Casualty Reinsurance The 2015 long term care premium deficiency discussed in Note 1 was recorded on a GAAP basis. There was no premium deficiency for statutory accounting purposes. Statutory accounting principles requires the use of prescribed discount rates in calculating the reserves for long term care future policy benefits which are lower than the discount rates used on a GAAP basis and results in higher carried reserves relative to GAAP reserves. The payment of dividends by CNA’s insurance subsidiaries without prior approval of the insurance department of each subsidiary’s domiciliary jurisdiction is generally limited by formula. Dividends in excess of these amounts are subject to prior approval by the respective insurance regulator. Dividends from CCC are subject to the insurance holding company laws of the State of Illinois, the domiciliary state of CCC. Under these laws, ordinary dividends, or dividends that do not require prior approval by the Illinois Department of Insurance (the “Department”) are determined based on the greater of the prior year’s statutory net income or 10% of statutory surplus as of the end of the prior year, as well as timing and amount of dividends paid in the preceding 12 months. Additionally, ordinary dividends may only be paid from earned surplus, which is calculated by removing unrealized gains from unassigned surplus. As of December 31, 2016, CCC is in a positive earned surplus position. The maximum allowable dividend CCC could pay during 2017 that would not be subject to the Department’s prior approval is $1.1 billion, less dividends paid during the preceding 12 months measured at that point in time. CCC paid dividends of $765 million in 2016. The actual level of dividends paid in any year is determined after an assessment of available dividend capacity, holding company liquidity and cash needs as well as the impact the dividends will have on the statutory surplus of the applicable insurance company. Combined statutory capital and surplus and statutory net income (loss), determined in accordance with accounting practices prescribed or permitted by insurance and/or other regulatory authorities for the Combined Continental Casualty Companies are presented in the table below. Statutory Capital and Surplus Statutory Net Income December 31 Year Ended December 31 2016 (a) 2015 2016 (a) 2015 2014 (In millions) Combined Continental Casualty Companies $ 10,748 $ 10,723 $ 1,033 $ 1,148 $ 914 (a) Information derived from the statutory-basis financial statements to be filed with insurance regulators. CNA’s domestic insurance subsidiaries are subject to risk-based capital (“RBC”) requirements. RBC is a method developed by the NAIC to determine the minimum amount of statutory capital appropriate for an insurance company to support its overall business operations in consideration of its size and risk profile. The formula for determining the amount of RBC specifies various factors, weighted based on the perceived degree of risk, which are applied to certain financial balances and financial activity. The adequacy of a company’s actual capital is evaluated by a comparison to the RBC results, as determined by the formula. Companies below minimum RBC requirements are classified within certain levels, each of which requires specified corrective action. The statutory capital and surplus presented above for CCC was approximately 270% and 266% of company action level RBC at December 31, 2016 and 2015. Company action level RBC is the level of RBC which triggers a heightened level of regulatory supervision. The statutory capital and surplus of CCC’s foreign insurance subsidiaries, which is not significant to the overall statutory capital and surplus, also met or exceeded their respective regulatory and other capital requirements.

Benefit Plans

Benefit Plans	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Benefit Plans	Pension Plans – The Company has several non-contributory Other Postretirement Benefit Plans – The Company has several postretirement benefit plans covering eligible employees and retirees. Participants generally become eligible after reaching age 55 with required years of service. Actual requirements for coverage vary by plan. Benefits for retirees who were covered by bargaining units vary by each unit and contract. Benefits for certain retirees are in the form of a Company health care account. Benefits for retirees reaching age 65 are generally integrated with Medicare. Other retirees, based on plan provisions, must use Medicare as their primary coverage, with the Company reimbursing a portion of the unpaid amount; or are reimbursed for the Medicare Part B premium or have no Company coverage. The benefits provided by the Company are basically health and, for certain retirees, life insurance type benefits. The Company funds certain of these benefit plans, and accrues postretirement benefits during the active service of those employees who would become eligible for such benefits when they retire. The Company uses December 31 as the measurement date for its plans. Weighted average assumptions used to determine benefit obligations: Pension Benefits Other Postretirement Benefits December 31 2016 2015 2014 2016 2015 2014 Discount rate 3.9% 4.0% 3.7% 3.7% 3.7% 3.4% Expected long term rate of return on plan assets 7.5% 7.5% 7.5% 5.3% 5.3% 5.3% Rate of compensation increase 3.9% to 5.5% 3.5% to 5.5% 3.5% to 5.5% Weighted average assumptions used to determine net periodic benefit cost: Pension Benefits Other Postretirement Benefits Year Ended December 31 2016 2015 2014 2016 2015 2014 Discount rate 4.0% 3.8% 4.4% 3.7% 3.4% 4.0% Expected long term rate of return on plan assets 7.5% 7.5% 7.5% 5.3% 5.3% 5.3% Rate of compensation increase 3.5% to 5.5% 3.5% to 5.5% 3.5% to 5.5% The expected long term rate of return for plan assets is determined based on widely-accepted capital market principles, long term return analysis for global fixed income and equity markets as well as the active total return oriented portfolio management style. Long term trends are evaluated relative to market factors such as inflation, interest rates and fiscal and monetary policies, in order to assess the capital market assumptions as applied to the plan. Consideration of diversification needs and rebalancing is maintained. Assumed health care cost trend rates: December 31 2016 2015 2014 Health care cost trend rate assumed for next year 4.0% to 7.0% 4.0% to 7.5% 4.0% to 8.0% Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 4.0% to 5.0% 4.0% to 5.0% 4.0% to 5.0% Year that the rate reaches the ultimate trend rate 2017-2021 2016-2021 2015-2021 Assumed health care cost trend rates have a significant effect on the amounts reported for the health care plans. An increase or decrease in the assumed health care cost trend rate of 1% in each year would not have a significant impact on the Company’s service and interest cost as of December 31, 2016. An increase of 1% in each year would increase the Company’s accumulated postretirement benefit obligation as of December 31, 2016 by $2 million and a decrease of 1% in each year would decrease the Company’s accumulated postretirement benefit obligation as of December 31, 2016 by $2 million. Net periodic benefit cost components: Pension Benefits Other Postretirement Benefits Year Ended December 31 2016 2015 2014 2016 2015 2014 (In millions) Service cost $ 8 $ 12 $ 16 $ 1 $ 1 $ 1 Interest cost 128 127 149 3 3 4 Expected return on plan assets (177 ) (193 ) (209 ) (5 ) (5 ) (4) Amortization of unrecognized net loss 46 42 30 1 1 Amortization of unrecognized prior service benefit (1 ) (1 ) (1 ) (3 ) (10 ) (18) Settlement/Curtailment 3 3 86 (86) Net periodic benefit cost $ 7 $ (10 ) $ 71 $ (4 ) $ (10 ) $ (102) In 2016, the CNA Retirement Plan paid $88 million to settle its obligation to certain retirees through the purchase of a group annuity contract from a third party insurance company. The transaction reduced the plan’s projected benefit obligation by $86 million. In 2015, CNA eliminated future benefit accruals associated with the CNA Retirement Plan effective June 30, 2015. This amendment resulted in a $55 million curtailment which is a decrease in the plan benefit obligation liability and a reduction of the unrecognized actuarial losses included in AOCI. In connection with the curtailment, CNA remeasured the plan benefit obligation which resulted in an increase in the discount rate used to determine the benefit obligation from 3.9% to 4.0%. During 2014, CNA offered a limited-time lump sum settlement payment opportunity to the majority of the terminated vested participants of the CNA Retirement Plan. Settlement payments of $253 million were made from CNA Retirement Plan assets and an $84 million settlement charge was recorded by the Company in the fourth quarter of 2014 to recognize a portion of the unrecognized actuarial losses previously reflected in AOCI. This settlement charge is included in Other operating expenses in the Consolidated Statements of Income. In the second quarter of 2014, CNA eliminated certain postretirement medical benefits associated with the CNA Health and Group Benefits Program. This change was a negative plan amendment which resulted in an $86 million curtailment gain reported in Other operating expenses in the Consolidated Statements of Income. In connection with the plan amendment, CNA remeasured the plan benefit obligation which resulted in a decrease to the discount rate used to determine the benefit obligation from 3.6% to 3.1%. The following provides a reconciliation of benefit obligations and plan assets: Pension Benefits Other Postretirement Benefits 2016 2015 2016 2015 (In millions) Change in benefit obligation: Benefit obligation at January 1 $ 3,227 $ 3,446 $ 82 $ 97 Service cost 8 12 1 1 Interest cost 128 127 3 3 Plan participants’ contributions 5 5 Amendments/curtailments 1 (55 ) Actuarial (gain) loss 72 (96 ) (13 ) (11) Benefits paid from plan assets (188 ) (187 ) (12 ) (13) Settlements (101 ) (12 ) Foreign exchange (16 ) (8 ) Benefit obligation at December 31 3,131 3,227 66 82 Change in plan assets: Fair value of plan assets at January 1 2,500 2,713 86 87 Actual return on plan assets 211 (21 ) 3 2 Company contributions 19 15 4 5 Plan participants’ contributions 5 5 Benefits paid from plan assets (188 ) (187 ) (12 ) (13) Settlements (103 ) (12 ) Foreign exchange (16 ) (8 ) Fair value of plan assets at December 31 2,423 2,500 86 86 Funded status $ (708 ) $ (727 ) $ 20 $ 4 Amounts recognized in the Consolidated Balance Sheets consist of: Other assets $ 4 $ 11 $ 44 $ 38 Other liabilities (712 ) (738 ) (24 ) (34) Net amount recognized $ (708 ) $ (727 ) $ 20 $ 4 Amounts recognized in Accumulated other comprehensive income (loss), not yet recognized in net periodic (benefit) cost: Prior service credit $ (3 ) $ (5 ) $ (6 ) $ (9) Net actuarial loss 1,097 1,106 (2 ) 8 Net amount recognized $ 1,094 $ 1,101 $ (8 ) $ (1) Information for plans with projected and accumulated benefit obligations in excess of plan assets: Projected benefit obligation $ 3,103 $ 3,129 Accumulated benefit obligation 3,089 3,114 $ 24 $ 34 Fair value of plan assets 2,391 2,391 The accumulated benefit obligation for all defined benefit pension plans was $3.1 billion and $3.2 billion at December 31, 2016 and 2015. The Company employs a total return approach whereby a mix of equity and fixed maturity securities are used to maximize the long term return of plan assets for a prudent level of risk and to manage cash flows according to plan requirements. The target allocation of plan assets is 40% to 60% invested in equity securities and limited partnerships, with the remainder primarily invested in fixed maturity securities. The intent of this strategy is to minimize the Company’s expenses by generating investment returns that exceed the growth of the plan liabilities over the long run. Risk tolerance is established after careful consideration of the plan liabilities, plan funded status and corporate financial conditions. The investment portfolio contains a diversified blend of fixed maturity, equity and short term securities. Alternative investments, including limited partnerships, are used to enhance risk adjusted long term returns while improving portfolio diversification. At December 31, 2016, the Company had committed $119 million to future capital calls from various third party limited partnership investments in exchange for an ownership interest in the related partnerships. Investment risk is monitored through annual liability measurements, periodic asset/liability studies and quarterly investment portfolio reviews. The table below presents the estimated amounts to be recognized from AOCI into net periodic cost (benefit) during 2017. Other Pension Postretirement Benefits Benefits (In millions) Amortization of net actuarial (gain) loss $ 43 $ (1) Amortization of prior service credit (2) Total estimated amounts to be recognized $ 43 $ (3) The table below presents the estimated future minimum benefit payments at December 31, 2016. Other Pension Postretirement Expected future benefit payments Benefits Benefits (In millions) 2017 $ 217 $ 6 2018 210 6 2019 212 6 2020 214 5 2021 212 5 2022 – 2026 1,041 20 In 2017, it is expected that contributions of approximately $15 million will be made to pension plans and $3 million to postretirement health care and life insurance benefit plans. Pension plan assets measured at fair value on a recurring basis are summarized below. December 31, 2016 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 500 $ 10 $ 510 States, municipalities and political subdivisions 63 63 Asset-backed 186 186 Total fixed maturities $ - 749 10 759 Equity securities 404 105 509 Short term investments 18 35 53 Fixed income mutual funds 92 92 Other assets 15 37 52 Total limited partnerships measured at net asset value (a) 958 Total $ 529 $ 926 $ 10 $ 2,423 December 31, 2015 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 455 $ 10 $ 465 States, municipalities and political subdivisions 106 106 Asset-backed 219 219 Total fixed maturities $ - 780 10 790 Equity securities 373 107 480 Short term investments 30 28 58 Fixed income mutual funds 95 95 Other assets 52 52 Total limited partnerships measured at net asset value (a) 1,025 Total $ 498 $ 967 $ 10 $ 2,500 (a) In May of 2015, the FASB issued ASU 2015-17, 2015-07”), 2015-07 The limited partnership investments held within the plans are recorded at fair value, which represents the plans’ shares of the net asset value of each partnership, as determined by the general partner. Limited partnerships comprising 87% of the carrying value as of December 31, 2016 and 2015 employ hedge fund strategies that generate returns through investing in marketable securities in the public fixed income and equity markets and the remainder were primarily invested in private debt and equity. Within hedge fund strategies, approximately 57% were equity related, 38% pursued a multi-strategy approach and 5% were focused on distressed investments at December 31, 2016. For a discussion of the valuation methodologies used to measure fixed maturity securities, equities and short term investments, see Note 4. The tables below present reconciliations for all pension plan assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2016 and 2015: Net Actual Return on Assets Purchases, Net Transfers Balance at Still Held at Sold During Sales, and In (Out) of Balance at 2016 January 1, December 31, the Year Settlements Level 3 December 31, (In millions) Fixed maturity securities: Corporate and other bonds $ 10 $ 10 Total $ 10 $ - $ - $ - $ - $ 10 2015 (In millions) Fixed maturity securities: Corporate and other bonds $ 15 $ (5 ) $ 10 Total $ 15 $ - $ - $ - $ (5 ) $ 10 Other postretirement benefits plan assets measured at fair value on a recurring basis are summarized below. December 31, 2016 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 19 $ 19 States, municipalities and political subdivisions 44 44 Asset-backed 15 15 Total fixed maturities $ - 78 $ - 78 Short term investments 3 3 Fixed income mutual funds 5 5 Total $ 8 $ 78 $ - $ 86 December 31, 2015 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 17 $ 17 States, municipalities and political subdivisions 42 42 Asset-backed 19 19 Total fixed maturities $ - 78 $ - 78 Short term investments 3 3 Fixed income mutual funds 5 5 Total $ 8 $ 78 $ - $ 86 There were no Level 3 assets at December 31, 2016 and 2015. Savings Plans – The Company and its subsidiaries have several contributory savings plans which allow employees to make regular contributions based upon a percentage of their salaries. Matching contributions are made up to specified percentages of employees’ contributions. The contributions by the Company and its subsidiaries to these plans amounted to $107 million, $115 million and $125 million for the years ended December 31, 2016, 2015 and 2014. Stock-based Compensation – In 2016, shareholders approved the Loews Corporation 2016 Incentive Compensation Plan (the “2016 Loews Plan”) which replaced a previously existing plan. The aggregate number of shares of Loews common stock authorized under the 2016 Loews Plan is 6,000,000 shares, plus up to 3,000,000 shares that may be forfeited under the prior plan. The maximum number of shares of Loews common stock with respect to which awards may be granted to any individual in any calendar year is 500,000 shares. In accordance with the 2016 Loews Plan and the prior plan, the Company’s stock-based compensation consists of the following: SARs: Time-based Restricted Stock Units: Performance-based Restricted Stock Units: In 2016, the Company granted an aggregate of 367,908 RSUs and PSUs at a weighted average grant-date fair value of $39.74 per unit. 16,079 RSUs were forfeited during the year. 5,982,880 SARs were outstanding at December 31, 2016 with a weighted average exercise price of $40.90. The Company recognized compensation expense that decreased net income by $32 million, $14 million and $12 million for the years ended December 31, 2016, 2015 and 2014. Several of the Company’s subsidiaries also maintain their own stock-based compensation plans. Such amounts include the Company’s share of expense related to its subsidiaries’ plans.

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2016
Insurance [Abstract]
Reinsurance	CNA cedes insurance to reinsurers to limit its maximum loss, provide greater diversification of risk, minimize exposures on larger risks and to exit certain lines of business. The ceding of insurance does not discharge the primary liability of CNA. A credit exposure exists with respect to reinsurance ceded to the extent that any reinsurer is unable to meet its obligations. A collectability exposure also exists to the extent that the reinsurer disputes the liabilities assumed under reinsurance agreements. Property and casualty reinsurance coverages are tailored to the specific risk characteristics of each product line and CNA’s retained amount varies by type of coverage. Reinsurance contracts are purchased to protect specific lines of business such as property and workers’ compensation. Corporate catastrophe reinsurance is also purchased for property and workers’ compensation exposure. Currently most reinsurance contracts are purchased on an excess of loss basis. CNA also utilizes facultative reinsurance in certain lines. In addition, CNA assumes reinsurance, primarily through Hardy and as a member of various reinsurance pools and associations. The following table presents the amounts receivable from reinsurers: December 31 2016 2015 (In millions) Reinsurance receivables related to insurance reserves: Ceded claim and claim adjustment expenses $ 4,094 $ 4,087 Ceded future policy benefits 212 207 Reinsurance receivables related to paid losses 147 197 Reinsurance receivables 4,453 4,491 Less allowance for doubtful accounts 37 38 Reinsurance receivables, net of allowance for doubtful accounts $ 4,416 $ 4,453 CNA has established an allowance for doubtful accounts on reinsurance receivables related to credit risk. CNA reviews the allowance quarterly and adjusts the allowance as necessary to reflect changes in estimates of uncollectible balances. The allowance may also be reduced by write-offs of reinsurance receivable balances. CNA attempts to mitigate its credit risk related to reinsurance by entering into reinsurance arrangements with reinsurers that have credit ratings above certain levels and by obtaining collateral. On a limited basis, CNA may enter into reinsurance agreements with reinsurers that are not rated, primarily captive reinsurers. The primary methods of obtaining collateral are through reinsurance trusts, letters of credit and funds withheld balances. Such collateral was approximately $3.0 billion and $3.2 billion at December 31, 2016 and 2015. CNA’s largest recoverables from a single reinsurer, including ceded unearned premium reserves as of December 31, 2016 were approximately $2.4 billion from a subsidiary of Berkshire Hathaway Group, $350 million from the Gateway Rivers Insurance Company and $212 million from subsidiaries of Wilton Re. These amounts are substantially collaterized. The recoverable from the Berkshire Hathaway Group includes amounts related to third party reinsurance for which NICO has assumed the credit risk under the terms of the loss portfolio transfer as discussed in Note 8. The effects of reinsurance on earned premiums are presented in the following table: Direct Assumed Ceded Net Assumed/ (In millions) Year Ended December 31, 2016 Property and casualty $ 10,400 $ 258 $ 4,270 $ 6,388 4.0% Long term care 486 50 536 9.3 Earned premiums $ 10,886 $ 308 $ 4,270 $ 6,924 4.4% Year Ended December 31, 2015 Property and casualty $ 9,853 $ 274 $ 3,754 $ 6,373 4.3% Long term care 498 50 548 9.1 Earned premiums $ 10,351 $ 324 $ 3,754 $ 6,921 4.7% Year Ended December 31, 2014 Property and casualty $ 9,452 $ 277 $ 3,073 $ 6,656 4.2% Long term care 508 48 556 8.6 Earned premiums $ 9,960 $ 325 $ 3,073 $ 7,212 4.5% Included in the direct and ceded earned premiums for the years ended December 31, 2016, 2015 and 2014 are $3.9 billion, $3.3 billion and $2.6 billion related to property business that is 100% reinsured under a significant third party captive program. The third party captives that participate in this program are affiliated with the non-insurance Long term care premiums are from long duration contracts; property and casualty premiums are from short duration contracts. Insurance claims and policyholders’ benefits reported on the Consolidated Statements of Income are net of reinsurance recoveries of $3.0 billion, $2.6 billion and $1.4 billion for the years ended December 31, 2016, 2015 and 2014, including $2.6 billion, $2.3 billion and $1.5 billion related to the significant third party captive program discussed above. Reinsurance recoveries in 2014 were unfavorably affected by the commutation of a workers’ compensation reinsurance pool.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data (Unaudited)	2016 Quarter Ended Dec. 31 Sept. 30 June 30 March 31 (In millions, except per share data) Total revenues $ 3,338 $ 3,287 $ 3,307 $ 3,173 Net income (loss) (a) 290 327 (65 ) 102 Per share-basic and diluted 0.86 0.97 (0.19 ) 0.30 2015 Quarter Ended Dec. 31 Sept. 30 June 30 March 31 (In millions, except per share data) Total revenues $ 3,333 $ 3,169 $ 3,435 $ 3,478 Net income (loss) (b) (201 ) 182 170 109 Per share-basic and diluted (0.58 ) 0.50 0.46 0.29 The sum of the quarterly per share amounts may not equal per share amounts reported for year-to-date (a) Net loss for the second quarter of 2016 includes the impact of a $267 million asset impairment charge at Diamond Offshore. (b) Net loss for the fourth quarter of 2015 includes the impact of a $177 million charge related to recognition of a premium deficiency in CNA’s long term care business and a $182 million asset impairment charge at Diamond Offshore.

Legal Proceedings

Legal Proceedings	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings	CNA Financial In September of 2016, a class action lawsuit was filed against CCC, Continental Assurance Company (“CAC”), CNA, the Investment Committee of the CNA 401(k) Plus Plan, The Northern Trust Company and John Does 1-10 Other Litigation The Company and its subsidiaries are parties to other litigation arising in the ordinary course of business. The outcome of this litigation will not, in the opinion of management, materially affect the Company’s results of operations or equity.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	CNA Financial In the course of selling business entities and assets to third parties, CNA agreed to guarantee the performance of certain obligations of a previously owned subsidiary and to indemnify purchasers for losses arising out of breaches of representation and warranties with respect to the business entities or assets sold, including, in certain cases, losses arising from undisclosed liabilities or certain named litigation. Such guarantee and indemnification agreements in effect for sales of business entities, assets and third party loans may include provisions that survive indefinitely. As of December 31, 2016, the aggregate amount related to quantifiable guarantees was $375 million and the aggregate amount related to quantifiable indemnification agreements was $258 million. Should CNA be required to make payments under the guarantee, it would have the right to seek reimbursement in certain cases from an affiliate of a previously owned subsidiary. In addition, CNA has agreed to provide indemnification to third-party purchasers for certain losses associated with sold business entities or assets that are not limited by a contractual monetary amount. As of December 31, 2016, CNA had outstanding unlimited indemnifications in connection with the sales of certain of its business entities or assets that included tax liabilities arising prior to a purchaser’s ownership of an entity or asset, defects in title at the time of sale, employee claims arising prior to closing and in some cases losses arising from certain litigation and undisclosed liabilities. Certain provisions of the indemnification agreements survive indefinitely, while others survive until the applicable statutes of limitation expire, or until the agreed upon contract terms expire. CNA also provided guarantees, if the primary obligor fails to perform, to holders of structured settlement annuities provided by a previously owned subsidiary. As of December 31, 2016, the potential amount of future payments CNA could be required to pay under these guarantees was approximately $1.9 billion, which will be paid over the lifetime of the annuitants. CNA does not believe any payment is likely under these guarantees, as CNA is the beneficiary of a trust that must be maintained at a level that approximates the discounted reserves for these annuities. CNA recently identified rating errors related to its multi-peril package product within its Small Business unit. CNA recorded a charge which reduced earned premium by $16 million in anticipation of voluntarily issuing $30 million of premium refunds related to affected policies written from December 1, 2015 through December 31, 2016. Earned premium in 2017 will be negatively impacted by the portion of the $30 million that has not yet been earned through December 31, 2016 and the expected refund amount will increase further because of premium written in 2017, prior to CNA’s actions to correct its rating process. CNA is currently in dialogue with state regulators and providing them with details regarding the anticipated premium refunds and other corrective actions. CNA is reviewing other business lines to determine whether other similar issues exist. Fines or penalties related to the foregoing or further refunds which may be required are reasonably possible, but the amount of such losses, if any, cannot be estimated at this time.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	As discussed in Note 2, HighMount and the CAC business are classified and presented as discontinued operations. The Consolidated Statements of Income include discontinued operations of HighMount as follows: Year Ended December 31 2014 (In millions) Revenues: Other revenue, primarily operating $ 150 Total 150 Expenses: Other operating expenses Impairment of natural gas and oil properties 29 Operating 173 Interest 8 Total 210 Loss before income tax (60 ) Income tax benefit 4 Results of discontinued operations, net of income tax (56 ) Impairment loss, net of tax benefit of $62 (138 ) Loss from discontinued operations $ (194 ) In 2014, HighMount recorded ceiling test impairment charges of $29 million ($19 million after tax) related to the carrying value of its natural gas and oil properties. The 2014 write-down was primarily attributable to insufficient reserve additions from exploration activities due to variability in well performance where HighMount was testing different horizontal target zones and hydraulic fracture designs. Had the effects of HighMount’s cash flow hedges not been considered in calculating the ceiling limitation, the impairment would have been $29 million ($18 million after tax) for the year ended December 31, 2014. The Consolidated Statements of Income include discontinued operations of the CAC business as follows: Year Ended December 31 2014 (In millions) Revenues: Net investment income $ 94 Investment gains 3 Total 97 Expenses: Insurance claims and policyholders’ benefits 75 Other operating expenses 2 Total 77 Income before income tax 20 Income tax expense (6 ) Results of discontinued operations, net of income tax 14 Loss on sale, net of tax benefit of $40 (211 ) Amounts attributable to noncontrolling interests 20 Loss from discontinued operations $ (177 )

Segments

Segments	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segments	The Company has five reportable segments comprised of its four individual operating subsidiaries, CNA, Diamond Offshore, Boardwalk Pipeline and Loews Hotels; and the Corporate segment. Each of the operating subsidiaries are headed by a chief executive officer who is responsible for the operation of its business and has the duties and authority commensurate with that position. CNA’s core business is the sale of property and casualty insurance coverage primarily through a network of independent agents, brokers and managing general underwriters. CNA’s operations also include its long term care business that is in run-off, run-off, Diamond Offshore owns and operates offshore drilling rigs that are chartered on a contract basis for fixed terms by companies engaged in exploration and production of hydrocarbons. Offshore rigs are mobile units that can be relocated based on market demand. Diamond Offshore’s fleet consists of 24 drilling rigs, which consist of four drillships, 19 semisubmersible rigs, and one jack-up Boardwalk Pipeline is engaged in the interstate transportation and storage of natural gas and NGLs. This segment consists of interstate natural gas pipeline systems originating in the Gulf Coast region, Oklahoma and Arkansas, and extending north and east through the midwestern states of Tennessee, Kentucky, Illinois, Indiana and Ohio, natural gas storage facilities in four states and NGL pipelines and storage facilities in Louisiana and Texas, with approximately 14,365 miles of pipeline. Loews Hotels operates a chain of 25 hotels, 24 of which are in the United States and one of which is in Canada. The Corporate segment consists of investment income from the Parent Company’s cash and investments, interest expense and other unallocated expenses. Purchase accounting adjustments have been pushed down to the appropriate subsidiary. The accounting policies of the segments are the same as those described in the summary of significant accounting policies in Note 1. In the following tables certain financial measures are presented to provide information used by management to monitor the Company’s operating performance. These schedules present the reportable segments of the Company and their contribution to the consolidated financial statements. Amounts presented will not necessarily be the same as those in the individual financial statements of the Company’s subsidiaries due to adjustments for purchase accounting, income taxes and noncontrolling interests. Statements of Income and Total assets by segment are presented in the following tables. Year Ended December 31, 2016 CNA Diamond Boardwalk Loews Corporate Total (In millions) Revenues: Insurance premiums $ 6,924 $ 6,924 Net investment income 1,988 $ 1 $ 146 2,135 Investment gains (losses) 62 (12) 50 Contract drilling revenues 1,525 1,525 Other revenues 410 75 $ 1,316 $ 667 3 2,471 Total 9,384 1,589 1,316 667 149 13,105 Expenses: Insurance claims and policyholders’ benefits 5,283 5,283 Amortization of deferred acquisition costs 1,235 1,235 Contract drilling expenses 772 772 Other operating expenses 1,558 1,198 835 621 131 4,343 Interest 167 90 183 24 72 536 Total 8,243 2,060 1,018 645 203 12,169 Income (loss) before income tax 1,141 (471 ) 298 22 (54) 936 Income tax (expense) benefit (279) 111 (61) (10 ) 19 (220) Net income (loss) 862 (360 ) 237 12 (35) 716 Amounts attributable to noncontrolling interests (88) 174 (148) (62) Net income (loss) attributable to Loews Corporation $ 774 $ (186 ) $ 89 $ 12 $ (35) $ 654 December 31, 2016 (In millions) Total assets $ 55,207 $ 6,371 $ 8,706 $ 1,498 $ 4,812 $ 76,594 Year Ended December 31, 2015 CNA Diamond Boardwalk Loews Corporate Total (In millions) Revenues: Insurance premiums $ 6,921 $ 6,921 Net investment income 1,840 $ 3 $ 1 $ 22 1,866 Investment losses (71) (71) Contract drilling revenues 2,360 2,360 Other revenues 411 65 1,253 $ 604 6 2,339 Total 9,101 2,428 1,254 604 28 13,415 Expenses: Insurance claims and policyholders’ benefits 5,384 5,384 Amortization of deferred acquisition costs 1,540 1,540 Contract drilling expenses 1,228 1,228 Other operating expenses 1,469 1,508 851 555 116 4,499 Interest 155 94 176 21 74 520 Total 8,548 2,830 1,027 576 190 13,171 Income (loss) before income tax 553 (402 ) 227 28 (162) 244 Income tax (expense) benefit (71) 117 (46) (16 ) 59 43 Net income (loss) 482 (285 ) 181 12 (103) 287 Amounts attributable to noncontrolling interests (49) 129 (107) (27) Net income (loss) attributable to Loews Corporation $ 433 $ (156 ) $ 74 $ 12 $ (103) $ 260 December 31, 2015 (In millions) Total assets $ 55,025 $ 7,154 $ 8,365 $ 1,416 $ 4,046 $ 76,006 Year Ended December 31, 2014 CNA Diamond Boardwalk Loews Corporate Total (In millions) Revenues: Insurance premiums $ 7,212 $ 7,212 Net investment income 2,067 $ 1 $ 1 $ 94 2,163 Investment gains 54 54 Contract drilling revenues 2,737 2,737 Other revenues 359 87 1,235 $ 475 3 2,159 Total 9,692 2,825 1,236 475 97 14,325 Expenses: Insurance claims and policyholders’ benefits 5,591 5,591 Amortization of deferred acquisition costs 1,317 1,317 Contract drilling expenses 1,524 1,524 Other operating expenses 1,386 725 931 440 103 3,585 Interest 183 62 165 14 74 498 Total 8,477 2,311 1,096 454 177 12,515 Income (loss) before income tax 1,215 514 140 21 (80) 1,810 Income tax (expense) benefit (322) (142 ) (11) (10 ) 28 (457) Income (loss) from continuing operations 893 372 129 11 (52) 1,353 Discontinued operations, net (197) (194) (391) Net income (loss) 696 372 129 11 (246) 962 Amounts attributable to noncontrolling interests (71) (189 ) (111) (371) Net income (loss) attributable to Loews Corporation $ 625 $ 183 $ 18 $ 11 $ (246) $ 591

