The Travelers Companies, Inc. (TRV) 10-K 11 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 05, 2016	Jun. 30, 2015
Document and Entity Information
Registrant name	TRAVELERS COMPANIES, INC.
Central index key	86,312
Document type	10-K
Document period end date	Dec. 31, 2015
Amendment flag	false
Current fiscal year end date	--12-31
Well-known seasoned issuer	Yes
Voluntary filers	No
Current reporting status	Yes
Filer category	Large Accelerated Filer
Entity public float			$ 29,961,887,660
Common stock shares outstanding		294,977,349
Document fiscal year focus	2,015
Document fiscal period focus	FY

Consolidated Statement of Incom

Consolidated Statement of Income - USD ($) shares in Millions, $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Premiums										$ 23,874	$ 23,713	$ 22,637
Net investment income										2,379	2,787	2,716
Fee income										445	438	395
Net realized investment gains	[1]									3	79	166
Other revenues										99	145	277
Total revenues		$ 6,674	$ 6,794	$ 6,706	$ 6,626	$ 6,783	$ 6,886	$ 6,785	$ 6,708	26,800	27,162	26,191
Claims and expenses
Claims and claim adjustment expenses										13,723	13,870	13,307
Amortization of deferred acquisition costs										3,885	3,882	3,821
General and administrative expenses										4,079	3,952	3,757
Interest expense										373	369	361
Total claims and expenses		5,465	5,487	5,630	5,478	5,323	5,628	5,884	5,238	22,060	22,073	21,246
Income before income taxes		1,209	1,307	1,076	1,148	1,460	1,258	901	1,470	4,740	5,089	4,945
Income tax expense		343	379	264	315	422	339	218	418	1,301	1,397	1,272
Net income		$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	$ 3,439	$ 3,692	$ 3,673
Net income per share
Basic		$ 2.87	$ 3	$ 2.56	$ 2.58	$ 3.15	$ 2.72	$ 1.98	$ 2.98	$ 10.99	$ 10.82	$ 9.84
Diluted		$ 2.83	$ 2.97	$ 2.53	$ 2.55	$ 3.11	$ 2.69	$ 1.95	$ 2.95	$ 10.88	$ 10.70	$ 9.74
Weighted average number of common shares outstanding
Basic										310.6	338.8	370.3
Diluted										313.9	342.5	374.3
Cash dividends declared per common share										$ 2.38	$ 2.15	$ 1.96
[1]	Total other-than-temporary impairment (OTTI) losses were $(54) million, $(22) million and $(10) million for the years ended December 31, 2015, 2014 and 2013, respectively. Of total OTTI, credit losses of $(52) million, $(26) million and $(15) million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(2) million, $4 million and $5 million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.

Consolidated Statement of Inco3

Consolidated Statement of Income Parentheticals - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidated Statement of Income
Total other-than-temporary impairment losses	$ (54)	$ (22)	$ (10)
Other-than-temporary impairment, credit losses recognized in net realized investment gains	(52)	(26)	(15)
Unrealized gains (losses) from other changes in total other-than-temporary impairments recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income	$ (2)	$ 4	$ 5

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidated Statement of Comprehensive Income
Net income	$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	$ 3,439	$ 3,692	$ 3,673
Other comprehensive income (loss):
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income									(1,020)	976	(2,734)
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income									(14)	2	3
Net changes in benefit plan assets and obligations									66	(494)	647
Net changes in unrealized foreign currency translation									(461)	(289)	(112)
Other comprehensive income (loss) before income taxes									(1,429)	195	(2,196)
Income tax expense (benefit)									(392)	125	(770)
Other comprehensive income (loss), net of taxes									(1,037)	70	(1,426)
Comprehensive income									$ 2,402	$ 3,762	$ 2,247

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets
Fixed maturities, available for sale, at fair value (amortized cost $58,878 and $60,801)	$ 60,658	$ 63,474
Equity securities, available for sale, at fair value (cost $528 and $579)	705	899
Real estate investments	989	938
Short-term securities	4,671	4,364
Other investments	3,447	3,586
Total investments	70,470	73,261
Cash	380	374	$ 294	$ 330
Investment income accrued	642	685
Premiums receivable	6,437	6,298
Reinsurance recoverables	8,910	9,260
Ceded unearned premiums	656	678
Deferred acquisition costs	1,849	1,835	1,804
Deferred taxes	296	33
Contractholder receivables	4,374	4,362
Goodwill	3,573	3,611
Other intangible assets	279	304
Other assets	2,318	2,377
Total assets	100,184	103,078
Liabilities
Claims and claim adjustment expense reserves	48,295	49,850	50,895
Unearned premium reserves	11,971	11,839	11,850
Contractholder payables	4,374	4,362
Payables for reinsurance premiums	296	336
Debt	6,344	6,349
Other liabilities	5,306	5,506
Total liabilities	76,586	78,242
Shareholders' equity
Common stock (1,750.0 shares authorized; 295.9 and 322.2 shares issued and outstanding)	22,172	21,843
Retained earnings	29,945	27,251
Accumulated other comprehensive income (loss)	(157)	880
Treasury stock, at cost (467.6 and 437.3 shares)	(28,362)	(25,138)
Total shareholders' equity	23,598	24,836	$ 24,796
Total liabilities and shareholders' equity	$ 100,184	$ 103,078

Consolidated Balance Sheet Pare

Consolidated Balance Sheet Parentheticals - USD ($) shares in Millions, $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Consolidated Balance Sheet
Fixed maturities, available for sale, amortized cost	$ 58,878	$ 60,801
Equity securities, available for sale, cost	$ 528	$ 579
Common stock, shares authorized	1,750	1,750
Common stock, shares issued	295.9	322.2
Common stock, shares outstanding	295.9	322.2
Treasury stock, at cost, shares	467.6	437.3

Consolidated Statement of Chang

Consolidated Statement of Changes in Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common stock [Member]	Retained earnings [Member]	Accumulated other comprehensive income (loss), net of tax [Member]	Treasury stock, at cost [Member]	Common shares outstanding [Member]
Shareholders' equity, beginning of year at Dec. 31, 2012		$ 21,161	$ 21,352	$ 2,236	$ (19,344)
Shareholders' Equity [Rollforward]
Employee share-based compensation		158
Compensation amortization under share-based plans and other changes		181
Net income	$ 3,673		3,673
Dividends			(734)
Other comprehensive income (loss)	(1,426)			(1,426)
Treasury stock acquired - share repurchase authorization					(2,400)
Net shares acquired related to employee share-based compensation plans					(61)
Shareholders' equity, end of year at Dec. 31, 2013	24,796	21,500	24,291	810	(21,805)
Balance, beginning of year at Dec. 31, 2012						377.4
Common shares outstanding
Treasury stock acquired - share repurchase authorization						(28.4)
Net shares issued under employee share-based compensation plans						4.5
Balance, end of year at Dec. 31, 2013						353.5
Shareholders' Equity [Rollforward]
Employee share-based compensation		149
Compensation amortization under share-based plans and other changes		194
Net income	3,692		3,692
Dividends			(735)
Other			3
Other comprehensive income (loss)	70			70
Treasury stock acquired - share repurchase authorization					(3,275)
Net shares acquired related to employee share-based compensation plans	(58)				(58)
Shareholders' equity, end of year at Dec. 31, 2014	$ 24,836	21,843	27,251	880	(25,138)
Common shares outstanding
Treasury stock acquired - share repurchase authorization						(35.1)
Net shares issued under employee share-based compensation plans						3.8
Balance, end of year at Dec. 31, 2014	322.2					322.2
Shareholders' Equity [Rollforward]
Employee share-based compensation		133
Compensation amortization under share-based plans and other changes		196
Net income	$ 3,439		3,439
Dividends			(744)
Other			(1)
Other comprehensive income (loss)	(1,037)			(1,037)
Treasury stock acquired - share repurchase authorization	(3,150)				(3,150)
Net shares acquired related to employee share-based compensation plans	(74)				(74)
Shareholders' equity, end of year at Dec. 31, 2015	$ 23,598	$ 22,172	$ 29,945	$ (157)	$ (28,362)
Common shares outstanding
Treasury stock acquired - share repurchase authorization	(29.6)					(29.6)
Net shares issued under employee share-based compensation plans						3.3
Balance, end of year at Dec. 31, 2015	295.9					295.9