Schedule I - Condensed Financia

Schedule I - Condensed Financial Information of Registrant	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule I - Condensed Financial Information of Registrant	Condensed Financial Information of Registrant LOEWS CORPORATION BALANCE SHEETS ASSETS December 31 2016 2015 (In millions) Current assets, principally investment in short term instruments $ 3,096 $ 2,888 Investments in securities 1,931 1,487 Investments in capital stocks of subsidiaries, at equity 15,114 15,129 Other assets 389 97 Total assets $ 20,530 $ 19,601 LIABILITIES AND SHAREHOLDERS’ EQUITY Current liabilities $ 140 $ 260 Short term debt 400 Long term debt 1,775 1,279 Deferred income tax and other 452 101 Total liabilities 2,367 2,040 Shareholders’ equity 18,163 17,561 Total liabilities and shareholders’ equity $ 20,530 $ 19,601 STATEMENTS OF INCOME AND COMPREHENSIVE INCOME (LOSS) Year Ended December 31 2016 2015 2014 (In millions) Revenues: Equity in income of subsidiaries (a) $ 655 $ 302 $ 1,034 Interest and other 165 74 92 Total 820 376 1,126 Expenses: Administrative 127 108 97 Interest 72 74 74 Total 199 182 171 Income before income tax 621 194 955 Income tax benefit 33 66 7 Income from continuing operations 654 260 962 Discontinued operations, net (371) Net income 654 260 591 Equity in other comprehensive income (loss) of subsidiaries 134 (638 ) (59) Total comprehensive income (loss) $ 788 $ (378 ) $ 532 Condensed Financial Information of Registrant LOEWS CORPORATION STATEMENTS OF CASH FLOWS Year Ended December 31 2016 2015 2014 (In millions) Operating Activities: Net income $ 654 $ 260 $ 591 Adjustments to reconcile net income to net cash provided (used) by operating activities: Equity method investees 115 488 95 Provision for deferred income taxes 10 113 (62 ) Changes in operating assets and liabilities, net: Receivables 2 (6 ) (2 ) Accounts payable and accrued liabilities 52 71 200 Trading securities (614 ) 718 (269 ) Other, net (15 ) (8 ) (23 ) 204 1,636 530 Investing Activities: Investments in and advances to subsidiaries 50 (285 ) 130 Change in investments, primarily short term (127 ) 7 Other (2 ) (4 ) (2 ) (79 ) (289 ) 135 Financing Activities: Dividends paid (84 ) (90 ) (95 ) Issuance of common stock 7 6 Purchases of treasury shares (134 ) (1,265 ) (622 ) Principal payments in debt (400 ) Issuance of debt 495 Other (2 ) 1 2 (125 ) (1,347 ) (709 ) Net change in cash - - (44 ) Cash, beginning of year 44 Cash, end of year $ - $ - $ - (a) Cash dividends paid to the Company by affiliates amounted to $780, $816 and $782 for the years ended December 31, 2016, 2015 and 2014.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2016
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	LOEWS CORPORATION AND SUBSIDIARIES Valuation and Qualifying Accounts Column A Column B Column C Column D Column E Additions Balance at Charged to Charged Balance at Beginning Costs and to Other End of Description of Period Expenses Accounts Deductions Period (In millions) For the Year Ended December 31, 2016 Deducted from assets: Allowance for doubtful accounts $ 96 $ - $ - $ 6 $ 90 Total $ 96 $ - $ - $ 6 $ 90 For the Year Ended December 31, 2015 Deducted from assets: Allowance for doubtful accounts $ 117 $ - $ - $ 21 $ 96 Total $ 117 $ - $ - $ 21 $ 96 For the Year Ended December 31, 2014 Deducted from assets: Allowance for doubtful accounts $ 329 $ - $ - $ 212 $ 117 Total $ 329 $ - $ - $ 212 $ 117

Schedule V - Supplemental Infor

Schedule V - Supplemental Information Concerning Property and Casualty Insurance Operations	12 Months Ended
	Dec. 31, 2016
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]
Schedule V - Supplemental Information Concerning Property and Casualty Insurance Operations	LOEWS CORPORATION AND SUBSIDIARIES Supplemental Information Concerning Property and Casualty Insurance Operations Consolidated Property and Casualty Operations December 31 2016 2015 (In millions) Deferred acquisition costs $ 599 $ 598 Reserves for unpaid claim and claim adjustment expenses 22,343 22,663 Discount deducted from claim and claim adjustment expense reserves above (based on interest rates ranging from 3.5% to 8.0%) 1,572 1,534 Unearned premiums 3,762 3,671 Year Ended December 31 2016 2015 2014 (In millions) Net written premiums $ 6,988 $ 6,962 $ 7,088 Net earned premiums 6,924 6,921 7,212 Net investment income 1,952 1,807 2,031 Incurred claim and claim adjustment expenses related to current year 5,025 4,934 5,043 Incurred claim and claim adjustment expenses related to prior years (342 ) (255 ) (39) Amortization of deferred acquisition costs 1,235 1,540 1,317 Paid claim and claim adjustment expenses 5,134 4,945 5,297

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation
Principles of consolidation	Principles of consolidation
Accounting estimates	Accounting estimates
Investments	Investments available-for-sale available-for-sale The cost of fixed maturity securities classified as available-for-sale To the extent that unrealized gains on fixed income securities supporting long term care products and structured settlements not funded by annuities would result in a premium deficiency if those gains were realized, a related increase in Insurance reserves is recorded, net of tax and noncontrolling interests, as a reduction of net unrealized gains through Other comprehensive income (“Shadow Adjustments”). Shadow Adjustments decreased $87 million (after tax and noncontrolling interests) and $159 million (after tax and noncontrolling interests) for the years ended December 31, 2016 and 2015. As of December 31, 2016 and 2015, net unrealized gains on investments included in Accumulated other comprehensive income (“AOCI”) were correspondingly reduced by Shadow Adjustments of $909 million and $996 million (after tax and noncontrolling interests). For asset-backed securities included in fixed maturity securities, the Company recognizes income using an effective yield based on anticipated prepayments and the estimated economic life of the securities. When estimates of prepayments change, the effective yield is recalculated to reflect actual payments to date and anticipated future payments. The amortized cost of high credit quality fixed rate securities is adjusted to the amount that would have existed had the new effective yield been applied since the acquisition of the securities. Such adjustments are reflected in Net investment income on the Consolidated Statements of Income. Interest income on lower rated and variable rate securities is determined using the prospective yield method. The Company’s carrying value of investments in limited partnerships is its share of the net asset value of each partnership, as determined by the general partner. Certain partnerships for which results are not available on a timely basis are reported on a lag, primarily three months or less. These investments are accounted for under the equity method and changes in net asset values are recorded within Net investment income on the Consolidated Statements of Income. Investments in derivative securities are carried at fair value with changes in fair value reported as a component of Investment gains (losses), Income (loss) from trading portfolio, or Other comprehensive income (loss), depending on their hedge designation. A derivative is typically defined as an instrument whose value is “derived” from an underlying instrument, index or rate, has a notional amount, requires little or no initial investment and can be net settled. Derivatives include, but are not limited to, the following types of investments: interest rate swaps, interest rate caps and floors, put and call options, warrants, futures, forwards, commitments to purchase securities, credit default swaps and combinations of the foregoing. Derivatives embedded within non-derivative A security is impaired if the fair value of the security is less than its cost adjusted for accretion, amortization and previously recorded other-than-temporary impairment (“OTTI”) losses, otherwise defined as an unrealized loss. When a security is impaired, the impairment is evaluated to determine whether it is temporary or other-than-temporary. Significant judgment is required in the determination of whether an OTTI loss has occurred for a security. CNA follows a consistent and systematic process for determining and recording an OTTI loss. CNA has established a committee responsible for the OTTI process referred to as the Impairment Committee. The Impairment Committee is responsible for evaluating all securities in an unrealized loss position on at least a quarterly basis. The Impairment Committee’s assessment of whether an OTTI loss has occurred incorporates both quantitative and qualitative information. Fixed maturity securities that CNA intends to sell, or it more likely than not will be required to sell before recovery of amortized cost, are considered to be other-than-temporarily impaired and the entire difference between the amortized cost basis and fair value of the security is recognized as an OTTI loss in earnings. The remaining fixed maturity securities in an unrealized loss position are evaluated to determine if a credit loss exists. The factors considered by the Impairment Committee include: (i) the financial condition and near term and long term prospects of the issuer, (ii) whether the debtor is current on interest and principal payments, (iii) credit ratings of the securities and (iv) general market conditions and industry or sector specific outlook. CNA also considers results and analysis of cash flow modeling for asset-backed securities, and when appropriate, other fixed maturity securities. The focus of the analysis for asset-backed securities is on assessing the sufficiency and quality of underlying collateral and timing of cash flows based on scenario tests. If the present value of the modeled expected cash flows equals or exceeds the amortized cost of a security, no credit loss is judged to exist and the asset-backed security is deemed to be temporarily impaired. If the present value of the expected cash flows is significantly less than amortized cost, the security is judged to be other-than-temporarily impaired for credit reasons and that shortfall, referred to as the credit component, is recognized as an OTTI loss in earnings. The difference between the adjusted amortized cost basis and fair value, referred to as the non-credit non-credit CNA performs the discounted cash flow analysis using stressed scenarios to determine future expectations regarding recoverability. Significant assumptions enter into these cash flow projections including delinquency rates, probable risk of default, loss severity upon a default, over collateralization and interest coverage triggers and credit support from lower level tranches. CNA applies the same impairment model as described above for the majority of its non-redeemable
Joint venture investments	Joint venture investments The following tables present summarized financial information for these joint ventures: Year Ended December 31 2016 2015 (In millions) Total assets $ 1,749 $ 1,577 Total liabilities 1,444 1,231 Year Ended December 31 2016 2015 2014 Revenues $ 693 $ 606 $ 491 Net income 80 71 32
Hedging	Hedging
Securities lending activities	Securities lending activities Securities lending is typically done on a matched-book basis where the collateral is invested to substantially match the term of the loan. This matching of terms tends to limit risk. In accordance with the Company’s lending agreements, securities on loan are returned immediately to the Company upon notice. Collateral is not reflected as an asset of the Company. There was no collateral held at December 31, 2016 and 2015.
Revenue recognition	Revenue recognition Insurance receivables include balances due currently or in the future, including amounts due from insureds related to losses under high deductible policies, and are presented at unpaid balances, net of an allowance for doubtful accounts. Amounts are considered past due based on policy payment terms. The allowance is determined based on periodic evaluations of aged receivables, management’s experience and current economic conditions. Insurance receivables and any related allowance are written off after collection efforts are exhausted or a negotiated settlement is reached. Property and casualty contracts that are retrospectively rated contain provisions that result in an adjustment to the initial policy premium depending on the contract provisions and loss experience of the insured during the experience period. For such contracts, CNA estimates the amount of ultimate premiums that it may earn upon completion of the experience period and recognizes either an asset or a liability for the difference between the initial policy premium and the estimated ultimate premium. CNA adjusts such estimated ultimate premium amounts during the course of the experience period based on actual results to date. The resulting adjustment is recorded as either a reduction of or an increase to the earned premiums for the period. Contract drilling revenue from dayrate drilling contracts is recognized as services are performed. In connection with such drilling contracts, Diamond Offshore may receive fees (either lump-sum Revenues from transportation and storage services are recognized in the period the service is provided based on contractual terms and the related transported and stored volumes. The majority of Boardwalk Pipeline’s operating subsidiaries are subject to Federal Energy Regulatory Commission (“FERC”) regulations and, accordingly, certain revenues collected may be subject to possible refunds to its customers. An estimated refund liability is recorded considering regulatory proceedings, advice of counsel and estimated total exposure.
Claim and claim adjustment expense reserves	Claim and claim adjustment expense reserves Claim and claim adjustment expense reserves are presented net of anticipated amounts due from insureds related to losses under deductible policies of $1.2 billion as of December 31, 2016 and 2015. A significant portion of these amounts are supported by collateral. CNA also has an allowance for uncollectible deductible amounts, which is presented as a component of the allowance for doubtful accounts included in Receivables on the Consolidated Balance Sheets. Structured settlements have been negotiated for certain property and casualty insurance claims. Structured settlements are agreements to provide fixed periodic payments to claimants. CNA’s obligations for structured settlements not funded by annuities are included in claim and claim adjustment expense reserves and carried at present values determined using interest rates ranging from 5.5% to 8.0% at December 31, 2016 and 2015. At December 31, 2016 and 2015, the discounted reserves for unfunded structured settlements were $544 million and $560 million, net of discount of $841 million and $880 million. For the years ended December 31, 2016, 2015 and 2014, the amount of interest recognized on the discounted reserves of unfunded structured settlements was $42 million, $42 million and $43 million. This interest accretion is presented as a component of Insurance claims and policyholders’ benefits on the Consolidated Statements of Income but is excluded from the disclosure of prior year development. Workers’ compensation lifetime claim reserves are calculated using mortality assumptions determined through statutory regulation and economic factors. At December 31, 2016 and 2015, workers’ compensation lifetime claim reserves are discounted at a 3.5% interest rate. As of December 31, 2016 and 2015, the discounted reserves for workers’ compensation lifetime claim reserves were $371 million and $396 million, net of discount of $202 million and $218 million. For the years ended December 31, 2016, 2015 and 2014, the amount of interest accretion recognized on the discounted reserves of workers’ compensation lifetime claim reserves was $17 million, $20 million and $22 million. Long term care claim reserves are calculated using mortality and morbidity assumptions based on CNA and industry experience. Long term care claim reserves are discounted at interest rates ranging from 4.5% to 6.8% at December 31, 2016 and 2015. At December 31, 2016 and 2015, such discounted reserves totaled $2.2 billion, net of discount of $529 million and $435 million.
Future policy benefits reserves	Future policy benefits reserves
Guaranty fund and other insurance-related assessments	Guaranty fund and other insurance-related assessments
Reinsurance	Reinsurance Reinsurance receivables related to paid losses are presented at unpaid balances. Reinsurance receivables related to unpaid losses are estimated in a manner consistent with claim and claim adjustment expense reserves or future policy benefits reserves. Reinsurance receivables are reported net of an allowance for doubtful accounts on the Consolidated Balance Sheets. The cost of reinsurance is primarily accounted for over the life of the underlying reinsured policies using assumptions consistent with those used to account for the underlying policies or over the reinsurance contract period. The ceding of insurance does not discharge the primary liability of CNA. CNA has established an allowance for doubtful accounts on reinsurance receivables which relates to both amounts already billed on ceded paid losses as well as ceded reserves that will be billed when losses are paid in the future. The allowance for doubtful accounts on reinsurance receivables is estimated on the basis of periodic evaluations of balances due from reinsurers, reinsurer solvency, management’s experience and current economic conditions. Reinsurer financial strength ratings are updated and reviewed on an annual basis or sooner if CNA becomes aware of significant changes related to a reinsurer. Because billed receivables generally approximate 3% or less of total reinsurance receivables, the age of the reinsurance receivables related to paid losses is not a significant input into the allowance analysis. Changes in the allowance for doubtful accounts on reinsurance receivables are presented as a component of Insurance claims and policyholders’ benefits on the Consolidated Statements of Income. Amounts are considered past due based on the reinsurance contract terms. Reinsurance receivables related to paid losses and any related allowance are written off after collection efforts have been exhausted or a negotiated settlement is reached with the reinsurer. Reinsurance receivables related to paid losses from insolvent insurers are written off when the settlement due from the estate can be reasonably estimated. At the time reinsurance receivables related to paid losses are written off, any required adjustment to reinsurance receivables related to unpaid losses is recorded as a component of Insurance claims and policyholders’ benefits on the Consolidated Statements of Income. Reinsurance contracts that do not effectively transfer the economic risk of loss on the underlying policies are recorded using the deposit method of accounting, which requires that premium paid or received by the ceding company or assuming company be accounted for as a deposit asset or liability. CNA had $3 million recorded as deposit assets at December 31, 2016 and 2015, and $6 million and $8 million recorded as deposit liabilities as of December 31, 2016 and 2015. Income on reinsurance contracts accounted for under the deposit method is recognized using an effective yield based on the anticipated timing of payments and the remaining life of the contract. When the anticipated timing of payments changes, the effective yield is recalculated to reflect actual payments to date and the estimated timing of future payments. The deposit asset or liability is adjusted to the amount that would have existed had the new effective yield been applied since the inception of the contract. A loss portfolio transfer is a retroactive reinsurance contract. If the cumulative claim and allocated claim adjustment expenses ceded under a loss portfolio transfer exceed the consideration paid, the resulting gain from such excess is deferred and amortized into earnings in future periods in proportion to actual recoveries under the loss portfolio transfer. In any period in which there is a gain position and a revised estimate of claim and allocated claim adjustment expenses, a portion of the deferred gain is cumulatively recognized in earnings as if the revised estimate was available at the inception date of the loss portfolio transfer.
Deferred acquisition costs	Deferred acquisition costs CNA evaluates deferred acquisition costs for recoverability. Anticipated investment income is considered in the determination of the recoverability of deferred acquisition costs. Adjustments, if necessary, are recorded in current period results of operations. Deferred acquisition costs related to long term care contracts issued prior to January 1, 2004 include costs which vary with and are primarily related to the acquisition of business. As noted under Future policy benefits reserves, all of the long term care deferred acquisition costs of $289 million were written off as of December 31, 2015 in recognition of a premium deficiency.
Investments in life settlement contracts and related revenue recognition	Investments in life settlement contracts and related revenue recognition CNA accounts for its investments in life settlement contracts using the fair value method. Under the fair value method, each life settlement contract is carried at its fair value at the end of each reporting period. The change in fair value estimated through CNA’s internal valuation process, life insurance proceeds received and periodic maintenance costs, such as premiums, necessary to keep the underlying policy in force, are recorded in Other revenues on the Consolidated Statements of Income. The increase in fair value recognized in Other revenues for the years ended December 31, 2016, 2015 and 2014 on contracts still held was $7 million, $1 million and $8 million. The gains recognized during the years ended December 31, 2016, 2015 and 2014 on contracts that settled were $8 million, $24 million and $25 million. In December of 2016, CNA reached agreement on terms to sell the entire portfolio of life settlement contracts to a third party. CNA expects to consummate this transaction in 2017. As a result, the portfolio was determined to be held for sale as of December 31, 2016. Therefore, the contracts were measured at the lower of the carrying amount or the fair value per the agreed terms, resulting in a $10 million loss recognized within Other operating expenses. As of December 31, 2016, there were 526 life settlement contracts with a total fair value of $58 million, included in Other assets on the Consolidated Balance Sheets, and a face value of $285 million.
Goodwill	Goodwill
Property, plant and equipment	Property, plant and equipment The principal service lives used in computing provisions for depreciation are as follows: Years Pipeline equipment 30 to 50 Offshore drilling equipment 15 to 30 Other 3 to 40
Impairment of long-lived assets	Impairment of long-lived assets
Income taxes	Income taxes The Company recognizes uncertain tax positions that it has taken or expects to take on a tax return. The tax benefit of a qualifying position is the largest amount of tax benefit that is greater than 50% likely of being realized upon ultimate settlement with a taxing authority having full knowledge of all relevant information. See Note 10 for additional information on the provision for income taxes.
Pension and postretirement benefits	Pension and postretirement benefits
Stock-based compensation	Stock-based compensation
Net income per share	Net income per share For each of the years ended December 31, 2016, 2015 and 2014, approximately 0.4 million, 0.3 million and 0.6 million potential shares attributable to issuances and exercises under the Loews Corporation 2016 Incentive Compensation Plan and the prior plan were included in the calculation of diluted net income per share. For those same periods, approximately 3.7 million, 4.8 million and 2.3 million shares attributable to employee stock-based compensation awards were not included in the calculation of diluted net income per share because the effect would have been antidilutive.
Foreign currency	Foreign currency
Regulatory accounting	Regulatory accounting
Supplementary cash flow information	Supplementary cash flow information
Accounting changes	Accounting changes – 2015-03, 835-30): Simplifying In May of 2015, the FASB issued ASU 2015-09, –
Recently issued ASUs	Recently issued ASUs – 2014-09, In January of 2016, the FASB issued ASU 2016-01, – 825-10): In February of 2016, the FASB issued ASU 2016-02, 2014-09. In June of 2016, the FASB issued ASU 2016-13, available-for-sale available-for-sale

Summary of Significant Accoun32

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Financial Information for Joint Ventures	The following tables present summarized financial information for these joint ventures: Year Ended December 31 2016 2015 (In millions) Total assets $ 1,749 $ 1,577 Total liabilities 1,444 1,231 Year Ended December 31 2016 2015 2014 Revenues $ 693 $ 606 $ 491 Net income 80 71 32
Principal Service Lives	The principal service lives used in computing provisions for depreciation are as follows: Years Pipeline equipment 30 to 50 Offshore drilling equipment 15 to 30 Other 3 to 40

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Text Block [Abstract]
Net Investment Income and Investment Gains (Losses)	Net investment income is as follows: Year Ended December 31 2016 2015 2014 (In millions) Fixed maturity securities $ 1,819 $ 1,751 $ 1,803 Limited partnership investments 199 119 304 Short term investments 9 11 4 Equity securities 10 12 12 Income from trading portfolio (a) 112 2 64 Other 45 34 34 Total investment income 2,194 1,929 2,221 Investment expenses (59) (63) (58) Net investment income $ 2,135 $ 1,866 $ 2,163 (a) Includes net unrealized gains (losses) related to changes in fair value on trading securities still held of $44, $(46) and $42 for the years ended December 31, 2016, 2015 and 2014. As of December 31, 2016, the Company held no non-income non-income Investment gains (losses) are as follows: Year Ended December 31 2016 2015 2014 (In millions) Fixed maturity securities $ 54 $ (66 ) $ 41 Equity securities (5 ) (23 ) 1 Derivative instruments (2 ) 10 (1) Short term investments and other 3 8 13 Investment gains (losses) (a) $ 50 $ (71 ) $ 54 (a) Includes gross realized gains of $209, $133 and $178 and gross realized losses of $160, $222 and $136 on available-for-sale
Schedule of Net Change in Unrealized Gains (Losses) on Available-for-Sale Investments	Net change in unrealized gains (losses) on available-for-sale Year Ended December 31 2016 2015 2014 (In millions) Fixed maturity securities $ 225 $ (1,114 ) $ 1,511 Equity securities (2 ) (6 ) 6 Other 1 1 Total net change in unrealized gains (losses) on available-for-sale $ 224 $ (1,119 ) $ 1,517
Components of OTTI Losses Recognized in Earnings by Asset Type	The components of OTTI losses recognized in earnings by asset type are as follows: Year Ended December 31 2016 2015 2014 (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 59 $ 104 $ 18 States, municipalities and political subdivisions 18 46 Asset-backed: Residential mortgage-backed 10 8 5 Other asset-backed 3 1 1 Total asset-backed 13 9 6 Total fixed maturities available-for-sale 72 131 70 Equity securities available-for-sale 9 25 7 Net OTTI losses recognized in earnings $ 81 $ 156 $ 77
Amortized Cost and Fair Values of Securities	The amortized cost and fair values of securities are as follows: Cost or Gross Gross Unrealized Amortized Unrealized Unrealized Estimated OTTI Losses December 31, 2016 Cost Gains Losses Fair Value (Gains) (In millions) Fixed maturity securities: Corporate and other bonds $ 17,711 $ 1,323 $ 76 $ 18,958 $ (1) States, municipalities and political subdivisions 12,060 1,213 33 13,240 (16) Asset-backed: Residential mortgage-backed 5,004 120 51 5,073 (28) Commercial mortgage-backed 2,016 48 24 2,040 Other asset-backed 1,022 8 5 1,025 Total asset-backed 8,042 176 80 8,138 (28) U.S. Treasury and obligations of government-sponsored enterprises 83 10 93 Foreign government 435 13 3 445 Redeemable preferred stock 18 1 19 Fixed maturities available-for-sale 38,349 2,736 192 40,893 (45) Fixed maturities, trading 598 3 601 Total fixed maturities 38,947 2,739 192 41,494 (45) Equity securities: Common stock 13 6 19 Preferred stock 93 2 4 91 Equity securities available-for-sale 106 8 4 110 - Equity securities, trading 465 60 86 439 Total equity securities 571 68 90 549 - Total $ 39,518 $ 2,807 $ 282 $ 42,043 $ (45) December 31, 2015 (In millions) Fixed maturity securities: Corporate and other bonds $ 17,097 $ 1,019 $ 347 $ 17,769 States, municipalities and political subdivisions 11,729 1,453 8 13,174 $ (4) Asset-backed: Residential mortgage-backed 4,935 154 17 5,072 (37) Commercial mortgage-backed 2,154 55 12 2,197 Other asset-backed 923 6 8 921 Total asset-backed 8,012 215 37 8,190 (37) U.S. Treasury and obligations of government-sponsored enterprises 62 5 67 Foreign government 334 13 1 346 Redeemable preferred stock 33 2 35 Fixed maturities available-for-sale 37,267 2,707 393 39,581 (41) Fixed maturities, trading 140 20 120 Total fixed maturities 37,407 2,707 413 39,701 (41) Equity securities: Common stock 46 3 1 48 Preferred stock 145 7 3 149 Equity securities available-for-sale 191 10 4 197 - Equity securities, trading 633 56 134 555 Total equity securities 824 66 138 752 - Total $ 38,231 $ 2,773 $ 551 $ 40,453 $ (41)
Securities Available-for-Sale in Gross Unrealized Loss Position	The available-for-sale Less than 12 Months 12 Months or Longer Total Gross Gross Gross Estimated Unrealized Estimated Unrealized Estimated Unrealized December 31, 2016 Fair Value Losses Fair Value Losses Fair Value Losses (In millions) Fixed maturity securities: Corporate and other bonds $ 2,615 $ 61 $ 254 $ 15 $ 2,869 $ 76 States, municipalities and political subdivisions 959 32 23 1 982 33 Asset-backed: Residential mortgage-backed 2,136 44 201 7 2,337 51 Commercial mortgage-backed 756 22 69 2 825 24 Other asset-backed 398 5 24 422 5 Total asset-backed 3,290 71 294 9 3,584 80 U.S. Treasury and obligations of government-sponsored enterprises 5 5 Foreign government 108 3 108 3 Total fixed maturity securities 6,977 167 571 25 7,548 192 Equity securities 12 13 4 25 4 Total $ 6,989 $ 167 $ 584 $ 29 $ 7,573 $ 196 December 31, 2015 (In millions) Fixed maturity securities: Corporate and other bonds $ 4,882 $ 302 $ 174 $ 45 $ 5,056 $ 347 States, municipalities and political subdivisions 338 8 75 413 8 Asset-backed: Residential mortgage-backed 963 9 164 8 1,127 17 Commercial mortgage-backed 652 10 96 2 748 12 Other asset-backed 552 8 5 557 8 Total asset-backed 2,167 27 265 10 2,432 37 U.S. Treasury and obligations of government-sponsored enterprises 4 4 Foreign government 54 1 54 1 Redeemable preferred stock 3 3 Total fixed maturity securities 7,448 338 514 55 7,962 393 Equity securities: Common stock 3 1 3 1 Preferred stock 13 3 13 3 Total equity securities 16 4 16 4 Total $ 7,464 $ 342 $ 514 $ 55 $ 7,978 $ 397
Pretax Credit Loss Component Reflected in Retained Earnings on Fixed Maturity Securities	The following table presents the activity related to the pretax credit loss component reflected in Retained earnings on fixed maturity securities still held at December 31, 2016, 2015 and 2014 for which a portion of an OTTI loss was recognized in Other comprehensive income. Year Ended December 31 2016 2015 2014 (In millions) Beginning balance of credit losses on fixed maturity securities $ 53 $ 62 $ 74 Reductions for securities sold during the period (16 ) (9 ) (9 ) Reductions for securities the Company intends to sell or more likely than not will be required to sell (1 ) (3 ) Ending balance of credit losses on fixed maturity securities $ 36 $ 53 $ 62
Available-for-Sale Fixed Maturity Securities by Contractual Maturity	The following table presents available-for-sale December 31 2016 2015 Cost or Cost or Amortized Estimated Amortized Estimated Cost Fair Value Cost Fair Value (In millions) Due in one year or less $ 1,779 $ 1,828 $ 1,574 $ 1,595 Due after one year through five years 7,566 7,955 7,738 8,082 Due after five years through ten years 15,892 16,332 14,652 14,915 Due after ten years 13,112 14,778 13,303 14,989 Total $ 38,349 $ 40,893 $ 37,267 $ 39,581
Summary of Aggregate Contractual or Notional Amount and Estimated Fair Value Related to Derivative Financial Instruments	The following tables present the aggregate contractual or notional amount and estimated fair value related to derivative financial instruments. December 31 2016 2015 Contractual/ Contractual/ Notional Estimated Fair Value Notional Estimated Fair Value Amount Asset (Liability) Amount Asset (Liability) (In millions) Without hedge designation: Equity markets: Options – purchased $ 223 $ 14 $ 501 $ 16 – written 267 $ (8) 614 $ (28) Futures – long 312 (1) Futures – short 225 1 Interest rate risk: Futures – long 63 Foreign exchange: Currency forwards – long 133 2 – short 152 Currency options – long 550 7 Commodities: Futures – long 42 Embedded derivative on funds withheld liability 174 3 179 5