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities
Net income		$ 3,439	$ 3,692	$ 3,673
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment gains	[1]	(3)	(79)	(166)
Depreciation and amortization		818	864	867
Deferred federal income tax expense		117	121	167
Amortization of deferred acquisition costs		3,885	3,882	3,821
Equity in income from other investments		(218)	(486)	(357)
Premiums receivable		(185)	(207)	54
Reinsurance recoverables		272	400	1,284
Deferred acquisition costs		(3,920)	(3,926)	(3,759)
Claims and claim adjustment expense reserves		(1,075)	(704)	(2,057)
Unearned premium reserves		248	73	27
Other operating activities		56	63	262
Net cash provided by operating activities		3,434	3,693	3,816
Cash flows from investing activities
Proceeds from maturities of fixed maturities		11,116	10,894	7,904
Proceeds from sales of investments:
Fixed maturities		1,950	1,049	1,635
Equity securities		59	158	86
Real estate investments		31	15	18
Other investments		713	855	762
Purchases of investments:
Fixed maturities		(12,090)	(11,325)	(9,467)
Equity securities		(49)	(52)	(57)
Real estate investments		(123)	(48)	(107)
Other investments		(534)	(554)	(446)
Net sales (purchases) of short-term securities		(326)	(498)	111
Securities transactions in course of settlement		(113)	82	21
Acquisition, net of cash acquired		(13)	(12)	(997)
Other investing activities		(304)	(358)	(373)
Net cash provided by (used in) investing activities		317	206	(910)
Cash flows from financing activities
Treasury stock acquired - share repurchase authorization		(3,150)	(3,275)	(2,400)
Treasury stock acquired - net employee share-based compensation		(74)	(57)	(61)
Dividends paid to shareholders		(739)	(729)	(729)
Payment of debt		(400)		(500)
Issuance of debt		392		494
Issuance of common stock - employee share options		183	195	206
Excess tax benefits from share-based payment arrangements		55	57	51
Net cash used in financing activities		(3,733)	(3,809)	(2,939)
Effect of exchange rate changes on cash		(12)	(10)	(3)
Net increase (decrease) in cash		6	80	(36)
Cash at beginning of year		374	294	330
Cash at end of year		380	374	294
Supplemental disclosure of cash flow information
Income taxes paid		1,207	1,147	1,057
Interest paid		$ 365	$ 365	$ 355
[1]	Total other-than-temporary impairment (OTTI) losses were $(54) million, $(22) million and $(10) million for the years ended December 31, 2015, 2014 and 2013, respectively. Of total OTTI, credit losses of $(52) million, $(26) million and $(15) million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(2) million, $4 million and $5 million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Summary of Significant Accounting Policies disclosure
Summary of Significant Accounting Policies disclosure [Text Block]	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES The consolidated financial statements include the accounts of The Travelers Companies, Inc. (together with its subsidiaries, the Company). The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and claims and expenses during the reporting period. Actual results could differ from those estimates. Certain reclassifications have been made to the 2014 and 2013 financial statements to conform to the 2015 presentation. All material intercompany transactions and balances have been eliminated. On November 1, 2013, the Company acquired all of the issued and outstanding shares of The Dominion of Canada General Insurance Company (Dominion) for an aggregate purchase price of approximately $1.035 billion. Dominion primarily markets personal lines and small commercial insurance business in Canada. At the acquisition date, the Company recorded at fair value $3.91 billion of assets acquired and $2.88 billion of liabilities assumed as part of purchase accounting, including $16 million of identifiable intangible assets and $273 million of goodwill. Dominion is included in the Company's Business and International Insurance segment. The unearned premium reserve related to the acquired insurance and reinsurance contracts was carried over and included in the Company's unearned premium reserve. Premium revenue from the acquired business is recognized on a pro rata basis beginning with the acquisition date over the remaining policy terms in accordance with the Company's accounting policy. The Company recognized an intangible asset for the value of business acquired (VOBA) of $76 million at the acquisition date. VOBA represented the present value of future gross profits of the business acquired from Dominion, was reported as part of the Company's deferred acquisition costs, and was amortized in proportion to the premium revenue recognized from the acquired business. In April 2014, the Financial Accounting Standards Board (FASB) issued revised guidance to reduce diversity in practice for reporting discontinued operations. Under the previous guidance, any component of an entity that was a reportable segment, an operating segment, a reporting unit, a subsidiary or an asset group was eligible for discontinued operations presentation. The revised guidance only allows disposals of components of an entity that represent a strategic shift (e.g., disposal of a major geographical area, a major line of business, a major equity method investment or other major parts of an entity) and that have a major effect on a reporting entity's operations and financial results to be reported as discontinued operations. The revised guidance also requires expanded disclosure in the financial statements for discontinued operations as well as for disposals of significant components of an entity that do not qualify for discontinued operations presentation. The updated guidance was effective for the quarter ending March 31, 2015. The adoption of this guidance did not have any effect on the Company's results of operations, financial position or liquidity. In May 2014, the FASB issued updated guidance to clarify the principles for recognizing revenue. While insurance contracts are not within the scope of this updated guidance, the Company's fee income related to providing claims and policy management services as well as claim and loss prevention services will be subject to this updated guidance. The updated guidance requires an entity to recognize revenue as performance obligations are met, in order to reflect the transfer of promised goods or services to customers in an amount that reflects the consideration the entity is entitled to receive for those goods or services. The following steps are applied in the updated guidance: (1) identify the contract(s) with a customer; (2) identify the performance obligations in the contract; (3) determine the transaction price; (4) allocate the transaction price to the performance obligations in the contract; and (5) recognize revenue when, or as, the entity satisfies a performance obligation. In July 2015, the FASB deferred the effective date of the updated guidance by one year. The updated guidance is effective for the quarter ending March 31, 2018. The adoption of this guidance is not expected to have a material effect on the Company's results of operations, financial position or liquidity. In June 2014, the FASB issued updated guidance to resolve diversity in practice concerning employee share-based payments that contain performance targets that could be achieved after the requisite service period. Many reporting entities account for performance targets that could be achieved after the requisite service period as performance conditions that affect the vesting of the award and, therefore, do not reflect the performance targets in the estimate of the grant-date fair value of the award. Other reporting entities treat those performance targets as nonvesting conditions that affect the grant-date fair value of the award. The updated guidance requires that a performance target that affects vesting and that can be achieved after the requisite service period be treated as a performance condition. As such, the performance target that affects vesting should not be reflected in estimating the fair value of the award at the grant date. Compensation cost should be recognized in the period in which it becomes probable that the performance target will be achieved and should represent the compensation cost attributable to the periods for which service has been rendered. If the performance target becomes probable of being achieved before the end of the service period, the remaining unrecognized compensation cost for which requisite service has not yet been rendered is recognized prospectively over the remaining service period. The total amount of compensation cost recognized during and after the service period should reflect the number of awards that are expected to vest and should be adjusted to reflect those awards that ultimately vest. The updated guidance is effective for annual and interim periods beginning after December 15, 2015, with early adoption permitted. The adoption of this guidance is not expected to have a material effect on the Company's results of operations, financial position or liquidity. In August 2014, the FASB issued guidance to address the diversity in practice in determining when there is substantial doubt about an entity's ability to continue as a going concern and when an entity must disclose certain relevant conditions and events. The new guidance requires an entity to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about the entity's ability to continue as a going concern within one year after the date that the financial statements are issued (or available to be issued). The new guidance allows the entity to consider the mitigating effects of management's plans that will alleviate the substantial doubt and requires certain disclosures when substantial doubt is alleviated as a result of consideration of management's plans. If conditions or events raise substantial doubt that is not alleviated, an entity should disclose that there is substantial doubt about the entity's ability to continue as a going concern within one year after the date that the financial statements are issued (or available to be issued), along with the principal conditions or events that raise substantial doubt, management's evaluation of the significance of those conditions or events in relation to the entity's ability to meet its obligations and management's plans that are intended to mitigate those conditions. The guidance is effective for annual periods ending after December 15, 2016, and interim and annual periods thereafter. In November 2014, the FASB issued updated guidance to clarify when the separation of certain embedded derivative features in a hybrid financial instrument that is issued in the form of a share is required. That is, an entity will continue to evaluate whether the economic characteristics and risks of the embedded derivative feature are clearly and closely related to those of the host contract. Specifically, the amendments clarify that an entity should consider all relevant terms and features, including the embedded derivative feature being evaluated for bifurcation, in evaluating the nature of the host contract. Furthermore, the amendments clarify that no single term or feature would necessarily determine the economic characteristics and risks of the host contract. Rather, the nature of the host contract depends upon the economic characteristics and risks of the entire hybrid financial instrument. The updated guidance is effective for reporting periods beginning after December 15, 2015. Early adoption is permitted. The adoption of this guidance is not expected to have a material effect on the Company's results of operations, financial position or liquidity. In February 2015, the FASB issued updated guidance that makes targeted amendments to the current consolidation accounting guidance. The update is in response to accounting complexity concerns, particularly from the asset management industry. The guidance simplifies consolidation accounting by reducing the number of approaches to consolidation, provides a scope exception to registered money market funds and similar unregistered money market funds and ends the indefinite deferral granted to investment companies from applying the variable interest entity guidance. The updated guidance is effective for annual and interim periods beginning after December 15, 2015. The adoption of this guidance is not expected to have a material effect on the Company's results of operations, financial position or liquidity. In April 2015, the FASB issued updated guidance to clarify the required presentation of debt issuance costs. The amended guidance requires that debt issuance costs be presented in the balance sheet as a direct reduction from the carrying amount of the recognized debt liability, consistent with the treatment of debt discounts. Amortization of debt issuance costs is to be reported as interest expense. The recognition and measurement guidance for debt issuance costs are not affected by the updated guidance. The updated guidance is effective for reporting periods beginning after December 15, 2015. Early adoption is permitted. The updated guidance is consistent with the Company's accounting policy and its adoption will not have any effect on the Company's results of operations, financial position or liquidity. In September 2015, the FASB issued updated guidance regarding business combinations that requires an acquirer to recognize post-close measurement adjustments for provisional amounts in the period the adjustment amounts are determined rather than retrospectively. The acquirer is also required to recognize, in the same period's financial statements, the effect on earnings of changes in depreciation, amortization, or other income effects, if any, as a result of the provisional amount, calculated as if the accounting had been completed at the acquisition date. The updated guidance is to be applied prospectively effective for annual and interim periods beginning after December 15, 2015. In connection with business combinations which have already been completed, the adoption of this guidance is not expected to have a material effect on the Company's results of operations, financial position or liquidity. In January 2016, the FASB issued updated guidance to address the recognition, measurement, presentation, and disclosure of certain financial instruments. The updated guidance requires equity investments, except those accounted for under the equity method of accounting, that have readily determinable fair value to be measured at fair value with changes in fair value recognized in net income. Equity investments that do not have readily determinable fair values may be remeasured at fair value either upon the occurrence of an observable price change or upon identification of an impairment. A qualitative assessment for impairment is required for equity investments without readily determinable fair values. The updated guidance also eliminates the requirement to disclose the method and significant assumptions used to estimate the fair value of financial instruments measured at amortized cost on the balance sheet. The updated guidance is effective for the quarter ending March 31, 2018 and will require recognition of a cumulative effect adjustment at adoption. The Company will not be able to determine the impact that the updated guidance will have on its results of operations until the updated guidance is adopted, but does not currently expect the adoption of this guidance to impact its financial position or liquidity. Fixed maturities include bonds, notes and redeemable preferred stocks. Fixed maturities, including instruments subject to securities lending agreements, are classified as available for sale and are reported at fair value, with unrealized investment gains and losses, net of income taxes, charged or credited directly to other comprehensive income. Equity securities, which include public common and non-redeemable preferred stocks, are classified as available for sale with changes in fair value, net of income taxes, charged or credited directly to other comprehensive income. The Company's real estate investments include warehouses, office buildings and other commercial land and properties that are directly owned. Real estate is recorded on the purchase date at the purchase price, which generally represents fair value, and is supported by internal analysis or external appraisals that use discounted cash flow analyses and other acceptable valuation techniques. Real estate held for investment purposes is subsequently carried at cost less accumulated depreciation. Buildings are depreciated on a straight-line basis over the shorter of the expected useful life of the building or 39 years. Real estate held for sale is carried at lower of cost or fair value, less estimated costs to sell. Short-term securities have an original maturity of less than one year and are carried at amortized cost, which approximates fair value. Investments in Private Equity Limited Partnerships, Hedge Funds and Real Estate Partnerships The Company uses the equity method of accounting for investments in private equity limited partnerships, hedge funds and real estate partnerships. The partnerships and the hedge funds generally report investments on their balance sheet at fair value. The financial statements prepared by the investee are received by the Company on a lag basis, with the lag period generally dependent upon the type of underlying investments. The private equity and real estate partnerships provide financial information quarterly which is generally available to investors, including the Company, within three to six months following the date of the reporting period. The hedge funds provide financial information monthly, which is generally available to investors within one month following the date of the reporting period. The Company regularly requests financial information from the partnerships prior to the receipt of the partnerships' financial statements and records any material information obtained from these requests in its consolidated financial statements. Other Also included in other investments are non-public common equities, preferred equities and derivatives. Non-public common equities and preferred equities are reported at fair value with changes in fair value, net of income taxes, charged or credited directly to other comprehensive income. The Company's derivative financial instruments are carried at fair value, with the changes in fair value reflected in the consolidated statement of income in net realized investment gains (losses). For a further discussion of the derivatives used by the Company, see note 3. Investment income from fixed maturities is recognized based on the constant effective yield method which includes an adjustment for estimated principal pre-payments, if any. The effective yield used to determine amortization for fixed maturities subject to prepayment risk (e.g., asset-backed, loan-backed and structured securities) is recalculated and adjusted periodically based upon actual historical and/or projected future cash flows, which are obtained from a widely-accepted securities data provider. The adjustments to the yield for highly rated prepayable fixed maturities are accounted for using the retrospective method. The adjustments to the yield for non-highly rated prepayable fixed maturities are accounted for using the prospective method. Dividends on equity securities (including those with transfer restrictions) are recognized in income when declared. Rental income on real estate is recognized on a straight-line basis over the lease term. See note 3 for further discussion. Investments in private equity limited partnerships, hedge funds, real estate partnerships and joint ventures are accounted for using the equity method of accounting, whereby the Company's share of the investee's earnings or losses in the fund is reported in net investment income. Accrual of income is suspended on non-securitized fixed maturities that are in default, or on which it is likely that future payments will not be made as scheduled. Interest income on investments in default is recognized only when payments are received. Investments included in the consolidated balance sheet that were not income-producing for the preceding 12 months were not material. For fixed maturities where the Company records an other-than-temporary impairment, a determination is made as to the cause of the impairment and whether the Company expects a recovery in the value. For fixed maturities where the Company expects a recovery in value, not necessarily to par, the constant effective yield method is utilized, and the investment is amortized to the expected recovery amount. Net realized investment gains and losses are included as a component of pretax revenues based upon specific identification of the investments sold on the trade date. Included in net realized investment gains (losses) are other-than-temporary impairment losses on invested assets other than those investments accounted for using the equity method of accounting as described in the "Investment Impairments" section that follows. The Company conducts a periodic review to identify and evaluate invested assets having other-than-temporary impairments. Some of the factors considered in identifying other-than-temporary impairments include: (1) for fixed maturity investments, whether the Company intends to sell the investment or whether it is more likely than not that the Company will be required to sell the investment prior to an anticipated recovery in value; (2) for non-fixed maturity investments, the Company's ability and intent to retain the investment for a reasonable period of time sufficient to allow for an anticipated recovery in value; (3) the likelihood of the recoverability of principal and interest for fixed maturity securities (i.e., whether there is a credit loss) or cost for equity securities; (4) the length of time and extent to which the fair value has been less than amortized cost for fixed maturity securities or cost for equity securities; and (5) the financial condition, near-term and long-term prospects for the issuer, including the relevant industry conditions and trends, and implications of rating agency actions and offering prices. For fixed maturity investments that the Company does not intend to sell or for which it is more likely than not that the Company would not be required to sell before an anticipated recovery in value, the Company separates the credit loss component of the impairment from the amount related to all other factors and reports the credit loss component in net realized investment gains (losses). The impairment related to all other factors is reported in other comprehensive income. For equity securities (including public common and non-redeemable preferred stock) and for fixed maturity investments the Company intends to sell or for which it is more likely than not that the Company will be required to sell before an anticipated recovery in value, the full amount of the impairment is included in net realized investment gains (losses). Upon recognizing an other-than-temporary impairment, the new cost basis of the investment is the previous amortized cost basis less the other-than-temporary impairment recognized in net realized investment gains (losses). The new cost basis is not adjusted for any subsequent recoveries in fair value; however, for fixed maturity investments the difference between the new cost basis and the expected cash flows is accreted on a quarterly basis to net investment income over the remaining expected life of the investment. The Company determines the credit loss component of fixed maturity investments by utilizing discounted cash flow modeling to determine the present value of the security and comparing the present value with the amortized cost of the security. If the amortized cost is greater than the present value of the expected cash flows, the difference is considered a credit loss and recognized in net realized investment gains (losses). For non-structured fixed maturities (U.S. Treasury securities, obligations of U.S. government and government agencies and authorities, obligations of states, municipalities and political subdivisions, debt securities issued by foreign governments and certain corporate debt), the estimate of expected cash flows is determined by projecting a recovery value and a recovery time frame and assessing whether further principal and interest will be received. The determination of recovery value incorporates an issuer valuation assumption utilizing one or a combination of valuation methods as deemed appropriate by the Company. The Company determines the undiscounted recovery value by allocating the estimated value of the issuer to the Company's assessment of the priority of claims. The present value of the cash flows is determined by applying the effective yield of the security at the date of acquisition (or the most recent implied rate used to accrete the security if the implied rate has changed as a result of a previous impairment) and an estimated recovery time frame. Generally, that time frame for securities for which the issuer is in bankruptcy is 12 months. For securities for which the issuer is financially troubled but not in bankruptcy, that time frame is generally 24 months. Included in the present value calculation are expected principal and interest payments; however, for securities for which the issuer is classified as bankrupt or in default, the present value calculation assumes no interest payments and a single recovery amount. In estimating the recovery value, significant judgment is involved in the development of assumptions relating to a myriad of factors related to the issuer including, but not limited to, revenue, margin and earnings projections, the likely market or liquidation values of assets, potential additional debt to be incurred pre- or post-bankruptcy/restructuring, the ability to shift existing or new debt to different priority layers, the amount of restructuring/bankruptcy expenses, the size and priority of unfunded pension obligations, litigation or other contingent claims, the treatment of intercompany claims and the likely outcome with respect to inter-creditor conflicts. For structured fixed maturity securities (primarily residential and commercial mortgage-backed securities and asset-backed securities), the Company estimates the present value of the security by projecting future cash flows of the assets underlying the securitization, allocating the flows to the various tranches based on the structure of the securitization and determining the present value of the cash flows using the effective yield of the security at the date of acquisition (or the most recent implied rate used to accrete the security if the implied rate has changed as a result of a previous impairment or changes in expected cash flows). The Company incorporates levels of delinquencies, defaults and severities as well as credit attributes of the remaining assets in the securitization, along with other economic data, to arrive at its best estimate of the parameters applied to the assets underlying the securitization. In order to project cash flows, the following assumptions are applied to the assets underlying the securitization: (1) voluntary prepayment rates, (2) default rates and (3) loss severity. The key assumptions made for the Prime, Alt-A and first-lien Sub-Prime mortgage-backed securities at December 31, 2015 were as follows: (at December 31, 2015) Prime Alt-A Sub-Prime Voluntary prepayment rates 1% - 33% 3% - 18% 2% - 10% Percentage of remaining pool liquidated due to defaults 1% - 46% 8% - 62% 22% - 61% Loss severity 30% - 65% 55% - 120% 70% - 120% On at least an annual basis, the Company obtains independent appraisals for substantially all of its real estate investments. In addition, the carrying value of all real estate investments is reviewed for impairment on a quarterly basis or when events or changes in circumstances indicate that the carrying amount may not be recoverable. The review for impairment considers the valuation from the independent appraisal, when applicable, and incorporates an estimate of the undiscounted cash flows expected to result from the use and eventual disposition of the real estate property. An impairment loss is recognized if the expected future undiscounted cash flows are less than the carrying value of the real estate property. The impairment loss is the amount by which the carrying amount exceeds fair value. The Company reviews its investments in private equity limited partnerships, hedge funds and real estate partnerships for impairment no less frequently than quarterly and monitors the performance throughout the year through discussions with the managers/general partners. If the Company becomes aware of an impairment of a partnership's investments at the balance sheet date prior to receiving the partnership's financial statements, it will recognize an impairment by recording a reduction in the carrying value of the partnership with a corresponding charge to net investment income. The Company may, from time to time, sell invested assets subsequent to the balance sheet date that it did not intend to sell at the balance sheet date. Conversely, the Company may not sell invested assets that it asserted that it intended to sell at the balance sheet date. Such changes in intent are due to events occurring subsequent to the balance sheet date. The types of events that may result in a change in intent include, but are not limited to, significant changes in the economic facts and circumstances related to the invested asset (e.g., a downgrade or upgrade from a rating agency), significant unforeseen changes in liquidity needs, or changes in tax laws or the regulatory environment. The Company has engaged in securities lending activities from which it generates net investment income by lending certain of its investments to other institutions for short periods of time. Borrowers of these securities provide collateral equal to at least 102% of the market value of the loaned securities plus accrued interest. This collateral is held by a third-party custodian, and the Company has the right to access the collateral only in the event that the institution borrowing the Company's securities is in default under the lending agreement. Therefore, the Company does not recognize the receipt of the collateral held by the third-party custodian or the obligation to return the collateral. The loaned securities remain a recorded asset of the Company. The Company accepts only cash as collateral for securities on loan and restricts the manner in which that cash is invested. Amounts recoverable from reinsurers are estimated in a manner consistent with the associated claim liability. The Company reports its reinsurance recoverables net of an allowance for estimated uncollectible reinsurance recoverables. The allowance is based upon the Company's ongoing review of amounts outstanding, length of collection periods, changes in reinsurer credit standing, disputes, applicable coverage defenses and other relevant factors. Amounts deemed to be uncollectible, including amounts due from known insolvent reinsurers, are written off against the allowance for estimated uncollectible reinsurance recoverables. Any subsequent collections of amounts previously written off are reported as part of claims and claim adjustment expenses. The Company evaluates and monitors the financial condition of its reinsurers under voluntary reinsurance arrangements to minimize its exposure to significant losses from reinsurer insolvencies. Incremental direct costs of acquired, new and renewal insurance contracts, consisting of commissions (other than contingent commissions) and premium-related taxes, are capitalized and charged to expense pro rata over the contract periods in which the related premiums are earned. Deferred acquisition costs are reviewed to determine if they are recoverable from future income and, if not, are charged to expense. Future investment income attributable to related premiums is taken into account in measuring the recoverability of the carrying value of this asset. All other acquisition expenses are charged to operations as incurred. Under certain workers' compensation insurance contracts with deductible features, the Company is obligated to pay the claimant for the full amount of the claim. The Company is subsequently reimbursed by the policyholder for the deductible amount. These amounts are included on a gross basis in the consolidated balance sheet in contractholder payables and contractholder receivables, respectively. The Company performs a review, on at least an annual basis, of goodwill held by the reporting units which are the Company's three operating and reportable segments: Business and International Insurance; Bond & Specialty Insurance; and Personal Insurance. The Company estimates the fair value of its reporting units and compares it to their carrying value, including goodwill. If the carrying values of the reporting units were to exceed their fair value, the amount of the impairment would be calculated and goodwill adjusted accordingly. The Company uses a discounted cash flow model to estimate the fair value of its reporting units. The discounted cash flow model is an income approach to valuation that is based on a detailed cash flow analysis for deriving a current fair value of reporting units and is representative of the Company's reporting units' current and expected future financial performance. The discount rate assumptions reflect the Company's assessment of the risks inherent in the projected future cash flows and the Company's weighted-average cost of capital, and are compared against available market data for reasonableness. Other indefinite-lived intangible assets held by the Company are also reviewed for impairment on at least an annual basis. The classification of the asset as indefinite-lived is reassessed and an impairment is recognized if the carrying amount of the asset exceeds its fair value. Intangible assets that are deemed to have a finite useful life are amortized over their useful lives. The carrying amount of intangible assets with a finite useful life is regularly reviewed for indicators of impairment in value. Impairment is recognized only if the carrying amount of the intangible asset is not recoverable from its undiscounted cash flows and is measured as the difference between the carrying amount and the fair value of the asset. As a result of the reviews performed for the years ended December 31, 2015, 2014 and 2013, the Company determined that the estimated fair value substantially exceeded the respective carrying value of its reporting units for those years and that goodwill was not impaired. The Company also determined during its reviews for each year that its other indefinite-lived intangible assets and finite-lived i