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	Assets and liabilities measured at fair value on a recurring basis are summarized in the tables below: December 31, 2016 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 18,828 $ 130 $ 18,958 States, municipalities and political subdivisions 13,239 1 13,240 Asset-backed: Residential mortgage-backed 4,944 129 5,073 Commercial mortgage-backed 2,027 13 2,040 Other asset-backed 968 57 1,025 Total asset-backed 7,939 199 8,138 U.S. Treasury and obligations of government-sponsored enterprises $ 93 93 Foreign government 445 445 Redeemable preferred stock 19 19 Fixed maturities available-for-sale 112 40,451 330 40,893 Fixed maturities trading 595 6 601 Total fixed maturities $ 112 $ 41,046 $ 336 $ 41,494 Equity securities available-for-sale $ 91 $ 19 $ 110 Equity securities trading 438 1 439 Total equity securities $ 529 $ - $ 20 $ 549 Short term investments $ 3,833 $ 853 $ 4,686 Other invested assets 55 5 60 Receivables 1 1 Life settlement contracts $ 58 58 Payable to brokers (44 ) (44) December 31, 2015 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 17,601 $ 168 $ 17,769 States, municipalities and political subdivisions 13,172 2 13,174 Asset-backed: Residential mortgage-backed 4,938 134 5,072 Commercial mortgage-backed 2,175 22 2,197 Other asset-backed 868 53 921 Total asset-backed 7,981 209 8,190 U.S. Treasury and obligations of government-sponsored enterprises $ 66 1 67 Foreign government 346 346 Redeemable preferred stock 35 35 Fixed maturities available-for-sale 101 39,101 379 39,581 Fixed maturities trading 35 85 120 Total fixed maturities $ 101 $ 39,136 $ 464 $ 39,701 Equity securities available-for-sale $ 177 $ 20 $ 197 Equity securities trading 554 1 555 Total equity securities $ 731 $ - $ 21 $ 752 Short term investments $ 3,600 $ 1,134 $ 4,734 Other invested assets 102 44 146 Receivables 9 $ 3 12 Life settlement contracts 74 74 Payable to brokers (196 ) (196)
Reconciliations of Assets and Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs	The tables below present reconciliations for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2016 and 2015: Purchases Sales Settlements Transfers into Transfers out of Balance, Unrealized Held at Net Realized Gains 2016 Balance, Included in Included (In millions) Fixed maturity securities: Corporate and other bonds $ 168 $ 1 $ 1 $ 163 $ (36 ) $ (103 ) $ (64 ) $ 130 States, municipalities and 2 (1 ) 1 Asset-backed: Residential mortgage-backed 134 3 (5 ) 15 (14 ) $ 56 (60 ) 129 Commercial mortgage-backed 22 (1 ) (1 ) 32 (17 ) 3 (25 ) 13 Other asset-backed 53 (2 ) 1 86 (25 ) (1 ) 2 (57 ) 57 Total asset-backed 209 - (5 ) 133 (25 ) (32 ) 61 (142 ) 199 $ - Fixed maturities available-for-sale 379 1 (4 ) 296 (61 ) (136 ) 61 (206 ) 330 Fixed maturities trading 85 5 2 (86 ) 6 3 Total fixed maturities $ 464 $ 6 $ (4 ) $ 298 $ (147 ) $ (136 ) $ 61 $ (206 ) $ 336 $ 3 Equity securities available-for-sale $ 20 $ (1 ) $ 19 $ (2 ) Equity securities trading 1 1 $ (1 ) 1 Total equity securities $ 21 $ - $ - $ - $ (1 ) $ - $ - $ - $ 20 $ (2 ) Life settlement contracts $ 74 $ 5 $ (21 ) $ 58 $ (3 ) Derivative financial instruments, net 3 (1 ) $ (2 ) - 2015 Balance, Purchases Sales Settlements Transfers into Transfers out of Balance, Unrealized Net Realized Gains Included in Included in (In millions) Fixed maturity securities: Corporate and other bonds $ 162 $ (2 ) $ (3 ) $ 65 $ (13 ) $ (35 ) $ 40 $ (46 ) $ 168 $ (2 ) States, municipalities and political subdivisions 94 1 (10 ) (83 ) 2 Asset-backed: Residential mortgage-backed 189 5 (3 ) 81 (35 ) 14 (117 ) 134 Commercial mortgage-backed 83 7 (4 ) 23 (17 ) 17 (87 ) 22 Other asset-backed 655 3 3 130 (263 ) (52 ) 7 (430 ) 53 Total asset-backed 927 15 (4 ) 234 (263 ) (104 ) 38 (634 ) 209 - Fixed maturities available-for-sale 1,183 14 (7 ) 299 (276 ) (149 ) 78 (763 ) 379 (2 ) Fixed maturities trading 90 (3 ) (2 ) 85 (3 ) Total fixed maturities $ 1,273 $ 11 $ (7 ) $ 299 $ (278 ) $ (149 ) $ 78 $ (763 ) $ 464 $ (5 ) Equity securities available-for-sale $ 16 $ (1 ) $ 4 $ 1 $ 20 Equity securities trading 1 $ 1 1 $ (2 ) 1 $ 1 Total equity securities $ 17 $ 1 $ (1 ) $ 5 $ (2 ) $ - $ 1 $ - $ 21 $ 1 Life settlement contracts $ 82 $ 25 $ (33 ) $ 74 $ 1 Derivative financial instruments, net $ 3 3
Quantitative Information about Significant Unobservable Inputs Utilized by Company in Fair Value Measurements of Level 3 Assets	The following tables present quantitative information about the significant unobservable inputs utilized by the Company in the fair value measurements of Level 3 assets. Valuations for assets and liabilities not presented in the tables below are primarily based on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of unobservable inputs from these broker quotes is neither provided nor reasonably available to the Company. The valuation of life settlement contracts as of December 31, 2016 was based on the terms of the pending sale of the contracts to a third party, therefore the contracts are not included in the table below. December 31, 2016 Estimated Valuation Techniques Unobservable Inputs Range (Weighted Average) (In millions) Fixed maturity securities $ 106 Discounted cash flow Credit spread 2% – 40% (4%) December 31, 2015 Fixed maturity securities $ 138 Discounted cash flow Credit spread 3% – 184% (6%) Life settlement contracts 74 Discounted cash flow Discount rate risk premium 9% Mortality assumption 55% – 1,676% (164%)
Carrying Amount, Estimated Fair Value and Level of Fair Value Hierarchy of Company's Financial Assets and Liabilities	The carrying amount, estimated fair value and the level of the fair value hierarchy of the Company’s financial assets and liabilities which are not measured at fair value on the Consolidated Balance Sheets are presented in the following tables. The carrying amounts and estimated fair values of short term debt and long term debt exclude capital lease obligations. The carrying amounts reported on the Consolidated Balance Sheets for cash and short term investments not carried at fair value and certain other assets and liabilities approximate fair value due to the short term nature of these items. Carrying Amount Estimated Fair Value December 31, 2016 Level 1 Level 2 Level 3 Total (In millions) Assets: Other invested assets, primarily mortgage loans $ 591 $ 594 $ 594 Liabilities: Short term debt 107 $ 104 3 107 Long term debt 10,655 10,150 646 10,796 December 31, 2015 Assets: Other invested assets, primarily mortgage loans $ 678 $ 688 $ 688 Liabilities: Short term debt 1,038 $ 1,050 2 1,052 Long term debt 9,507 8,538 595 9,133

Receivables (Tables)

Receivables (Tables)	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Receivables	December 31 2016 2015 (In millions) Reinsurance (Note 15) $ 4,453 $ 4,491 Insurance 2,255 2,129 Receivable from brokers 178 471 Accrued investment income 410 408 Federal income taxes 7 45 Other, primarily customer accounts 431 593 Total 7,734 8,137 Less:allowance for doubtful accounts on reinsurance receivables 37 38 allowance for other doubtful accounts 53 58 Receivables $ 7,644 $ 8,041

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Components of Property, Plant and Equipment	December 31 2016 2015 (In millions) Pipeline equipment (net of accumulated depreciation of $2,174 and $1,887) $ 7,631 $ 7,462 Offshore drilling equipment (net of accumulated depreciation of $3,310 and $3,335) 5,693 6,071 Other (net of accumulated depreciation of $873 and $811) 1,527 1,450 Construction in process 379 494 Property, plant and equipment $ 15,230 $ 15,477
Depreciation Expense and Capital Expenditures	Depreciation expense and capital expenditures are as follows: Year Ended December 31 2016 2015 2014 Depre- Capital Depre- Capital Depre- Capital (In millions) CNA Financial $ 67 $ 128 $ 74 $ 123 $ 69 $ 72 Diamond Offshore 384 629 494 812 457 2,050 Boardwalk Pipeline 321 648 327 390 292 378 Loews Hotels 63 164 54 389 37 289 Corporate 6 3 6 4 6 24 Total $ 841 $ 1,572 $ 955 $ 1,718 $ 861 $ 2,813

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Goodwill	CNA Diamond Boardwalk Loews Corporate (In millions) Balance, December 31, 2014 $ 374 $ 117 $ 20 $ 237 $ - $ - Impairments (20 ) (20 ) Other adjustments (3 ) (3 ) Balance, December 31, 2015 351 114 - 237 - - Other adjustments (5 ) (5 ) Balance, December 31, 2016 $ 346 $ 109 $ - $ 237 $ - $ -

Claim and Claim Adjustment Ex38

Claim and Claim Adjustment Expense Reserves (Tables)	12 Months Ended
	Dec. 31, 2016
Reconciliation of Claim and Claim Adjustment Expense Reserves	The following table presents a reconciliation between beginning and ending claim and claim adjustment expense reserves, including claim and claim adjustment expense reserves of non-core Year Ended December 31 2016 2015 2014 (In millions) Reserves, beginning of year: Gross $ 22,663 $ 23,271 $ 24,089 Ceded 4,087 4,344 4,972 Net reserves, beginning of year 18,576 18,927 19,117 Change in net reserves due to disposition of subsidiaries (13 ) Net incurred claim and claim adjustment expenses: Provision for insured events of current year 5,025 4,934 5,043 Decrease in provision for insured events of prior years (342 ) (255 ) (36 ) Amortization of discount 175 166 161 Total net incurred (a) 4,858 4,845 5,168 Net payments attributable to: Current year events (967 ) (856 ) (945 ) Prior year events (4,167 ) (4,089 ) (4,355 ) Total net payments (5,134 ) (4,945 ) (5,300 ) Foreign currency translation adjustment and other (51 ) (251 ) (45 ) Net reserves, end of year 18,249 18,576 18,927 Ceded reserves, end of year 4,094 4,087 4,344 Gross reserves, end of year $ 22,343 $ 22,663 $ 23,271 (a) Total net incurred above does not agree to Insurance claims and policyholders’ benefits as reflected in the Consolidated Statements of Income due to amounts related to retroactive reinsurance deferred gain accounting, uncollectible reinsurance and loss deductible receivables and benefit expenses related to future policy benefits, which are not reflected in the table above.
Schedule of Gross and Net Carried Claim and Claim Adjustment Expense Reserves	The following tables present the gross and net carried reserves: December 31, 2016 Property Non-Core Total (In millions) Gross Case Reserves $ 7,164 $ 4,696 $ 11,860 Gross IBNR Reserves 9,207 1,276 10,483 Total Gross Carried Claim and Claim Adjustment Expense Reserves $ 16,371 $ 5,972 $ 22,343 Net Case Reserves $ 6,582 $ 3,045 $ 9,627 Net IBNR Reserves 8,328 294 8,622 Total Net Carried Claim and Claim Adjustment Expense Reserves $ 14,910 $ 3,339 $ 18,249 December 31, 2015 Gross Case Reserves $ 7,608 $ 4,494 $ 12,102 Gross IBNR Reserves 9,191 1,370 10,561 Total Gross Carried Claim and Claim Adjustment Expense Reserves $ 16,799 $ 5,864 $ 22,663 Net Case Reserves $ 6,992 $ 2,844 $ 9,836 Net IBNR Reserves 8,371 369 8,740 Total Net Carried Claim and Claim Adjustment Expense Reserves $ 15,363 $ 3,213 $ 18,576
Detail of the Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development ("development")	The following table and discussion presents detail of the net prior year claim and allocated claim adjustment expense reserve development (“development”): Year Ended December 31 2016 2015 2014 (In millions) Medical professional liability $ (37 ) $ (43 ) $ 39 Other professional liability and management liability (130 ) (87 ) Surety (63 ) (69 ) (82 ) Commercial auto (46 ) (22 ) 31 General liability (28 ) (33 ) 45 Workers’ compensation 150 80 139 Other (134 ) (123 ) (106 ) Total pretax (favorable) unfavorable development $ (288 ) $ (210 ) $ (21 )
Schedule of Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development for Segment	Property and Casualty Operations – Line of Business Composition The table below presents the net liability for unpaid claim and claim adjustment expenses, by line of business for property and casualty operations: December 31 2016 (In millions) Medical professional liability $ 1,779 Other professional liability and management liability 3,063 Surety 394 Commercial auto 424 General liability 3,248 Workers’ compensation 4,306 Other 1,696 Total net liability for unpaid claim and claim adjustment expenses $ 14,910
Reconciliation of Net Liability for Unpaid Claim and Claim Adjustment Expenses for Property and Casualty Operations to Amount Presented in Consolidated Balance Sheets	The table below reconciles the net liability for unpaid claim and claim adjustment expenses for property and casualty operations to the amount presented in the Consolidated Balance Sheets. As of December 31, 2016 (In millions) Net liability for unpaid claim and claim adjustment expenses Property and casualty operations $ 14,910 Non-core 3,339 Total net claim and claim adjustment expenses 18,249 Reinsurance receivables (b) Property and casualty operations 1,461 Non-core 2,633 Total reinsurance receivables 4,094 Total gross liability for unpaid claims and claims adjustment expenses $ 22,343 (a) Non-core (b) Reinsurance receivables presented do not include reinsurance receivables related to paid losses.
Schedule of Historical Claims Duration	The table below presents information about average historical claims duration as of December 31, 2016 and is presented as required supplementary information, which is unaudited. Average Annual Percentage Payout of Ultimate Net Incurred Claim and Allocated Claim Adjustment Expenses in Year: 1 2 3 4 5 6 7 8 9 10 Total Medical professional liability 3.1 % 18.2 % 22.3 % 19.6 % 12.7 % 8.0 % 5.0 % 4.8 % 3.7 % 0.3 % 97.7% Other professional liability and management liability 5.7 % 20.6 % 21.0 % 17.0 % 10.0 % 6.3 % 5.6 % 3.8 % 1.9 % 3.2 % 95.1% Surety (a) 23.4 % 32.8 % 20.2 % 8.9 % 3.7 % 1.5 % (0.7 )% 2.0 % 1.0 % 2.0 % 94.8% Commercial auto 27.2 % 23.1 % 18.3 % 13.9 % 9.1 % 3.9 % 1.3 % 0.2 % 0.3 % 0.3 % 97.6% General liability 5.0 % 16.3 % 20.5 % 20.1 % 15.3 % 8.0 % 4.2 % 2.7 % 1.1 % 1.3 % 94.5% Workers’ compensation 13.5 % 21.4 % 14.6 % 10.5 % 7.5 % 5.7 % 4.6 % 3.0 % 2.1 % 0.3 % 83.2% (a) Due to the nature of the Surety business, average annual percentage payout of ultimate net incurred claim and allocated claim adjustment expenses has been calculated using only the payouts of mature accident years presented in the loss reserve development tables.
Schedule of Impact of Loss Portfolio Transfer on the Consolidated Statement of Operations	The following table presents the impact of the loss portfolio transfer on the Consolidated Statements of Income. Year Ended December 31 2016 2015 2014 (In millions) Net A&EP adverse development before consideration of LPT $ 200 $ 150 $ - Retroactive reinsurance benefit recognized (107 ) (85 ) (13 ) Pretax impact of A&EP reserve development and the LPT $ 93 $ 65 $ (13 )
Medical Professional Liability [Member]
Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses	December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative Number of December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Claims (In millions, except reported claims data) Accident Year 2007 $ 448 $ 452 $ 444 $ 427 $ 395 $ 391 $ 390 $ 401 $ 399 $ 385 $ 9 12,122 2008 426 451 496 480 468 468 467 455 442 9 14,094 2009 462 469 494 506 480 471 463 432 12 15,573 2010 483 478 478 486 470 446 403 16 15,206 2011 486 492 507 533 501 491 23 17,428 2012 526 529 575 567 559 47 18,375 2013 534 540 560 567 95 19,565 2014 511 548 585 165 19,286 2015 480 539 278 16,798 2016 469 400 11,600 Total $ 4,872 $ 1,054
Schedule of Net Strengthening or (Releases) of Prior Accident Year Reserves	Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 4 $ (8) $ (17) $ (32) $ (4) $ (1) $ 11 $ (2) $ (14) $ (63) 2008 25 45 (16) (12) (1) (12) (13) 16 2009 7 25 12 (26) (9) (8) (31) (30) 2010 (5) 8 (16) (24) (43) (80) 2011 6 15 26 (32) (10) 5 2012 3 46 (8) (8) 33 2013 6 20 7 33 2014 37 37 74 2015 59 59 Total net development for the accident years presented above $ 63 $ (29) $ (16) Total net development for accident years prior to 2007 (24) (14) (21) Total $ 39 $ (43) $ (37) (a) Data presented for these calendar years is required supplemental information, which is unaudited.
Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses	Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 11 $ 68 $ 134 $ 201 $ 247 $ 296 $ 326 $ 352 $ 364 $ 365 2008 9 90 207 282 332 377 395 409 428 2009 9 75 180 278 328 353 377 396 2010 11 93 186 273 338 361 371 2011 18 121 225 315 379 407 2012 15 121 236 359 428 2013 18 121 259 364 2014 25 149 274 2015 22 105 2016 18 Total $ 3,156 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 1,716 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 30 Liability for unallocated claim adjustment expenses for accident years presented 33 Total net liability for unpaid claim and claim adjustment expenses $ 1,779
Other Professional Liability and Management Liability [Member]
Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses	December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Number of (In millions, except reported claims data) Accident Year 2007 $ 804 $ 817 $ 806 $ 754 $ 734 $ 724 $ 704 $ 681 $ 662 $ 662 $ 13 16,011 2008 916 933 954 924 915 880 850 845 827 35 16,326 2009 829 873 903 898 891 900 895 903 50 17,263 2010 825 827 850 848 846 836 823 39 17,796 2011 876 904 933 948 944 910 107 18,620 2012 907 894 876 870 833 107 18,228 2013 844 841 879 840 137 17,324 2014 841 859 854 306 16,886 2015 847 851 478 16,391 2016 859 742 15,045 Total $ 8,362 $ 2,014
Schedule of Net Strengthening or (Releases) of Prior Accident Year Reserves	Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 13 $ (11) $ (52) $ (20) $ (10) $ (20) $ (23) $ (19) $ (142) 2008 17 21 (30) (9) (35) (30) (5) $ (18) (89) 2009 44 30 (5) (7) 9 (5) 8 74 2010 2 23 (2) (2) (10) (13) (2) 2011 28 29 15 (4) (34) 34 2012 (13) (18) (6) (37) (74) 2013 (3) 38 (39) (4) 2014 18 (5) 13 2015 4 4 Total net development for the accident years presented above $ (52) $ 7 $ (134) Total net development for accident years prior to 2007 (35) (7) 4 Total $ (87) $ - $ (130) (a) Data presented for these calendar years is required supplemental information, which is unaudited.
Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses	Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 32 $ 162 $ 307 $ 397 $ 472 $ 524 $ 564 $ 585 $ 593 $ 614 2008 39 181 376 515 600 641 678 719 741 2009 37 195 358 550 638 719 769 798 2010 31 203 404 541 630 670 721 2011 71 313 502 604 682 726 2012 57 248 398 570 648 2013 51 240 426 583 2014 51 212 375 2015 48 209 2016 60 Total $ 5,475 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 2,887 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 104 Liability for unallocated claim adjustment expenses for accident years presented 72 Total net liability for unpaid claim and claim adjustment expenses $ 3,063
Surety [Member]
Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses	December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Number of (In millions, except reported claims data) Accident Year 2007 $ 98 $ 107 $ 81 $ 57 $ 59 $ 56 $ 51 $ 49 $ 49 $ 50 6,270 2008 114 114 73 68 61 52 48 45 44 7,153 2009 114 114 103 85 68 59 52 53 $ 1 6,654 2010 112 112 111 84 76 66 63 8 5,943 2011 120 121 116 87 75 70 9 5,760 2012 120 122 98 70 52 16 5,473 2013 120 121 115 106 24 4,890 2014 123 124 94 51 4,737 2015 131 131 100 4,279 2016 124 110 2,902 Total $ 787 $ 319
Schedule of Net Strengthening or (Releases) of Prior Accident Year Reserves	Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 9 $ (26) $ (24) $ 2 $ (3) $ (5) $ (2) $ 1 $ (48) 2008 (41) (5) (7) (9) (4) $ (3) (1) (70) 2009 (11) (18) (17) (9) (7) 1 (61) 2010 (1) (27) (8) (10) (3) (49) 2011 1 (5) (29) (12) (5) (50) 2012 2 (24) (28) (18) (68) 2013 1 (6) (9) (14) 2014 1 (30) (29) 2015 Total net development for the accident years presented above $ (75) $ (65) $ (64) Total net development for accident years prior to 2007 (7) (4) 1 Total $ (82) $ (69) $ (63) (a) Data presented for these calendar years is required supplemental information, which is unaudited.
Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses	Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 12 $ 30 $ 40 $ 45 $ 46 $ 46 $ 46 $ 48 $ 49 $ 50 2008 9 27 35 39 42 43 43 43 43 2009 13 24 34 41 43 45 46 47 2010 13 34 50 55 57 58 55 2011 19 42 55 58 60 60 2012 5 32 34 35 35 2013 16 40 69 78 2014 7 30 38 2015 7 26 2016 5 Total $ 437 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 350 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 16 Liability for unallocated claim adjustment expenses for accident years presented 28 Total net liability for unpaid claim and claim adjustment expenses $ 394
Commercial Auto [Member]
Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses	December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative Number of December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Claims (In millions, except reported claims data) Accident Year 2007 $ 348 $ 367 $ 368 $ 360 $ 355 $ 358 $ 356 $ 355 $ 354 $ 352 67,473 2008 322 323 316 306 309 305 298 298 296 56,407 2009 287 272 274 278 281 277 275 272 47,325 2010 262 274 279 283 291 286 281 $ 1 46,324 2011 262 273 279 293 290 285 5 46,676 2012 270 282 292 296 300 11 45,279 2013 242 259 257 241 20 38,513 2014 231 221 210 40 32,958 2015 199 197 65 29,714 2016 196 105 25,196 Total $ 2,630 $ 247
Schedule of Net Strengthening or (Releases) of Prior Accident Year Reserves	Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 19 $ 1 $ (8) $ (5) $ 3 $ (2) $ (1) $ (1) $ (2) $ 4 2008 1 (7) (10) 3 (4) (7) (2) (26) 2009 (15) 2 4 3 (4) (2) (3) (15) 2010 12 5 4 8 (5) (5) 19 2011 11 6 14 (3) (5) 23 2012 12 10 4 4 30 2013 17 (2) (16) (1) 2014 (10) (11) (21) 2015 (2) (2) Total net development for the accident years presented above $ 37 $ (19) $ (42) Total net development for accident years prior to 2007 (6) (3) (4) Total $ 31 $ (22) $ (46) (a) Data presented for these calendar years is required supplemental information, which is unaudited.
Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses	Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 93 $ 185 $ 250 $ 295 $ 329 $ 340 $ 348 $ 349 $ 350 $ 351 2008 83 158 210 244 274 289 291 292 293 2009 72 128 188 229 257 269 270 270 2010 72 137 197 240 265 274 279 2011 78 141 193 241 264 275 2012 77 157 214 253 276 2013 73 132 164 195 2014 63 100 135 2015 52 95 2016 51 Total $ 2,220 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 410 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 4 Liability for unallocated claim adjustment expenses for accident years presented 10 Total net liability for unpaid claim and claim adjustment expenses $ 424
General Liability [Member]
Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses	December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative Number of December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Claims (In millions, except reported claims data) Accident Year 2007 $ 774 $ 673 $ 678 $ 639 $ 610 $ 600 $ 559 $ 545 $ 548 $ 540 $ 28 53,553 2008 611 604 630 647 633 632 613 600 591 18 44,586 2009 591 637 634 633 629 623 619 622 16 43,955 2010 566 597 599 649 695 675 659 25 43,378 2011 537 534 564 610 611 621 41 38,101 2012 539 563 579 570 558 63 34,037 2013 615 645 634 643 142 32,897 2014 627 634 635 224 26,744 2015 573 574 330 21,687 2016 622 495 16,720 Total $ 6,065 $ 1,382
Schedule of Net Strengthening or (Releases) of Prior Accident Year Reserves	Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ (101) $ 5 $ (39) $ (29) $ (10) $ (41) $ (14) $ 3 $ (8) $ (234) 2008 (7) 26 17 (14) (1) (19) (13) (9) (20) 2009 46 (3) (1) (4) (6) (4) 3 31 2010 31 2 50 46 (20) (16) 93 2011 (3) 30 46 1 10 84 2012 24 16 (9) (12) 19 2013 30 (11) 9 28 2014 7 1 8 2015 1 1 Total net development for the accident years presented above $ 99 $ (46) $ (21) Total net development for accident years prior to 2007 (54) 13 (7) Total $ 45 $ (33) $ (28) (a) Data presented for these calendar years is required supplemental information, which is unaudited.
Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses	Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 30 $ 130 $ 236 $ 328 $ 413 $ 458 $ 481 $ 492 $ 497 $ 504 2008 31 129 261 390 473 528 550 560 567 2009 33 112 270 392 486 532 557 584 2010 27 139 267 414 530 577 608 2011 27 135 253 389 484 534 2012 27 127 233 340 417 2013 33 135 257 377 2014 29 115 245 2015 31 132 2016 34 Total $ 4,002 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 2,063 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 1,130 Liability for unallocated claim adjustment expenses for accident years presented 55 Total net liability for unpaid claim and claim adjustment expenses $ 3,248
Workers' Compensation [Member]
Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses	December 31, 2016 Cumulative Net Incurred Claim and Allocated Claim Adjustment Expenses Cumulative Number of December 31 2007 (a) 2008 (a) 2009 (a) 2010 (a) 2011 (a) 2012 (a) 2013 (a) 2014 (a) 2015 (a) 2016 IBNR Claims (In millions, except reported claims data) Accident Year 2007 $ 568 $ 580 $ 596 $ 604 $ 603 $ 603 $ 604 $ 610 $ 608 $ 627 $ 32 71,049 2008 558 575 593 606 608 612 622 630 638 36 59,883 2009 583 587 594 596 600 611 617 625 46 51,111 2010 576 619 641 663 683 697 717 45 48,056 2011 593 628 637 648 642 666 52 44,571 2012 589 616 648 661 671 86 41,683 2013 528 563 584 610 121 38,102 2014 459 474 474 157 32,996 2015 416 426 206 31,296 2016 421 287 27,042 Total $ 5,875 $ 1,068
Schedule of Net Strengthening or (Releases) of Prior Accident Year Reserves	Net Strengthening or (Releases) of Prior Accident Year Reserves Years Ended December 31 Total Accident Year 2007 $ 12 $ 16 $ 8 $ (1 ) $ 1 $ 6 $ (2 ) $ 19 $ 59 2008 17 18 13 $ 2 4 10 8 8 80 2009 4 7 2 4 11 6 8 42 2010 43 22 22 20 14 20 141 2011 35 9 11 (6 ) 24 73 2012 27 32 13 10 82 2013 35 21 26 82 2014 15 15 2015 10 10 Total net development for the accident years presented above $ 125 $ 69 $ 125 Adjustment for development on a discounted basis 1 (4 ) 1 Total net development for accident years prior to 2007 13 15 24 Total $ 139 $ 80 $ 150 (a) Data presented for these calendar years is required supplemental information, which is unaudited.
Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses	Cumulative Net Paid Claim and Allocated Claim Adjustment Expenses Accident Year 2007 $ 100 $ 246 $ 337 $ 390 $ 429 $ 471 $ 502 $ 522 $ 533 $ 535 2008 92 233 323 381 425 461 489 505 520 2009 88 223 315 381 435 468 495 516 2010 94 245 352 433 500 531 565 2011 97 245 353 432 471 515 2012 86 229 338 411 465 2013 79 211 297 366 2014 60 157 213 2015 50 130 2016 52 Total $ 3,877 Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented $ 1,998 Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007 2,334 Other (b) (30) Liability for unallocated claim adjustment expenses for accident years presented 4 Total net liability for unpaid claim and claim adjustment expenses $ 4,306 (b) Other includes the effect of discounting lifetime claim reserves.