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2015
Segment Information disclosure
Segment Information disclosure [Text Block]	2. SEGMENT INFORMATION The accounting policies used to prepare the segment reporting data for the Company's three reportable business segments are the same as those described in the Summary of Significant Accounting Policies in note 1. Except as described below for certain legal entities, the Company allocates its invested assets and the related net investment income to its reportable business segments. Pretax net investment income is allocated based upon an investable funds concept, which takes into account liabilities (net of non-invested assets) and appropriate capital considerations for each segment. For investable funds, a benchmark investment yield is developed that reflects the estimated duration of the loss reserves' future cash flows, the interest rate environment at the time the losses were incurred and A+ rated corporate debt instrument yields. For capital, a benchmark investment yield is developed that reflects the average yield on the total investment portfolio. The benchmark investment yields are applied to each segment's investable funds and capital, respectively, to produce a total notional investment income by segment. The Company's actual net investment income is allocated to each segment in proportion to the respective segment's notional investment income to total notional investment income. There are certain legal entities within the Company that are dedicated to specific reportable business segments. The invested assets and related net investment income from these legal entities are reported in the applicable business segment and are not allocated among the other business segments. The cost of the Company's catastrophe treaty program is included in the Company's ceded premiums and is allocated among reportable business segments based on an estimate of actual market reinsurance pricing using expected losses calculated by the Company's catastrophe model, adjusted for any experience adjustments. The following tables summarize the components of the Company's operating revenues, operating income, net written premiums and total assets by reportable business segments. (for the year ended December 31, in millions) Business and Bond & Personal Total 2015 Premiums 14,521 2,085 7,268 23,874 Net investment income 1,824 223 332 2,379 Fee income 445 — — 445 Other revenues 23 22 48 93 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating revenues(1) 16,813 2,330 7,648 26,791 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization and depreciation 2,907 467 1,322 4,696 Income tax expense 769 272 402 1,443 Operating income(1) 2,170 633 889 3,692 2014 Premiums 14,512 2,076 7,125 23,713 Net investment income 2,156 252 379 2,787 Fee income 438 — — 438 Other revenues 46 19 80 145 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating revenues(1) 17,152 2,347 7,584 27,083 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization and depreciation 2,909 482 1,347 4,738 Income tax expense 798 348 366 1,512 Operating income(1) 2,347 727 824 3,898 2013 Premiums 13,332 1,981 7,324 22,637 Net investment income 2,087 260 369 2,716 Fee income 395 — — 395 Other revenues 160 20 103 283 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating revenues(1) 15,974 2,261 7,796 26,031 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization and depreciation 2,751 473 1,461 4,685 Income tax expense 758 227 366 1,351 Operating income(1) 2,404 573 838 3,815 (1) Operating revenues for reportable business segments exclude net realized investment gains. Operating income for reportable business segments equals net income excluding the after-tax impact of net realized investment gains. Net written premiums by market were as follows: (for the year ended December 31, in millions) 2015 2014 2013 Business and International Insurance: Domestic: Select Accounts 2,716 2,707 2,724 Middle Market 6,325 6,108 5,862 National Accounts 1,048 1,047 1,010 First Party 1,564 1,579 1,552 Specialized Distribution 1,111 1,074 1,085 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Domestic 12,764 12,515 12,233 International 1,819 2,121 1,279 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Business and International Insurance 14,583 14,636 13,512 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Bond & Specialty Insurance 2,081 2,103 2,030 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Personal Insurance: Automobile 3,700 3,390 3,370 Homeowners and Other 3,757 3,775 3,855 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Personal Insurance 7,457 7,165 7,225 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total consolidated net written premiums 24,121 23,904 22,767 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (for the year ended December 31, in millions) 2015 2014 2013 Revenue reconciliation Earned premiums Business and International Insurance: Domestic: Workers' compensation 3,868 3,713 3,560 Commercial automobile 1,925 1,901 1,904 Commercial property 1,772 1,756 1,698 General liability 1,914 1,852 1,790 Commercial multi-peril 3,132 3,070 3,093 Other 39 42 39 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Domestic 12,650 12,334 12,084 International 1,871 2,178 1,248 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Business and International Insurance 14,521 14,512 13,332 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Bond & Specialty Insurance: Fidelity and surety 954 936 913 General liability 955 963 891 Other 176 177 177 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Bond & Specialty Insurance 2,085 2,076 1,981 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Personal Insurance: Automobile 3,512 3,316 3,431 Homeowners and Other 3,756 3,809 3,893 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Personal Insurance 7,268 7,125 7,324 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total earned premiums 23,874 23,713 22,637 Net investment income 2,379 2,787 2,716 Fee income 445 438 395 Other revenues 93 145 283 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating revenues for reportable segments 26,791 27,083 26,031 Other revenues 6 — (6 ) Net realized investment gains 3 79 166 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total consolidated revenues 26,800 27,162 26,191 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income reconciliation, net of tax Total operating income for reportable segments 3,692 3,898 3,815 Interest Expense and Other(1) (255 ) (257 ) (248 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating income 3,437 3,641 3,567 Net realized investment gains 2 51 106 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total consolidated net income 3,439 3,692 3,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The primary component of Interest Expense and Other was after-tax interest expense of $242 million, $240 million and $235 million in 2015, 2014 and 2013, respectively. (at December 31, in millions) 2015 2014 Asset reconciliation: Business and International Insurance 79,692 82,310 Bond & Specialty Insurance 7,360 7,525 Personal Insurance 12,748 12,798 ​ ​ ​ ​ ​ ​ ​ Total assets for reportable segments 99,800 102,633 Other assets(1) 384 445 ​ ​ ​ ​ ​ ​ ​ Total consolidated assets 100,184 103,078 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The primary components of other assets at December 31, 2015 and 2014 were other intangible assets and deferred taxes. The Company does not have revenue from transactions with a single customer amounting to 10 percent or more of its revenues. The following table presents revenues of the Company's operations based on location: (for the year ended December 31, in millions) 2015 2014 2013 U.S. 25,112 25,091 25,138 Non-U.S.: Canada 1,202 1,474 529 Other Non-U.S. 486 597 524 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Non-U.S. 1,688 2,071 1,053 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues 26,800 27,162 26,191 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Investments

Investments	12 Months Ended
	Dec. 31, 2015
Investments disclosure
Investments disclsoure [Text Block]	3. INVESTMENTS The amortized cost and fair value of investments in fixed maturities classified as available for sale were as follows: Gross Unrealized Amortized (at December 31, 2015, in millions) Gains Losses Fair Value U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 2,202 8 16 2,194 Obligations of states, municipalities and political subdivisions: Local general obligation 12,744 577 3 13,318 Revenue 9,492 472 4 9,960 State general obligation 1,978 97 2 2,073 Pre-refunded 5,813 247 — 6,060 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total obligations of states, municipalities and political subdivisions 30,027 1,393 9 31,411 Debt securities issued by foreign governments 1,829 45 1 1,873 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,863 124 6 1,981 All other corporate bonds 22,854 523 288 23,089 Redeemable preferred stock 103 7 — 110 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 58,878 2,100 320 60,658 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Unrealized Amortized (at December 31, 2014, in millions) Gains Losses Fair Value U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 2,022 36 5 2,053 Obligations of states, municipalities and political subdivisions: Local general obligation 12,366 644 5 13,005 Revenue 9,833 575 4 10,404 State general obligation 2,467 137 1 2,603 Pre-refunded 7,229 332 — 7,561 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total obligations of states, municipalities and political subdivisions 31,895 1,688 10 33,573 Debt securities issued by foreign governments 2,320 48 — 2,368 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 2,052 165 4 2,213 All other corporate bonds 22,390 844 99 23,135 Redeemable preferred stock 122 10 — 132 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 60,801 2,791 118 63,474 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The amortized cost and fair value of fixed maturities by contractual maturity follow. Actual maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. (at December 31, 2015, in millions) Amortized Fair Due in one year or less 6,240 6,324 Due after 1 year through 5 years 16,741 17,296 Due after 5 years through 10 years 16,008 16,260 Due after 10 years 18,026 18,797 ​ ​ ​ ​ ​ ​ ​ 57,015 58,677 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,863 1,981 ​ ​ ​ ​ ​ ​ ​ Total 58,878 60,658 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Pre-refunded bonds of $6.06 billion and $7.56 billion at December 31, 2015 and 2014, respectively, were bonds for which states or municipalities have established irrevocable trusts, almost exclusively comprised of U.S. Treasury securities, which were created to satisfy their responsibility for payments of principal and interest. The Company's fixed maturity investment portfolio at December 31, 2015 and 2014 included $1.98 billion and $2.21 billion, respectively, of residential mortgage-backed securities, which include pass-through securities and collateralized mortgage obligations (CMOs). Included in the totals at December 31, 2015 and 2014 were $676 million and $872 million, respectively, of GNMA, FNMA, FHLMC (excluding FHA project loans) and Canadian government guaranteed residential mortgage-backed pass-through securities classified as available for sale. Also included in those totals were residential CMOs classified as available for sale with a fair value of $1.30 billion and $1.34 billion at December 31, 2015 and 2014, respectively. Approximately 48% and 46% of the Company's CMO holdings at December 31, 2015 and 2014, respectively, were guaranteed by or fully collateralized by securities issued by GNMA, FNMA or FHLMC. The average credit rating of the $683 million and $725 million of non-guaranteed CMO holdings at December 31, 2015 and 2014, respectively, was "Baa2" and "Ba1," respectively. The average credit rating of all of the above securities was "Aa3" at both December 31, 2015 and 2014. At December 31, 2015 and 2014, the Company held commercial mortgage-backed securities (CMBS, including FHA project loans) of $865 million and $715 million, respectively, which are included in "All other corporate bonds" in the tables above. At December 31, 2015 and 2014, approximately $303 million and $202 million of these securities, respectively, or the loans backing such securities, contained guarantees by the U.S. government or a government-sponsored enterprise. The average credit rating of the $562 million and $513 million of non-guaranteed securities at December 31, 2015 and 2014, respectively, was "Aaa" at both dates. The CMBS portfolio is supported by loans that are diversified across economic sectors and geographical areas. The average credit rating of the CMBS portfolio was "Aaa" at both December 31, 2015 and 2014. At December 31, 2015 and 2014, the Company had $269 million and $296 million, respectively, of securities on loan as part of a tri-party lending agreement. Proceeds from sales of fixed maturities classified as available for sale were $1.95 billion, $1.05 billion and $1.64 billion in 2015, 2014 and 2013, respectively. Gross gains of $95 million, $44 million and $66 million and gross losses of $14 million, $12 million and $25 million were realized on those sales in 2015, 2014 and 2013, respectively. At December 31, 2015 and 2014, the Company's insurance subsidiaries had $4.66 billion and $4.78 billion, respectively, of securities on deposit at financial institutions in certain states pursuant to the respective states' insurance regulatory requirements. Funds deposited with third parties to be used as collateral to secure various liabilities on behalf of insureds, cedants and other creditors had a fair value of $28 million and $39 million at December 31, 2015 and 2014, respectively. Other investments pledged as collateral securing outstanding letters of credit had a fair value of $21 million and $22 million at December 31, 2015 and 2014, respectively. In addition, the Company utilized a Lloyd's trust deposit at December 31, 2015 and 2014, whereby owned securities with a fair value of approximately $140 million and $151 million, respectively, held by an insurance subsidiary were pledged into a Lloyd's trust account to support capital requirements for the Company's operations at Lloyd's. The cost and fair value of investments in equity securities were as follows: Gross Fair (at December 31, 2015, in millions) Cost Gains Losses Public common stock 386 164 7 543 Non-redeemable preferred stock 142 26 6 162 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 528 190 13 705 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Fair (at December 31, 2014, in millions) Cost Gains Losses Public common stock 400 295 4 691 Non-redeemable preferred stock 179 31 2 208 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 579 326 6 899 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Proceeds from sales of equity securities classified as available for sale were $59 million, $158 million and $86 million in 2015, 2014 and 2013, respectively. Gross gains of $16 million, $27 million and $16 million and gross losses of $10 million, $3 million and $1 million were realized on those sales in 2015, 2014 and 2013, respectively. The Company's real estate investments include warehouses, office buildings and other commercial land and properties that are directly owned. The Company negotiates commercial leases with individual tenants through unrelated, licensed real estate brokers. Negotiated terms and conditions include, among others, rental rates, length of lease period and improvements to the premises to be provided by the landlord. Proceeds from the sale of real estate investments were $31 million, $15 million and $18 million in 2015, 2014 and 2013, respectively. Gross gains of $4 million, $6 million and $7 million were realized on those sales in 2015, 2014 and 2013, respectively, and there were no gross losses. The Company had no real estate held for sale at December 31, 2015 and 2014. Accumulated depreciation on real estate held for investment purposes was $320 million and $290 million at December 31, 2015 and 2014, respectively. Future minimum rental income on operating leases relating to the Company's real estate properties is expected to be $92 million, $74 million, $61 million, $49 million and $36 million for 2016, 2017, 2018, 2019 and 2020, respectively, and $59 million for 2021 and thereafter. The Company's short-term securities consist of Aaa-rated registered money market funds, U.S. Treasury securities, high-quality commercial paper (primarily A1/P1) and high-quality corporate securities purchased within a year to their maturity with a combined average of 67 days to maturity at December 31, 2015. The amortized cost of these securities, which totaled $4.67 billion and $4.36 billion at December 31, 2015 and 2014, respectively, approximated their fair value. Entities which do not have sufficient equity at risk to allow the entity to finance its activities without additional financial support or in which the equity investors, as a group, do not have the characteristic of a controlling financial interest are referred to as variable interest entities (VIE). A VIE is consolidated by the variable interest holder that is determined to have the controlling financial interest (primary beneficiary) as a result of having both the power to direct the activities of a VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or right to receive benefits from the VIE that could potentially be significant to the VIE. The Company determines whether it is the primary beneficiary of an entity subject to consolidation based on a qualitative assessment of the VIE's capital structure, contractual terms, nature of the VIE's operations and purpose and the Company's relative exposure to the related risks of the VIE on the date it becomes initially involved in the VIE. The Company reassesses its VIE determination with respect to an entity on an ongoing basis. The Company is a passive investor in limited partner equity interests issued by third party VIEs. These include certain of the Company's investments in private equity limited partnerships, hedge funds and real estate partnerships where the Company is not related to the general partner. These investments are generally accounted for under the equity method and reported in the Company's consolidated balance sheet as other investments unless the Company is deemed the primary beneficiary. These equity interests generally cannot be redeemed. Distributions from these investments are received by the Company as a result of liquidation of the underlying investments of the funds and/or as income distribution. The Company's maximum exposure to loss with respect to these investments is limited to the investment carrying amounts reported in the Company's consolidated balance sheet and any unfunded commitment. Neither the carrying amounts nor the unfunded commitments related to these VIEs are material. The following tables summarize, for all investments in an unrealized loss position at December 31, 2015 and 2014, the aggregate fair value and gross unrealized loss by length of time those securities have been continuously in an unrealized loss position. The fair value amounts reported in the tables are estimates that are prepared using the process described in note 4. The Company also relies upon estimates of several factors in its review and evaluation of individual investments, using the process described in note 1, in determining whether such investments are other-than-temporarily impaired. Less than 12 months 12 months or longer Total (at December 31, 2015, in millions) Fair Gross Fair Gross Fair Gross Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 1,820 15 28 1 1,848 16 Obligations of states, municipalities and political subdivisions 928 7 142 2 1,070 9 Debt securities issued by foreign governments 172 1 — — 172 1 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 473 4 57 2 530 6 All other corporate bonds 7,725 197 710 91 8,435 288 Redeemable preferred stock 8 — — — 8 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 11,126 224 937 96 12,063 320 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities Public common stock 48 6 33 1 81 7 Non-redeemable preferred stock 47 3 38 3 85 6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total equity securities 95 9 71 4 166 13 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 11,221 233 1,008 100 12,229 333 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months 12 months or longer Total (at December 31, 2014, in millions) Fair Gross Fair Gross Fair Gross Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 180 2 125 3 305 5 Obligations of states, municipalities and political subdivisions 173 1 797 9 970 10 Debt securities issued by foreign governments 50 — 24 — 74 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 68 — 192 4 260 4 All other corporate bonds 2,148 38 2,355 61 4,503 99 Redeemable preferred stock — — — — — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 2,619 41 3,493 77 6,112 118 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities Public common stock 81 4 1 — 82 4 Non-redeemable preferred stock 44 1 42 1 86 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total equity securities 125 5 43 1 168 6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 2,744 46 3,536 78 6,280 124 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The following table summarizes, for all fixed maturities and equity securities reported at fair value for which fair value is less than 80% of amortized cost at December 31, 2015, the gross unrealized investment loss by length of time those securities have continuously been in an unrealized loss position of greater than 20% of amortized cost: Period For Which Fair Value Is Less Than 80% of Amortized Cost (in millions) 3 Months Greater Than Greater Than Greater Than Total Fixed maturities Mortgage-backed securities — — — — — Other 51 17 6 7 81 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 51 17 6 7 81 Equity securities 3 1 — — 4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 54 18 6 7 85 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ These unrealized losses at December 31, 2015 represented less than 1% of the combined fixed maturity and equity security portfolios on a pretax basis and less than 1% of shareholders' equity on an after-tax basis. Impairment charges included in net realized investment gains in the consolidated statement of income were as follows: (for the year ended December 31, in millions) 2015 2014 2013 Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities — — — Obligations of states, municipalities and political subdivisions — — — Debt securities issued by foreign governments — — — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities — 1 2 All other corporate bonds 13 15 3 Redeemable preferred stock — — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 13 16 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities Public common stock 37 9 5 Non-redeemable preferred stock — — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total equity securities 37 9 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other investments 2 1 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 52 26 15 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The following tables present the cumulative amount of and the changes during the reporting period in the credit losses of other-than-temporary impairments (OTTI) on fixed maturities recognized in the consolidated statement of income for which a portion of the OTTI was recognized in other comprehensive income: Year ended December 31, 2015 Cumulative Additions for Additions for Reductions Adjustments to Cumulative OTTI Fixed maturities Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 40 — — (6 ) (2 ) 32 All other corporate bonds 59 2 — (4 ) (6 ) 51 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 99 2 — (10 ) (8 ) 83 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2014 Cumulative Additions for Additions for Reductions Adjustments to Cumulative OTTI Fixed maturities Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 53 — 1 (5 ) (9 ) 40 All other corporate bonds 65 — 3 (6 ) (3 ) 59 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 118 — 4 (11 ) (12 ) 99 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Concentrations of credit risk arise from exposure to counterparties that are engaged in similar activities and have similar economic characteristics that could cause their ability to meet contractual obligations to be similarly affected by changes in economic or other conditions. The Company seeks to mitigate credit risk by actively monitoring the creditworthiness of counterparties, obtaining collateral as deemed appropriate and applying controls that include credit approvals, limits of credit exposure and other monitoring procedures. At December 31, 2015 and 2014, other than U.S. Treasury securities, obligations of U.S. government and government agencies and authorities and obligations of the Canadian government, the Company was not exposed to any concentration of credit risk of a single issuer greater than 5% of the Company's shareholders' equity. Included in fixed maturities are below investment grade securities totaling $1.71 billion and $1.91 billion at December 31, 2015 and 2014, respectively. The Company defines its below investment grade securities as those securities rated below investment grade by external rating agencies, or the equivalent by the Company when a public rating does not exist. Such securities include below investment grade bonds that are publicly traded and certain other privately issued bonds that are classified as below investment grade loans. (for the year ended December 31, in millions) 2015 2014 2013 Gross investment income Fixed maturities 2,091 2,244 2,310 Equity securities 39 40 31 Short-term securities 12 9 11 Real estate investments 48 44 37 Other investments 230 489 364 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross investment income 2,420 2,826 2,753 Investment expenses 41 39 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net investment income 2,379 2,787 2,716 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Changes in net unrealized gains on investment securities that are included as a separate component of other comprehensive income (loss) were as follows: (at and for the year ended December 31, in millions) 2015 2014 2013 Changes in net unrealized investment gains Fixed maturities (893 ) 913 (2,804 ) Equity securities (143 ) 63 74 Other investments 2 2 (1 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in net pretax unrealized gains on investment securities (1,034 ) 978 (2,731 ) Related tax expense (benefit) (357 ) 334 (950 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in net unrealized gains on investment securities (677 ) 644 (1,781 ) Balance, beginning of year 1,966 1,322 3,103 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, end of year 1,289 1,966 1,322 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ From time to time, the Company enters into U.S. Treasury note futures contracts to modify the effective duration of specific assets within the investment portfolio. U.S. Treasury futures contracts require a daily mark-to-market and settlement with the broker. At December 31, 2015 and 2014, the Company had $400 million and $350 million notional value of open U.S. Treasury futures contracts, respectively. Net realized investment gains in 2015, 2014 and 2013 included net losses of $5 million, net losses of $1 million and net gains of $115 million, respectively, related to U.S. Treasury futures contracts. The Company purchases investments that have embedded derivatives, primarily convertible debt securities. These embedded derivatives are carried at fair value with changes in value reflected in net realized investment gains. Derivatives embedded in convertible debt securities are reported on a combined basis with their host instrument and are classified as fixed maturities. The Company also sells a small amount of U.S. equity index put option contracts that are settled for cash upon their expiration or when they are rolled over. Net realized investment gains (losses) related to these derivatives in 2015, 2014 and 2013 were not significant.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Measurements disclosure
Fair Value Measurements disclosure [Text Block]	4. FAIR VALUE MEASUREMENTS The Company's estimates of fair value for financial assets and financial liabilities are based on the framework established in the fair value accounting guidance. The framework is based on the inputs used in valuation, gives the highest priority to quoted prices in active markets and requires that observable inputs be used in the valuations when available. The disclosure of fair value estimates in the fair value accounting guidance hierarchy is based on whether the significant inputs into the valuation are observable. In determining the level of the hierarchy in which the estimate is disclosed, the highest priority is given to unadjusted quoted prices in active markets and the lowest priority to unobservable inputs that reflect the Company's significant market assumptions. The level in the fair value hierarchy within which the fair value measurement is reported is based on the lowest level input that is significant to the measurement in its entirety. The three levels of the hierarchy are as follows: • Level 1 — Unadjusted quoted market prices for identical assets or liabilities in active markets that the Company has the ability to access. • Level 2 — Quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in inactive markets; or valuations based on models where the significant inputs are observable (e.g., interest rates, yield curves, prepayment speeds, default rates, loss severities, etc.) or can be corroborated by observable market data. • Level 3 — Valuations based on models where significant inputs are not observable. The unobservable inputs reflect the Company's own assumptions about the inputs that market participants would use. The fair value of a financial instrument is the estimated amount at which the instrument could be exchanged in an orderly transaction between knowledgeable, unrelated, willing parties, i.e., not in a forced transaction. The estimated fair value of a financial instrument may differ from the amount that could be realized if the security was sold in an immediate sale, e.g., a forced transaction. Additionally, the valuation of investments is more subjective when markets are less liquid due to the lack of market based inputs, which may increase the potential that the estimated fair value of an investment is not reflective of the price at which an actual transaction would occur. For investments that have quoted market prices in active markets, the Company uses the unadjusted quoted market prices as fair value and includes these prices in the amounts disclosed in Level 1 of the hierarchy. The Company receives the quoted market prices from third party, nationally recognized pricing services. When quoted market prices are unavailable, the Company utilizes these pricing services to determine an estimate of fair value. The fair value estimates provided from these pricing services are included in the amount disclosed in Level 2 of the hierarchy. If quoted market prices and an estimate from a pricing service are unavailable, the Company produces an estimate of fair value based on internally developed valuation techniques, which, depending on the level of observable market inputs, will render the fair value estimate as Level 2 or Level 3. The Company bases all of its estimates of fair value for assets on the bid price as it represents what a third-party market participant would be willing to pay in an arm's length transaction. The Company utilized a pricing service to estimate fair value measurements for approximately 98% of its fixed maturities at both December 31, 2015 and 2014. The pricing service utilizes market quotations for fixed maturity securities that have quoted prices in active markets. Since fixed maturities other than U.S. Treasury securities generally do not trade on a daily basis, the pricing service prepares estimates of fair value measurements for these securities using its proprietary pricing applications, which include available relevant market information, benchmark curves, benchmarking of like securities, sector groupings and matrix pricing. Additionally, the pricing service uses an Option Adjusted Spread model to develop prepayment and interest rate scenarios. The pricing service evaluates each asset class based on relevant market information, relevant credit information, perceived market movements and sector news. The market inputs utilized in the pricing evaluation, listed in the approximate order of priority, include: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, reference data, and industry and economic events. The extent of the use of each market input depends on the asset class and the market conditions. Depending on the security, the priority of the use of inputs may change or some market inputs may not be relevant. For some securities, additional inputs may be necessary. The pricing service utilized by the Company has indicated that it will only produce an estimate of fair value if there is objectively verifiable information to produce a valuation. If the pricing service discontinues pricing an investment, the Company would be required to produce an estimate of fair value using some of the same methodologies as the pricing service but would have to make assumptions for any market-based inputs that were unavailable due to market conditions. The Company reviews the estimates of fair value provided by the pricing service and compares the estimates to the Company's knowledge of the market to determine if the estimates obtained are representative of the prices in the market. In addition, the Company has periodic discussions with the pricing service to discuss and understand any changes in process and their responsiveness to changes occurring in the markets. In addition, the Company has implemented various other processes including randomly selecting purchased or sold securities and comparing execution prices to the estimates from the pricing service as well as reviewing reports that contain securities whose valuation did not change from their previous valuation (stale price review). The Company also uses an additional independent pricing service to further test the primary pricing service's valuation of the Company's fixed maturity portfolio. The fair value estimates of most fixed maturity investments are based on observable market information rather than market quotes. Accordingly, the estimates of fair value for such fixed maturities, other than U.S. Treasury securities, provided by the pricing service are included in the amount disclosed in Level 2 of the hierarchy. The estimated fair value of U.S. Treasury securities is included in the amount disclosed in Level 1 as the estimates are based on unadjusted market prices. The Company also holds certain fixed maturity investments which are not priced by the pricing service and, accordingly, estimates the fair value of such fixed maturities using an internal matrix that is based on market information regarding interest rates, credit spreads and liquidity. The underlying source data for calculating the matrix of credit spreads relative to the U.S. Treasury curve are the BofA Merrill Lynch U.S. Corporate Index and the BofA Merrill Lynch High Yield BB Rated Index. The Company includes the fair value estimates of these corporate bonds in Level 2, since all significant inputs are market observable. While the vast majority of the Company's fixed maturities are included in Level 2, the Company holds a number of municipal bonds and corporate bonds which are not valued by the pricing service and estimates the fair value of these bonds using an internal pricing matrix with some unobservable inputs that are significant to the valuation. Due to the limited amount of observable market information, the Company includes the fair value estimates for these particular bonds in Level 3. The fair value of the fixed maturities for which the Company used an internal pricing matrix was $101 million and $92 million at December 31, 2015 and 2014, respectively. Additionally, the Company holds a small amount of other fixed maturity investments that have characteristics that make them unsuitable for matrix pricing. For these fixed maturities, the Company obtains a quote from a broker (primarily the market maker). The fair value of the fixed maturities for which the Company received a broker quote was $117 million and $140 million at December 31, 2015 and 2014, respectively. Due to the disclaimers on the quotes that indicate that the price is indicative only, the Company includes these fair value estimates in Level 3. For public common stock and non-redeemable preferred stocks, the Company receives prices from pricing services that are based on observable market transactions and includes these estimates in the amount disclosed in Level 1. When current market quotes in active markets are unavailable for certain non-redeemable preferred stocks held by the Company, the Company receives an estimate of fair value from the pricing services. The services utilize similar methodologies to price the non-redeemable preferred stocks as they do for the fixed maturities. The Company includes the fair value estimate for these non-redeemable preferred stocks in the amount disclosed in Level 2. The Company holds investments in various publicly-traded securities which are reported in other investments. These investments include mutual funds and other small holdings. The $18 million and $19 million fair value of these investments at December 31, 2015 and 2014, respectively, was disclosed in Level 1. At December 31, 2015 and 2014, the Company held investments in non-public common and preferred equity securities, with fair value estimates of $38 million and $36 million, respectively, reported in other investments, where the fair value estimate is determined either internally or by an external fund manager based on recent filings, operating results, balance sheet stability, growth and other business and market sector fundamentals. Due to the significant unobservable inputs in these valuations, the Company includes the total fair value estimate for all of these investments at December 31, 2015 and 2014 in the amount disclosed in Level 3. At December 31, 2015 and 2014, the Company held $2 million and $4 million, respectively, of convertible bonds containing embedded conversion options that are valued separately from the host bond contract in the amount disclosed in Level 2—fixed maturities. The following tables present the level within the fair value hierarchy at which the Company's financial assets and financial liabilities are measured on a recurring basis. An investment transferred between levels during a period is transferred at its fair value as of the beginning of that period. (at December 31, 2015, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 2,194 2,194 — — Obligations of states, municipalities and political subdivisions 31,411 — 31,398 13 Debt securities issued by foreign governments 1,873 — 1,873 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,981 — 1,957 24 All other corporate bonds 23,089 — 22,915 174 Redeemable preferred stock 110 3 100 7 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 60,658 2,197 58,243 218 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities Public common stock 543 543 — — Non-redeemable preferred stock 162 55 107 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total equity securities 705 598 107 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other investments 56 18 — 38 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 61,419 2,813 58,350 256 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ During the year ended December 31, 2015, the Company's transfers between Level 1 and Level 2 were not significant. (at December 31, 2014, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 2,053 2,049 4 — Obligations of states, municipalities and political subdivisions 33,573 — 33,560 13 Debt securities issued by foreign governments 2,368 — 2,368 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 2,213 — 2,203 10 All other corporate bonds 23,135 — 22,934 201 Redeemable preferred stock 132 2 122 8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 63,474 2,051 61,191 232 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities Public common stock 691 691 — — Non-redeemable preferred stock 208 82 126 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total equity securities 899 773 126 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other investments 55 19 — 36 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 64,428 2,843 61,317 268 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ During the year ended December 31, 2014, the Company's transfers between Level 1 and Level 2 were not significant. The following tables present the changes in the Level 3 fair value category for the years ended December 31, 2015 and 2014. (in millions) Fixed Other Total Balance at December 31, 2014 232 36 268 Total realized and unrealized investment gains (losses): Reported in net realized investment gains(1) 1 2 3 Reported in increases (decreases) in other comprehensive income (4 ) 1 (3 ) Purchases, sales and settlements/maturities: Purchases 202 1 203 Sales (7 ) (2 ) (9 ) Settlements/maturities (41 ) — (41 ) Gross transfers into Level 3 21 — 21 Gross transfers out of Level 3 (186 ) — (186 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at December 31, 2015 218 38 256 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date — (1 ) (1 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Includes impairments on investments held at the end of the period as well as amortization on fixed maturities. (in millions) Fixed Other Total Balance at December 31, 2013 255 34 289 Total realized and unrealized investment gains (losses): Reported in net realized investment gains(1) 3 1 4 Reported in increases (decreases) in other comprehensive income (2 ) 1 (1 ) Purchases, sales and settlements/maturities: Purchases 232 1 233 Sales (1 ) (1 ) (2 ) Settlements/maturities (90 ) — (90 ) Gross transfers into Level 3 18 — 18 Gross transfers out of Level 3 (183 ) — (183 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at December 31, 2014 232 36 268 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date — — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Includes impairments on investments held at the end of the period as well as amortization on fixed maturities. The Company uses various financial instruments in the normal course of its business. The Company's insurance contracts are excluded from fair value of financial instruments accounting guidance and, therefore, are not included in the amounts discussed below. The following tables present the carrying value and fair value of the Company's financial assets and financial liabilities disclosed, but not carried, at fair value, and the level within the fair value hierarchy at which such assets and liabilities are categorized. (at December 31, 2015, in millions) Carrying Fair Level 1 Level 2 Level 3 Financial assets: Short-term securities 4,671 4,671 1,685 2,958 28 Financial liabilities: Debt 6,244 7,180 — 7,180 — Commercial paper 100 100 — 100 — (at December 31, 2014, in millions) Carrying Fair Level 1 Level 2 Level 3 Financial assets: Short-term securities 4,364 4,364 1,283 3,042 39 Financial liabilities: Debt 6,249 7,522 — 7,522 — Commercial paper 100 100 — 100 — The Company utilized a pricing service to estimate fair value for approximately 99% and 98% of short-term securities at December 31, 2015 and 2014, respectively. A description of the process and inputs used by the pricing service to estimate fair value is discussed in the " Fixed Maturities " section above. Estimates of fair value for U.S. Treasury securities and money market funds are based on market quotations received from the pricing service and are disclosed in Level 1 of the hierarchy. The fair value of other short-term fixed maturity securities is estimated by the pricing service using observable market inputs and is disclosed in Level 2 of the hierarchy. For short-term securities where an estimate is not obtained from the pricing service, the carrying value approximates fair value and is included in Level 3 of the hierarchy. The Company utilized a pricing service to estimate fair value for 100% of its debt, including commercial paper, at December 31, 2015 and 2014. The pricing service utilizes market quotations for debt that have quoted prices in active markets. Since fixed maturities other than U.S. Treasury securities generally do not trade on a daily basis, the fair value estimates are based on market observable inputs and disclosed in Level 2 of the hierarchy. The Company had no material assets or liabilities that were measured at fair value on a non-recurring basis during the years ended December 31, 2015 and 2014.