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2016
Leases [Abstract]
Future Minimum Lease Payments to be Made Under Non-Cancelable Operating Leases Along with Lease and Sublease Minimum Receipts to be Received on Owned and Leased Properties	The table below presents the future minimum lease payments to be made under non-cancelable Future Minimum Lease Year Ended December 31 Payments Receipts (In millions) 2017 $ 72 $ 5 2018 59 5 2019 51 4 2020 54 4 2021 53 4 Thereafter 349 19 Total $ 638 $ 41

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Current and Deferred Components of Income Tax Expense (Benefit)	The current and deferred components of income tax expense (benefit) are as follows: Year Ended December 31 2016 2015 2014 (In millions) Income tax expense (benefit): Federal: Current $ 71 $ 79 $ 370 Deferred 102 (234 ) (23 ) State and city: Current 13 21 12 Deferred 13 5 6 Foreign 21 86 92 Total $ 220 $ (43 ) $ 457
Components of U.S. and Foreign Income and Reconciliation between Federal Income Tax Expense at Statutory Rates and Actual Income Tax Expense (Benefit)	The components of U.S. and foreign income before income tax and a reconciliation between the federal income tax expense at statutory rates and the actual income tax expense (benefit) is as follows: Year Ended December 31 2016 2015 2014 (In millions) Income before income tax: U.S. $ 1,207 $ 543 $ 1,499 Foreign (271 ) (299 ) 311 Total $ 936 $ 244 $ 1,810 Income tax expense at statutory rate $ 328 $ 86 $ 633 Increase (decrease) in income tax expense resulting from: Exempt investment income (126 ) (126 ) (121 ) Foreign related tax differential 40 (18 ) (48 ) Amortization of deferred charges associated with intercompany rig sales to other tax jurisdictions 38 44 Taxes related to domestic affiliate (14 ) (10 ) 14 Partnership earnings not subject to taxes (52 ) (38 ) (39 ) Allowance for foreign tax credits 62 Unrecognized tax positions, including foreign currency revaluation (42 ) 1 (42 ) Other (a) 24 24 16 Income tax expense (benefit) $ 220 $ (43 ) $ 457 (a) Includes state and local taxes, adjustments to prior year estimates and other non-deductible
Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits, Excluding Tax Carryforwards and Interest and Penalties	A reconciliation of the beginning and ending amount of unrecognized tax benefits, excluding tax carryforwards and interest and penalties, is as follows: Year Ended December 31 2016 2015 2014 (In millions) Balance at January 1 $ 54 $ 57 $ 91 Additions for tax positions related to the current year 4 7 6 Additions for tax positions related to a prior year 1 Reductions for tax positions related to a prior year (20 ) (3 ) (35 ) Lapse of statute of limitations (4 ) (7 ) (5 ) Balance at December 31 $ 35 $ 54 $ 57
Summary of Deferred Tax Assets and Liabilities	The following table summarizes deferred tax assets and liabilities: December 31 2016 2015 (In millions) Deferred tax assets: Insurance reserves: Property and casualty claim and claim adjustment expense reserves $ 125 $ 178 Unearned premium reserves 206 230 Receivables 26 30 Employee benefits 407 419 Life settlement contracts 56 48 Deferred retroactive reinsurance benefit 117 84 Net operating loss carryforwards 178 245 Tax credit carryforwards 289 131 Basis differential in investment in subsidiary 17 19 Other 246 282 Total deferred tax assets 1,667 1,666 Valuation allowance (210 ) (147 ) Net deferred tax assets 1,457 1,519 Deferred tax liabilities: Deferred acquisition costs (120 ) (117 ) Net unrealized gains (295 ) (166 ) Property, plant and equipment (1,019 ) (998 ) Basis differential in investment in subsidiary (409 ) (428 ) Other liabilities (235 ) (173 ) Total deferred tax liabilities (2,078 ) (1,882 ) Net deferred tax liabilities (a) $ (621 ) $ (363 ) (a) Includes $15 and $19 of deferred tax assets reflected in Other assets in the Consolidated Balance Sheets at December 31, 2016 and 2015.

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Long-Term Debt Instruments	December 31 2016 2015 (In millions) Loews Corporation (Parent Company): Senior: 5.3% notes due 2016 (effective interest rate of 5.4%) (authorized, $400) $ 400 2.6% notes due 2023 (effective interest rate of 2.8%) (authorized, $500) $ 500 500 3.8% notes due 2026 (effective interest rate of 3.9%) (authorized, $500) 500 6.0% notes due 2035 (effective interest rate of 6.2%) (authorized, $300) 300 300 4.1% notes due 2043 (effective interest rate of 4.3%) (authorized, $500) 500 500 CNA Financial: Senior: 6.5% notes due 2016 (effective interest rate of 6.6%) (authorized, $350) 350 7.0% notes due 2018 (effective interest rate of 7.1%) (authorized, $150) 150 150 7.4% notes due 2019 (effective interest rate of 7.5%) (authorized, $350) 350 350 5.9% notes due 2020 (effective interest rate of 6.0%) (authorized, $500) 500 500 5.8% notes due 2021 (effective interest rate of 5.9%) (authorized, $400) 400 400 7.3% debentures due 2023 (effective interest rate of 7.3%) (authorized, $250) 243 243 4.0% notes due 2024 (effective interest rate of 4.0%) (authorized, $550) 550 550 4.5% notes due 2026 (effective interest rate of 4.5%) (authorized, $500) 500 Variable rate note due 2036 (effective interest rate of 4.3% and 3.8%) 30 30 Capital lease obligation 5 4 Diamond Offshore: Senior: Commercial paper (weighted average interest rate of 0.9%) 287 Variable rate revolving credit facility due 2020 (effective interest rate of 1.9%) 104 5.9% notes due 2019 (effective interest rate of 6.0%) (authorized, $500) 500 500 3.5% notes due 2023 (effective interest rate of 3.6%) (authorized, $250) 250 250 5.7% notes due 2039 (effective interest rate of 5.8%) (authorized, $500) 500 500 4.9% notes due 2043 (effective interest rate of 5.0%) (authorized, $750) 750 750 Boardwalk Pipeline: Senior: Variable rate revolving credit facility due 2021 (effective interest rate of 2.0% and 1.7%) 180 375 5.9% notes due 2016 (effective interest rate of 6.0%) (authorized, $250) 250 5.5% notes due 2017 (effective interest rate of 5.6%) (authorized, $300) 300 300 6.3% notes due 2017 (effective interest rate of 6.4%) (authorized, $275) 275 275 5.2% notes due 2018 (effective interest rate of 5.4%) (authorized, $185) 185 185 5.8% notes due 2019 (effective interest rate of 5.9%) (authorized, $350) 350 350 4.5% notes due 2021 (effective interest rate of 5.0%) (authorized, $440) 440 440 4.0% notes due 2022 (effective interest rate of 4.4%) (authorized, $300) 300 300 3.4% notes due 2023 (effective interest rate of 3.5%) (authorized, $300) 300 300 5.0% notes due 2024 (effective interest rate of 5.2%) (authorized, $600 and $350) 600 600 6.0% notes due 2026 (effective interest rate of 6.2%) (authorized, $550) 550 7.3% debentures due 2027 (effective interest rate of 8.1%) (authorized, $100) 100 100 Capital lease obligation 9 10 Loews Hotels: Senior debt, principally mortgages (effective interest rates approximate 4.1%) 650 598 10,871 10,647 Less unamortized discount and issuance costs 93 87 Debt $ 10,778 $ 10,560
Schedule of Debt by Subsidiary	December 31, 2016 Principal Unamortized Net Short Term Long Term (In millions) Loews Corporation $ 1,800 $ 25 $ 1,775 $ 1,775 CNA Financial 2,728 13 2,715 $ 2 2,713 Diamond Offshore 2,104 19 2,085 104 1,981 Boardwalk Pipeline 3,589 31 3,558 1 3,557 Loews Hotels 650 5 645 3 642 Total $ 10,871 $ 93 $ 10,778 $ 110 $ 10,668

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Components of Accumulated Other Comprehensive Income	The tables below display the changes in AOCI by component for the years ended December 31, 2014, 2015 and 2016: OTTI Gains (Losses) Unrealized Discontinued Cash Flow Pension Foreign Translation Total (In millions) Balance, January 1, 2014 $ 23 $ 622 $ (3) $ (4) $ (432 ) $ 133 $ 339 Sale of subsidiaries (5 ) (15) 20 Other comprehensive income (loss) before reclassifications, after tax of $(8), $(132), $(3), $1, $132 and $0 15 295 2 (2) (244 ) (94 ) (28) Reclassification of (gains) losses from accumulated other comprehensive income, after tax of $0, $10, $16, $0, $(7) and $0 (28) (21) (1) 9 (41) Other comprehensive income (loss) 15 267 (19) (3) (235 ) (94 ) (69) Amounts attributable to noncontrolling interests (1 ) (28) 2 1 26 10 10 Balance, December 31, 2014 32 846 - (6) (641 ) 49 280 Other comprehensive loss before reclassifications, after tax of $13, $313, $0, $1, $16 and $0 (23 ) (600) (2) (31 ) (139 ) (795) Reclassification of losses from accumulated other comprehensive income, after tax of $(8), $(31), $0, $(2), $(11) and $0 14 43 7 13 77 Other comprehensive income (loss) (9 ) (557) - 5 (18 ) (139 ) (718) Issuance of equity securities by subsidiary 1 1 Amounts attributable to noncontrolling interests 1 58 (2) 9 14 80 Balance, December 31, 2015 24 347 - (3) (649 ) (76 ) (357) Other comprehensive income (loss) before reclassifications, after tax of $(4), $(133), $0, $0, $9 and $0 9 283 (22 ) (114 ) 156 Reclassification of (gains) losses from accumulated other comprehensive income, after tax of $3, $16, $0, $0, $(15) and $0 (6 ) (26) 2 27 (3) Other comprehensive income (loss) 3 257 - 2 5 (114 ) 153 Amounts attributable to noncontrolling interests (28) (1) (2 ) 12 (19) Balance, December 31, 2016 $ 27 $ 576 $ - $ (2) $ (646 ) $ (178 ) $ (223)

Statutory Accounting Practices

Statutory Accounting Practices (Tables)	12 Months Ended
	Dec. 31, 2016
Text Block [Abstract]
Combined Statutory Capital and Surplus and Net Income (Loss)	Combined statutory capital and surplus and statutory net income (loss), determined in accordance with accounting practices prescribed or permitted by insurance and/or other regulatory authorities for the Combined Continental Casualty Companies are presented in the table below. Statutory Capital and Surplus Statutory Net Income December 31 Year Ended December 31 2016 (a) 2015 2016 (a) 2015 2014 (In millions) Combined Continental Casualty Companies $ 10,748 $ 10,723 $ 1,033 $ 1,148 $ 914 (a) Information derived from the statutory-basis financial statements to be filed with insurance regulators.

Benefit Plans (Tables)

Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Weighted-Average Assumptions Used to Determine Benefit Obligations	Weighted average assumptions used to determine benefit obligations: Pension Benefits Other Postretirement Benefits December 31 2016 2015 2014 2016 2015 2014 Discount rate 3.9% 4.0% 3.7% 3.7% 3.7% 3.4% Expected long term rate of return on plan assets 7.5% 7.5% 7.5% 5.3% 5.3% 5.3% Rate of compensation increase 3.9% to 5.5% 3.5% to 5.5% 3.5% to 5.5%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Cost	Weighted average assumptions used to determine net periodic benefit cost: Pension Benefits Other Postretirement Benefits Year Ended December 31 2016 2015 2014 2016 2015 2014 Discount rate 4.0% 3.8% 4.4% 3.7% 3.4% 4.0% Expected long term rate of return on plan assets 7.5% 7.5% 7.5% 5.3% 5.3% 5.3% Rate of compensation increase 3.5% to 5.5% 3.5% to 5.5% 3.5% to 5.5%
Assumed Health Care Cost Trend Rates	Assumed health care cost trend rates: December 31 2016 2015 2014 Health care cost trend rate assumed for next year 4.0% to 7.0% 4.0% to 7.5% 4.0% to 8.0% Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) 4.0% to 5.0% 4.0% to 5.0% 4.0% to 5.0% Year that the rate reaches the ultimate trend rate 2017-2021 2016-2021 2015-2021
Components of Net Periodic Benefit Cost	Net periodic benefit cost components: Pension Benefits Other Postretirement Benefits Year Ended December 31 2016 2015 2014 2016 2015 2014 (In millions) Service cost $ 8 $ 12 $ 16 $ 1 $ 1 $ 1 Interest cost 128 127 149 3 3 4 Expected return on plan assets (177 ) (193 ) (209 ) (5 ) (5 ) (4) Amortization of unrecognized net loss 46 42 30 1 1 Amortization of unrecognized prior service benefit (1 ) (1 ) (1 ) (3 ) (10 ) (18) Settlement/Curtailment 3 3 86 (86) Net periodic benefit cost $ 7 $ (10 ) $ 71 $ (4 ) $ (10 ) $ (102)
Reconciliation of Benefit Obligations and Plan Assets	The following provides a reconciliation of benefit obligations and plan assets: Pension Benefits Other Postretirement Benefits 2016 2015 2016 2015 (In millions) Change in benefit obligation: Benefit obligation at January 1 $ 3,227 $ 3,446 $ 82 $ 97 Service cost 8 12 1 1 Interest cost 128 127 3 3 Plan participants’ contributions 5 5 Amendments/curtailments 1 (55 ) Actuarial (gain) loss 72 (96 ) (13 ) (11) Benefits paid from plan assets (188 ) (187 ) (12 ) (13) Settlements (101 ) (12 ) Foreign exchange (16 ) (8 ) Benefit obligation at December 31 3,131 3,227 66 82 Change in plan assets: Fair value of plan assets at January 1 2,500 2,713 86 87 Actual return on plan assets 211 (21 ) 3 2 Company contributions 19 15 4 5 Plan participants’ contributions 5 5 Benefits paid from plan assets (188 ) (187 ) (12 ) (13) Settlements (103 ) (12 ) Foreign exchange (16 ) (8 ) Fair value of plan assets at December 31 2,423 2,500 86 86 Funded status $ (708 ) $ (727 ) $ 20 $ 4 Amounts recognized in the Consolidated Balance Sheets consist of: Other assets $ 4 $ 11 $ 44 $ 38 Other liabilities (712 ) (738 ) (24 ) (34) Net amount recognized $ (708 ) $ (727 ) $ 20 $ 4 Amounts recognized in Accumulated other comprehensive income (loss), not yet recognized in net periodic (benefit) cost: Prior service credit $ (3 ) $ (5 ) $ (6 ) $ (9) Net actuarial loss 1,097 1,106 (2 ) 8 Net amount recognized $ 1,094 $ 1,101 $ (8 ) $ (1) Information for plans with projected and accumulated benefit obligations in excess of plan assets: Projected benefit obligation $ 3,103 $ 3,129 Accumulated benefit obligation 3,089 3,114 $ 24 $ 34 Fair value of plan assets 2,391 2,391
Estimated Amounts to be Recognized from AOCI into Net Periodic Cost (Benefit)	The table below presents the estimated amounts to be recognized from AOCI into net periodic cost (benefit) during 2017. Other Pension Postretirement Benefits Benefits (In millions) Amortization of net actuarial (gain) loss $ 43 $ (1) Amortization of prior service credit (2) Total estimated amounts to be recognized $ 43 $ (3)
Estimated Future Minimum Benefit Payments	The table below presents the estimated future minimum benefit payments at December 31, 2016. Other Pension Postretirement Expected future benefit payments Benefits Benefits (In millions) 2017 $ 217 $ 6 2018 210 6 2019 212 6 2020 214 5 2021 212 5 2022 – 2026 1,041 20
Pension Benefits [Member]
Defined Benefit Plan, Fair Value of Plan Assets Measured on Recurring Basis	Pension plan assets measured at fair value on a recurring basis are summarized below. December 31, 2016 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 500 $ 10 $ 510 States, municipalities and political subdivisions 63 63 Asset-backed 186 186 Total fixed maturities $ - 749 10 759 Equity securities 404 105 509 Short term investments 18 35 53 Fixed income mutual funds 92 92 Other assets 15 37 52 Total limited partnerships measured at net asset value (a) 958 Total $ 529 $ 926 $ 10 $ 2,423 December 31, 2015 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 455 $ 10 $ 465 States, municipalities and political subdivisions 106 106 Asset-backed 219 219 Total fixed maturities $ - 780 10 790 Equity securities 373 107 480 Short term investments 30 28 58 Fixed income mutual funds 95 95 Other assets 52 52 Total limited partnerships measured at net asset value (a) 1,025 Total $ 498 $ 967 $ 10 $ 2,500 (a) In May of 2015, the FASB issued ASU 2015-17, 2015-07”), 2015-07
Plan Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)	The tables below present reconciliations for all pension plan assets measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2016 and 2015: Net Actual Return on Assets Purchases, Net Transfers Balance at Still Held at Sold During Sales, and In (Out) of Balance at 2016 January 1, December 31, the Year Settlements Level 3 December 31, (In millions) Fixed maturity securities: Corporate and other bonds $ 10 $ 10 Total $ 10 $ - $ - $ - $ - $ 10 2015 (In millions) Fixed maturity securities: Corporate and other bonds $ 15 $ (5 ) $ 10 Total $ 15 $ - $ - $ - $ (5 ) $ 10
Other Postretirement Benefits [Member]
Defined Benefit Plan, Fair Value of Plan Assets Measured on Recurring Basis	Other postretirement benefits plan assets measured at fair value on a recurring basis are summarized below. December 31, 2016 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 19 $ 19 States, municipalities and political subdivisions 44 44 Asset-backed 15 15 Total fixed maturities $ - 78 $ - 78 Short term investments 3 3 Fixed income mutual funds 5 5 Total $ 8 $ 78 $ - $ 86 December 31, 2015 Level 1 Level 2 Level 3 Total (In millions) Fixed maturity securities: Corporate and other bonds $ 17 $ 17 States, municipalities and political subdivisions 42 42 Asset-backed 19 19 Total fixed maturities $ - 78 $ - 78 Short term investments 3 3 Fixed income mutual funds 5 5 Total $ 8 $ 78 $ - $ 86

Reinsurance (Tables)

Reinsurance (Tables)	12 Months Ended
	Dec. 31, 2016
Insurance [Abstract]
Summary of Amounts Receivable from Reinsurers	The following table presents the amounts receivable from reinsurers: December 31 2016 2015 (In millions) Reinsurance receivables related to insurance reserves: Ceded claim and claim adjustment expenses $ 4,094 $ 4,087 Ceded future policy benefits 212 207 Reinsurance receivables related to paid losses 147 197 Reinsurance receivables 4,453 4,491 Less allowance for doubtful accounts 37 38 Reinsurance receivables, net of allowance for doubtful accounts $ 4,416 $ 4,453
Summary of Effects of Reinsurance on Earned Premiums	The effects of reinsurance on earned premiums are presented in the following table: Direct Assumed Ceded Net Assumed/ (In millions) Year Ended December 31, 2016 Property and casualty $ 10,400 $ 258 $ 4,270 $ 6,388 4.0% Long term care 486 50 536 9.3 Earned premiums $ 10,886 $ 308 $ 4,270 $ 6,924 4.4% Year Ended December 31, 2015 Property and casualty $ 9,853 $ 274 $ 3,754 $ 6,373 4.3% Long term care 498 50 548 9.1 Earned premiums $ 10,351 $ 324 $ 3,754 $ 6,921 4.7% Year Ended December 31, 2014 Property and casualty $ 9,452 $ 277 $ 3,073 $ 6,656 4.2% Long term care 508 48 556 8.6 Earned premiums $ 9,960 $ 325 $ 3,073 $ 7,212 4.5%

Quarterly Financial Data (Una46

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	2016 Quarter Ended Dec. 31 Sept. 30 June 30 March 31 (In millions, except per share data) Total revenues $ 3,338 $ 3,287 $ 3,307 $ 3,173 Net income (loss) (a) 290 327 (65 ) 102 Per share-basic and diluted 0.86 0.97 (0.19 ) 0.30 2015 Quarter Ended Dec. 31 Sept. 30 June 30 March 31 (In millions, except per share data) Total revenues $ 3,333 $ 3,169 $ 3,435 $ 3,478 Net income (loss) (b) (201 ) 182 170 109 Per share-basic and diluted (0.58 ) 0.50 0.46 0.29 The sum of the quarterly per share amounts may not equal per share amounts reported for year-to-date (a) Net loss for the second quarter of 2016 includes the impact of a $267 million asset impairment charge at Diamond Offshore. (b) Net loss for the fourth quarter of 2015 includes the impact of a $177 million charge related to recognition of a premium deficiency in CNA’s long term care business and a $182 million asset impairment charge at Diamond Offshore.

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Discontinued Operations Reflected in Consolidated Condensed Statements of Income	The Consolidated Statements of Income include discontinued operations of HighMount as follows: Year Ended December 31 2014 (In millions) Revenues: Other revenue, primarily operating $ 150 Total 150 Expenses: Other operating expenses Impairment of natural gas and oil properties 29 Operating 173 Interest 8 Total 210 Loss before income tax (60 ) Income tax benefit 4 Results of discontinued operations, net of income tax (56 ) Impairment loss, net of tax benefit of $62 (138 ) Loss from discontinued operations $ (194 ) The Consolidated Statements of Income include discontinued operations of the CAC business as follows: Year Ended December 31 2014 (In millions) Revenues: Net investment income $ 94 Investment gains 3 Total 97 Expenses: Insurance claims and policyholders’ benefits 75 Other operating expenses 2 Total 77 Income before income tax 20 Income tax expense (6 ) Results of discontinued operations, net of income tax 14 Loss on sale, net of tax benefit of $40 (211 ) Amounts attributable to noncontrolling interests 20 Loss from discontinued operations $ (177 )

Segments (Tables)

Segments (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Consolidating Statement of Income and Total Assets by Segment	Statements of Income and Total assets by segment are presented in the following tables. Year Ended December 31, 2016 CNA Diamond Boardwalk Loews Corporate Total (In millions) Revenues: Insurance premiums $ 6,924 $ 6,924 Net investment income 1,988 $ 1 $ 146 2,135 Investment gains (losses) 62 (12) 50 Contract drilling revenues 1,525 1,525 Other revenues 410 75 $ 1,316 $ 667 3 2,471 Total 9,384 1,589 1,316 667 149 13,105 Expenses: Insurance claims and policyholders’ benefits 5,283 5,283 Amortization of deferred acquisition costs 1,235 1,235 Contract drilling expenses 772 772 Other operating expenses 1,558 1,198 835 621 131 4,343 Interest 167 90 183 24 72 536 Total 8,243 2,060 1,018 645 203 12,169 Income (loss) before income tax 1,141 (471 ) 298 22 (54) 936 Income tax (expense) benefit (279) 111 (61) (10 ) 19 (220) Net income (loss) 862 (360 ) 237 12 (35) 716 Amounts attributable to noncontrolling interests (88) 174 (148) (62) Net income (loss) attributable to Loews Corporation $ 774 $ (186 ) $ 89 $ 12 $ (35) $ 654 December 31, 2016 (In millions) Total assets $ 55,207 $ 6,371 $ 8,706 $ 1,498 $ 4,812 $ 76,594 Year Ended December 31, 2015 CNA Diamond Boardwalk Loews Corporate Total (In millions) Revenues: Insurance premiums $ 6,921 $ 6,921 Net investment income 1,840 $ 3 $ 1 $ 22 1,866 Investment losses (71) (71) Contract drilling revenues 2,360 2,360 Other revenues 411 65 1,253 $ 604 6 2,339 Total 9,101 2,428 1,254 604 28 13,415 Expenses: Insurance claims and policyholders’ benefits 5,384 5,384 Amortization of deferred acquisition costs 1,540 1,540 Contract drilling expenses 1,228 1,228 Other operating expenses 1,469 1,508 851 555 116 4,499 Interest 155 94 176 21 74 520 Total 8,548 2,830 1,027 576 190 13,171 Income (loss) before income tax 553 (402 ) 227 28 (162) 244 Income tax (expense) benefit (71) 117 (46) (16 ) 59 43 Net income (loss) 482 (285 ) 181 12 (103) 287 Amounts attributable to noncontrolling interests (49) 129 (107) (27) Net income (loss) attributable to Loews Corporation $ 433 $ (156 ) $ 74 $ 12 $ (103) $ 260 December 31, 2015 (In millions) Total assets $ 55,025 $ 7,154 $ 8,365 $ 1,416 $ 4,046 $ 76,006 Year Ended December 31, 2014 CNA Diamond Boardwalk Loews Corporate Total (In millions) Revenues: Insurance premiums $ 7,212 $ 7,212 Net investment income 2,067 $ 1 $ 1 $ 94 2,163 Investment gains 54 54 Contract drilling revenues 2,737 2,737 Other revenues 359 87 1,235 $ 475 3 2,159 Total 9,692 2,825 1,236 475 97 14,325 Expenses: Insurance claims and policyholders’ benefits 5,591 5,591 Amortization of deferred acquisition costs 1,317 1,317 Contract drilling expenses 1,524 1,524 Other operating expenses 1,386 725 931 440 103 3,585 Interest 183 62 165 14 74 498 Total 8,477 2,311 1,096 454 177 12,515 Income (loss) before income tax 1,215 514 140 21 (80) 1,810 Income tax (expense) benefit (322) (142 ) (11) (10 ) 28 (457) Income (loss) from continuing operations 893 372 129 11 (52) 1,353 Discontinued operations, net (197) (194) (391) Net income (loss) 696 372 129 11 (246) 962 Amounts attributable to noncontrolling interests (71) (189 ) (111) (371) Net income (loss) attributable to Loews Corporation $ 625 $ 183 $ 18 $ 11 $ (246) $ 591

Summary of Significant Accoun49

Summary of Significant Accounting Policies - Additional Information (Detail) $ / shares in Units, shares in Millions	Dec. 31, 2016USD ($)Contract	Dec. 31, 2015USD ($)	Dec. 31, 2016USD ($)Contractshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)shares
Summary Of Significant Accounting Policies [Line Items]
Net investment income and the amortized cost of fixed maturity securities				$ 39,000,000
Decrease in basic net income per share | $ / shares				$ 0.06
Decrease in diluted net income per share | $ / shares				$ 0.06
Net investment income cumulative adjustment relating to prior periods				$ 22,000,000
Increase (decrease) in Shadow Adjustments			$ (87,000,000)	(159,000,000)
Net unrealized gains on investments included in "AOCI"	$ 909,000,000	$ 996,000,000	909,000,000	996,000,000
Investment in joint venture entities	217,000,000	234,000,000	217,000,000	234,000,000
Equity income (loss) for the investments			41,000,000	43,000,000	$ (62,000,000)
Maximum exposure to loss for the VIE investments	337,000,000		$ 337,000,000
Initial collateral deposit as a percentage of the fair value of the securities loaned			100.00%
Collateral held	$ 0	$ 0	$ 0	$ 0
Interest rate used to discount workers' compensation lifetime claim reserves	3.50%	3.50%	3.50%	3.50%
Discounted reserves for workers' compensation lifetime claim reserves	$ 371,000,000	$ 396,000,000	$ 371,000,000	$ 396,000,000
Discounted reserves for workers' compensation lifetime claims reserves, discount amount	$ 202,000,000	$ 218,000,000	202,000,000	218,000,000
Interest recognized on discounted reserves for workers' compensation lifetime claim reserves			$ 17,000,000	20,000,000	$ 22,000,000
Gross premium valuation indicated a premium deficiency				296,000,000
Write off of deferred acquisition cost asset				289,000,000
Increase to active life reserves				$ 7,000,000
Long term care active life reserves, interest rate range, minimum	6.60%	6.60%	6.60%	6.60%
Long term care active life reserves, interest rate range, maximum	7.00%	7.00%	7.00%	7.00%
Liability balance for guaranty fund	$ 125,000,000	$ 129,000,000	$ 125,000,000	$ 129,000,000
Billed receivables percentage of total reinsurance receivables	3.00%		3.00%
Tax benefit of a qualifying position is the largest amount of tax benefit threshold	50.00%		50.00%
Potential shares attributable to exercises included in diluted EPS calculation | shares			0.4	0.3	0.6
Shares excluded from diluted EPS calculation | shares			3.7	4.8	2.3
Foreign currency transaction gain (loss)			$ (21,000,000)	$ (8,000,000)	$ (22,000,000)
Cash payments made for interest on long term debt, net of capitalized interest			511,000,000	513,000,000	501,000,000
Cash payments for federal, foreign, state and local income taxes amount			114,000,000	110,000,000	189,000,000
Accrued capital expenditures not included in investing activities			$ 18,000,000	3,000,000
Previously accrued capital expenditures included in Investment activities					14,000,000
Accounting Standards Update 2015-03 [Member]
Summary Of Significant Accounting Policies [Line Items]
Decrease in other assets and long term debt		23,000,000
CNA Financial [Member]
Summary Of Significant Accounting Policies [Line Items]
Subsidiary ownership percentage			90.00%
Anticipated amounts due from insureds related to losses under deductible policies	$ 1,200,000,000	$ 1,200,000,000
Discounted reserves for unfunded structured settlements			$ 544,000,000	560,000,000
Discounted reserves for unfunded structured settlements, discount amount			841,000,000	880,000,000
Interest recognized on discounted reserves for unfunded structured settlements			$ 42,000,000	$ 42,000,000	43,000,000
Interest rate used to discount long term care claim reserves, minimum	4.50%	4.50%	4.50%	4.50%
Interest rate used to discount long term care claim reserves, maximum	6.80%	6.80%	6.80%	6.80%
Discounted reserves for long term care claim reserves	$ 2,200,000,000	$ 2,200,000,000	$ 2,200,000,000	$ 2,200,000,000
Discounted reserves for long term care claim reserves, discount amount	529,000,000	435,000,000	529,000,000	435,000,000
Deposit assets	3,000,000	3,000,000	3,000,000	3,000,000
Deposit liabilities	$ 6,000,000	$ 8,000,000	$ 6,000,000	8,000,000
Number of life settlement contracts | Contract	526		526
Investments in life settlement contracts	$ 58,000,000		$ 58,000,000
Face Amount of Life Insurance Policies Total	285,000,000		285,000,000
CNA Financial [Member] | Other Operating Expenses [Member]
Summary Of Significant Accounting Policies [Line Items]
Loss recognized on life settlement portfolio held for sale	$ 10,000,000
CNA Financial [Member] | Other Revenues [Member]
Summary Of Significant Accounting Policies [Line Items]
Increase in fair value recognized on life settlement contracts			7,000,000	1,000,000	8,000,000
Gain recognized on matured life settlement contracts			$ 8,000,000	$ 24,000,000	$ 25,000,000
Diamond Offshore Drilling, Inc. [Member]
Summary Of Significant Accounting Policies [Line Items]
Subsidiary ownership percentage			53.00%
Boardwalk Pipeline Partners, LP [Member]
Summary Of Significant Accounting Policies [Line Items]
Subsidiary ownership percentage			51.00%
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage equity method investments in associated companies	20.00%		20.00%
Share-based payment awards requisite service period			3 years
Minimum [Member] | CNA Financial [Member] | Structured Settlement Annuity [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest rate used in determining present value of obligations of structured settlements unfunded by annuities	5.50%	5.50%	5.50%	5.50%
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage equity method investments in associated companies	50.00%		50.00%
Share-based payment awards requisite service period			4 years
Maximum [Member] | CNA Financial [Member] | Structured Settlement Annuity [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest rate used in determining present value of obligations of structured settlements unfunded by annuities	8.00%	8.00%	8.00%	8.00%

Summary of Significant Accoun50

Summary of Significant Accounting Policies - Summary of Financial Information for Joint Ventures (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]
Total assets	$ 1,749	$ 1,577
Total liabilities	1,444	1,231
Revenues	693	606	$ 491
Net income	$ 80	$ 71	$ 32