Reinsurance

Reinsurance	12 Months Ended
	Dec. 31, 2015
Reinsurance disclosure
Reinsurance disclosure [Text Block]	5. REINSURANCE The Company's consolidated financial statements reflect the effects of assumed and ceded reinsurance transactions. Assumed reinsurance refers to the acceptance of certain insurance risks that other insurance companies have underwritten. Ceded reinsurance involves transferring certain insurance risks (along with the related written and earned premiums) the Company has underwritten to other insurance companies who agree to share these risks. The primary purpose of ceded reinsurance is to protect the Company, at a cost, from losses in excess of the amount it is prepared to accept and to protect the Company's capital. Reinsurance is placed on both a quota-share and excess-of-loss basis. Ceded reinsurance arrangements do not discharge the Company as the primary insurer, except for instances where the primary policy or policies have been novated, such as in certain structured settlement agreements. The Company utilizes a corporate catastrophe excess-of-loss reinsurance treaty with unaffiliated reinsurers to manage its exposure to losses resulting from catastrophes and to protect its capital. In addition to the coverage provided under this treaty, the Company also utilizes catastrophe bonds to protect against certain weather-related and earthquake losses in the Northeastern United States, and a Northeast catastrophe reinsurance treaty to protect against losses resulting from weather-related and earthquake catastrophes in the Northeastern United States. The Company also utilizes excess-of-loss treaties to protect against earthquake losses up to a certain threshold in the Business and International Insurance segment (for certain markets) and for the Personal Insurance segment, and several reinsurance treaties specific to its international operations. The Company monitors the financial condition of its reinsurers under voluntary reinsurance arrangements to evaluate the collectability of amounts due from reinsurers and as a basis for determining the reinsurers with which the Company conducts ongoing business. In addition, in the ordinary course of business, the Company may become involved in coverage disputes with its reinsurers. Some of these disputes could result in lawsuits and arbitrations brought by or against the reinsurers to determine the Company's rights and obligations under the various reinsurance agreements. The Company employs dedicated specialists and strategies to manage reinsurance collections and disputes. Included in reinsurance recoverables are amounts related to involuntary reinsurance arrangements. The Company is required to participate in various involuntary reinsurance arrangements through assumed reinsurance, principally with regard to residual market mechanisms in workers' compensation and automobile insurance, as well as homeowners' insurance in certain coastal areas. In addition, the Company provides services for several of these involuntary arrangements (mandatory pools and associations) under which it writes such residual market business directly, then cedes 100% of this business to the mandatory pool. Such participations and servicing arrangements are arranged to mitigate credit risk to the Company, as any ceded balances are jointly backed by all the pool members. Also included in reinsurance recoverables are amounts related to certain structured settlements. Structured settlements are annuities purchased from various life insurance companies to settle certain personal physical injury claims, of which workers' compensation claims comprise a significant portion. In cases where the Company did not receive a release from the claimant, the structured settlement is included in reinsurance recoverables and the related claim cost is included in the liability for claims and claim adjustment expense reserves, as the Company retains the contingent liability to the claimant. If it is expected that the life insurance company is not able to pay, the Company would recognize an impairment of the related reinsurance recoverable if, and to the extent, the purchased annuities are not covered by state guaranty associations. In the event that the life insurance company fails to make the required annuity payments, the Company would be required to make such payments. The following is a summary of reinsurance financial data reflected in the consolidated statement of income: (for the year ended December 31, in millions) 2015 2014 2013 Written premiums Direct 24,939 24,844 23,952 Assumed 843 788 705 Ceded (1,661 ) (1,728 ) (1,890 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total net written premiums 24,121 23,904 22,767 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earned premiums Direct 24,740 24,810 23,891 Assumed 814 743 717 Ceded (1,680 ) (1,840 ) (1,971 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total net earned premiums 23,874 23,713 22,637 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Percentage of assumed earned premiums to net earned premiums 3.4 % 3.1 % 3.2 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ceded claims and claim adjustment expenses incurred 1,034 953 1,019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ceded premiums include the premiums paid for coverage provided by the Company's catastrophe bonds. Reinsurance recoverables include amounts recoverable on both paid and unpaid claims and were as follows: (at December 31, in millions) 2015 2014 Gross reinsurance recoverables on paid and unpaid claims and claim adjustment expenses 3,848 4,270 Allowance for uncollectible reinsurance (157 ) (203 ) ​ ​ ​ ​ ​ ​ ​ Net reinsurance recoverables 3,691 4,067 Mandatory pools and associations 2,015 1,909 Structured settlements 3,204 3,284 ​ ​ ​ ​ ​ ​ ​ Total reinsurance recoverables 8,910 9,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Terrorism Risk Insurance Program is a Federal program administered by the Department of the Treasury authorized through December 31, 2020 that provides for a system of shared public and private compensation for certain insured losses resulting from certified acts of terrorism. In order for a loss to be covered under the program (subject losses), the loss must meet certain aggregate industry loss minimums and must be the result of an event that is certified as an act of terrorism by the U.S. Secretary of the Treasury, in consultation with the Secretary of Homeland Security and the Attorney General of the United States. The annual aggregate industry loss minimum under the program is $120 million for 2016, but will increase over the life of the program to $200 million by December 31, 2020. The program excludes from participation the following types of insurance: Federal crop insurance, private mortgage insurance, financial guaranty insurance, medical malpractice insurance, health or life insurance, flood insurance, reinsurance, commercial automobile, professional liability (other than directors and officers'), surety, burglary and theft, and farm-owners multi-peril. In the case of a war declared by Congress, only workers' compensation losses are covered by the program. All commercial property and casualty insurers licensed in the United States are generally required to participate in the program. Under the program, a participating insurer, in exchange for making terrorism insurance available, is entitled to be reimbursed by the Federal Government for 84% of subject losses in 2016, after an insurer deductible, subject to an annual cap. This reimbursement percentage will decrease over the remaining five-year life of the program to 80% of subject losses by December 31, 2020. The deductible for any calendar year is equal to 20% of the insurer's direct earned premiums for covered lines for the preceding calendar year. The Company's estimated deductible under the program is $2.43 billion for 2016. The annual cap limits the amount of aggregate subject losses for all participating insurers to $100 billion. Once subject losses have reached the $100 billion aggregate during a program year, participating insurers will not be liable under the program for additional covered terrorism losses for that program year. There have been no terrorism-related losses that have triggered program coverage since the program was established. Since the law is untested, there is substantial uncertainty as to how it will be applied if an act of terrorism is certified under the program. It is also possible that future legislative action could change or eliminate the program. Further, given the unpredictable frequency and severity of terrorism losses, as well as the limited terrorism coverage in the Company's own reinsurance program, future losses from acts of terrorism, particularly involving nuclear, biological, chemical or radiological events, could be material to the Company's operating results, financial position and/or liquidity in future periods. In addition, the Company may not have sufficient resources to respond to claims arising from a high frequency of high severity natural catastrophes and/or of man-made catastrophic events involving conventional means. While the Company seeks to manage its exposure to man-made catastrophic events involving conventional means, the Company may not have sufficient resources to respond to claims arising out of one or more man-made catastrophic events involving nuclear, biological, chemical or radiological means.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill and Other Intangible Assets disclosure
Goodwill and Other Intangible Assets disclosure [Text Block]	6. GOODWILL AND OTHER INTANGIBLE ASSETS The following table presents the carrying amount of the Company's goodwill by segment: (at December 31, in millions) 2015 2014 Business and International Insurance(1) 2,439 2,477 Bond & Specialty Insurance 496 496 Personal Insurance 612 612 Other 26 26 ​ ​ ​ ​ ​ ​ ​ Total 3,573 3,611 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Includes goodwill associated with the Company's international business which is subject to the impact of changes in foreign currency exchange rates. The following tables present a summary of the Company's other intangible assets by major asset class: (at December 31, 2015, in millions) Gross Accumulated Net Subject to amortization(1) 210 148 62 Not subject to amortization 217 — 217 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 427 148 279 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (at December 31, 2014, in millions) Gross Accumulated Net Subject to amortization(1) 669 582 87 Not subject to amortization 217 — 217 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 886 582 304 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Intangible assets subject to amortization are comprised of fair value adjustments on claims and claim adjustment expense reserves, reinsurance recoverables and other contract and customer-related intangibles. At December 31, 2014, the Company had certain customer-related intangibles with a gross carrying amount of $460 million and accumulated amortization of $446 million which became fully amortized during the second quarter of 2015. Fair value adjustments of $5 million and $191 million were recorded in connection with the acquisition of Dominion in 2013 and in connection with the merger of The St. Paul Companies, Inc. and Travelers Property Casualty Corp. in 2004, respectively, and were based on management's estimate of nominal claims and claim adjustment expense reserves and reinsurance recoverables. The method used calculated a risk adjustment to a risk-free discounted reserve that would, if reserves ran off as expected, produce results that yielded the assumed cost-of-capital on the capital supporting the loss reserves. The fair value adjustments are reported as other intangible assets on the consolidated balance sheet, and the amounts measured in accordance with the acquirer's accounting policies for insurance contracts have been reported as part of the claims and claim adjustment expense reserves and reinsurance recoverables. The intangible assets are being recognized into income over the expected payment pattern. Because the time value of money and the risk adjustment (cost of capital) components of the intangible assets run off at different rates, the amount recognized in income may be a net benefit in some periods and a net expense in other periods. Additionally, $5 million of contract-related intangibles were recorded related to operating leases in connection with the acquisition of Dominion in 2013. Amortization expense of intangible assets was $26 million, $46 million and $46 million for the years ended December 31, 2015, 2014 and 2013, respectively. Intangible asset amortization expense is estimated to be $11 million in 2016, $9 million in 2017, $8 million in 2018, $6 million in 2019 and $5 million in 2020.