Summary of Significant Accoun51

Summary of Significant Accounting Policies - Principal Service Lives (Detail)	12 Months Ended
	Dec. 31, 2016
Minimum [Member] | Pipeline Equipment [Member]
Property, Plant and Equipment [Line Items]
Principal service life	30 years
Minimum [Member] | Offshore Drilling Equipment [Member]
Property, Plant and Equipment [Line Items]
Principal service life	15 years
Minimum [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Principal service life	3 years
Maximum [Member] | Pipeline Equipment [Member]
Property, Plant and Equipment [Line Items]
Principal service life	50 years
Maximum [Member] | Offshore Drilling Equipment [Member]
Property, Plant and Equipment [Line Items]
Principal service life	30 years
Maximum [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Principal service life	40 years

Acquisitions and Divestitures -

Acquisitions and Divestitures - Additional Information (Detail) $ in Millions	1 Months Ended	12 Months Ended
	Oct. 31, 2014USD ($)	Dec. 31, 2016USD ($)Hotel	Dec. 31, 2015USD ($)Hotel	Dec. 31, 2014USD ($)PropertyHotel
Business Acquisition [Line Items]
Number of remaining natural gas and oil properties | Property				0
Purchase price		$ 79	$ 157	$ 448
Bluegrass Project [Member]
Business Acquisition [Line Items]
Previous period capitalized costs recorded as charge in present period in other operating expenses, net of tax and noncontrolling interest				55
Bluegrass Project [Member] | Other Operating Expenses [Member]
Business Acquisition [Line Items]
Previous period capitalized costs recorded as charge in present period in other operating expenses				$ 94
Evangeline Pipeline System [Member]
Business Acquisition [Line Items]
Purchase price	$ 295
CAC [Member]
Business Acquisition [Line Items]
Percentage of coinsurance agreement				100.00%
Recognized loss due to difference between market value and book value of funds withheld assets				$ 31
Boardwalk Pipeline Partners, LP [Member] | Bluegrass Project [Member]
Business Acquisition [Line Items]
Previous period capitalized costs recorded as charge in present period in other operating expenses				10
Loews Hotels [Member]
Business Acquisition [Line Items]
Amount paid for acquisition, funded with cash and property-level debt		$ 84	$ 330	$ 230
Number of hotel properties acquired | Hotel		1	2	3

Investments - Net Investment In

Investments - Net Investment Income and Investment Gains (Losses) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Investment Income [Line Items]
Total investment income	$ 2,194	$ 1,929	$ 2,221
Investment expenses	(59)	(63)	(58)
Investment gains (losses)	50	(71)	54
Net investment income	2,135	1,866	2,163
Fixed Maturity Securities [Member]
Net Investment Income [Line Items]
Total investment income	1,819	1,751	1,803
Investment gains (losses)	54	(66)	41
Equity Securities [Member]
Net Investment Income [Line Items]
Total investment income	10	12	12
Investment gains (losses)	(5)	(23)	1
Derivative Instruments [Member]
Net Investment Income [Line Items]
Investment gains (losses)	(2)	10	(1)
Short Term Investments [Member]
Net Investment Income [Line Items]
Total investment income	9	11	4
Investment gains (losses)	3	8	13
Limited Partnership Investments [Member]
Net Investment Income [Line Items]
Total investment income	199	119	304
Income from Trading Portfolio [Member]
Net Investment Income [Line Items]
Total investment income	112	2	64
Other [Member]
Net Investment Income [Line Items]
Total investment income	$ 45	$ 34	$ 34

Investments - Net Investment 54

Investments - Net Investment Income and Investment Gains (Losses) (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net Investment Income [Line Items]
Net unrealized gains (losses) on trading securities	$ 44	$ (46)	$ 42
Fixed Maturity Securities [Member]
Net Investment Income [Line Items]
Gross realized gains on available-for-sale securities	209	133	178
Gross realized losses on available-for-sale securities	$ 160	$ 222	$ 136

Investments - Additional Inform

Investments - Additional Information (Detail)	Dec. 31, 2016USD ($)Investment	Dec. 31, 2016USD ($)Investment	Dec. 31, 2015USD ($)Investment	Dec. 31, 2014
Schedule of Investments [Line Items]
Value of non-income producing fixed maturity securities held	$ 0	$ 0	$ 54,000,000
Number of Investments not exceeds 10% of shareholders equity | Investment	0	0	0
Additional other than temporary impairment losses	$ 0
Carrying value of limited partnerships	$ 3,200,000,000	$ 3,200,000,000	$ 3,300,000,000
Undistributed earnings of limited partnerships		$ 820,000,000	$ 952,000,000
Percentage of carrying value reported on a current basis		70.40%
Percentage of carrying value reported on one month lag		13.40%
Percentage of limited partnerships comprising of the carrying value that employ hedge fund strategies	76.60%	76.60%	76.60%
Percentage of limited partnerships comprising of the carrying value that invested in private debt and equity	19.80%	19.80%	23.40%
Percentage of limited partnerships employing hedge fund strategies focused on equity investments	59.80%	59.80%
Percentage of limited partnerships employing hedge fund strategies with a multi-strategy approach	25.50%	25.50%
Percentage of limited partnerships employing hedge fund strategies focused on distressed investments	11.10%	11.10%
Percentage of limited partnerships employing hedge fund strategies focused on fixed income investments	3.60%	3.60%
Ownership percentage of aggregate partnership equity	3.50%	3.50%	2.80%
Changes in ownership percentage of aggregate partnership equity		4.00%	2.80%	4.30%
Withdrawal provisions limited partnership investments, description		The Company's limited partnership investments contain withdrawal provisions that generally limit liquidity for a period of thirty days up to one year and in some cases do not permit withdrawals until the termination of the partnership. Typically, withdrawals require advance written notice of up to 90 days.
Future capital call commitments	$ 380,000,000	$ 380,000,000
Commitments to purchase various privately placed debt securities, including bank loans	130,000,000	130,000,000
Commitments to sell various privately placed debt securities, including bank loans	121,000,000	121,000,000
Securities deposited	2,300,000,000	2,300,000,000	$ 2,800,000,000
Cash and securities with carrying values deposited as collateral for letters of credit	514,000,000	514,000,000	364,000,000
Securities deposited as collateral for letters of credit	261,000,000	261,000,000	263,000,000
Ten Largest Limited Partnership Holdings [Member]
Schedule of Investments [Line Items]
Carrying value of limited partnerships	$ 1,500,000,000	$ 1,500,000,000	$ 1,500,000,000

Investments - Schedule of Net C

Investments - Schedule of Net Change in Unrealized Gains (Losses) on Available-for-Sale Investments (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Total net change in unrealized gains (losses) on available-for-sale investments	$ 224	$ (1,119)	$ 1,517
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total net change in unrealized gains (losses) on available-for-sale investments	225	(1,114)	1,511
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total net change in unrealized gains (losses) on available-for-sale investments	(2)	(6)	$ 6
Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Total net change in unrealized gains (losses) on available-for-sale investments	$ 1	$ 1

Investments - Components of OTT

Investments - Components of OTTI Losses Recognized in Earnings by Asset Type (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	$ 81	$ 156	$ 77
Corporate and Other Bonds [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	59	104	18
States, Municipalities and Political Subdivisions [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings		18	46
Residential Mortgage-Backed [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	10	8	5
Other Asset-Backed [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	3	1	1
Total Asset-Backed [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	13	9	6
Total Fixed Maturities Available-for-Sale [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	72	131	70
Common Stock [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Net OTTI losses recognized in earnings	$ 9	$ 25	$ 7

Investments - Amortized Cost an

Investments - Amortized Cost and Fair Values of Securities (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	$ 39,518	$ 38,231
Gross Unrealized Gains	2,807	2,773
Gross Unrealized Losses	282	551
Estimated Fair Value	42,043	40,453
Unrealized OTTI Losses (Gains)	(45)	(41)
Fixed Maturity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	38,947	37,407
Gross Unrealized Gains	2,739	2,707
Gross Unrealized Losses	192	413
Estimated Fair Value	41,494	39,701
Unrealized OTTI Losses (Gains)	(45)	(41)
Corporate and Other Bonds [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	17,711	17,097
Gross Unrealized Gains	1,323	1,019
Gross Unrealized Losses	76	347
Estimated Fair Value	18,958	17,769
Unrealized OTTI Losses (Gains)	(1)
States, Municipalities and Political Subdivisions [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	12,060	11,729
Gross Unrealized Gains	1,213	1,453
Gross Unrealized Losses	33	8
Estimated Fair Value	13,240	13,174
Unrealized OTTI Losses (Gains)	(16)	(4)
Residential Mortgage-Backed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	5,004	4,935
Gross Unrealized Gains	120	154
Gross Unrealized Losses	51	17
Estimated Fair Value	5,073	5,072
Unrealized OTTI Losses (Gains)	(28)	(37)
Commercial Mortgage-Backed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	2,016	2,154
Gross Unrealized Gains	48	55
Gross Unrealized Losses	24	12
Estimated Fair Value	2,040	2,197
Other Asset-Backed [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	1,022	923
Gross Unrealized Gains	8	6
Gross Unrealized Losses	5	8
Estimated Fair Value	1,025	921
Total Asset-Backed [Member] | Fixed Maturity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	8,042	8,012
Gross Unrealized Gains	176	215
Gross Unrealized Losses	80	37
Estimated Fair Value	8,138	8,190
Unrealized OTTI Losses (Gains)	(28)	(37)
U.S. Treasury and Obligations of Government-Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	83	62
Gross Unrealized Gains	10	5
Estimated Fair Value	93	67
Foreign Government [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	435	334
Gross Unrealized Gains	13	13
Gross Unrealized Losses	3	1
Estimated Fair Value	445	346
Redeemable Preferred Stock [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	18	33
Gross Unrealized Gains	1	2
Estimated Fair Value	19	35
Total Fixed Maturities Available-for-Sale [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	38,349	37,267
Gross Unrealized Gains	2,736	2,707
Gross Unrealized Losses	192	393
Estimated Fair Value	40,893	39,581
Unrealized OTTI Losses (Gains)	(45)	(41)
Fixed Maturities Trading [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	598	140
Gross Unrealized Gains	3
Gross Unrealized Losses		20
Estimated Fair Value	601	120
Common Stock [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	13	46
Gross Unrealized Gains	6	3
Gross Unrealized Losses		1
Estimated Fair Value	19	48
Preferred Stock [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	93	145
Gross Unrealized Gains	2	7
Gross Unrealized Losses	4	3
Estimated Fair Value	91	149
Equity Securities Available-for-Sale [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	106	191
Gross Unrealized Gains	8	10
Gross Unrealized Losses	4	4
Estimated Fair Value	110	197
Equity Securities Trading [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	465	633
Gross Unrealized Gains	60	56
Gross Unrealized Losses	86	134
Estimated Fair Value	439	555
Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Cost or Amortized Cost	571	824
Gross Unrealized Gains	68	66
Gross Unrealized Losses	90	138
Estimated Fair Value	$ 549	$ 752

Investments - Securities Availa

Investments - Securities Available-for-Sale in Gross Unrealized Loss Position (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Corporate and Other Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	$ 2,615	$ 4,882
Gross Unrealized Losses, Less than 12 Months	61	302
Estimated Fair Value, 12 Months or Longer	254	174
Gross Unrealized Losses, 12 Months or Longer	15	45
Total Estimated Fair Value	2,869	5,056
Total Gross Unrealized Losses	76	347
States, Municipalities and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	959	338
Gross Unrealized Losses, Less than 12 Months	32	8
Estimated Fair Value, 12 Months or Longer	23	75
Gross Unrealized Losses, 12 Months or Longer	1
Total Estimated Fair Value	982	413
Total Gross Unrealized Losses	33	8
Residential Mortgage-Backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	2,136	963
Gross Unrealized Losses, Less than 12 Months	44	9
Estimated Fair Value, 12 Months or Longer	201	164
Gross Unrealized Losses, 12 Months or Longer	7	8
Total Estimated Fair Value	2,337	1,127
Total Gross Unrealized Losses	51	17
Commercial Mortgage-Backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	756	652
Gross Unrealized Losses, Less than 12 Months	22	10
Estimated Fair Value, 12 Months or Longer	69	96
Gross Unrealized Losses, 12 Months or Longer	2	2
Total Estimated Fair Value	825	748
Total Gross Unrealized Losses	24	12
Other Asset-Backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	398	552
Gross Unrealized Losses, Less than 12 Months	5	8
Estimated Fair Value, 12 Months or Longer	24	5
Total Estimated Fair Value	422	557
Total Gross Unrealized Losses	5	8
Total Asset-Backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	3,290	2,167
Gross Unrealized Losses, Less than 12 Months	71	27
Estimated Fair Value, 12 Months or Longer	294	265
Gross Unrealized Losses, 12 Months or Longer	9	10
Total Estimated Fair Value	3,584	2,432
Total Gross Unrealized Losses	80	37
U.S. Treasury and Obligations of Government-Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	5	4
Total Estimated Fair Value	5	4
Foreign Government [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	108	54
Gross Unrealized Losses, Less than 12 Months	3	1
Total Estimated Fair Value	108	54
Total Gross Unrealized Losses	3	1
Total Fixed Maturities Available-for-Sale [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	6,977	7,448
Gross Unrealized Losses, Less than 12 Months	167	338
Estimated Fair Value, 12 Months or Longer	571	514
Gross Unrealized Losses, 12 Months or Longer	25	55
Total Estimated Fair Value	7,548	7,962
Total Gross Unrealized Losses	192	393
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	12	16
Gross Unrealized Losses, Less than 12 Months		4
Estimated Fair Value, 12 Months or Longer	13
Gross Unrealized Losses, 12 Months or Longer	4
Total Estimated Fair Value	25	16
Total Gross Unrealized Losses	4	4
Fixed Maturity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	6,989	7,464
Gross Unrealized Losses, Less than 12 Months	167	342
Estimated Fair Value, 12 Months or Longer	584	514
Gross Unrealized Losses, 12 Months or Longer	29	55
Total Estimated Fair Value	7,573	7,978
Total Gross Unrealized Losses	$ 196	397
Redeemable Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months		3
Total Estimated Fair Value		3
Common Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months		3
Gross Unrealized Losses, Less than 12 Months		1
Total Estimated Fair Value		3
Total Gross Unrealized Losses		1
Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months		13
Gross Unrealized Losses, Less than 12 Months		3
Total Estimated Fair Value		13
Total Gross Unrealized Losses		$ 3

Investments - Pretax Credit Los

Investments - Pretax Credit Loss Component Reflected in Retained Earnings on Fixed Maturity Securities (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Beginning balance of credit losses on fixed maturity securities	$ 53	$ 62	$ 74
Reductions for securities sold during the period	(16)	(9)	(9)
Reductions for securities the Company intends to sell or more likely than not will be required to sell	(1)		(3)
Ending balance of credit losses on fixed maturity securities	$ 36	$ 53	$ 62

Investments - Available-for-Sal

Investments - Available-for-Sale Fixed Maturity Securities by Contractual Maturity (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Cost or Amortized Cost, Due in one year or less	$ 1,779	$ 1,574
Cost or Amortized Cost, Due after one year through five years	7,566	7,738
Cost or Amortized Cost, Due after five years through ten years	15,892	14,652
Cost or Amortized Cost, Due after ten years	13,112	13,303
Cost or Amortized Cost, Total	38,349	37,267
Estimated Fair Value, Due in one year or less	1,828	1,595
Estimated Fair Value, Due after one year through five years	7,955	8,082
Estimated Fair Value, Due after five years through ten years	16,332	14,915
Estimated Fair Value, Due after ten years	14,778	14,989
Estimated Fair Value, Total	$ 40,893	$ 39,581

Investments - Summary of Aggreg

Investments - Summary of Aggregate Contractual or Notional Amount and Estimated Fair Value Related to Derivative Financial Instruments (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Embedded Derivative on Funds Withheld Liability [Member]
Derivative [Line Items]
Contractual/Notional Amount	$ 174,000,000	$ 179,000,000
Estimated Fair Value, Asset	3,000,000	5,000,000
Without Hedge Designation [Member] | Equity Markets, Options - Purchased [Member]
Derivative [Line Items]
Contractual/Notional Amount	223,000,000	501,000,000
Estimated Fair Value, Asset	14,000,000	16,000,000
Without Hedge Designation [Member] | Equity Markets, Options - Written [Member]
Derivative [Line Items]
Contractual/Notional Amount	267,000,000	614,000,000
Estimated Fair Value, (Liability)	(8,000,000)	(28,000,000)
Without Hedge Designation [Member] | Equity Futures [Member] | Short [Member]
Derivative [Line Items]
Contractual/Notional Amount	225,000,000
Estimated Fair Value, Asset	1,000,000
Without Hedge Designation [Member] | Equity Futures [Member] | Long [Member]
Derivative [Line Items]
Contractual/Notional Amount		312,000,000
Estimated Fair Value, (Liability)		(1,000,000)
Without Hedge Designation [Member] | Interest Rate Futures [Member] | Long [Member]
Derivative [Line Items]
Contractual/Notional Amount		63,000,000
Without Hedge Designation [Member] | Currency Forwards [Member] | Short [Member]
Derivative [Line Items]
Contractual/Notional Amount		152,000,000
Without Hedge Designation [Member] | Currency Forwards [Member] | Long [Member]
Derivative [Line Items]
Contractual/Notional Amount		133,000,000
Estimated Fair Value, Asset		2,000,000
Without Hedge Designation [Member] | Currency Options [Member] | Long [Member]
Derivative [Line Items]
Contractual/Notional Amount		550,000,000
Estimated Fair Value, Asset		$ 7,000,000
Without Hedge Designation [Member] | Commodities Futures [Member] | Long [Member]
Derivative [Line Items]
Contractual/Notional Amount	$ 42,000,000

Fair Value - Assets and Liabili

Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Payable to Brokers [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, measured on a recurring basis	$ (44)	$ (196)
Corporate and Other Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	18,958	17,769
States, Municipalities and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	13,240	13,174
Residential Mortgage-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	5,073	5,072
Commercial Mortgage-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	2,040	2,197
Other Asset-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	1,025	921
Total Asset-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	8,138	8,190
U.S. Treasury and Obligations of Government-Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	93	67
Foreign Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	445	346
Redeemable Preferred Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	19	35
Total Fixed Maturities Available-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	40,893	39,581
Fixed Maturities Trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	601	120
Fixed Maturity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	41,494	39,701
Equity Securities Available-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	110	197
Equity Securities Trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	439	555
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	549	752
Other Invested Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	60	146
Receivables [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	1	12
Life Settlement Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	58	74
Short Term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	4,686	4,734
Level 1 [Member] | Payable to Brokers [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, measured on a recurring basis	(44)	(196)
Level 1 [Member] | U.S. Treasury and Obligations of Government-Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	93	66
Level 1 [Member] | Redeemable Preferred Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	19	35
Level 1 [Member] | Total Fixed Maturities Available-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	112	101
Level 1 [Member] | Fixed Maturity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	112	101
Level 1 [Member] | Equity Securities Available-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	91	177
Level 1 [Member] | Equity Securities Trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	438	554
Level 1 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	529	731
Level 1 [Member] | Other Invested Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	55	102
Level 1 [Member] | Receivables [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	1
Level 1 [Member] | Short Term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	3,833	3,600
Level 2 [Member] | Corporate and Other Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	18,828	17,601
Level 2 [Member] | States, Municipalities and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	13,239	13,172
Level 2 [Member] | Residential Mortgage-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	4,944	4,938
Level 2 [Member] | Commercial Mortgage-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	2,027	2,175
Level 2 [Member] | Other Asset-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	968	868
Level 2 [Member] | Total Asset-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	7,939	7,981
Level 2 [Member] | U.S. Treasury and Obligations of Government-Sponsored Enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis		1
Level 2 [Member] | Foreign Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	445	346
Level 2 [Member] | Total Fixed Maturities Available-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	40,451	39,101
Level 2 [Member] | Fixed Maturities Trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	595	35
Level 2 [Member] | Fixed Maturity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	41,046	39,136
Level 2 [Member] | Other Invested Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	5	44
Level 2 [Member] | Receivables [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis		9
Level 2 [Member] | Short Term Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	853	1,134
Level 3 [Member] | Corporate and Other Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	130	168
Level 3 [Member] | States, Municipalities and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	1	2
Level 3 [Member] | Residential Mortgage-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	129	134
Level 3 [Member] | Commercial Mortgage-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	13	22
Level 3 [Member] | Other Asset-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	57	53
Level 3 [Member] | Total Asset-Backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	199	209
Level 3 [Member] | Total Fixed Maturities Available-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	330	379
Level 3 [Member] | Fixed Maturities Trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	6	85
Level 3 [Member] | Fixed Maturity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	336	464
Level 3 [Member] | Equity Securities Available-for-Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	19	20
Level 3 [Member] | Equity Securities Trading [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	1	1
Level 3 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	20	21
Level 3 [Member] | Receivables [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis		3
Level 3 [Member] | Life Settlement Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	$ 58	$ 74

Fair Value - Reconciliations of

Fair Value - Reconciliations of Assets and Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Derivative financial instruments, net, Beginning balance	$ 3
Derivative financial instruments, net, Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	(1)
Derivative financial instruments, net, Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI	0	$ 0
Derivative financial instruments, net, Purchases	0	0
Derivative financial instruments, net, Sales	(2)	3
Derivative financial instruments, net, Settlements	0	0
Derivative financial instruments, net, Transfers into Level 3	0	0
Derivative financial instruments, net, Transfers out of Level 3	0	0
Derivative financial instruments, net, Ending balance		3
Corporate and Other Bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	168	162
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	1	(2)
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI	1	(3)
Purchases	163	65
Sales	(36)	(13)
Settlements	(103)	(35)
Transfers into Level 3		40
Transfers out of Level 3	(64)	(46)
Ending balance	130	168
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31		(2)
States, Municipalities and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	2	94
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income		1
Settlements	(1)	(10)
Transfers out of Level 3		(83)
Ending balance	1	2
Residential Mortgage-Backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	134	189
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	3	5
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI	(5)	(3)
Purchases	15	81
Settlements	(14)	(35)
Transfers into Level 3	56	14
Transfers out of Level 3	(60)	(117)
Ending balance	129	134
Commercial Mortgage-Backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	22	83
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	(1)	7
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI	(1)	(4)
Purchases	32	23
Settlements	(17)	(17)
Transfers into Level 3	3	17
Transfers out of Level 3	(25)	(87)
Ending balance	13	22
Other Asset-Backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	53	655
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	(2)	3
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI	1	3
Purchases	86	130
Sales	(25)	(263)
Settlements	(1)	(52)
Transfers into Level 3	2	7
Transfers out of Level 3	(57)	(430)
Ending balance	57	53
Total Asset-Backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	209	927
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income		15
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI	(5)	(4)
Purchases	133	234
Sales	(25)	(263)
Settlements	(32)	(104)
Transfers into Level 3	61	38
Transfers out of Level 3	(142)	(634)
Ending balance	199	209
Total Fixed Maturities Available-for-Sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	379	1,183
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	1	14
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI	(4)	(7)
Purchases	296	299
Sales	(61)	(276)
Settlements	(136)	(149)
Transfers into Level 3	61	78
Transfers out of Level 3	(206)	(763)
Ending balance	330	379
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31		(2)
Fixed Maturities Trading [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	85	90
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	5	(3)
Purchases	2
Sales	(86)	(2)
Ending balance	6	85
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	3	(3)
Fixed Maturity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	464	1,273
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	6	11
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI	(4)	(7)
Purchases	298	299
Sales	(147)	(278)
Settlements	(136)	(149)
Transfers into Level 3	61	78
Transfers out of Level 3	(206)	(763)
Ending balance	336	464
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	3	(5)
Equity Securities Available-for-Sale [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	20	16
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	(1)
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI		(1)
Purchases		4
Transfers into Level 3		1
Ending balance	19	20
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(2)
Equity Securities Trading [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	1	1
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	1	1
Purchases		1
Sales	(1)	(2)
Ending balance	1	1
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31		1
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	21	17
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income		1
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in OCI		(1)
Purchases		5
Sales	(1)	(2)
Transfers into Level 3		1
Ending balance	20	21
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	(2)	1
Life Settlement Contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	74	82
Net Realized Gains (Losses) and Net Change in Unrealized Gains (Losses), Included in Net Income	5	25
Settlements	(21)	(33)
Ending balance	58	74
Unrealized Gains (Losses) Recognized in Net Income on Level 3 Assets and Liabilities Held at December 31	$ (3)	$ 1

Fair Value - Additional Informa

Fair Value - Additional Information (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Transfers out of Level 2 to Level 1, Assets	$ 0	$ 63,000,000
Transfers out of Level 1 to Level 2, Assets	$ 0	$ 52,000,000

Fair Value - Quantitative Infor

Fair Value - Quantitative Information about Significant Unobservable Inputs Utilized by Company in Fair Value Measurements of Level 3 Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fixed Maturity Securities [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value	$ 106	$ 138
Valuation Techniques	Discounted cash flow
Fixed Maturity Securities [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit spread adjustment	2.00%	3.00%
Fixed Maturity Securities [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit spread adjustment	40.00%	184.00%
Fixed Maturity Securities [Member] | Weighted Average [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Credit spread adjustment	4.00%	6.00%
Life Settlement Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Discount rate risk premium		9.00%
Life Settlement Contracts [Member] | Discounted Cash Flow [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Fair Value		$ 74
Life Settlement Contracts [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortality assumption		55.00%
Life Settlement Contracts [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortality assumption		1676.00%
Life Settlement Contracts [Member] | Weighted Average [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortality assumption		164.00%

Fair Value - Carrying Amount, E

Fair Value - Carrying Amount, Estimated Fair Value and Level of Fair Value Hierarchy of Company's Financial Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Estimate Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other invested assets, primarily mortgage loans	$ 594	$ 688
Short term debt	107	1,052
Long term debt	10,796	9,133
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other invested assets, primarily mortgage loans	591	678
Short term debt	107	1,038
Long term debt	10,655	9,507
Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Short term debt	104	1,050
Long term debt	10,150	8,538
Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other invested assets, primarily mortgage loans	594	688
Short term debt	3	2
Long term debt	$ 646	$ 595

Receivables - Receivables (Deta

Receivables - Receivables (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Receivables [Abstract]
Reinsurance (Note 15)	$ 4,453	$ 4,491
Insurance	2,255	2,129
Receivable from brokers	178	471
Accrued investment income	410	408
Federal income taxes	7	45
Other, primarily customer accounts	431	593
Total	7,734	8,137
Less:allowance for doubtful accounts on reinsurance receivables	37	38
allowance for other doubtful accounts	53	58
Receivables	$ 7,644	$ 8,041

Property, Plant and Equipment -

Property, Plant and Equipment - Components of Property, Plant and Equipment (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Construction in process	$ 379	$ 494
Property, plant and equipment	15,230	15,477
Pipeline Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	7,631	7,462
Offshore Drilling Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	5,693	6,071
Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 1,527	$ 1,450

Property, Plant and Equipment70

Property, Plant and Equipment - Components of Property, Plant and Equipment (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Pipeline Equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 2,174	$ 1,887
Offshore Drilling Equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation	3,310	3,335
Other [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 873	$ 811

Property, Plant and Equipment71

Property, Plant and Equipment - Depreciation Expense and Capital Expenditures (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation	$ 841	$ 955	$ 861
Capital Expend.	1,572	1,718	2,813
CNA Financial [Member]
Property, Plant and Equipment [Line Items]
Depreciation	67	74	69
Capital Expend.	128	123	72
Diamond Offshore [Member]
Property, Plant and Equipment [Line Items]
Depreciation	384	494	457
Capital Expend.	629	812	2,050
Boardwalk Pipeline [Member]
Property, Plant and Equipment [Line Items]
Depreciation	321	327	292
Capital Expend.	648	390	378
Loews Hotels [Member]
Property, Plant and Equipment [Line Items]
Depreciation	63	54	37
Capital Expend.	164	389	289
Corporate [Member]
Property, Plant and Equipment [Line Items]
Depreciation	6	6	6
Capital Expend.	$ 3	$ 4	$ 24

Property, Plant and Equipment72

Property, Plant and Equipment - Additional Information (Detail)	1 Months Ended	6 Months Ended	12 Months Ended
	Feb. 29, 2016	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)RigDrilling_RigTransactionsDrillship	Dec. 31, 2015USD ($)RigDrilling_RigDrillship	Dec. 31, 2014USD ($)Rig
Property, Plant and Equipment [Line Items]
Capitalized interest related to the construction and upgrade of qualifying assets			$ 51,000,000	$ 36,000,000	$ 80,000,000
Net book value of equipment			15,230,000,000	15,477,000,000
Construction in process			$ 379,000,000	494,000,000
Diamond Offshore [Member]
Property, Plant and Equipment [Line Items]
Asset impairment loss, before tax and noncontrolling interests		$ 672,000,000		861,000,000
Asset impairment loss, net of tax and noncontrolling interests		$ 263,000,000		341,000,000
Number of rigs sold after impaired | Rig			20
Number of cold-stacked rigs | Rig			8
Number of rigs previously impaired, currently operating | Rig			2
Diamond Offshore [Member] | Ultra-deepwater Drillships [Member]
Property, Plant and Equipment [Line Items]
Net book value of equipment				$ 655,000,000
Construction in process					$ 225,000,000
Number of equipment's delivered | Drillship				1
Diamond Offshore [Member] | Ultra-deepwater Semisubmersible Rig [Member]
Property, Plant and Equipment [Line Items]
Net book value of equipment			$ 774,000,000
Construction in process				$ 270,000,000
Number of equipment's delivered | Drillship			1
Diamond Offshore [Member] | Drilling Rigs [Member]
Property, Plant and Equipment [Line Items]
Number rigs evaluated for impairment | Drilling_Rig			15	25
Number of equipment impaired | Rig			8	17
Diamond Offshore [Member] | Ultra Deepwater [Member]
Property, Plant and Equipment [Line Items]
Number of equipment impaired | Rig			3	2
Diamond Offshore [Member] | Deepwater [Member]
Property, Plant and Equipment [Line Items]
Number of equipment impaired | Rig			3	1
Diamond Offshore [Member] | Mid-Water Rigs [Member]
Property, Plant and Equipment [Line Items]
Number of equipment impaired | Rig			2
Diamond Offshore [Member] | Mid Water Floater [Member]
Property, Plant and Equipment [Line Items]
Number of equipment impaired | Rig				9
Diamond Offshore [Member] | Jack-ups [Member]
Property, Plant and Equipment [Line Items]
Number of equipment impaired | Rig				5
Diamond Offshore [Member] | Mid Water Drilling Rigs [Member]
Property, Plant and Equipment [Line Items]
Number of equipment impaired | Rig					6,000,000
Asset impairment loss, before tax and noncontrolling interests					$ 109,000,000
Asset impairment loss, net of tax and noncontrolling interests					$ 55,000,000
Number of property plant and equipment scrapped | Rig					6
Diamond Offshore Drilling, Inc. [Member]
Property, Plant and Equipment [Line Items]
Number of sale and leaseback transactions | Transactions			4
Proceed from sale and leaseback transactions			$ 210,000,000
Gain (loss) on sale sale and leaseback transactions			0
Aggregate amount of future commitments under the operating leases and contractual services agreements			655,000,000
Diamond Offshore Drilling, Inc. [Member] | Ge Oil And Gas [Member]
Property, Plant and Equipment [Line Items]
Service agreement term	10 years
Diamond Offshore Drilling, Inc. [Member] | Wells Control Equipment [Member]
Property, Plant and Equipment [Line Items]
Aggregate equipment lease expense			$ 34,000,000