Insurance Claim Reserves

Insurance Claim Reserves	12 Months Ended
	Dec. 31, 2015
Insurance Claim Reserves disclosure
Insurance Claim Reserves disclosure [Text Block]	7. INSURANCE CLAIM RESERVES Claims and claim adjustment expense reserves were as follows: (at December 31, in millions) 2015 2014 Property-casualty 48,272 49,824 Accident and health 23 26 ​ ​ ​ ​ ​ ​ ​ Total 48,295 49,850 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The following table presents a reconciliation of beginning and ending property casualty reserve balances for claims and claim adjustment expenses: (at and for the year ended December 31, in millions) 2015 2014 2013 Claims and claim adjustment expense reserves at beginning of year 49,824 50,865 50,888 Less reinsurance recoverables on unpaid losses 8,788 9,280 10,254 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net reserves at beginning of year 41,036 41,585 40,634 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated claims and claim adjustment expenses for claims arising in the current year 14,412 14,621 14,060 Estimated decrease in claims and claim adjustment expenses for claims arising in prior years (897 ) (957 ) (944 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total increases 13,515 13,664 13,116 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and claim adjustment expense payments for claims arising in: Current year 5,666 5,828 5,485 Prior years 8,669 8,099 8,477 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total payments 14,335 13,927 13,962 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Acquisitions(1) 2 — 1,792 Unrealized foreign exchange (gain) loss (395 ) (286 ) 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net reserves at end of year 39,823 41,036 41,585 Plus reinsurance recoverables on unpaid losses 8,449 8,788 9,280 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and claim adjustment expense reserves at end of year 48,272 49,824 50,865 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Amount in 2015 represents acquired net claims and claim adjustment expense reserves of Travelers Participações em Seguros Brasil S.A. at October 1, 2015. Amount in 2013 represents acquired net claims and claim adjustment expense reserves of Dominion at November 1, 2013. Dominion's gross reserves on that date were $2,144 million. Dominion's reinsurance recoverables on unpaid losses on that date were $352 million. Gross claims and claim adjustment expense reserves at December 31, 2015 decreased by $1.55 billion from December 31, 2014, primarily reflecting the impact of (i) payments related to operations in runoff, including a $579 million payment related to the settlement of the Asbestos Direct Action Litigation as described in more detail in note 16, (ii) net favorable prior year reserve development and (iii) changes in foreign currency exchange rates. Gross claims and claim adjustment expense reserves at December 31, 2014 decreased by $1.04 billion from December 31, 2013, primarily reflecting the impact of (i) net favorable prior year reserve development and (ii) payments related to operations in runoff. Reinsurance recoverables on unpaid losses at December 31, 2015 decreased by $339 million from December 31, 2014, primarily reflecting the impact of cash collections in 2015. Reinsurance recoverables on unpaid losses at December 31, 2014 declined by $492 million from December 31, 2013, reflecting the impacts of (i) net favorable prior year reserve development, (ii) cash collections, (iii) commutation agreements, as well as (iv) a slightly lower level of reinsurance purchased in 2014. The following disclosures regarding reserve development are on a "net of reinsurance" basis. In 2015, estimated claims and claim adjustment expenses incurred included $897 million of net favorable development for claims arising in prior years, including $941 million of net favorable prior year reserve development impacting the Company's results of operations and $51 million of accretion of discount. Business and International Insurance. Net favorable prior year reserve development in 2015 totaled $405 million, primarily driven by better than expected loss experience in (i) the general liability product line (excluding increases to asbestos and environmental reserves discussed below), for both primary and excess coverages for accident years 2005 through 2013, reflecting a more favorable legal environment than the Company previously expected, (ii) the workers' compensation line of business for accident years 2006 and prior, (iii) the property product line related to catastrophe losses for accident years 2011, 2012 and 2014 and non-catastrophe losses for accident years 2013 and 2014 and (iv) the Company's operations in Canada and at Lloyd's. These factors contributing to net favorable prior year reserve development in 2015 were partially offset by $224 million and $72 million increases to asbestos and environmental reserves, respectively, which are discussed in further detail in the "Asbestos and Environmental Reserves" section below. Bond & Specialty Insurance. Net favorable prior year reserve development in 2015 totaled $258 million, primarily driven by better than expected loss experience in the fidelity and surety product line for accident years 2008 through 2014, which was partially driven by a reduction in outstanding exposures related to the financial crisis that commenced in 2007. Personal Insurance. Net favorable prior year reserve development in 2015 totaled $278 million, primarily driven by better than expected loss experience in (i) the Homeowners and Other product line for liability coverages for accident years 2011 through 2014, for non-catastrophe weather-related losses and non-weather-related losses for accident year 2014 and (ii) the Automobile product line for liability coverages for accident years 2012 through 2014. In 2014, estimated claims and claim adjustment expenses incurred included $957 million of net favorable development for claims arising in prior years, including $941 million of net favorable prior year reserve development impacting the Company's results of operations and $50 million of accretion of discount. Business and International Insurance. Net favorable prior year reserve development in 2014 totaled $322 million, primarily driven by (i) better than expected loss experience in the general liability product line (excluding increases to asbestos and environmental reserves discussed below), primarily related to excess coverages for accident years 2008 through 2012, reflecting a more favorable legal environment than the Company previously expected, (ii) a $162 million benefit resulting from better than expected loss experience related to, and the commutation of reinsurance treaties associated with, a workers' compensation reinsurance pool for accident years 1996 and prior, (iii) better than expected loss experience in the property product line for accident years 2010 through 2013, including catastrophe losses from Storm Sandy for accident year 2012 and (iv) better than expected loss experience in the commercial auto product line for accident years 2011 and 2012. These factors contributing to net favorable prior year reserve development in 2014 were partially offset by (i) $250 million and $87 million increases to asbestos and environmental reserves, respectively, which are discussed in further detail in the "Asbestos and Environmental Reserves" section below, (ii) an increase in unallocated loss adjustment expense reserves of $77 million for interest awarded as part of damages pursuant to a court decision in the third quarter of 2014 related to a legal matter, which is discussed in more detail in the "Settlement of Asbestos Direct Action Litigation" section of note 16 and (iii) higher than expected loss experience for liability coverages in the commercial multi-peril product line for accident years 2010 through 2013. Bond & Specialty Insurance. Net favorable prior year reserve development in 2014 totaled $450 million, primarily driven by better than expected loss experience in the contract surety product line for accident years 2012 and prior. Personal Insurance. Net favorable prior year reserve development in 2014 totaled $169 million, primarily driven by better than expected loss experience in the Homeowners and Other product line for non-catastrophe weather-related losses for accident year 2013 and catastrophe losses for accident years 2011 through 2013. In 2013, estimated claims and claim adjustment expenses incurred included $944 million of net favorable development for claims arising in prior years, including $840 million of net favorable prior year reserve development impacting the Company's results of operations and $48 million of accretion of discount. Business and International Insurance. Net favorable prior year reserve development in 2013 totaled $399 million, primarily driven by better than expected loss experience in (i) the general liability product line for excess coverages for accident years 2012 and prior (excluding increases to asbestos and environmental reserves discussed below), reflecting a more favorable legal environment than the Company previously expected, (ii) the property product line related to both catastrophe and non-catastrophe losses for accident years 2010 through 2012, (iii) the workers' compensation line of business (which was largely offset by a $42 million charge that was precipitated by legislation in New York enacted during the first quarter of 2013 related to the New York Fund for Reopened Cases for workers' compensation) and (iv) the surety line of business in Canada and the marine line of business in the Company's operations at Lloyd's. These factors contributing to net favorable prior year reserve development in 2013 were partially offset by $190 million and $65 million increases to asbestos and environmental reserves, respectively, which are discussed in further detail in the "Asbestos and Environmental Reserves" section below and by higher than expected loss experience in the public and product liability line of business in the United Kingdom. Bond & Specialty Insurance. Net favorable prior year reserve development in 2013 totaled $232 million, primarily driven by better than expected loss experience in the contract surety product line for accident years 2010 and prior. Personal Insurance. Net favorable prior year reserve development in 2013 totaled $209 million, primarily driven by better than expected loss experience in the Homeowners and Other product line for catastrophe losses incurred in 2012, and non-catastrophe weather-related losses and non-weather-related losses for accident years 2012 and 2011. At December 31, 2015 and 2014, the Company's claims and claim adjustment expense reserves included $2.17 billion and $2.70 billion, respectively, for asbestos and environmental-related claims, net of reinsurance. It is difficult to estimate the reserves for asbestos and environmental-related claims due to the vagaries of court coverage decisions, plaintiffs' expanded theories of liability, the risks inherent in complex litigation and other uncertainties, including, without limitation, those which are set forth below. Asbestos Reserves. Because each policyholder presents different liability and coverage issues, the Company generally reviews the exposure presented by each policyholder at least annually. Among the factors which the Company may consider in the course of this review are: available insurance coverage, including the role of any umbrella or excess insurance the Company has issued to the policyholder; limits and deductibles; an analysis of the policyholder's potential liability; the jurisdictions involved; past and anticipated future claim activity and loss development on pending claims; past settlement values of similar claims; allocated claim adjustment expense; potential role of other insurance; the role, if any, of non-asbestos claims or potential non-asbestos claims in any resolution process; and applicable coverage defenses or determinations, if any, including the determination as to whether or not an asbestos claim is a products/completed operation claim subject to an aggregate limit and the available coverage, if any, for that claim. In the third quarter of 2015, the Company completed its annual in-depth asbestos claim review, including a review of active policyholders and litigation cases for potential product and "non-product" liability, and noted the continuation of the following trends: • continued high level of litigation activity in certain jurisdictions involving individuals alleging serious asbestos-related illness, primarily involving mesothelioma claims; • while overall payment patterns have been generally stable, there has been an increase in severity for certain policyholders due to the continued high level of litigation activity; and • continued moderate level of asbestos-related bankruptcy activity. While the Company believes that over the past several years there has been a reduction in the volatility associated with the Company's overall asbestos exposure, there nonetheless remains a high degree of uncertainty with respect to future exposure from asbestos claims. In the Home Office and Field Office category, which accounts for the vast majority of policyholders with active asbestos-related claims, both the number of policyholders tendering asbestos claims for the first time and the number of policyholders with open asbestos claims declined when compared with 2014. Gross asbestos payments in this category were essentially unchanged when compared with 2014, while net asbestos-related payments increased in 2015 due to significant reinsurance billings relating to one policyholder in 2014. Payments on behalf of policyholders in these categories continue to be influenced by the high level of litigation activity in a limited number of jurisdictions where individuals alleging serious asbestos-related injury, primarily mesothelioma, continue to target defendants who were not traditionally primary targets of asbestos litigation. The Company's quarterly asbestos reserve reviews include an analysis of exposure and claim payment patterns by policyholder category, as well as recent settlements, policyholder bankruptcies, judicial rulings and legislative actions. The Company also analyzes developing payment patterns among policyholders in the Home Office and Field Office, and Assumed Reinsurance and Other categories as well as projected reinsurance billings and recoveries. In addition, the Company reviews its historical gross and net loss and expense paid experience, year-by-year, to assess any emerging trends, fluctuations, or characteristics suggested by the aggregate paid activity. Conventional actuarial methods are not utilized to establish asbestos reserves nor have the Company's evaluations resulted in any way of determining a meaningful average asbestos defense or indemnity payment. The completion of these reviews and analyses in 2015, 2014 and 2013 resulted in $224 million, $250 million and $190 million increases, respectively, in the Company's net asbestos reserves. In each year, the reserve increases were primarily driven by increases in the Company's estimate of projected settlement and defense costs related to a broad number of policyholders in the Home Office category due to a higher level of litigation activity surrounding mesothelioma claims than previously anticipated. In addition, the reserve increase in 2013 also reflected higher projected payments on assumed reinsurance accounts. The increase in the estimate of projected settlement and defense costs resulted from payment trends that continue to be higher than previously anticipated due to the impact of the current litigation environment discussed above. Notwithstanding these trends, the Company's overall view of the underlying asbestos environment is essentially unchanged from recent periods and there remains a high degree of uncertainty with respect to future exposure to asbestos claims. Net asbestos paid loss and loss expenses in 2015, 2014 and 2013 were $770 million, $242 million and $218 million, respectively. Net payments in 2015 included the payment of the $502 million settlement amounts related to the Settlement of Asbestos Direct Action Litigation as described in more detail in note 16. Approximately 69%, 8% and 1% of total net paid losses in 2015, 2014 and 2013, respectively, related to policyholders with whom the Company had entered into settlement agreements limiting the Company's liability. Environmental Reserves. In establishing environmental reserves, the Company evaluates the exposure presented by each policyholder and the anticipated cost of resolution, if any. In the course of this analysis, the Company generally considers the probable liability, available coverage and relevant judicial interpretations. In addition, the Company considers the many variables presented, such as: the nature of the alleged activities of the policyholder at each site; the number of sites; the total number of potentially responsible parties at each site; the nature of the alleged environmental harm and the corresponding remedy at each site; the nature of government enforcement activities at each site; the ownership and general use of each site; the overall nature of the insurance relationship between the Company and the policyholder, including the role of any umbrella or excess insurance the Company has issued to the policyholder; the involvement of other insurers; the potential for other available coverage, including the number of years of coverage; the role, if any, of non-environmental claims or potential non-environmental claims in any resolution process; and the applicable law in each jurisdiction. The evaluation of the exposure presented by a policyholder can change as information concerning that policyholder and the many variables presented is developed. Conventional actuarial methods are not used to estimate these reserves. The Company continues to receive notices from policyholders tendering claims for the first time, frequently under policies issued prior to the mid-1980s. These policyholders continue to present smaller exposures, have fewer sites and are lower tier defendants. Further, in many instances, clean-up costs have been reduced because regulatory agencies are willing to accept risk-based site analyses and more efficient clean-up technologies. Over the past several years, the Company has experienced generally favorable trends in the number of new policyholders tendering environmental claims for the first time and in the number of pending declaratory judgment actions relating to environmental matters. However, the degree to which those favorable trends have continued has been less than anticipated. In addition, reserve development on existing environmental claims has been greater than anticipated. As a result of these factors, in 2015, 2014 and 2013, the Company increased its net environmental reserves by $72 million, $87 million and $65 million, respectively. Asbestos and Environmental Reserves. As a result of the processes and procedures discussed above, management believes that the reserves carried for asbestos and environmental claims are appropriately established based upon known facts, current law and management's judgment. However, the uncertainties surrounding the final resolution of these claims continue, and it is difficult to determine the ultimate exposure for asbestos and environmental claims and related litigation. As a result, these reserves are subject to revision as new information becomes available and as claims develop. The continuing uncertainties include, without limitation, the risks and lack of predictability inherent in complex litigation, any impact from the bankruptcy protection sought by various asbestos producers and other asbestos defendants, a further increase or decrease in the cost to resolve, and/or the number of, asbestos and environmental claims beyond that which is anticipated, the emergence of a greater number of asbestos claims than anticipated as a result of extended life expectancies resulting from medical advances and lifestyle improvements, the role of any umbrella or excess policies the Company has issued, the resolution or adjudication of disputes pertaining to the amount of available coverage for asbestos and environmental claims in a manner inconsistent with the Company's previous assessment of these claims, the number and outcome of direct actions against the Company, future developments pertaining to the Company's ability to recover reinsurance for asbestos and environmental claims and the unavailability of other insurance sources potentially available to policyholders, whether through exhaustion of policy limits or through the insolvency of other participating insurers. In addition, uncertainties arise from the insolvency or bankruptcy of policyholders and other defendants. It is also not possible to predict changes in the legal, regulatory and legislative environment and their impact on the future development of asbestos and environmental claims. This environment could be affected by changes in applicable legislation and future court and regulatory decisions and interpretations, including the outcome of legal challenges to legislative and/or judicial reforms establishing medical criteria for the pursuit of asbestos claims. It is also difficult to predict the ultimate outcome of complex coverage disputes until settlement negotiations near completion and significant legal questions are resolved or, failing settlement, until the dispute is adjudicated. This is particularly the case with policyholders in bankruptcy where negotiations often involve a large number of claimants and other parties and require court approval to be effective. As part of its continuing analysis of asbestos and environmental reserves, the Company continues to study the implications of these and other developments. Because of the uncertainties set forth above, additional liabilities may arise for amounts in excess of the Company's current reserves. In addition, the Company's estimate of claims and claim adjustment expenses may change. These additional liabilities or increases in estimates, or a range of either, cannot now be reasonably estimated and could result in income statement charges that could be material to the Company's operating results in future periods. The Company has geographic exposure to catastrophe losses, which can be caused by a variety of events, including, among others, hurricanes, tornadoes and other windstorms, earthquakes, hail, wildfires, severe winter weather, floods, tsunamis, volcanic eruptions and other naturally-occurring events, such as solar flares. Catastrophes can also result from terrorist attacks and other intentionally destructive acts including those involving nuclear, biological, chemical, radiological, cyber-attacks, explosions and infrastructure failures. The incidence and severity of catastrophes are inherently unpredictable. The extent of losses from a catastrophe is a function of both the total amount of insured exposure in the area affected by the event and the severity of the event. Most catastrophes are restricted to small geographic areas; however, hurricanes and earthquakes may produce significant damage in larger areas, especially those that are heavily populated. The Company generally seeks to mitigate its exposure to catastrophes through individual risk selection and the purchase of catastrophe reinsurance. There are also risks which impact the estimation of ultimate costs for catastrophes. For example, the estimation of reserves related to hurricanes can be affected by the inability of the Company and its insureds to access portions of the impacted areas, the complexity of factors contributing to the losses, the legal and regulatory uncertainties and the nature of the information available to establish the reserves. Complex factors include, but are not limited to: determining whether damage was caused by flooding versus wind; evaluating general liability and pollution exposures; estimating additional living expenses; the impact of demand surge; the potential impact of changing climate conditions, including higher frequency and severity of weather-related events; infrastructure disruption; fraud; the effect of mold damage and business income interruption costs; and reinsurance collectibility. The timing of a catastrophe's occurrence, such as at or near the end of a reporting period, can also affect the information available to the Company in estimating reserves for that reporting period. The estimates related to catastrophes are adjusted as actual claims emerge.

Debt

Debt	12 Months Ended
	Dec. 31, 2015
Debt disclosure
Debt disclosure [Text Block]	8. DEBT Debt outstanding was as follows: (at December 31, in millions) 2015 2014 Short-term: Commercial paper 100 100 6.25% Senior notes due June 20, 2016 400 — 5.50% Senior notes due December 1, 2015 — 400 ​ ​ ​ ​ ​ ​ ​ Total short-term debt 500 500 ​ ​ ​ ​ ​ ​ ​ Long-term: 6.25% Senior notes due June 20, 2016 — 400 5.75% Senior notes due December 15, 2017 450 450 5.80% Senior notes due May 15, 2018 500 500 5.90% Senior notes due June 2, 2019 500 500 3.90% Senior notes due November 1, 2020 500 500 7.75% Senior notes due April 15, 2026 200 200 7.625% Junior subordinated debentures due December 15, 2027 125 125 6.375% Senior notes due March 15, 2033 500 500 6.75% Senior notes due June 20, 2036 400 400 6.25% Senior notes due June 15, 2037 800 800 5.35% Senior notes due November 1, 2040 750 750 4.60% Senior notes due August 1, 2043 500 500 4.30% Senior notes due August 25, 2045 400 — 8.50% Junior subordinated debentures due December 15, 2045 56 56 8.312% Junior subordinated debentures due July 1, 2046 73 73 6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 107 107 ​ ​ ​ ​ ​ ​ ​ Total long-term debt 5,861 5,861 ​ ​ ​ ​ ​ ​ ​ Total debt principal 6,361 6,361 Unamortized fair value adjustment 49 50 Unamortized debt issuance costs (66 ) (62 ) ​ ​ ​ ​ ​ ​ ​ Total debt 6,344 6,349 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2015 Debt Issuance. On August 25, 2015, the Company issued $400 million aggregate principal amount of 4.30% senior notes that will mature on August 25, 2045. The net proceeds of the issuance, after original issuance discount and the deduction of underwriting expenses and commissions and other expenses, totaled approximately $392 million. Interest on the senior notes is payable semi-annually in arrears on February 25 and August 25, commencing on February 25, 2016. Prior to February 25, 2045, the senior notes may be redeemed, in whole or in part, at the Company's option, at any time or from time to time, at a redemption price equal to the greater of (a) 100% of the principal amount of any senior notes to be redeemed or (b) the sum of the present values of the remaining scheduled payments of principal and interest on any senior notes to be redeemed (exclusive of interest accrued to the date of redemption) discounted to the date of redemption on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the then current rate of a treasury security having a maturity comparable to the remaining term of these senior notes, plus 25 basis points. On or after February 25, 2045, the senior notes may be redeemed, in whole or in part, at the Company's option, at any time or from time to time, at a redemption price equal to 100% of the principal amount of any senior notes to be redeemed. 2015 Debt Repayment. On December 1, 2015, the Company's $400 million, 5.50% senior notes matured and were fully paid. 2013 Debt Issuance. On July 25, 2013, the Company issued $500 million aggregate principal amount of 4.60% senior notes that will mature on August 1, 2043. The net proceeds of the issuance, after original issuance discount and the deduction of underwriting expenses and commissions and other expenses, totaled approximately $494 million. Interest on the senior notes is payable semi-annually in arrears on February 1 and August 1. The senior notes are redeemable in whole at any time or in part from time to time, at the Company's option, at a redemption price equal to the greater of (a) 100% of the principal amount of senior notes to be redeemed or (b) the sum of the present value of the remaining scheduled payments of principal and interest on the senior notes to be redeemed (exclusive of interest accrued to the date of redemption) discounted to the date of redemption on a semi-annual basis (assuming a 360-day year consisting of twelve 30-day months) at the then current treasury rate (as defined) plus 15 basis points. 2013 Debt Repayment. On March 15, 2013, the Company's $500 million, 5.00% senior notes matured and were fully paid. Commercial Paper —The Company maintains an $800 million commercial paper program, supported by a $1.0 billion bank credit agreement that expires on June 7, 2018. (See "Credit Agreement" discussion that follows.) Interest rates on commercial paper issued in 2015 ranged from 0.09% to 0.30%, and in 2014 ranged from 0.08% to 0.15%. Senior Notes —The Company's various senior debt issues are unsecured obligations that rank equally with one another. Interest payments are made semi-annually. The Company generally may redeem some or all of the notes prior to maturity in accordance with terms unique to each debt instrument. Junior Subordinated Debentures —The Company's $107 million remaining aggregate principal amount of 6.25% fixed-to-floating rate debentures bear interest at an annual rate of 6.25% from the date of issuance to, but excluding, March 15, 2017, payable semi-annually in arrears on March 15 and September 15. From and including March 15, 2017, the debentures will bear interest at an annual rate equal to three-month LIBOR plus 2.215%, payable quarterly on March 15, June 15, September 15 and December 15 of each year. The Company can redeem the debentures at its option, in whole or in part, at any time on or after March 15, 2017 at a redemption price of 100% of the principal amount being redeemed plus accrued but unpaid interest. The Company can redeem the debentures at its option prior to March 15, 2017 (a) in whole at any time or in part from time to time or (b) in whole, but not in part, in the event of certain tax or rating agency events relating to the debentures, at a redemption price equal to the greater of 100% of the principal amount being redeemed and the applicable make-whole amount, in each case plus any accrued and unpaid interest. The Company has the right, on one or more occasions, to defer the payment of interest on the debentures. The Company will not be required to settle deferred interest until it has deferred interest for five consecutive years or, if earlier, made a payment of current interest during a deferral period. The Company may defer interest for up to ten consecutive years without giving rise to an event of default. Deferred interest will accumulate additional interest at an annual rate equal to the annual interest rate then applicable to the debentures. The debentures have a final maturity date of March 15, 2067 and a scheduled maturity date of March 15, 2037. The Company can redeem the debentures at its option any time (as described above) using any source of funds, including cash. If the Company chooses not to redeem the debentures, then during the 180-day period ending not more than 15 and not less than ten business days prior to the scheduled maturity date, the Company will be required to use commercially reasonable efforts to sell enough qualifying capital securities to permit repayment of the debentures at the scheduled maturity date. If any debentures remain outstanding after the scheduled maturity date, unless and until the Company redeems the debentures (as described above) using any source of funds, including cash, the Company shall be required to use its commercially reasonable efforts on a quarterly basis to raise sufficient proceeds from the sale of qualifying capital securities to permit the repayment in full of the debentures. If there are remaining debentures at the final maturity date, the Company is required to redeem the debentures using any source of funds. Qualifying capital securities are securities (other than common stock, qualifying warrants, mandatorily convertible preferred stock, debt exchangeable for common equity, and debt exchangeable for preferred equity) which generally are treated by the ratings agencies as having similar equity content to the debentures. The Company's three other junior subordinated debenture instruments are all similar in nature to each other. Three separate business trusts issued preferred securities to investors and used the proceeds to purchase the Company's subordinated debentures. Interest on each of the instruments is paid semi-annually. The Company's consolidated balance sheet includes the debt instruments acquired in the merger, which were recorded at fair value as of the acquisition date. The resulting fair value adjustment is being amortized over the remaining life of the respective debt instruments using the effective-interest method. The amortization of the fair value adjustment reduced interest expense by $1 million for each of the years ended December 31, 2015 and 2014. The following table presents merger-related unamortized fair value adjustments and the related effective interest rate: Unamortized Effective (in millions) Issue Rate Maturity Date 2015 2014 Subordinated debentures 7.625 % Dec. 2027 15 16 6.147 % 8.500 % Dec. 2045 15 15 6.362 % 8.312 % Jul. 2046 19 19 6.362 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 49 50 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Travelers Companies, Inc. fully and unconditionally guarantees the payment of all principal, premiums, if any, and interest on certain debt obligations of its subsidiaries TPC and Travelers Insurance Group Holdings Inc. The guarantees pertain to the $200 million 7.75% notes due 2026 and the $500 million 6.375% notes due 2033. Maturities —The amount of debt obligations, other than commercial paper, that become due in each of the next five years is as follows: 2016, $400 million; 2017, $450 million; 2018, $500 million; 2019, $500 million; and 2020, $500 million. The Company is party to a five-year, $1.0 billion revolving credit agreement with a syndicate of financial institutions that expires in June 2018. Pursuant to the credit agreement covenants, the Company must maintain a minimum consolidated net worth, defined as shareholders' equity determined in accordance with GAAP plus (a) trust preferred securities (not to exceed 15% of total capital) and (b) mandatorily convertible securities (combined with trust preferred securities, not to exceed 25% of total capital) less goodwill and other intangible assets, of $13.73 billion. In addition, the credit agreement contains other customary restrictive covenants as well as certain customary events of default, including with respect to a change in control, which is defined to include the acquisition of 35% or more of the Company's voting stock and certain changes in the composition of the Company's board of directors. At December 31, 2015, the Company was in compliance with these covenants. Generally, the cost of borrowing under this agreement will range from LIBOR plus 87.5 basis points to LIBOR plus 150 basis points, depending on the Company's credit ratings. At December 31, 2015, that cost would have been LIBOR plus 112.5 basis points, had there been any amounts outstanding under the credit agreement. This credit agreement also supports the Company's commercial paper program. In June 2013, the Company filed with the Securities and Exchange Commission a universal shelf registration statement for the potential offering and sale of securities to replace the Company's previous registration statement that had expired in the normal course of business. The Company may offer these securities from time to time at prices and on other terms to be determined at the time of offering.

Shareholders' Equity and Divide

Shareholders' Equity and Dividend Availability	12 Months Ended
	Dec. 31, 2015
Shareholders' Equity and Dividend Availability disclosure
Shareholders' Equity and Dividend Availability disclosure [Text Block]	9. SHAREHOLDERS' EQUITY AND DIVIDEND AVAILABILITY The number of authorized shares of the Company is 1.755 billion, consisting of five million of preferred stock, 1.745 billion shares of voting common stock and five million undesignated shares. The Company's Articles of Incorporation authorize the board of directors to establish, from the undesignated shares, one or more classes and series of shares, and to further designate the type of shares and terms thereof. In May 2013, the Company's shareholders voted to amend the Company's Articles of Incorporation to provide authority to issue up to five million additional shares of preferred stock. Subsequent to this amendment of the Company's Articles of Incorporation, the Company filed a shelf registration statement with the Securities and Exchange Commission in June 2013 pursuant to which it may publicly sell securities, including the new preferred stock, from time to time. The Company is governed by the Minnesota Business Corporation Act. All authorized shares of voting common stock have no par value. Shares of common stock reacquired are considered authorized and unissued shares. The Company's board of directors has approved common share repurchase authorizations under which repurchases may be made from time to time in the open market, pursuant to pre-set trading plans meeting the requirements of Rule 10b5-1 under the Securities Exchange Act of 1934, in private transactions or otherwise. The authorizations do not have a stated expiration date. The timing and actual number of shares to be repurchased in the future will depend on a variety of factors, including the Company's financial position, earnings, share price, catastrophe losses, maintaining capital levels commensurate with the Company's desired ratings from independent rating agencies, funding of the Company's qualified pension plan, capital requirements of the Company's operating subsidiaries, legal requirements, regulatory constraints, other investment opportunities (including mergers and acquisitions and related financings), market conditions and other factors. In April 2015, the board of directors approved a share repurchase authorization that added an additional $5.0 billion of repurchase capacity. The following table summarizes repurchase activity in 2015 and remaining repurchase capacity at December 31, 2015. Quarterly Period Ending Number of Cost of Average price Remaining capacity March 31, 2015 5.6 600 106.97 884 June 30, 2015 7.9 800 101.62 5,084 September 30, 2015 7.3 750 102.81 4,334 December 31, 2015 8.8 1,000 113.47 3,334 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 29.6 3,150 106.46 3,334 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Company's Amended and Restated 2004 Stock Incentive Plan and the 2014 Stock Incentive Plan provide settlement alternatives to employees in which the Company retains shares to cover tax withholding costs and exercise costs. During the years ended December 31, 2015 and 2014, the Company acquired $74 million and $58 million, respectively, of its common stock under this plan. Common shares acquired are reported as treasury stock in the consolidated balance sheet. The Company's U.S. insurance subsidiaries, domiciled principally in the State of Connecticut, are subject to various regulatory restrictions that limit the maximum amount of dividends available to be paid by each insurance subsidiary to its respective parent company without prior approval of insurance regulatory authorities. A maximum of $3.81 billion is available by the end of 2016 for such dividends to the holding company, TRV, without prior approval of the Connecticut Insurance Department. The Company may choose to accelerate the timing within 2016 and/or increase the amount of dividends from its insurance subsidiaries in 2016, which could result in certain dividends being subject to approval by the Connecticut Insurance Department. In addition to the regulatory restrictions on the availability of dividends that can be paid by the Company's U.S. insurance subsidiaries, the maximum amount of dividends that may be paid to the Company's shareholders is limited, to a lesser degree, by certain covenants contained in its line of credit agreement with a syndicate of financial institutions that require the Company to maintain a minimum consolidated net worth as described in note 8. TRV is not dependent on dividends or other forms of repatriation from its foreign operations to support its liquidity needs. The undistributed earnings of the Company's foreign operations are not material and are intended to be permanently reinvested in those operations. TRV and its two non-insurance holding company subsidiaries received dividends of $3.75 billion, $4.10 billion and $2.90 billion from their U.S. insurance subsidiaries in 2015, 2014 and 2013, respectively. For the years ended December 31, 2015, 2014 and 2013, TRV declared cash dividends per common share of $2.38, $2.15 and $1.96, respectively, and paid cash dividends of $739 million, $729 million and $729 milllion, respectively. Statutory net income of the Company's domestic and international insurance subsidiaries was $3.80 billion, $3.97 billion and $4.18 billion for the years ended December 31, 2015, 2014 and 2013, respectively. Statutory capital and surplus of the Company's domestic and international insurance subsidiaries was $20.57 billion and $21.05 billion at December 31, 2015 and 2014, respectively.