Goodwill - Schedule of Changes

Goodwill - Schedule of Changes in Goodwill (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Goodwill, beginning balance	$ 351	$ 374
Impairments		(20)
Other adjustments	(5)	(3)
Goodwill, ending balance	346	351
CNA Financial [Member]
Goodwill [Line Items]
Goodwill, beginning balance	114	117
Other adjustments	(5)	(3)
Goodwill, ending balance	109	114
Diamond Offshore [Member]
Goodwill [Line Items]
Goodwill, beginning balance		20
Impairments		(20)
Boardwalk Pipeline [Member]
Goodwill [Line Items]
Goodwill, beginning balance	237	237
Goodwill, ending balance	$ 237	$ 237

Goodwill - Additional Informati

Goodwill - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)
Goodwill [Line Items]
Goodwill impairment charge	$ 20
Diamond Offshore Drilling, Inc. [Member]
Goodwill [Line Items]
Goodwill impairment charge	$ 20

Claim and Claim Adjustment Ex75

Claim and Claim Adjustment Expense Reserves - Additional Information (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2010	Dec. 31, 1996
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Catastrophe losses, net of reinsurance	$ 165	$ 141	$ 156
Net A&EP adverse development before consideration of LPT	200	150
Fair value of the collateral trust account	2,800	2,800
Property and Casualty Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Favorable net prior year development	316	218	50
Asbestos and Environmental Pollution Reserves [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net A&EP claim and allocated claim adjustment expense reserves				$ 1,600
Aggregate limit under A&EP Loss Portfolio Transfer				4,000
Ceded A&EP claim and allocated claim adjustment expense reserves				1,200
Reinsurance premium paid to NICO under A&EP Loss Portfolio Transfer				2,000
Net reinsurance receivables transferred to NICO under A&EP Loss Portfolio Transfer				215
Total consideration				$ 2,200
Cumulative amounts ceded under the Loss Portfolio Transfer	2,800	2,600
Remaining unrecognized retroactive reinsurance benefit	334	241
Non Core Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Favorable net prior year development	$ 43	$ 50	$ 17
Workers Compensation Reinsurance Pool [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Favorable net prior year development					$ 26

Claim and Claim Adjustment Ex76

Claim and Claim Adjustment Expense Reserves - Reconciliation of Claim and Claim Adjustment Expense Reserves (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Liability for Claims and Claims Adjustment Expense [Line Items]
Gross reserves, beginning of year	$ 22,663	$ 23,271	$ 24,089
Ceded reserves, beginning of year	4,087	4,344	4,972
Net reserves, beginning of year	18,576	18,927	19,117
Change in net reserves due to disposition of subsidiaries			(13)
Net incurred claim and claim adjustment expenses:
Provision for insured events of current year	5,025	4,934	5,043
Decrease in provision for insured events of prior years	(342)	(255)	(36)
Amortization of discount	175	166	161
Total net incurred	4,858	4,845	5,168
Net payments attributable to:
Current year events	(967)	(856)	(945)
Prior year events	(4,167)	(4,089)	(4,355)
Total net payments	(5,134)	(4,945)	(5,300)
Foreign currency translation adjustment and other	(51)	(251)	(45)
Net reserves, end of year	18,249	18,576	18,927
Ceded reserves, end of year	4,094	4,087	4,344
Gross reserves, end of year	$ 22,343	$ 22,663	$ 23,271

Claim and Claim Adjustment Ex77

Claim and Claim Adjustment Expense Reserves - Schedule of Gross and Net Carried Claim and Claim Adjustment Expense Reserves (Detail) - CNA Financial [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Gross Case Reserves	$ 11,860	$ 12,102
Gross IBNR Reserves	10,483	10,561
Total Gross Carried Claim and Claim Adjustment Expense Reserves	22,343	22,663	$ 23,271	$ 24,089
Net Case Reserves	9,627	9,836
Net IBNR Reserves	8,622	8,740
Total Net Carried Claim and Claim Adjustment Expense Reserves	18,249	18,576	$ 18,927	$ 19,117
Property and Casualty Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Gross Case Reserves	7,164	7,608
Gross IBNR Reserves	9,207	9,191
Total Gross Carried Claim and Claim Adjustment Expense Reserves	16,371	16,799
Net Case Reserves	6,582	6,992
Net IBNR Reserves	8,328	8,371
Total Net Carried Claim and Claim Adjustment Expense Reserves	14,910	15,363
Non Core Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Gross Case Reserves	4,696	4,494
Gross IBNR Reserves	1,276	1,370
Total Gross Carried Claim and Claim Adjustment Expense Reserves	5,972	5,864
Net Case Reserves	3,045	2,844
Net IBNR Reserves	294	369
Total Net Carried Claim and Claim Adjustment Expense Reserves	$ 3,339	$ 3,213

Claim and Claim Adjustment Ex78

Claim and Claim Adjustment Expense Reserves - Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Medical professional liability	$ (37)	$ (43)	$ 39
Other professional liability and management liability	(130)		(87)
Surety	(63)	(69)	(82)
Commercial auto	(46)	(22)	31
General liability	(28)	(33)	45
Workers' compensation	150	80	139
Other	(134)	(123)	(106)
Total pretax (favorable) unfavorable development	$ (288)	$ (210)	$ (21)

Claim and Claim Adjustment Ex79

Claim and Claim Adjustment Expense Reserves - Schedule of Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development for Segment (Detail) - CNA Financial [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	$ 18,249	$ 18,576	$ 18,927	$ 19,117
Property and Casualty Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	14,910	$ 15,363
Property and Casualty Operations [Member] | Medical Professional Liability [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	1,779
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	3,063
Property and Casualty Operations [Member] | Surety [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	394
Property and Casualty Operations [Member] | Commercial Auto [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	424
Property and Casualty Operations [Member] | General Liability [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	3,248
Property and Casualty Operations [Member] | Workers' Compensation [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	4,306
Property and Casualty Operations [Member] | Other [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	$ 1,696

Claim and Claim Adjustment Ex80

Claim and Claim Adjustment Expense Reserves - Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses (Medical Professional Liability) (Detail) - Property and Casualty Operations [Member] - Medical Professional Liability [Member] - CNA Financial [Member] $ in Millions	Dec. 31, 2016USD ($)Claim	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)	Dec. 31, 2007USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 4,872
IBNR	1,054
2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	385	$ 399	$ 401	$ 390	$ 391	$ 395	$ 427	$ 444	$ 452	$ 448
IBNR	$ 9
Cumulative number of claims | Claim	12,122
2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 442	455	467	468	468	480	496	451	$ 426
IBNR	$ 9
Cumulative number of claims | Claim	14,094
2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 432	463	471	480	506	494	469	$ 462
IBNR	$ 12
Cumulative number of claims | Claim	15,573
2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 403	446	470	486	478	478	$ 483
IBNR	$ 16
Cumulative number of claims | Claim	15,206
2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 491	501	533	507	492	$ 486
IBNR	$ 23
Cumulative number of claims | Claim	17,428
2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 559	567	575	529	$ 526
IBNR	$ 47
Cumulative number of claims | Claim	18,375
2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 567	560	540	$ 534
IBNR	$ 95
Cumulative number of claims | Claim	19,565
2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 585	548	$ 511
IBNR	$ 165
Cumulative number of claims | Claim	19,286
2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 539	$ 480
IBNR	$ 278
Cumulative number of claims | Claim	16,798
2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 469
IBNR	$ 400
Cumulative number of claims | Claim	11,600

Claim and Claim Adjustment Ex81

Claim and Claim Adjustment Expense Reserves - Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses (Medical Professional Liability) (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	$ 4,167	$ 4,089	$ 4,355
Total net liability for unpaid claim and claim adjustment expenses	18,249	18,576	18,927	$ 19,117
Property and Casualty Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	14,910	15,363
Property and Casualty Operations [Member] | Medical Professional Liability [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	3,156
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented	1,716
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	30
Liability for unallocated claim adjustment expenses for accident years presented	33
Total net liability for unpaid claim and claim adjustment expenses	1,779
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	365	364	352	326	$ 296	$ 247	$ 201	$ 134	$ 68	$ 11
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	428	409	395	377	332	282	207	90	$ 9
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	396	377	353	328	278	180	75	$ 9
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	371	361	338	273	186	93	$ 11
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	407	379	315	225	121	$ 18
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	428	359	236	121	$ 15
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	364	259	121	$ 18
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	274	149	$ 25
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	105	$ 22
Property and Casualty Operations [Member] | Medical Professional Liability [Member] | 2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 18

Claim and Claim Adjustment Ex82

Claim and Claim Adjustment Expense Reserves - Schedule of Net Strengthening or Releasing of Prior Accident Year Reserves (Medical Professional Liability) (Detail) - Property and Casualty Operations [Member] - Medical Professional Liability [Member] - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ (37)	$ (43)	$ 39
2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(14)	(2)	11	$ (1)	$ (4)	$ (32)	$ (17)	$ (8)	$ 4
Net Strengthening or (Releases) of Prior Accident Year Reserves	(63)
2008 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(13)	(12)	(1)		(12)	(16)	45	$ 25
Net Strengthening or (Releases) of Prior Accident Year Reserves	16
2009 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(31)	(8)	(9)	(26)	12	25	$ 7
Net Strengthening or (Releases) of Prior Accident Year Reserves	(30)
2010 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(43)	(24)	(16)	8		$ (5)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(80)
2011 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(10)	(32)	26	15	$ 6
Net Strengthening or (Releases) of Prior Accident Year Reserves	5
2012 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(8)	(8)	46	$ 3
Net Strengthening or (Releases) of Prior Accident Year Reserves	33
2013 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	7	20	6
Net Strengthening or (Releases) of Prior Accident Year Reserves	33
2014 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	37	37
Net Strengthening or (Releases) of Prior Accident Year Reserves	74
2015 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	59
Net Strengthening or (Releases) of Prior Accident Year Reserves	59
Total net development for the accident years presented above [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(16)	(29)	63
Total Net Development for Accident Years Prior to 2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ (21)	$ (14)	$ (24)

Claim and Claim Adjustment Ex83

Claim and Claim Adjustment Expense Reserves - Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses (Other Professional Liability and Management Liability) (Detail) - Property and Casualty Operations [Member] - Other Professional Liability and Management Liability [Member] - CNA Financial [Member] $ in Millions	Dec. 31, 2016USD ($)Claim	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)	Dec. 31, 2007USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 8,362
IBNR	2,014
2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	662	$ 662	$ 681	$ 704	$ 724	$ 734	$ 754	$ 806	$ 817	$ 804
IBNR	$ 13
Cumulative number of claims | Claim	16,011
2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 827	845	850	880	915	924	954	933	$ 916
IBNR	$ 35
Cumulative number of claims | Claim	16,326
2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 903	895	900	891	898	903	873	$ 829
IBNR	$ 50
Cumulative number of claims | Claim	17,263
2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 823	836	846	848	850	827	$ 825
IBNR	$ 39
Cumulative number of claims | Claim	17,796
2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 910	944	948	933	904	$ 876
IBNR	$ 107
Cumulative number of claims | Claim	18,620
2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 833	870	876	894	$ 907
IBNR	$ 107
Cumulative number of claims | Claim	18,228
2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 840	879	841	$ 844
IBNR	$ 137
Cumulative number of claims | Claim	17,324
2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 854	859	$ 841
IBNR	$ 306
Cumulative number of claims | Claim	16,886
2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 851	$ 847
IBNR	$ 478
Cumulative number of claims | Claim	16,391
2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 859
IBNR	$ 742
Cumulative number of claims | Claim	15,045

Claim and Claim Adjustment Ex84

Claim and Claim Adjustment Expense Reserves - Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses (Other Professional Liability and Management Liability) (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	$ 4,167	$ 4,089	$ 4,355
Total net liability for unpaid claim and claim adjustment expenses	18,249	18,576	18,927	$ 19,117
Property and Casualty Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	14,910	15,363
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	5,475
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented	2,887
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	104
Liability for unallocated claim adjustment expenses for accident years presented	72
Total net liability for unpaid claim and claim adjustment expenses	3,063
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	614	593	585	564	$ 524	$ 472	$ 397	$ 307	$ 162	$ 32
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	741	719	678	641	600	515	376	181	$ 39
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	798	769	719	638	550	358	195	$ 37
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	721	670	630	541	404	203	$ 31
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	726	682	604	502	313	$ 71
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	648	570	398	248	$ 57
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	583	426	240	$ 51
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	375	212	$ 51
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	209	$ 48
Property and Casualty Operations [Member] | Other Professional Liability and Management Liability [Member] | 2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 60

Claim and Claim Adjustment Ex85

Claim and Claim Adjustment Expense Reserves - Schedule of Net Strengthening or Releasing of Prior Accident Year Reserves (Other Professional Liability and Management Liability) (Detail) - Property and Casualty Operations [Member] - Other Professional Liability and Management Liability [Member] - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ (130)		$ (87)
2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves		$ (19)	(23)	$ (20)	$ (10)	$ (20)	$ (52)	$ (11)	$ 13
Net Strengthening or (Releases) of Prior Accident Year Reserves	(142)
2008 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(18)	(5)	(30)	(35)	(9)	(30)	21	$ 17
Net Strengthening or (Releases) of Prior Accident Year Reserves	(89)
2009 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	8	(5)	9	(7)	(5)	30	$ 44
Net Strengthening or (Releases) of Prior Accident Year Reserves	74
2010 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(13)	(10)	(2)	(2)	23	$ 2
Net Strengthening or (Releases) of Prior Accident Year Reserves	(2)
2011 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(34)	(4)	15	29	$ 28
Net Strengthening or (Releases) of Prior Accident Year Reserves	34
2012 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(37)	(6)	(18)	$ (13)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(74)
2013 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(39)	38	(3)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(4)
2014 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(5)	18
Net Strengthening or (Releases) of Prior Accident Year Reserves	13
2015 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	4
Net Strengthening or (Releases) of Prior Accident Year Reserves	4
Total net development for the accident years presented above [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(134)	7	(52)
Total Net Development for Accident Years Prior to 2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ 4	$ (7)	$ (35)

Claim and Claim Adjustment Ex86

Claim and Claim Adjustment Expense Reserves - Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses (Surety) (Detail) - Property and Casualty Operations [Member] - Surety [Member] - CNA Financial [Member] $ in Millions	Dec. 31, 2016USD ($)Claim	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)	Dec. 31, 2007USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 787
IBNR	319
2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 50	$ 49	$ 49	$ 51	$ 56	$ 59	$ 57	$ 81	$ 107	$ 98
Cumulative number of claims | Claim	6,270
2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 44	45	48	52	61	68	73	114	$ 114
Cumulative number of claims | Claim	7,153
2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 53	52	59	68	85	103	114	$ 114
IBNR	$ 1
Cumulative number of claims | Claim	6,654
2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 63	66	76	84	111	112	$ 112
IBNR	$ 8
Cumulative number of claims | Claim	5,943
2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 70	75	87	116	121	$ 120
IBNR	$ 9
Cumulative number of claims | Claim	5,760
2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 52	70	98	122	$ 120
IBNR	$ 16
Cumulative number of claims | Claim	5,473
2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 106	115	121	$ 120
IBNR	$ 24
Cumulative number of claims | Claim	4,890
2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 94	124	$ 123
IBNR	$ 51
Cumulative number of claims | Claim	4,737
2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 131	$ 131
IBNR	$ 100
Cumulative number of claims | Claim	4,279
2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 124
IBNR	$ 110
Cumulative number of claims | Claim	2,902

Claim and Claim Adjustment Ex87

Claim and Claim Adjustment Expense Reserves - Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses (Surety) (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	$ 4,167	$ 4,089	$ 4,355
Total net liability for unpaid claim and claim adjustment expenses	18,249	18,576	18,927	$ 19,117
Property and Casualty Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	14,910	15,363
Property and Casualty Operations [Member] | Surety [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	437
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented	350
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	16
Liability for unallocated claim adjustment expenses for accident years presented	28
Total net liability for unpaid claim and claim adjustment expenses	394
Property and Casualty Operations [Member] | Surety [Member] | 2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	50	49	48	46	$ 46	$ 46	$ 45	$ 40	$ 30	$ 12
Property and Casualty Operations [Member] | Surety [Member] | 2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	43	43	43	43	42	39	35	27	$ 9
Property and Casualty Operations [Member] | Surety [Member] | 2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	47	46	45	43	41	34	24	$ 13
Property and Casualty Operations [Member] | Surety [Member] | 2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	55	58	57	55	50	34	$ 13
Property and Casualty Operations [Member] | Surety [Member] | 2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	60	60	58	55	42	$ 19
Property and Casualty Operations [Member] | Surety [Member] | 2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	35	35	34	32	$ 5
Property and Casualty Operations [Member] | Surety [Member] | 2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	78	69	40	$ 16
Property and Casualty Operations [Member] | Surety [Member] | 2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	38	30	$ 7
Property and Casualty Operations [Member] | Surety [Member] | 2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	26	$ 7
Property and Casualty Operations [Member] | Surety [Member] | 2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 5

Claim and Claim Adjustment Ex88

Claim and Claim Adjustment Expense Reserves - Schedule of Net Strengthening or Releasing of Prior Accident Year Reserves (Surety) (Detail) - Property and Casualty Operations [Member] - Surety [Member] - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ (63)	$ (69)	$ (82)
2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	1		(2)	$ (5)	$ (3)	$ 2	$ (24)	$ (26)	$ 9
Net Strengthening or (Releases) of Prior Accident Year Reserves	(48)
2008 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(1)	(3)	(4)	(9)	(7)	(5)	$ (41)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(70)
2009 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	1	(7)	(9)	(17)	(18)	$ (11)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(61)
2010 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(3)	(10)	(8)	(27)	(1)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(49)
2011 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(5)	(12)	(29)	(5)	$ 1
Net Strengthening or (Releases) of Prior Accident Year Reserves	(50)
2012 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(18)	(28)	(24)	$ 2
Net Strengthening or (Releases) of Prior Accident Year Reserves	(68)
2013 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(9)	(6)	1
Net Strengthening or (Releases) of Prior Accident Year Reserves	(14)
2014 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(30)	1
Net Strengthening or (Releases) of Prior Accident Year Reserves	(29)
Total net development for the accident years presented above [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(64)	(65)	(75)
Total Net Development for Accident Years Prior to 2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ 1	$ (4)	$ (7)

Claim and Claim Adjustment Ex89

Claim and Claim Adjustment Expense Reserves - Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses (Commercial Auto) (Detail) - Property and Casualty Operations [Member] - Commercial Auto [Member] - CNA Financial [Member] $ in Millions	Dec. 31, 2016USD ($)Claim	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)	Dec. 31, 2007USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 2,630
IBNR	247
2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 352	$ 354	$ 355	$ 356	$ 358	$ 355	$ 360	$ 368	$ 367	$ 348
Cumulative number of claims | Claim	67,473
2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 296	298	298	305	309	306	316	323	$ 322
Cumulative number of claims | Claim	56,407
2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 272	275	277	281	278	274	272	$ 287
Cumulative number of claims | Claim	47,325
2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 281	286	291	283	279	274	$ 262
IBNR	$ 1
Cumulative number of claims | Claim	46,324
2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 285	290	293	279	273	$ 262
IBNR	$ 5
Cumulative number of claims | Claim	46,676
2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 300	296	292	282	$ 270
IBNR	$ 11
Cumulative number of claims | Claim	45,279
2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 241	257	259	$ 242
IBNR	$ 20
Cumulative number of claims | Claim	38,513
2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 210	221	$ 231
IBNR	$ 40
Cumulative number of claims | Claim	32,958
2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 197	$ 199
IBNR	$ 65
Cumulative number of claims | Claim	29,714
2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 196
IBNR	$ 105
Cumulative number of claims | Claim	25,196

Claim and Claim Adjustment Ex90

Claim and Claim Adjustment Expense Reserves - Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses (Commercial Auto) (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	$ 4,167	$ 4,089	$ 4,355
Total net liability for unpaid claim and claim adjustment expenses	18,249	18,576	18,927	$ 19,117
Property and Casualty Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	14,910	15,363
Property and Casualty Operations [Member] | Commercial Auto [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	2,220
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented	410
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	4
Liability for unallocated claim adjustment expenses for accident years presented	10
Total net liability for unpaid claim and claim adjustment expenses	424
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	351	350	349	348	$ 340	$ 329	$ 295	$ 250	$ 185	$ 93
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	293	292	291	289	274	244	210	158	$ 83
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	270	270	269	257	229	188	128	$ 72
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	279	274	265	240	197	137	$ 72
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	275	264	241	193	141	$ 78
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	276	253	214	157	$ 77
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	195	164	132	$ 73
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	135	100	$ 63
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	95	$ 52
Property and Casualty Operations [Member] | Commercial Auto [Member] | 2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 51

Claim and Claim Adjustment Ex91

Claim and Claim Adjustment Expense Reserves - Schedule of Net Strengthening or Releasing of Prior Accident Year Reserves (Commercial Auto) (Detail) - Property and Casualty Operations [Member] - Commercial Auto [Member] - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ (46)	$ (22)	$ 31
2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(2)	(1)	(1)	$ (2)	$ 3	$ (5)	$ (8)	$ 1	$ 19
Net Strengthening or (Releases) of Prior Accident Year Reserves	4
2008 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(2)		(7)	(4)	3	(10)	(7)	$ 1
Net Strengthening or (Releases) of Prior Accident Year Reserves	(26)
2009 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(3)	(2)	(4)	3	4	2	$ (15)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(15)
2010 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(5)	(5)	8	4	5	$ 12
Net Strengthening or (Releases) of Prior Accident Year Reserves	19
2011 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(5)	(3)	14	6	$ 11
Net Strengthening or (Releases) of Prior Accident Year Reserves	23
2012 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	4	4	10	$ 12
Net Strengthening or (Releases) of Prior Accident Year Reserves	30
2013 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(16)	(2)	17
Net Strengthening or (Releases) of Prior Accident Year Reserves	(1)
2014 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(11)	(10)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(21)
2015 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(2)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(2)
Total net development for the accident years presented above [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(42)	(19)	37
Total Net Development for Accident Years Prior to 2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ (4)	$ (3)	$ (6)

Claim and Claim Adjustment Ex92

Claim and Claim Adjustment Expense Reserves - Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses (General Liability) (Detail) - Property and Casualty Operations [Member] - General Liability [Member] - CNA Financial [Member] $ in Millions	Dec. 31, 2016USD ($)Claim	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)	Dec. 31, 2007USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 6,065
IBNR	1,382
2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	540	$ 548	$ 545	$ 559	$ 600	$ 610	$ 639	$ 678	$ 673	$ 774
IBNR	$ 28
Cumulative number of claims | Claim	53,553
2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 591	600	613	632	633	647	630	604	$ 611
IBNR	$ 18
Cumulative number of claims | Claim	44,586
2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 622	619	623	629	633	634	637	$ 591
IBNR	$ 16
Cumulative number of claims | Claim	43,955
2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 659	675	695	649	599	597	$ 566
IBNR	$ 25
Cumulative number of claims | Claim	43,378
2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 621	611	610	564	534	$ 537
IBNR	$ 41
Cumulative number of claims | Claim	38,101
2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 558	570	579	563	$ 539
IBNR	$ 63
Cumulative number of claims | Claim	34,037
2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 643	634	645	$ 615
IBNR	$ 142
Cumulative number of claims | Claim	32,897
2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 635	634	$ 627
IBNR	$ 224
Cumulative number of claims | Claim	26,744
2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 574	$ 573
IBNR	$ 330
Cumulative number of claims | Claim	21,687
2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 622
IBNR	$ 495
Cumulative number of claims | Claim	16,720

Claim and Claim Adjustment Ex93

Claim and Claim Adjustment Expense Reserves - Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses (General Liability) (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	$ 4,167	$ 4,089	$ 4,355
Total net liability for unpaid claim and claim adjustment expenses	18,249	18,576	18,927	$ 19,117
Property and Casualty Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	14,910	15,363
Property and Casualty Operations [Member] | General Liability [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	4,002
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented	2,063
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	1,130
Liability for unallocated claim adjustment expenses for accident years presented	55
Total net liability for unpaid claim and claim adjustment expenses	3,248
Property and Casualty Operations [Member] | General Liability [Member] | 2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	504	497	492	481	$ 458	$ 413	$ 328	$ 236	$ 130	$ 30
Property and Casualty Operations [Member] | General Liability [Member] | 2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	567	560	550	528	473	390	261	129	$ 31
Property and Casualty Operations [Member] | General Liability [Member] | 2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	584	557	532	486	392	270	112	$ 33
Property and Casualty Operations [Member] | General Liability [Member] | 2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	608	577	530	414	267	139	$ 27
Property and Casualty Operations [Member] | General Liability [Member] | 2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	534	484	389	253	135	$ 27
Property and Casualty Operations [Member] | General Liability [Member] | 2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	417	340	233	127	$ 27
Property and Casualty Operations [Member] | General Liability [Member] | 2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	377	257	135	$ 33
Property and Casualty Operations [Member] | General Liability [Member] | 2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	245	115	$ 29
Property and Casualty Operations [Member] | General Liability [Member] | 2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	132	$ 31
Property and Casualty Operations [Member] | General Liability [Member] | 2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 34

Claim and Claim Adjustment Ex94

Claim and Claim Adjustment Expense Reserves - Schedule of Net Strengthening or Releasing of Prior Accident Year Reserves (General Liability) (Detail) - Property and Casualty Operations [Member] - General Liability [Member] - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ (28)	$ (33)	$ 45
2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(8)	3	(14)	$ (41)	$ (10)	$ (29)	$ (39)	$ 5	$ (101)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(234)
2008 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(9)	(13)	(19)	(1)	(14)	17	26	$ (7)
Net Strengthening or (Releases) of Prior Accident Year Reserves	(20)
2009 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	3	(4)	(6)	(4)	(1)	(3)	$ 46
Net Strengthening or (Releases) of Prior Accident Year Reserves	31
2010 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(16)	(20)	46	50	2	$ 31
Net Strengthening or (Releases) of Prior Accident Year Reserves	93
2011 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	10	1	46	30	$ (3)
Net Strengthening or (Releases) of Prior Accident Year Reserves	84
2012 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(12)	(9)	16	$ 24
Net Strengthening or (Releases) of Prior Accident Year Reserves	19
2013 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	9	(11)	30
Net Strengthening or (Releases) of Prior Accident Year Reserves	28
2014 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	1	7
Net Strengthening or (Releases) of Prior Accident Year Reserves	8
2015 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	1
Net Strengthening or (Releases) of Prior Accident Year Reserves	1
Total net development for the accident years presented above [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	(21)	(46)	99
Total Net Development for Accident Years Prior to 2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ (7)	$ 13	$ (54)

Claim and Claim Adjustment Ex95

Claim and Claim Adjustment Expense Reserves - Schedule of Net Incurred Claims and Allocated Claim Adjustment Expenses (Workers' Compensation) (Detail) - Property and Casualty Operations [Member] - Workers' Compensation [Member] - CNA Financial [Member] $ in Millions	Dec. 31, 2016USD ($)Claim	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2011USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2009USD ($)	Dec. 31, 2008USD ($)	Dec. 31, 2007USD ($)
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 5,875
IBNR	1,068
2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	627	$ 608	$ 610	$ 604	$ 603	$ 603	$ 604	$ 596	$ 580	$ 568
IBNR	$ 32
Cumulative number of claims | Claim	71,049
2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 638	630	622	612	608	606	593	575	$ 558
IBNR	$ 36
Cumulative number of claims | Claim	59,883
2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 625	617	611	600	596	594	587	$ 583
IBNR	$ 46
Cumulative number of claims | Claim	51,111
2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 717	697	683	663	641	619	$ 576
IBNR	$ 45
Cumulative number of claims | Claim	48,056
2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 666	642	648	637	628	$ 593
IBNR	$ 52
Cumulative number of claims | Claim	44,571
2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 671	661	648	616	$ 589
IBNR	$ 86
Cumulative number of claims | Claim	41,683
2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 610	584	563	$ 528
IBNR	$ 121
Cumulative number of claims | Claim	38,102
2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 474	474	$ 459
IBNR	$ 157
Cumulative number of claims | Claim	32,996
2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 426	$ 416
IBNR	$ 206
Cumulative number of claims | Claim	31,296
2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 421
IBNR	$ 287
Cumulative number of claims | Claim	27,042

Claim and Claim Adjustment Ex96

Claim and Claim Adjustment Expense Reserves - Schedule of Net Cumulative Paid Claim and Claim Adjustment Expenses (Workers' Compensation) (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2007
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	$ 4,167	$ 4,089	$ 4,355
Total net liability for unpaid claim and claim adjustment expenses	18,249	18,576	18,927	$ 19,117
Property and Casualty Operations [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total net liability for unpaid claim and claim adjustment expenses	14,910	15,363
Property and Casualty Operations [Member] | Workers' Compensation [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	3,877
Net liability for unpaid claim and allocated claim adjustment expenses for the accident years presented	1,998
Net liability for unpaid claim and claim adjustment expenses for accident years prior to 2007	2,334
Other	(30)
Liability for unallocated claim adjustment expenses for accident years presented	4
Total net liability for unpaid claim and claim adjustment expenses	4,306
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2007 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	535	533	522	502	$ 471	$ 429	$ 390	$ 337	$ 246	$ 100
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2008 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	520	505	489	461	425	381	323	233	$ 92
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2009 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	516	495	468	435	381	315	223	$ 88
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2010 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	565	531	500	433	352	245	$ 94
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2011 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	515	471	432	353	245	$ 97
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2012 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	465	411	338	229	$ 86
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2013 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	366	297	211	$ 79
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2014 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	213	157	$ 60
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2015 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	130	$ 50
Property and Casualty Operations [Member] | Workers' Compensation [Member] | 2016 [Member]
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Total	$ 52

Claim and Claim Adjustment Ex97

Claim and Claim Adjustment Expense Reserves - Schedule of Net Strengthening or Releasing of Prior Accident Year Reserves (Workers' Compensation) (Detail) - Property and Casualty Operations [Member] - Workers' Compensation [Member] - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ 150	$ 80	$ 139
2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	19	(2)	6	$ 1		$ (1)	$ 8	$ 16	$ 12
Net Strengthening or (Releases) of Prior Accident Year Reserves	59
2008 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	8	8	10	4	$ 2	13	18	$ 17
Net Strengthening or (Releases) of Prior Accident Year Reserves	80
2009 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	8	6	11	4	2	7	$ 4
Net Strengthening or (Releases) of Prior Accident Year Reserves	42
2010 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	20	14	20	22	22	$ 43
Net Strengthening or (Releases) of Prior Accident Year Reserves	141
2011 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	24	(6)	11	9	$ 35
Net Strengthening or (Releases) of Prior Accident Year Reserves	73
2012 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	10	13	32	$ 27
Net Strengthening or (Releases) of Prior Accident Year Reserves	82
2013 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	26	21	35
Net Strengthening or (Releases) of Prior Accident Year Reserves	82
2014 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves		15
Net Strengthening or (Releases) of Prior Accident Year Reserves	15
2015 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	10
Net Strengthening or (Releases) of Prior Accident Year Reserves	10
Total net development for the accident years presented above [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	125	69	125
Adjustment for Development on a Discounted Basis [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	1	(4)	1
Total Net Development for Accident Years Prior to 2007 [Member]
Claims Development [Line Items]
Strengthening or (Releases) of Prior Accident Year Reserves	$ 24	$ 15	$ 13

Claim and Claim Adjustment Ex98

Claim and Claim Adjustment Expense Reserves - Reconciliation of Net Liability for Unpaid Claim and Claim Adjustment Expenses for Property and Casualty Operations to Amount Presented in Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Total reinsurance receivables	$ 4,094	$ 4,087
Total gross liability for unpaid claims and claims adjustment expenses	22,343	22,663
Property and Casualty Operations [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Total reinsurance receivables	1,461
Non Core Operations [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Total reinsurance receivables	2,633
CNA Financial [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Total net claim and claim adjustment expenses	18,249	18,576	$ 18,927	$ 19,117
CNA Financial [Member] | Property and Casualty Operations [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Total net claim and claim adjustment expenses	14,910	15,363
CNA Financial [Member] | Non Core Operations [Member]
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Total net claim and claim adjustment expenses	$ 3,339	$ 3,213

Claim and Claim Adjustment Ex99

Claim and Claim Adjustment Expense Reserves - Schedule of Historical Claims Duration (Detail) - CNA Financial [Member]	Dec. 31, 2016
Medical Professional Liability [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Claims in Year 1	3.10%
Average Annual Percentage Payout of Claims in Year 2	18.20%
Average Annual Percentage Payout of Claims in Year 3	22.30%
Average Annual Percentage Payout of Claims in Year 4	19.60%
Average Annual Percentage Payout of Claims in Year 5	12.70%
Average Annual Percentage Payout of Claims in Year 6	8.00%
Average Annual Percentage Payout of Claims in Year 7	5.00%
Average Annual Percentage Payout of Claims in Year 8	4.80%
Average Annual Percentage Payout of Claims in Year 9	3.70%
Average Annual Percentage Payout of Claims in Year 10	0.30%
Total	97.70%
Other Professional Liability and Management Liability [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Claims in Year 1	5.70%
Average Annual Percentage Payout of Claims in Year 2	20.60%
Average Annual Percentage Payout of Claims in Year 3	21.00%
Average Annual Percentage Payout of Claims in Year 4	17.00%
Average Annual Percentage Payout of Claims in Year 5	10.00%
Average Annual Percentage Payout of Claims in Year 6	6.30%
Average Annual Percentage Payout of Claims in Year 7	5.60%
Average Annual Percentage Payout of Claims in Year 8	3.80%
Average Annual Percentage Payout of Claims in Year 9	1.90%
Average Annual Percentage Payout of Claims in Year 10	3.20%
Total	95.10%
Surety [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Claims in Year 1	23.40%
Average Annual Percentage Payout of Claims in Year 2	32.80%
Average Annual Percentage Payout of Claims in Year 3	20.20%
Average Annual Percentage Payout of Claims in Year 4	8.90%
Average Annual Percentage Payout of Claims in Year 5	3.70%
Average Annual Percentage Payout of Claims in Year 6	1.50%
Average Annual Percentage Payout of Claims in Year 7	(0.70%)
Average Annual Percentage Payout of Claims in Year 8	2.00%
Average Annual Percentage Payout of Claims in Year 9	1.00%
Average Annual Percentage Payout of Claims in Year 10	2.00%
Total	94.80%
Commercial Auto [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Claims in Year 1	27.20%
Average Annual Percentage Payout of Claims in Year 2	23.10%
Average Annual Percentage Payout of Claims in Year 3	18.30%
Average Annual Percentage Payout of Claims in Year 4	13.90%
Average Annual Percentage Payout of Claims in Year 5	9.10%
Average Annual Percentage Payout of Claims in Year 6	3.90%
Average Annual Percentage Payout of Claims in Year 7	1.30%
Average Annual Percentage Payout of Claims in Year 8	0.20%
Average Annual Percentage Payout of Claims in Year 9	0.30%
Average Annual Percentage Payout of Claims in Year 10	0.30%
Total	97.60%
General Liability [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Claims in Year 1	5.00%
Average Annual Percentage Payout of Claims in Year 2	16.30%
Average Annual Percentage Payout of Claims in Year 3	20.50%
Average Annual Percentage Payout of Claims in Year 4	20.10%
Average Annual Percentage Payout of Claims in Year 5	15.30%
Average Annual Percentage Payout of Claims in Year 6	8.00%
Average Annual Percentage Payout of Claims in Year 7	4.20%
Average Annual Percentage Payout of Claims in Year 8	2.70%
Average Annual Percentage Payout of Claims in Year 9	1.10%
Average Annual Percentage Payout of Claims in Year 10	1.30%
Total	94.50%
Workers' Compensation [Member]
Short-duration Insurance Contracts, Historical Claims Duration [Line Items]
Average Annual Percentage Payout of Claims in Year 1	13.50%
Average Annual Percentage Payout of Claims in Year 2	21.40%
Average Annual Percentage Payout of Claims in Year 3	14.60%
Average Annual Percentage Payout of Claims in Year 4	10.50%
Average Annual Percentage Payout of Claims in Year 5	7.50%
Average Annual Percentage Payout of Claims in Year 6	5.70%
Average Annual Percentage Payout of Claims in Year 7	4.60%
Average Annual Percentage Payout of Claims in Year 8	3.00%
Average Annual Percentage Payout of Claims in Year 9	2.10%
Average Annual Percentage Payout of Claims in Year 10	0.30%
Total	83.20%

Claim and Claim Adjustment E100

Claim and Claim Adjustment Expense Reserves - Schedule of Impact of Loss Portfolio Transfer on the Consolidated Statement of Operations (Detail) - CNA Financial [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Claim And Claim Adjustment Expense Reserves [Line Items]
Net A&EP adverse development before consideration of LPT	$ 200	$ 150
Retroactive reinsurance benefit recognized	(107)	(85)	$ (13)
Pretax impact of A&EP reserve development and the LPT	$ 93	$ 65	$ (13)

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leased Assets [Line Items]
Rent expense	$ 97	$ 85	$ 94
Operating leases, Future Minimum Lease Payments, 2017	72
Operating leases, Future Minimum Lease Payments, 2018	$ 59
CNA Financial [Member]
Operating Leased Assets [Line Items]
Expected year for relocation of office space under lease agreement	2,018
Operating leases, Future Minimum Lease Payments, 2017	$ 10
Operating leases, Future Minimum Lease Payments, 2018	$ 4

Leases - Future Minimum Lease P

Leases - Future Minimum Lease Payments to be Made Under Non-Cancelable Operating Leases Along with Lease and Sublease Minimum Receipts to be Received on Owned and Leased Properties (Detail) $ in Millions	Dec. 31, 2016USD ($)
Leases [Abstract]
Operating leases, Future Minimum Lease Payments, 2017	$ 72
Operating leases, Future Minimum Lease Payments, 2018	59
Operating leases, Future Minimum Lease Payments, 2019	51
Operating leases, Future Minimum Lease Payments, 2020	54
Operating leases, Future Minimum Lease Payments, 2021	53
Operating leases, Future Minimum Lease Payments, Thereafter	349
Operating leases, Future Minimum Lease Payments, Total	638
Operating leases, Future Minimum Lease Receipts, 2017	5
Operating leases, Future Minimum Lease Receipts, 2018	5
Operating leases, Future Minimum Lease Receipts, 2019	4
Operating leases, Future Minimum Lease Receipts, 2020	4
Operating leases, Future Minimum Lease Receipts, 2021	4
Operating leases, Future Minimum Lease Receipts, Thereafter	19
Operating leases, Future Minimum Lease Receipts, Total	$ 41

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Undistributed earning related to foreign subsidiaries	$ 1,800
Reductions for tax positions related to a prior year	20	$ 3	$ 35
Income tax expense related to penalties		2
Income tax benefit related to penalties	23		22
Reductions in penalties related to uncertain tax positions	(23)
Net operating loss carryforwards	178	245
Valuation allowance	210	147
Other deferred tax assets	246	282
Federal [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 76
Net operating loss carryforwards expiration year	2034 and 2036
Tax credit carryforwards	$ 157
Foreign [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards expiration year	2020 and 2025
Net operating loss carryforwards in foreign tax jurisdictions	$ 59
Tax credit carryforwards	$ 98
Tax credit carryforwards expiration year	2024 and 2026
Net operating loss carryforwards indefinitely	$ 36
CNA Financial [Member]
Income Tax Contingency [Line Items]
Equity ownership percentage	80.00%
Diamond Offshore [Member]
Income Tax Contingency [Line Items]
Unrecognized tax benefits that would affect effective tax rate upon recognition	$ 36	$ 49	51
Reduction to income tax expense			$ 17
Potential tax expense related to income tax examination	22
Net operating loss carryforwards	91
Valuation allowance	210
Foreign tax credits	62
Other deferred tax assets	57
Diamond Offshore [Member] | Foreign [Member]
Income Tax Contingency [Line Items]
Foreign tax credit carrybacks	$ 33

Income Taxes - Schedule of Curr

Income Taxes - Schedule of Current and Deferred Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income tax expense (benefit):
Federal income tax expense (benefit), Current	$ 71	$ 79	$ 370
Federal income tax expense (benefit), Deferred	102	(234)	(23)
State and city income tax expense (benefit), Current	13	21	12
State and city income tax expense (benefit), Deferred	13	5	6
Foreign income tax expense (benefit)	21	86	92
Income tax expense (benefit)	$ 220	$ (43)	$ 457

Income Taxes - Components of U.

Income Taxes - Components of U.S. and Foreign Income and Reconciliation between Federal Income Tax Expense at Statutory Rates and Actual Income Tax Expense (Benefit) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income before income tax:
Income before income tax, U.S.	$ 1,207	$ 543	$ 1,499
Income before income tax, Foreign	(271)	(299)	311
Income before income tax	936	244	1,810
Income tax expense at statutory rate	328	86	633
Increase (decrease) in income tax expense resulting from:
Exempt investment income	(126)	(126)	(121)
Foreign related tax differential	40	(18)	(48)
Amortization of deferred charges associated with intercompany rig sales to other tax jurisdictions		38	44
Taxes related to domestic affiliate	(14)	(10)	14
Partnership earnings not subject to taxes	(52)	(38)	(39)
Allowance for foreign tax credits	62
Unrecognized tax positions, including foreign currency revaluation	(42)	1	(42)
Other	24	24	16
Income tax expense (benefit)	$ 220	$ (43)	$ 457

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits, Excluding Tax Carryforwards and Interest and Penalties (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Balance at January 1	$ 54	$ 57	$ 91
Additions for tax positions related to the current year	4	7	6
Additions for tax positions related to a prior year	1
Reductions for tax positions related to a prior year	(20)	(3)	(35)
Lapse of statute of limitations	(4)	(7)	(5)
Balance at December 31	$ 35	$ 54	$ 57

Income Taxes - Summary of Defer

Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Property and casualty claim and claim adjustment expense reserves	$ 125	$ 178
Unearned premium reserves	206	230
Receivables	26	30
Employee benefits	407	419
Life settlement contracts	56	48
Deferred retroactive reinsurance benefit	117	84
Net operating loss carryforwards	178	245
Tax credit carryforwards	289	131
Basis differential in investment in subsidiary	17	19
Other	246	282
Total deferred tax assets	1,667	1,666
Valuation allowance	(210)	(147)
Net deferred tax assets	1,457	1,519
Deferred tax liabilities:
Deferred acquisition costs	(120)	(117)
Net unrealized gains	(295)	(166)
Property, plant and equipment	(1,019)	(998)
Basis differential in investment in subsidiary	(409)	(428)
Other liabilities	(235)	(173)
Total deferred tax liabilities	(2,078)	(1,882)
Net deferred tax liabilities	$ (621)	$ (363)

Income Taxes - Summary of De108

Income Taxes - Summary of Deferred Tax Assets and Liabilities (Parenthetical) (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Deferred Tax Assets And Liabilities [Line Items]
Deferred tax assets	$ 1,667	$ 1,666
Other Assets [Member]
Schedule Of Deferred Tax Assets And Liabilities [Line Items]
Deferred tax assets	$ 15	$ 19

Debt - Schedule of Long-Term De

Debt - Schedule of Long-Term Debt Instruments (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Debt, Gross	$ 10,871	$ 10,647
Less unamortized discount and issuance costs	93	87
Debt	10,778	10,560
Commercial Paper [Member]
Debt Instrument [Line Items]
Debt, Gross		287
Loews Corporation [Member]
Debt Instrument [Line Items]
Debt, Gross	1,800
Less unamortized discount and issuance costs	25
CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross	2,728
Less unamortized discount and issuance costs	13
Capital lease obligation	5	4
Diamond Offshore [Member]
Debt Instrument [Line Items]
Debt, Gross	2,104
Less unamortized discount and issuance costs	19
Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	3,589
Less unamortized discount and issuance costs	31
Capital lease obligation	9	10
Loews Hotels [Member]
Debt Instrument [Line Items]
Debt, Gross	650	598
Less unamortized discount and issuance costs	5
5.3% Notes Due 2016 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Debt, Gross		400
2.6% Notes Due 2023 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Debt, Gross	500	500
3.8% Notes Due 2026 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Debt, Gross	500
6.0% Notes Due 2035 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Debt, Gross	300	300
4.1% Notes Due 2043 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Debt, Gross	500	500
6.5% Notes Due 2016 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross		350
7.0% Notes Due 2018 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross	150	150
7.4% Notes Due 2019 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross	350	350
5.9% Notes Due 2020 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross	500	500
5.8% Notes Due 2021 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross	400	400
7.3% Debentures Due 2023 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross	243	243
4.0% Notes Due 2024 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross	550	550
4.5% Notes Due 2026 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross	500
Variable Rate Note Due 2036 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt, Gross	30	30
Variable Rate Revolving Credit Facility Due 2020 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Debt, Gross	104
5.9% Notes Due 2019 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Debt, Gross	500	500
3.5% Senior Notes Due 2023 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Debt, Gross	250	250
5.7% Notes Due 2039 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Debt, Gross	500	500
4.9% Notes Due 2043 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Debt, Gross	750	750
Variable Rate Revolving Credit Facility Due 2021 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	180	375
5.9% Notes Due 2016 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross		250
5.5% Notes Due 2017 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	300	300
6.3% Notes Due 2017 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	275	275
5.2% Notes Due 2018 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	185	185
5.8% Notes Due 2019 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	350	350
4.5% Notes Due 2021 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	440	440
4.0% Notes Due 2022 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	300	300
3.4% Notes Due 2023 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	300	300
5.0% Notes Due 2024 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	600	600
6.0% Notes Due 2026 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	550
7.3% Debentures Due 2027 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt, Gross	$ 100	$ 100

Debt - Schedule of Long-Term110

Debt - Schedule of Long-Term Debt Instruments (Parenthetical) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Loews Hotels [Member]
Debt Instrument [Line Items]
Effective interest rate	4.10%
5.3% Notes Due 2016 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Stated interest rate	5.30%
Maturity year	2,016
Effective interest rate	5.40%
Debt authorized	$ 400,000,000
2.6% Notes Due 2023 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Stated interest rate	2.60%
Maturity year	2,023
Effective interest rate	2.80%
Debt authorized	$ 500,000,000
3.8% Notes Due 2026 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Stated interest rate	3.80%
Maturity year	2,026
Effective interest rate	3.90%
Debt authorized	$ 500,000,000
6.0% Notes Due 2035 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Stated interest rate	6.00%
Maturity year	2,035
Effective interest rate	6.20%
Debt authorized	$ 300,000,000
4.1% Notes Due 2043 [Member] | Loews Corporation [Member]
Debt Instrument [Line Items]
Stated interest rate	4.10%
Maturity year	2,043
Effective interest rate	4.30%
Debt authorized	$ 500,000,000
6.5% Notes Due 2016 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Stated interest rate	6.50%
Maturity year	2,016
Effective interest rate	6.60%
Debt authorized	$ 350,000,000
7.0% Notes Due 2018 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Stated interest rate	7.00%
Maturity year	2,018
Effective interest rate	7.10%
Debt authorized	$ 150,000,000
7.4% Notes Due 2019 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Stated interest rate	7.40%
Maturity year	2,019
Effective interest rate	7.50%
Debt authorized	$ 350,000,000
5.9% Notes Due 2020 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Stated interest rate	5.90%
Maturity year	2,020
Effective interest rate	6.00%
Debt authorized	$ 500,000,000
5.8% Notes Due 2021 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Stated interest rate	5.80%
Maturity year	2,021
Effective interest rate	5.90%
Debt authorized	$ 400,000,000
7.3% Debentures Due 2023 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Stated interest rate	7.30%
Maturity year	2,023
Effective interest rate	7.30%
Debt authorized	$ 250,000,000
4.0% Notes Due 2024 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Stated interest rate	4.00%
Maturity year	2,024
Effective interest rate	4.00%
Debt authorized	$ 550,000,000
4.5% Notes Due 2026 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Stated interest rate	4.50%
Maturity year	2,026
Effective interest rate	4.50%
Debt authorized	$ 500,000,000
Variable Rate Note Due 2036 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Maturity year	2,036
Effective interest rate	4.30%	3.80%
Variable Rate Revolving Credit Facility Due 2020 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Maturity year	2,020
Effective interest rate	1.90%
5.9% Notes Due 2019 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Stated interest rate	5.90%
Maturity year	2,019
Effective interest rate	6.00%
Debt authorized	$ 500,000,000
3.5% Senior Notes Due 2023 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Stated interest rate	3.50%
Maturity year	2,023
Effective interest rate	3.60%
Debt authorized	$ 250,000,000
5.7% Notes Due 2039 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Stated interest rate	5.70%
Maturity year	2,039
Effective interest rate	5.80%
Debt authorized	$ 500,000,000
4.9% Notes Due 2043 [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Stated interest rate	4.90%
Maturity year	2,043
Effective interest rate	5.00%
Debt authorized	$ 750,000,000
Variable Rate Revolving Credit Facility Due 2021 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Maturity year	2,021
Effective interest rate	2.00%	1.70%
5.9% Notes Due 2016 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	5.90%
Maturity year	2,016
Effective interest rate	6.00%
Debt authorized	$ 250,000,000
5.5% Notes Due 2017 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	5.50%
Maturity year	2,017
Effective interest rate	5.60%
Debt authorized	$ 300,000,000
6.3% Notes Due 2017 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	6.30%
Maturity year	2,017
Effective interest rate	6.40%
Debt authorized	$ 275,000,000
5.2% Notes Due 2018 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	5.20%
Maturity year	2,018
Effective interest rate	5.40%
Debt authorized	$ 185,000,000
5.8% Notes Due 2019 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	5.80%
Maturity year	2,019
Effective interest rate	5.90%
Debt authorized	$ 350,000,000
4.5% Notes Due 2021 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	4.50%
Maturity year	2,021
Effective interest rate	5.00%
Debt authorized	$ 440,000,000
4.0% Notes Due 2022 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	4.00%
Maturity year	2,022
Effective interest rate	4.40%
Debt authorized	$ 300,000,000
3.4% Notes Due 2023 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	3.40%
Maturity year	2,023
Effective interest rate	3.50%
Debt authorized	$ 300,000,000
5.0% Notes Due 2024 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	5.00%
Maturity year	2,024
Effective interest rate	5.20%
Debt authorized	$ 600,000,000	$ 350,000,000
6.0% Notes Due 2026 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	6.00%
Maturity year	2,026
Effective interest rate	6.20%
Debt authorized	$ 550,000,000
7.3% Debentures Due 2027 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Stated interest rate	7.30%
Maturity year	2,027
Effective interest rate	8.10%
Debt authorized	$ 100,000,000
Commercial Paper [Member]
Debt Instrument [Line Items]
Debt instrument, weighted average interest rate	0.90%
Commercial Paper [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Debt instrument, weighted average interest rate	0.90%

Debt - Schedule of Debt by Subs

Debt - Schedule of Debt by Subsidiary (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Principal	$ 10,871	$ 10,647
Unamortized Discount and Issuance Costs	93	87
Net	10,778
Short term debt	110	1,040
Long term debt	10,668	9,520
Loews Corporation [Member]
Debt Instrument [Line Items]
Principal	1,800
Unamortized Discount and Issuance Costs	25
Net	1,775
Long term debt	1,775
CNA Financial [Member]
Debt Instrument [Line Items]
Principal	2,728
Unamortized Discount and Issuance Costs	13
Net	2,715
Short term debt	2
Long term debt	2,713
Diamond Offshore [Member]
Debt Instrument [Line Items]
Principal	2,104
Unamortized Discount and Issuance Costs	19
Net	2,085
Short term debt	104
Long term debt	1,981
Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Principal	3,589
Unamortized Discount and Issuance Costs	31
Net	3,558
Short term debt	1
Long term debt	3,557
Loews Hotels [Member]
Debt Instrument [Line Items]
Principal	650	$ 598
Unamortized Discount and Issuance Costs	5
Net	645
Short term debt	3
Long term debt	$ 642

Debt - Additional Information (

Debt - Additional Information (Detail)	1 Months Ended				3 Months Ended		12 Months Ended
	Jan. 31, 2017USD ($)	Nov. 30, 2016	May 31, 2016USD ($)	Mar. 31, 2016USD ($)	Sep. 30, 2016	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)Extension	Feb. 15, 2017USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Aggregate of long term debt maturing, 2017							$ 110,000,000
Aggregate of long term debt maturing, 2018							534,000,000
Aggregate of long term debt maturing, 2019							1,300,000,000
Aggregate of long term debt maturing, 2020							550,000,000
Aggregate of long term debt maturing, 2021							1,600,000,000
Aggregate of long term debt maturing, Thereafter							6,800,000,000
CNA Financial [Member]
Debt Instrument [Line Items]
Acquisition of FHLBC stock							5,000,000
Outstanding borrowings							0		$ 0
Additional liquidity							111,000,000
Diamond Offshore [Member]
Debt Instrument [Line Items]
Additional available increase in borrowing capacity							$ 500,000,000
Number of one-year extensions | Extension							1
Boardwalk Pipeline [Member] | Subordinated Loan Agreement [Member]
Debt Instrument [Line Items]
Debt maturity date							Dec. 31, 2018
Credit facility, current borrowing capacity							$ 300,000,000
Boardwalk Pipeline [Member] | Subordinated Loan Agreement [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Credit facility, borrowings outstanding								$ 0
Revolving Credit Facility [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Repayments of commercial paper						$ 287,000,000
Revolving Credit Facility [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt maturity date					May 26, 2021
Credit facility, maximum borrowing capacity							1,500,000,000
Period extended for existing credit facility					1 year
Senior Unsecured Revolving Credit Facility [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							250,000,000
Additional available increase in borrowing capacity							$ 100,000,000
Senior unsecured revolving credit facility, term							5 years
Number of one-year extensions | Extension							2
Borrowings under current and prior credit agreements							$ 0		$ 0
Senior Unsecured Revolving Credit Facility [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							$ 1,500,000,000
Revolving credit facility maturity period							2020-10
Senior Unsecured Revolving Credit Facility [Member] | Diamond Offshore [Member] | Debt Instrument, Redemption, Period One [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							$ 40,000,000
Senior Unsecured Revolving Credit Facility [Member] | Diamond Offshore [Member] | Debt Instrument, Redemption, Period Two [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							60,000,000
Standby Letters of Credit [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							250,000,000
Swing Line Loans [Member] | Diamond Offshore [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							100,000,000
4.5% Senior Notes Due March 1, 2026 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt instrument principal amount				$ 500,000,000		$ 500,000,000
Debt instrument interest rate				4.50%		4.50%
Debt maturity date						Mar. 1, 2026
6.5% Senior Notes Due August 15, 2016 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt instrument principal amount				$ 350,000,000		$ 350,000,000
Debt instrument interest rate				6.50%		6.50%
Debt maturity date						Aug. 15, 2016
6.0% Senior Notes Due June 1, 2026 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt instrument principal amount			$ 550,000,000
Debt instrument interest rate			6.00%
Debt maturity date			Jun. 1, 2026
4.5% senior notes due July 15, 2027 [Member] | Boardwalk Pipeline [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	$ 500,000,000
Debt instrument interest rate	4.50%
Debt maturity date	Jul. 15, 2027
3.8% Senior Notes Due April 1, 2026 [Member]
Debt Instrument [Line Items]
Debt instrument principal amount				$ 500,000,000		$ 500,000,000
Debt instrument interest rate				3.80%		3.80%
Debt maturity date				Apr. 1, 2026
5.3% Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				5.30%		5.30%
Repayment of debt				$ 400,000,000
5.9% Notes Due 2020 [Member] | CNA Financial [Member]
Debt Instrument [Line Items]
Debt instrument principal amount							$ 500,000,000
Debt instrument interest rate							5.90%
5.9% Notes Due 2020 [Member] | Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Percentage of outstanding aggregate principal amount retired		5.90%

Shareholders' Equity - Componen

Shareholders' Equity - Components of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 22,810	$ 24,650	$ 24,906
Other comprehensive income (loss) before reclassifications, after tax	156	(795)	(28)
Reclassification of (gains) losses from accumulated other comprehensive income, after tax	(3)	77	(41)
Other comprehensive income (loss)	153	(718)	(69)
Issuance of equity securities by subsidiary		1
Amounts attributable to noncontrolling interests	(19)	80	10
Ending Balance	23,361	22,810	24,650
OTTI Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	24	32	23
Sale of subsidiaries			(5)
Other comprehensive income (loss) before reclassifications, after tax	9	(23)	15
Reclassification of (gains) losses from accumulated other comprehensive income, after tax	(6)	14
Other comprehensive income (loss)	3	(9)	15
Amounts attributable to noncontrolling interests		1	(1)
Ending Balance	27	24	32
Unrealized Gains (Losses) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	347	846	622
Sale of subsidiaries			(15)
Other comprehensive income (loss) before reclassifications, after tax	283	(600)	295
Reclassification of (gains) losses from accumulated other comprehensive income, after tax	(26)	43	(28)
Other comprehensive income (loss)	257	(557)	267
Amounts attributable to noncontrolling interests	(28)	58	(28)
Ending Balance	576	347	846
Discontinued Operations [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance			(3)
Sale of subsidiaries			20
Other comprehensive income (loss) before reclassifications, after tax			2
Reclassification of (gains) losses from accumulated other comprehensive income, after tax			(21)
Other comprehensive income (loss)			(19)
Amounts attributable to noncontrolling interests			2
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(3)	(6)	(4)
Other comprehensive income (loss) before reclassifications, after tax		(2)	(2)
Reclassification of (gains) losses from accumulated other comprehensive income, after tax	2	7	(1)
Other comprehensive income (loss)	2	5	(3)
Amounts attributable to noncontrolling interests	(1)	(2)	1
Ending Balance	(2)	(3)	(6)
Pension Liability [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(649)	(641)	(432)
Other comprehensive income (loss) before reclassifications, after tax	(22)	(31)	(244)
Reclassification of (gains) losses from accumulated other comprehensive income, after tax	27	13	9
Other comprehensive income (loss)	5	(18)	(235)
Issuance of equity securities by subsidiary		1
Amounts attributable to noncontrolling interests	(2)	9	26
Ending Balance	(646)	(649)	(641)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(76)	49	133
Other comprehensive income (loss) before reclassifications, after tax	(114)	(139)	(94)
Other comprehensive income (loss)	(114)	(139)	(94)
Amounts attributable to noncontrolling interests	12	14	10
Ending Balance	(178)	(76)	49
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(357)	280	339
Other comprehensive income (loss)	134	(638)	(59)
Ending Balance	$ (223)	$ (357)	$ 280

Shareholders' Equity - Compo114

Shareholders' Equity - Components of Accumulated Other Comprehensive Income (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
OTTI Gains (Losses) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Tax on change in other comprehensive income (loss) before reclassifications	$ (4)	$ 13	$ (8)
Tax on reclassification from accumulated other comprehensive income	3	(8)	0
Unrealized Gains (Losses) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Tax on change in other comprehensive income (loss) before reclassifications	(133)	313	(132)
Tax on reclassification from accumulated other comprehensive income	16	(31)	10
Discontinued Operations [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Tax on change in other comprehensive income (loss) before reclassifications	0	0	(3)
Tax on reclassification from accumulated other comprehensive income	0	0	16
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Tax on change in other comprehensive income (loss) before reclassifications	0	1	1
Tax on reclassification from accumulated other comprehensive income	0	(2)	0
Pension Liability [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Tax on change in other comprehensive income (loss) before reclassifications	9	16	132
Tax on reclassification from accumulated other comprehensive income	(15)	(11)	(7)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Tax on change in other comprehensive income (loss) before reclassifications	0	0	0
Tax on reclassification from accumulated other comprehensive income	$ 0	$ 0	$ 0

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Shareholders Equity [Line Items]
Common stock dividend declared	$ 0.25	$ 0.25	$ 0.25
Common stock dividend paid	$ 0.25	$ 0.25	$ 0.25
Treasury stock repurchased, shares	3.4	33.3	14.6
Purchase of Loews treasury stock	$ 134	$ 1,265	$ 622
CNA Financial [Member]
Shareholders Equity [Line Items]
Purchase of common stock	0.3
Common stock, aggregate cost	$ 8
Subsidiary ownership percentage	90.00%
Increase (decrease) in Additional paid-in capital	$ 3

Statutory Accounting Practic116

Statutory Accounting Practices - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Statutory Accounting Practices [Line Items]
Increase in statutory capital and surplus	$ 67	$ 90
Combined Continental Casualty Companies [Member]
Statutory Accounting Practices [Line Items]
Increase in statutory capital and surplus	10,748	$ 10,723
Dividends payable without prior supervisory approval	1,100
Dividends paid	$ 765
Statutory capital and surplus percentage	270.00%	266.00%

Statutory Accounting Practic117

Statutory Accounting Practices - Combined Statutory Capital and Surplus and Net Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statutory Accounting Practices [Line Items]
Statutory Capital and Surplus	$ 67	$ 90
Combined Continental Casualty Companies [Member]
Statutory Accounting Practices [Line Items]
Statutory Capital and Surplus	10,748	10,723
Statutory Net Income	$ 1,033	$ 1,148	$ 914

Benefit Plans - Additional Info

Benefit Plans - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Eligible age for several postretirement benefit plans			55 years
Eligible age for Medicare benefits			65 years
Increase of 1% in each year would increase the Company's accumulated postretirement benefit obligation			$ 2
Decrease of 1% in each year would decrease the Company's accumulated postretirement benefit obligation			$ 2
Health care cost trend rate			0.00%
Settlement payment			$ 88		$ 253
Settlement charges recognized due to settlement	$ 84		86
Defined benefit plan obligation, curtailment				$ 55
Gain recognized due to curtailment		$ 86
Accumulated benefit obligation for all defined benefit pension plans			3,100	$ 3,200
Future capital calls from various third party limited partnership investments			$ 119
Percentage of limited partnerships comprising of the carrying value that employ hedge fund strategies			76.60%	76.60%
Amount contributed to the savings plans			$ 107	$ 115	125
Stock-based Compensation, vesting period			4 years
Stock-based Compensation, expiration period			10 years
Recognized compensation expense			$ 32	$ 14	$ 12
Time-based Restricted Stock Units (RSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Terms of Award			Right to receive one share of the Company's common stock for each vested RSU
Forfeited during the year			16,079
Performance-based Restricted Stock Units (PSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Terms of Award			Receive one share of the Company's common stock for each vested PSU
Restricted Stock Units (RSUs) and Performance Stock Units (PSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Grants In Period			367,908
Weighted average grant date fair value			$ 39.74
Stock Appreciation Rights (SARs) [Member]
Defined Benefit Plan Disclosure [Line Items]
SARs outstanding			5,982,880
Weighted average grant date fair value			$ 40.90
2016 Loews Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Stock-based Compensation, number of shares authorized			6,000,000
Stock-based Compensation, maximum number of shares to be granted to each individual			500,000
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate			5.00%	5.00%	5.00%
Defined benefit plan obligation, discount rate		3.60%		4.00%
Maximum [Member] | 2016 Loews Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Stock-based Compensation, number of shares to be forfeited under prior plan			3,000,000
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate			4.00%	4.00%	4.00%
Defined benefit plan obligation, discount rate		3.10%		3.90%
Second Anniversary [Member] | Time-based Restricted Stock Units (RSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
vesting percentage			50.00%
Second Anniversary [Member] | Performance-based Restricted Stock Units (PSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
vesting percentage			50.00%
Third Anniversary [Member] | Time-based Restricted Stock Units (RSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
vesting percentage			50.00%
Third Anniversary [Member] | Performance-based Restricted Stock Units (PSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
vesting percentage			50.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocation of plan assets invested in equity securities and limited partnerships, Minimum			40.00%
Target allocation of plan assets invested in equity securities and limited partnerships, Maximum			60.00%
Percentage of hedge fund strategies			57.00%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement payment			$ 101	$ 12
Defined benefit plan obligation, discount rate	3.70%		3.90%	4.00%	3.70%
Expected contribution to plan(s), next fiscal year			$ 15
Fair value of plan assets	$ 2,713		2,423	$ 2,500	$ 2,713
Pension Benefits [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 15		10	$ 10	$ 15
Postretirement Healthcare and Life Insurance Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to plan(s), next fiscal year			$ 3
Multi-Strategy Approach [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of hedge fund strategies			38.00%
Distressed Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of hedge fund strategies			5.00%
Defined Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of limited partnerships comprising of the carrying value that employ hedge fund strategies			87.00%	87.00%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan obligation, discount rate	3.40%		3.70%	3.70%	3.40%
Fair value of plan assets	$ 87		$ 86	$ 86	$ 87
Other Postretirement Benefits [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			$ 0	$ 0

Benefit Plans - Weighted Averag

Benefit Plans - Weighted Average Assumptions Used to Determine Benefit Obligations (Detail)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2014
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		3.90%		3.10%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate		4.00%		3.60%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.90%	4.00%	3.70%
Expected long term rate of return on plan assets	7.50%	7.50%	7.50%
Pension Benefits [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	3.90%	3.50%	3.50%
Pension Benefits [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	5.50%	5.50%	5.50%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.70%	3.70%	3.40%
Expected long term rate of return on plan assets	5.30%	5.30%	5.30%

Benefit Plans - Weighted Ave120

Benefit Plans - Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.00%	3.80%	4.40%
Expected long term rate of return on plan assets	7.50%	7.50%	7.50%
Pension Benefits [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	3.50%	3.50%	3.50%
Pension Benefits [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	5.50%	5.50%	5.50%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.70%	3.40%	4.00%
Expected long term rate of return on plan assets	5.30%	5.30%	5.30%

Benefit Plans - Assumed Health

Benefit Plans - Assumed Health Care Cost Trend Rates (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	0.00%
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	4.00%	4.00%	4.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.00%	4.00%	4.00%
Year that the rate reaches the ultimate trend rate	2,017	2,016	2,015
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	7.00%	7.50%	8.00%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2,021	2,021	2,021

Benefit Plans - Components of N

Benefit Plans - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 8	$ 12	$ 16
Interest cost	128	127	149
Expected return on plan assets	(177)	(193)	(209)
Amortization of unrecognized net loss	46	42	30
Amortization of unrecognized prior service benefit	(1)	(1)	(1)
Settlement/Curtailment	3	3	86
Net periodic benefit cost	7	(10)	71
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	1
Interest cost	3	3	4
Expected return on plan assets	(5)	(5)	(4)
Amortization of unrecognized net loss		1	1
Amortization of unrecognized prior service benefit	(3)	(10)	(18)
Settlement/Curtailment			(86)
Net periodic benefit cost	$ (4)	$ (10)	$ (102)

Benefit Plans - Reconciliation

Benefit Plans - Reconciliation of Benefit Obligations and Plan Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in benefit obligation:
Settlements	$ (88)		$ (253)
Pension Benefits [Member]
Change in benefit obligation:
Benefit obligation, beginning balance	3,227	$ 3,446
Service cost	8	12	16
Interest cost	128	127	149
Amendments/curtailments	1	(55)
Actuarial (gain) loss	72	(96)
Benefits paid from plan assets	(188)	(187)
Settlements	(101)	(12)
Foreign exchange	(16)	(8)
Benefit obligation, ending balance	3,131	3,227	3,446
Change in plan assets:
Fair value of plan assets, beginning balance	2,500	2,713
Actual return on plan assets	211	(21)
Company contributions	19	15
Benefits paid from plan assets	(188)	(187)
Settlements	(103)	(12)
Foreign exchange	(16)	(8)
Fair value of plan assets, ending balance	2,423	2,500	2,713
Funded status	(708)	(727)
Amounts recognized in the Consolidated Balance Sheets consist of:
Other assets	4	11
Other liabilities	(712)	(738)
Net amount recognized	(708)	(727)
Other Postretirement Benefits [Member]
Change in benefit obligation:
Benefit obligation, beginning balance	82	97
Service cost	1	1	1
Interest cost	3	3	4
Plan participants' contributions	5	5
Actuarial (gain) loss	(13)	(11)
Benefits paid from plan assets	(12)	(13)
Benefit obligation, ending balance	66	82	97
Change in plan assets:
Fair value of plan assets, beginning balance	86	87
Actual return on plan assets	3	2
Company contributions	4	5
Plan participants' contributions	5	5
Benefits paid from plan assets	(12)	(13)
Fair value of plan assets, ending balance	86	86	$ 87
Funded status	20	4
Amounts recognized in the Consolidated Balance Sheets consist of:
Other assets	44	38
Other liabilities	(24)	(34)
Net amount recognized	$ 20	$ 4

Benefit Plans - Amounts Recogni

Benefit Plans - Amounts Recognized in Accumulated Other Comprehensive Income (Loss) Not Yet Recognized in Net Periodic (Benefit) Cost (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service credit	$ (3)	$ (5)
Net actuarial loss	1,097	1,106
Net amount recognized	1,094	1,101
Projected benefit obligation	3,103	3,129
Accumulated benefit obligation	3,089	3,114
Fair value of plan assets	2,391	2,391
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Prior service credit	(6)	(9)
Net actuarial loss	(2)	8
Net amount recognized	(8)	(1)
Accumulated benefit obligation	$ 24	$ 34

Benefit Plans - Estimated Amoun

Benefit Plans - Estimated Amounts to be Recognized from AOCI into Net Periodic Cost (Benefit) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of net actuarial (gain) loss	$ 43
Total estimated amounts to be recognized	43
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of net actuarial (gain) loss	(1)
Amortization of prior service credit	(2)
Total estimated amounts to be recognized	$ (3)

Benefit Plans - Estimated Futur

Benefit Plans - Estimated Future Minimum Benefit Payments (Detail) $ in Millions	Dec. 31, 2016USD ($)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future benefit payments 2017	$ 217
Expected future benefit payments 2018	210
Expected future benefit payments 2019	212
Expected future benefit payments 2020	214
Expected future benefit payments 2021	212
Expected future benefit payments 2022 - 2026	1,041
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected future benefit payments 2017	6
Expected future benefit payments 2018	6
Expected future benefit payments 2019	6
Expected future benefit payments 2020	5
Expected future benefit payments 2021	5
Expected future benefit payments 2022 - 2026	$ 20

Benefit Plans - Pension Plan As

Benefit Plans - Pension Plan Assets Measured at Fair Value on Recurring Basis (Detail) - Pension Benefits [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 2,423	$ 2,500	$ 2,713
Corporate and Other Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	510	465
States, Municipalities and Political Subdivisions [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	63	106
Total Asset-Backed [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	186	219
Total Fixed Maturities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	759	790
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	509	480
Short Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53	58
Fixed Income Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	95
Other Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52	52
Limited Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	958	1,025
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	529	498
Level 1 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	404	373
Level 1 [Member] | Short Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18	30
Level 1 [Member] | Fixed Income Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	92	95
Level 1 [Member] | Other Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	926	967
Level 2 [Member] | Corporate and Other Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	500	455
Level 2 [Member] | States, Municipalities and Political Subdivisions [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	63	106
Level 2 [Member] | Total Asset-Backed [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	186	219
Level 2 [Member] | Total Fixed Maturities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	749	780
Level 2 [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	105	107
Level 2 [Member] | Short Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	35	28
Level 2 [Member] | Other Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	37	52
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	10	15
Level 3 [Member] | Corporate and Other Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	10	10	$ 15
Level 3 [Member] | Total Fixed Maturities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 10	$ 10

Benefit Plans - Plan Assets Mea

Benefit Plans - Plan Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3) (Detail) - Pension Benefits [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning balance	$ 2,500	$ 2,713
Fair value of plan assets, ending balance	2,423	2,500
Corporate and Other Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning balance	465
Fair value of plan assets, ending balance	510	465
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning balance	10	15
Actual Return on Assets Still Held at December 31	0	0
Actual Return on Assets Sold During the Year Ended December 31	0	0
Net Purchases, Sales, and Settlements	0	0
Net Transfers In (Out) of Level 3		(5)
Fair value of plan assets, ending balance	10	10
Level 3 [Member] | Corporate and Other Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, beginning balance	10	15
Actual Return on Assets Still Held at December 31	0	0
Actual Return on Assets Sold During the Year Ended December 31	0	0
Net Purchases, Sales, and Settlements	0	0
Net Transfers In (Out) of Level 3		(5)
Fair value of plan assets, ending balance	$ 10	$ 10

Benefit Plans - Other Postretir

Benefit Plans - Other Postretirement Benefit Plan Assets Measured at Fair Value on Recurring Basis (Detail) - Other Postretirement Benefits [Member] - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 86	$ 86	$ 87
Corporate and Other Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19	17
States, Municipalities and Political Subdivisions [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44	42
Total Asset-Backed [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15	19
Total Fixed Maturities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	78	78
Short Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3	3
Fixed Income Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	5
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8	8
Level 1 [Member] | Short Term Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3	3
Level 1 [Member] | Fixed Income Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5	5
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	78	78
Level 2 [Member] | Corporate and Other Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19	17
Level 2 [Member] | States, Municipalities and Political Subdivisions [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44	42
Level 2 [Member] | Total Asset-Backed [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15	19
Level 2 [Member] | Total Fixed Maturities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 78	$ 78

Reinsurance - Summary of Amount

Reinsurance - Summary of Amounts Receivable from Reinsurers (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Reinsurance receivables related to insurance reserves:
Ceded claim and claim adjustment expenses	$ 4,094	$ 4,087
Ceded future policy benefits	212	207
Reinsurance receivables related to paid losses	147	197
Reinsurance receivables	4,453	4,491
Less allowance for doubtful accounts	37	38
Reinsurance receivables, net of allowance for doubtful accounts	$ 4,416	$ 4,453

Reinsurance - Additional Inform

Reinsurance - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effects of Reinsurance [Line Items]
Reinsurance collateral	$ 3,000	$ 3,200
Reinsurance recoveries	3,000	2,600	$ 1,400
Berkshire Hathaway Group [Member]
Effects of Reinsurance [Line Items]
Largest recoverables from a single reinsurer	2,400
Gateway Rivers Insurance Company [Member]
Effects of Reinsurance [Line Items]
Largest recoverables from a single reinsurer	350
Subsidiaries from Hartford Insurance Group [Member]
Effects of Reinsurance [Line Items]
Largest recoverables from a single reinsurer	212
Significant Captive Program [Member]
Effects of Reinsurance [Line Items]
Direct and ceded earned premiums	$ 3,900	3,300	2,600
Percentage reinsured of direct and ceded earned premiums	100.00%
Reinsurance recoveries	$ 2,600	$ 2,300	$ 1,500

Reinsurance - Summary of Effect

Reinsurance - Summary of Effects of Reinsurance on Earned Premiums (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Earned premiums, Direct	$ 10,886	$ 10,351	$ 9,960
Earned premiums, Assumed	308	324	325
Earned premiums, Ceded	4,270	3,754	3,073
Earned premiums, Net	$ 6,924	$ 6,921	$ 7,212
Percentage of amount assumed to net	4.40%	4.70%	4.50%
Property and Casualty Operations [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Earned premiums, Direct	$ 10,400	$ 9,853	$ 9,452
Earned premiums, Assumed	258	274	277
Earned premiums, Ceded	4,270	3,754	3,073
Earned premiums, Net	$ 6,388	$ 6,373	$ 6,656
Percentage of amount assumed to net	4.00%	4.30%	4.20%
Long Term Care [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Earned premiums, Direct	$ 486	$ 498	$ 508
Earned premiums, Assumed	50	50	48
Earned premiums, Net	$ 536	$ 548	$ 556
Percentage of amount assumed to net	9.30%	9.10%	8.60%

Quarterly Financial Data - Sche

Quarterly Financial Data - Schedule of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Data [Abstract]
Total revenues	$ 3,338	$ 3,287	$ 3,307	$ 3,173	$ 3,333	$ 3,169	$ 3,435	$ 3,478	$ 13,105	$ 13,415	$ 14,325
Net income (loss)	$ 290	$ 327	$ (65)	$ 102	$ (201)	$ 182	$ 170	$ 109	$ 654	$ 260	$ 591
Per share-basic and diluted	$ 0.86	$ 0.97	$ (0.19)	$ 0.30	$ (0.58)	$ 0.50	$ 0.46	$ 0.29	$ 1.93	$ 0.72	$ 1.55

Quarterly Financial Data - S134

Quarterly Financial Data - Schedule of Quarterly Financial Information (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Data [Line Items]
Asset impairment charge			$ 697	$ 865	$ 228
CNA Financial [Member]
Quarterly Financial Data [Line Items]
Charge related to recognition of premium deficiency and small deficiency in claim reserves		$ 177
Diamond Offshore Drilling, Inc. [Member]
Quarterly Financial Data [Line Items]
Asset impairment charge	$ 267	$ 182

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - CNA Financial [Member] $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Commitments [Line Items]
Aggregate amount related to indemnification agreements	$ 258
Aggregate amount related to quantifiable guarantees	375
Potential amount of future payments under guarantees	1,900
Charges recorded to reduce earned premium	16
Anticipated premium refunds related to affected policies	$ 30

Discontinued Operations - Sched

Discontinued Operations - Schedule of Discontinued Operations Reflected in Consolidated Condensed Statements of Income (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2014USD ($)
Expenses:
Loss from discontinued operations	$ (371)
HighMount [Member]
Revenues:
Other revenue, primarily operating	150
Total	150
Expenses:
Impairment of natural gas and oil properties	29
Operating	173
Interest	8
Total	210
Income (loss) before income tax	(60)
Income tax (expense) benefit	4
Results of discontinued operations, net of income tax	(56)
Impairment loss, net of tax benefit	(138)
Loss from discontinued operations	(194)
CAC [Member]
Revenues:
Net investment income	94
Investment gains	3
Total	97
Expenses:
Insurance claims and policyholders' benefits	75
Other operating expenses	2
Operating	77
Income (loss) before income tax	20
Income tax (expense) benefit	(6)
Results of discontinued operations, net of income tax	14
Loss on sale, net of tax benefit	(211)
Amounts attributable to noncontrolling interests	20
Loss from discontinued operations	$ (177)

Discontinued Operations - Sc137

Discontinued Operations - Schedule of Discontinued Operations Reflected in Consolidated Condensed Statements of Income (Parenthetical) (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2014USD ($)
HighMount [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax benefit on impairment loss	$ 62
CAC [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Loss on sale, tax benefit	$ 40

Discontinued Operations - Addit

Discontinued Operations - Additional Information (Detail) - HighMount [Member] $ in Millions	12 Months Ended
	Dec. 31, 2014USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment of natural gas and oil properties	$ 29
Impairment of natural gas and oil properties after tax	19
Effects of cash flow hedges not considered in calculating ceiling limitation, impairments	29
Effects of cash flow hedges not considered in calculating ceiling limitation after tax, impairments	$ 18

Segments - Additional Informati

Segments - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016RigHotelStateCountrySegmentmi
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	5
Number of individual operating subsidiaries | Segment	4
Number of offshore drilling rigs | Rig	24
Number of countries where drilling rigs are located | Country	5
Miles of natural gas and NGL pipeline | mi	14,365
Number of states having natural gas storage facilities | State	4
Total number of hotels owned and/or operated	25
United States [Member]
Segment Reporting Information [Line Items]
Number of hotels	24
Canada [Member]
Segment Reporting Information [Line Items]
Number of hotels	1

Segments - Consolidating Statem

Segments - Consolidating Statement of Income and Total Assets by Segment (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Insurance premiums									$ 6,924	$ 6,921	$ 7,212
Net investment income									2,135	1,866	2,163
Investment gains (losses)									50	(71)	54
Contract drilling revenues									1,525	2,360	2,737
Other revenues									2,471	2,339	2,159
Total	$ 3,338	$ 3,287	$ 3,307	$ 3,173	$ 3,333	$ 3,169	$ 3,435	$ 3,478	13,105	13,415	14,325
Expenses:
Insurance claims and policyholders' benefits									5,283	5,384	5,591
Amortization of deferred acquisition costs									1,235	1,540	1,317
Contract drilling expenses									772	1,228	1,524
Other operating expenses									4,343	4,499	3,585
Interest									536	520	498
Total									12,169	13,171	12,515
Income (loss) before income tax									936	244	1,810
Income tax (expense) benefit									(220)	43	(457)
Income from continuing operations									716	287	1,353
Discontinued operations, net											(391)
Net income									716	287	962
Amounts attributable to noncontrolling interests									(62)	(27)	(371)
Net income (loss) attributable to Loews Corporation	290	$ 327	$ (65)	$ 102	(201)	$ 182	$ 170	$ 109	654	260	591
Total assets	76,594				76,006				76,594	76,006
CNA Financial [Member] | Operating Segments [Member]
Revenues:
Insurance premiums									6,924	6,921	7,212
Net investment income									1,988	1,840	2,067
Investment gains (losses)									62	(71)	54
Other revenues									410	411	359
Total									9,384	9,101	9,692
Expenses:
Insurance claims and policyholders' benefits									5,283	5,384	5,591
Amortization of deferred acquisition costs									1,235	1,540	1,317
Other operating expenses									1,558	1,469	1,386
Interest									167	155	183
Total									8,243	8,548	8,477
Income (loss) before income tax									1,141	553	1,215
Income tax (expense) benefit									(279)	(71)	(322)
Income from continuing operations											893
Discontinued operations, net											(197)
Net income									862	482	696
Amounts attributable to noncontrolling interests									(88)	(49)	(71)
Net income (loss) attributable to Loews Corporation									774	433	625
Total assets	55,207				55,025				55,207	55,025
Diamond Offshore [Member] | Operating Segments [Member]
Revenues:
Net investment income									1	3	1
Investment gains (losses)									(12)
Contract drilling revenues									1,525	2,360	2,737
Other revenues									75	65	87
Total									1,589	2,428	2,825
Expenses:
Contract drilling expenses									772	1,228	1,524
Other operating expenses									1,198	1,508	725
Interest									90	94	62
Total									2,060	2,830	2,311
Income (loss) before income tax									(471)	(402)	514
Income tax (expense) benefit									111	117	(142)
Income from continuing operations											372
Net income									(360)	(285)	372
Amounts attributable to noncontrolling interests									174	129	(189)
Net income (loss) attributable to Loews Corporation									(186)	(156)	183
Total assets	6,371				7,154				6,371	7,154
Boardwalk Pipeline [Member] | Operating Segments [Member]
Revenues:
Net investment income										1	1
Other revenues									1,316	1,253	1,235
Total									1,316	1,254	1,236
Expenses:
Other operating expenses									835	851	931
Interest									183	176	165
Total									1,018	1,027	1,096
Income (loss) before income tax									298	227	140
Income tax (expense) benefit									(61)	(46)	(11)
Income from continuing operations											129
Net income									237	181	129
Amounts attributable to noncontrolling interests									(148)	(107)	(111)
Net income (loss) attributable to Loews Corporation									89	74	18
Total assets	8,706				8,365				8,706	8,365
Loews Hotels [Member] | Operating Segments [Member]
Revenues:
Other revenues									667	604	475
Total									667	604	475
Expenses:
Other operating expenses									621	555	440
Interest									24	21	14
Total									645	576	454
Income (loss) before income tax									22	28	21
Income tax (expense) benefit									(10)	(16)	(10)
Income from continuing operations											11
Net income									12	12	11
Net income (loss) attributable to Loews Corporation									12	12	11
Total assets	1,498				1,416				1,498	1,416
Corporate [Member]
Revenues:
Net investment income									146	22	94
Other revenues									3	6	3
Total									149	28	97
Expenses:
Other operating expenses									131	116	103
Interest									72	74	74
Total									203	190	177
Income (loss) before income tax									(54)	(162)	(80)
Income tax (expense) benefit									19	59	28
Income from continuing operations											(52)
Discontinued operations, net											(194)
Net income									(35)	(103)	(246)
Net income (loss) attributable to Loews Corporation									(35)	(103)	$ (246)
Total assets	$ 4,812				$ 4,046				$ 4,812	$ 4,046

Schedule I - Condensed Finan141

Schedule I - Condensed Financial Information of Registrant - Parent Company Only, Balance Sheets (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Other assets	$ 1,736	$ 1,699
Total assets	76,594	76,006
LIABILITIES AND SHAREHOLDERS' EQUITY
Total liabilities	53,233	53,196
Shareholders' equity	18,163	17,561
Total liabilities and equity	76,594	76,006
Loews Corporation [Member]
ASSETS
Current assets, principally investment in short term instruments	3,096	2,888
Investments in securities	1,931	1,487
Investments in capital stocks of subsidiaries, at equity	15,114	15,129
Other assets	389	97
Total assets	20,530	19,601
LIABILITIES AND SHAREHOLDERS' EQUITY
Current liabilities	140	260
Short term debt		400
Long term debt	1,775	1,279
Deferred income tax and other	452	101
Total liabilities	2,367	2,040
Shareholders' equity	18,163	17,561
Total liabilities and equity	$ 20,530	$ 19,601

Schedule I - Condensed Finan142

Schedule I - Condensed Financial Information of Registrant - Parent Company Only, Statements of Income and Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Equity in income of subsidiaries									$ 41	$ 43	$ (62)
Total	$ 3,338	$ 3,287	$ 3,307	$ 3,173	$ 3,333	$ 3,169	$ 3,435	$ 3,478	13,105	13,415	14,325
Expenses:
Interest									536	520	498
Total									12,169	13,171	12,515
Income before income tax									936	244	1,810
Income tax benefit									(220)	43	(457)
Income from continuing operations									716	287	1,353
Discontinued operations, net											(391)
Net income									716	287	962
Total comprehensive income (loss) attributable to Loews Corporation									788	(378)	532
Loews Corporation [Member]
Revenues:
Equity in income of subsidiaries									655	302	1,034
Interest and other									165	74	92
Total									820	376	1,126
Expenses:
Administrative									127	108	97
Interest									72	74	74
Total									199	182	171
Income before income tax									621	194	955
Income tax benefit									33	66	7
Income from continuing operations									654	260	962
Discontinued operations, net											(371)
Net income									654	260	591
Equity in other comprehensive income (loss) of subsidiaries									134	(638)	(59)
Total comprehensive income (loss) attributable to Loews Corporation									$ 788	$ (378)	$ 532

Schedule I - Condensed Finan143

Schedule I - Condensed Financial Information of Registrant - Parent Company Only, Statements of Income and Comprehensive Income (Loss) (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loews Corporation [Member]
Condensed Financial Statements, Captions [Line Items]
Cash dividends paid to the Company by affiliates	$ 780	$ 816	$ 782

Schedule I - Condensed Finan144

Schedule I - Condensed Financial Information of Registrant - Parent Company Only, Statements of Cash Flows (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Activities:
Net income	$ 716	$ 287	$ 962
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Equity method investees	221	182	64
Provision for deferred income taxes	102	(225)	11
Changes in operating assets and liabilities, net:
Receivables	24	120	738
Trading securities	(528)	674	(129)
Investing Activities:
Change in investments, primarily short term	158	120	1,396
Other	158	(172)	(108)
Financing Activities:
Dividends paid	(84)	(90)	(95)
Issuance of common stock		7	6
Purchases of treasury shares	(134)	(1,265)	(622)
Principal payments in debt	(3,418)	(1,929)	(2,269)
Issuance of debt	3,614	1,828	2,004
Other	(2)	4	16
Net change in cash	(113)	76	70
Cash, beginning of year	440	364	294
Cash, end of year	327	440	364
Loews Corporation [Member]
Operating Activities:
Net income	654	260	591
Adjustments to reconcile net income to net cash provided (used) by operating activities:
Equity method investees	115	488	95
Provision for deferred income taxes	10	113	(62)
Changes in operating assets and liabilities, net:
Receivables	2	(6)	(2)
Accounts payable and accrued liabilities	52	71	200
Trading securities	(614)	718	(269)
Other, net	(15)	(8)	(23)
Net cash flow operating activities	204	1,636	530
Investing Activities:
Investments in and advances to subsidiaries	50	(285)	130
Change in investments, primarily short term	(127)		7
Other	(2)	(4)	(2)
Net cash flow investing activities	(79)	(289)	135
Financing Activities:
Dividends paid	(84)	(90)	(95)
Issuance of common stock		7	6
Purchases of treasury shares	(134)	(1,265)	(622)
Principal payments in debt	(400)
Issuance of debt	495
Other	(2)	1	2
Net cash flow financing activities	$ (125)	$ (1,347)	(709)
Net change in cash			(44)
Cash, beginning of year			$ 44

Schedule II - Valuation and 145

Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 96	$ 117	$ 329
Charged to Costs and Expenses	0	0	0
Charged to Other Accounts	0	0	0
Deductions	6	21	212
Balance at End of Period	90	96	117
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	96	117	329
Charged to Costs and Expenses	0	0	0
Charged to Other Accounts	0	0	0
Deductions	6	21	212
Balance at End of Period	$ 90	$ 96	$ 117

Schedule V - Supplemental In146

Schedule V - Supplemental Information Concerning Property and Casualty Insurance Operations (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]
Deferred acquisition costs	$ 599	$ 598
Reserves for unpaid claim and claim adjustment expenses	22,343	22,663
Discount deducted from claim and claim adjustment expense reserves above (based on interest rates ranging from 3.5% to 8.0%)	1,572	1,534
Unearned premiums	3,762	3,671
Net written premiums	6,988	6,962	$ 7,088
Net earned premiums	6,924	6,921	7,212
Net investment income	1,952	1,807	2,031
Incurred claim and claim adjustment expenses related to current year	5,025	4,934	5,043
Incurred claim and claim adjustment expenses related to prior years	(342)	(255)	(39)
Amortization of deferred acquisition costs	1,235	1,540	1,317
Paid claim and claim adjustment expenses	$ 5,134	$ 4,945	$ 5,297

Schedule V - Supplemental In147

Schedule V - Supplemental Information Concerning Property and Casualty Insurance Operations (Parenthetical) (Detail)	Dec. 31, 2016	Dec. 31, 2015
Minimum [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Discount deducted from claim and claim adjustment expense reserves interest rates	3.50%	3.50%
Maximum [Member]
Supplemental Information for Property, Casualty Insurance Underwriters [Line Items]
Discount deducted from claim and claim adjustment expense reserves interest rates	8.00%	8.00%