Other Comprehensive Income and

Other Comprehensive Income and Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2015
Other Comprehensive Income and Accumulated Other Comprehensive Income disclosure
Other Comprehensive Income and Accumulated Other Comprehensive Income disclosure [Text Block]	10. OTHER COMPREHENSIVE INCOME AND ACCUMULATED OTHER COMPREHENSIVE INCOME The following table presents the changes in the Company's accumulated other comprehensive income (AOCI) for the years ended December 31, 2015, 2014 and 2013. (in millions) Changes in Net Changes in Net Net Benefit Plan Net Total Balance, December 31, 2012 2,908 195 (857 ) (10 ) 2,236 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss) (OCI) before reclassifications (1,740 ) (2 ) 358 (79 ) (1,463 ) Amounts reclassified from AOCI (43 ) 4 68 8 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net OCI, current period (1,783 ) 2 426 (71 ) (1,426 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2013 1,125 197 (431 ) (81 ) 810 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ OCI before reclassifications 667 (2 ) (363 ) (250 ) 52 Amounts reclassified from AOCI (24 ) 3 39 — 18 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net OCI, current period 643 1 (324 ) (250 ) 70 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2014 1,768 198 (755 ) (331 ) 880 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ OCI before reclassifications (641 ) (11 ) (18 ) (419 ) (1,089 ) Amounts reclassified from AOCI (27 ) 2 60 17 52 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net OCI, current period (668 ) (9 ) 42 (402 ) (1,037 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2015 1,100 189 (713 ) (733 ) (157 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The following table presents the pretax components of the Company's other comprehensive income (loss) and the related income tax expense (benefit). (for the year ended December 31, in millions) 2015 2014 2013 Changes in net unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income (1,020 ) 976 (2,734 ) Income tax expense (benefit) (352 ) 333 (951 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes (668 ) 643 (1,783 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Having credit losses recognized in the consolidated statement of income (14 ) 2 3 Income tax expense (benefit) (5 ) 1 1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes (9 ) 1 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net changes in benefit plan assets and obligations 66 (494 ) 647 Income tax expense (benefit) 24 (170 ) 221 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes 42 (324 ) 426 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net changes in unrealized foreign currency translation (461 ) (289 ) (112 ) Income tax benefit (59 ) (39 ) (41 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes (402 ) (250 ) (71 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total other comprehensive income (loss) (1,429 ) 195 (2,196 ) Total income tax expense (benefit) (392 ) 125 (770 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total other comprehensive income (loss), net of taxes (1,037 ) 70 (1,426 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The following table presents the pretax and related income tax (expense) benefit components of the amounts reclassified from the Company's AOCI to the Company's consolidated statement of income. (for the year ended December 31, in millions) 2015 2014 2013 Reclassification adjustments related to unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income(1) (42 ) (36 ) (66 ) Income tax expense(2) (15 ) (12 ) (23 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes (27 ) (24 ) (43 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Having credit losses recognized in the consolidated statement of income(1) 2 4 5 Income tax benefit(2) — 1 1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes 2 3 4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reclassification adjustment related to benefit plan assets and obligations(3) 93 60 105 Income tax benefit(2) 33 21 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes 60 39 68 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reclassification adjustment related to foreign currency translation(1) 26 — 8 Income tax benefit(2) 9 — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes 17 — 8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications 79 28 52 Total income tax benefit 27 10 15 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications, net of taxes 52 18 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) (Increases) decreases net realized investment gains on the consolidated statement of income. (2) (Increases) decreases income tax expense on the consolidated statement of income. (3) Increases (decreases) general and administrative expenses on the consolidated statement of income.

Earnings per Share

Earnings per Share	12 Months Ended
	Dec. 31, 2015
Earnings per Share disclosure
Earnings per Share disclosure [Text Block]	11. EARNINGS PER SHARE Basic earnings per share was computed by dividing income available to common shareholders by the weighted average number of common shares outstanding during the period. The computation of diluted earnings per share reflected the effect of potentially dilutive securities. The following is a reconciliation of the income and share data used in the basic and diluted earnings per share computations: (for the year ended December 31, in millions, except per share amounts) 2015 2014 2013 Basic and Diluted Net income, as reported 3,439 3,692 3,673 Participating share-based awards—allocated income (25 ) (27 ) (27 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income available to common shareholders—basic and diluted 3,414 3,665 3,646 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Shares Basic Weighted average shares outstanding 310.6 338.8 370.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted Weighted average shares outstanding 310.6 338.8 370.3 Weighted average effects of dilutive securities: Stock options and performance shares 3.3 3.7 4.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 313.9 342.5 374.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income Per Common Share Basic 10.99 10.82 9.84 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted 10.88 10.70 9.74 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Taxes disclosure
Income Taxes disclosure [Text Block]	12. INCOME TAXES (for the year ended December 31, in millions) 2015 2014 2013 Composition of income tax expense included in the consolidated statement of income Current expense: Federal 1,144 1,216 1,059 Foreign 29 28 30 State 9 10 6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total current tax expense 1,182 1,254 1,095 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred expense: Federal 117 121 167 Foreign 2 22 10 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total deferred tax expense 119 143 177 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total income tax expense included in the consolidated statement of income 1,301 1,397 1,272 Composition of income tax expense (benefit) included in shareholders' equity Expense (benefit) relating to share-based compensation, the changes in unrealized gain on investments, unrealized loss on foreign exchange and other items in other comprehensive income (448 ) 68 (822 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total income tax expense included in the consolidated financial statements 853 1,465 450 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (for the year ended December 31, in millions) 2015 2014 2013 Income before income taxes U.S. 4,621 4,899 4,804 Foreign 119 190 141 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total income before income taxes 4,740 5,089 4,945 Effective tax rate Statutory tax rate 35 % 35 % 35 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expected federal income tax expense 1,659 1,781 1,731 Tax effect of: Nontaxable investment income (345 ) (379 ) (409 ) Other, net (13 ) (5 ) (50 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total income tax expense 1,301 1,397 1,272 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective tax rate 27 % 27 % 26 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The Company paid income taxes of $1.21 billion, $1.15 billion and $1.06 billion during the years ended December 31, 2015, 2014 and 2013, respectively. The current income tax payable was $50 million and $139 million at December 31, 2015 and 2014, respectively, and was included in other liabilities in the consolidated balance sheet. The net deferred tax asset comprises the tax effects of temporary differences related to the following assets and liabilities: (at December 31, in millions) 2015 2014 Deferred tax assets Claims and claim adjustment expense reserves 691 768 Unearned premium reserves 731 709 Compensation-related liabilities 326 345 Other 320 346 ​ ​ ​ ​ ​ ​ ​ Total gross deferred tax assets 2,068 2,168 ​ ​ ​ ​ ​ ​ ​ Deferred tax liabilities Deferred acquisition costs 580 565 Investments 867 1,267 Internally developed software 134 130 Other 191 173 ​ ​ ​ ​ ​ ​ ​ Total gross deferred tax liabilities 1,772 2,135 ​ ​ ​ ​ ​ ​ ​ Net deferred tax asset 296 33 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ If the Company determines that any of its deferred tax assets will not result in future tax benefits, a valuation allowance must be established for the portion of these assets that are not expected to be realized. Based upon a review of the Company's anticipated future taxable income, and also including all other available evidence, both positive and negative, the Company's management concluded that it is more likely than not that the gross deferred tax assets will be realized. For tax return purposes, as of December 31, 2015, the Company had net operating loss (NOL) carryforwards in the United States, Brazil and the United Kingdom. The amount and timing of realizing the benefits of NOL carryforwards depend on future taxable income and limitations imposed by tax laws. The benefits of the NOL carryforwards have been recognized in the consolidated financial statements and are included in net deferred tax assets. The NOL amounts by jurisdiction and year of expiration are as follows: (in millions) Amount Year of United States 4 2018 Brazil 1 None United Kingdom 200 None U.S. income taxes have not been recognized on $383 million of the Company's foreign operations' undistributed earnings as of December 31, 2015, as such earnings are intended to be permanently reinvested in those operations. Furthermore, any taxes paid to foreign governments on these earnings may be used as credits against the U.S. tax on any dividend distributions from such earnings. The following is a reconciliation of the beginning and ending amount of unrecognized tax benefits for the years ended December 31, 2015 and 2014: (in millions) 2015 2014 Balance at January 1 23 21 Additions for tax positions of prior years 2 2 Reductions for tax positions of prior years (9 ) — Additions based on tax positions related to current year — — ​ ​ ​ ​ ​ ​ ​ Balance at December 31 16 23 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Included in the balances at December 31, 2015 and 2014 were $4 million and $2 million, respectively, of unrecognized tax benefits that, if recognized, would affect the annual effective tax rate. Also included in the balances at those dates were $12 million and $21 million, respectively, of tax positions for which the ultimate deductibility is certain, but for which there is uncertainty about the timing of deductibility. The timing of such deductibility would not affect the annual effective tax rate. The Company recognizes accrued interest and penalties, if any, related to unrecognized tax benefits in income taxes. During the years ended December 31, 2015, 2014 and 2013, the Company recognized approximately $(32) million, $31 million and $(67) million in interest, respectively. The Company had approximately $26 million and $58 million accrued for the payment of interest at December 31, 2015 and 2014, respectively. The IRS is conducting an examination of the Company's U.S. income tax returns for 2013 and 2014. The Company does not expect any significant changes to its liability for unrecognized tax benefits during the next twelve months.

Share-Based Incentive Compensat

Share-Based Incentive Compensation	12 Months Ended
	Dec. 31, 2015
Share-Based Incentive Compensation disclosure
Share-Based Incentive Compensation disclosure [Text Block]	13. SHARE-BASED INCENTIVE COMPENSATION The Company has a share-based incentive compensation plan, The Travelers Companies, Inc. 2014 Stock Incentive Plan (the 2014 Incentive Plan), the purposes of which are to align the interests of the Company's non-employee directors, executive officers and other employees with those of the Company's shareholders and to attract and retain personnel by providing incentives in the form of share-based awards. The 2014 Incentive Plan permits grants of nonqualified stock options, incentive stock options, stock appreciation rights, restricted stock, restricted stock units, deferred stock, deferred stock units, performance awards and other share-based or share-denominated awards with respect to the Company's common stock. The number of shares of the Company's common stock authorized for grant under the 2014 Incentive Plan is 10 million shares, subject to additional shares that may be available for awards as described below. The Company has a policy of issuing new shares to settle the exercise of stock option awards and the vesting of other equity awards. In connection with the adoption of the 2014 Incentive Plan, The Travelers Companies, Inc. Amended and Restated 2004 Stock Incentive Plan, as amended (the 2004 Incentive Plan) was terminated, joining several other legacy share-based incentive compensation plans that had been terminated in prior years (together, the legacy plans). Outstanding grants were not affected by the termination of the legacy plans. The 2014 Incentive Plan is currently the only plan pursuant to which future stock-based awards may be granted. In addition to the 10 million shares initially authorized for issuance under the 2014 Incentive Plan, the following will not be counted towards the 10 million shares available and will be available for future grants under the 2014 Incentive Plan: (i) shares of common stock subject to awards that expire unexercised, that are forfeited, terminated or canceled, that are settled in cash or other forms of property, or otherwise do not result in the issuance of shares of common stock, in whole or in part; (ii) shares that are used to pay the exercise price of stock options and shares used to pay withholding taxes on awards generally; and (iii) shares purchased by the Company on the open market using cash option exercise proceeds; provided, however, that the increase in the number of shares of common stock available for grant pursuant to such market purchases shall not be greater than the number that could be repurchased at fair market value on the date of exercise of the stock option giving rise to such option proceeds. In addition, the 10 million shares initially authorized for issuance under the 2014 Incentive Plan will be increased by any shares subject to awards under the 2004 Incentive Plan that were outstanding as of May 27, 2014 and subsequently expire, are forfeited, cancelled, settled in cash or otherwise terminate without the issuance of shares. The Company also has a compensation program for non-employee directors (the Director Compensation Program). Under the Director Compensation Program, non-employee directors' compensation consists of an annual retainer, a deferred stock award, committee chair fees and a lead director fee. Each non-employee director may choose to receive all or a portion of his or her annual retainer in the form of cash or deferred stock units which vest upon grant. The annual deferred stock awards vest in full one day prior to the date of the Company's annual meeting of shareholders occurring in the year following the year of the grant date, subject to continued service. The deferred stock awards, including dividend equivalents, accumulate until distribution either in a lump sum six months after termination of service as a director or, if the director so elects, in annual installments beginning at least six months following termination of service as a director. The deferred stock units issued under the Director Compensation Program are awarded under the 2014 Incentive Plan. Stock option awards granted to eligible officers and key employees have a ten-year term. Prior to January 1, 2007, stock options were granted with an exercise price equal to the fair market value of the Company's common stock on the day preceding the date of grant. Beginning January 1, 2007, all stock options are granted with an exercise price equal to the closing price of the Company's common stock on the date of grant. The stock options granted generally vest upon meeting certain years of service criteria. Except as the Compensation Committee of the board of directors may allow in the future, stock options cannot be sold or transferred by the participant. Stock options outstanding under the 2014 Incentive Plan and the 2004 Incentive Plan vest three years after grant date (cliff vest). The fair value of each option award is estimated on the date of grant by application of a variation of the Black-Scholes option pricing model using the assumptions noted in the following table. The expected term of newly granted stock options is the time to vest plus half the remaining time to expiration. This considers the vesting restriction and represents an even pattern of exercise behavior over the remaining term. The expected volatility assumption is based on the historical volatility of the Company's common stock for the same period as the estimated option term based on the mid-month of the option grant. The expected dividend is based upon the Company's current quarter dividend annualized and assumed to be constant over the expected option term. The risk-free interest rate for each option is the interpolated market yield for the mid-month of the option grant on a U.S. Treasury bill with a term comparable to the expected option term of the granted stock option. The following table provides information about options granted: (for the year ended December 31,) 2015 2014 2013 Assumptions used in estimating fair value of options on grant date Expected term of stock options 6 years 6 years 6 years Expected volatility of Company's stock 19.29% 27.2% - 27.5% 28.7% - 28.8% Weighted average volatility 19.29% 27.5% 28.8% Expected annual dividend per share $2.20 $2.00 - $2.20 $1.84 Risk-free rate 1.31% 1.81% - 1.82% 1.11% - 1.14% Additional information Weighted average grant-date fair value of options granted (per share) $15.78 $17.22 $17.09 Total intrinsic value of options exercised during the year (in millions) $120 $117 $122 ​ ​ ​ ​ ​ ​ A summary of stock option activity under the 2014 Incentive Plan and the legacy plans as of and for the year ended December 31, 2015 is as follows: Stock Options Number Weighted Weighted Aggregate Outstanding, beginning of year 10,024,860 63.08 Original grants 2,244,464 106.04 Exercised (2,310,548 ) 55.16 Forfeited or expired (94,521 ) 87.17 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding, end of year 9,864,255 74.48 6.6 years 379 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Vested at end of year(1) 7,226,516 68.80 6.0 years 318 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at end of year 4,155,912 53.51 4.3 years 247 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Represents awards for which the requisite service has been rendered, including those that are retirement eligible. On February 2, 2016, the Company, under the 2014 Stock Incentive Plan, granted 2,808,558 stock option awards with an exercise price of $106.03 per share. The fair value attributable to the stock option awards on the date of grant was $13.26 per share. The Company issues restricted stock unit awards to eligible officers and key employees under the Equity Awards program established pursuant to the 2014 Incentive Plan. A restricted stock unit represents the right to receive a share of common stock. These restricted stock unit awards are granted at market price, generally vest three years from the date of grant, do not have voting rights and the underlying shares of common stock are not issued until the vesting criteria is satisfied. In addition, the Company's board of directors can be issued deferred stock units from (i) an annual award; (ii) deferred compensation (in lieu of cash retainer); and (iii) dividend equivalents earned on outstanding deferred compensation. The Company also has a Performance Share Awards Program established pursuant to the 2004 Incentive Plan and which continues pursuant to the 2014 Incentive Plan. Under the program, the Company may issue performance share awards to certain employees of the Company who hold positions of Vice President (or its equivalent) or above. The performance share awards provide the recipient the right to earn shares of the Company's common stock based upon the Company's attainment of certain performance goals and the recipient meeting certain years of service criteria. The performance goals for performance share awards are based on the Company's adjusted return on equity over a three-year performance period. Vesting of performance shares is contingent upon the Company attaining the relevant performance period minimum threshold return on equity and the recipient meeting certain years of service criteria, generally three years for full vesting, subject to proration for certain termination conditions. If the performance period return on equity is below the minimum threshold, none of the performance shares will vest. If performance meets or exceeds the minimum performance threshold, a range of performance shares will vest (50% to 150% for awards granted in 2014, 2015 and 2016), depending on the actual return on equity attained. The fair value of restricted stock units, deferred stock units and performance shares is measured at the market price of the Company stock at date of grant. Under terms of the 2014 Incentive Plan, holders of deferred stock units and performance shares may receive dividend equivalents. The total fair value of shares that vested during the years ended December 31, 2015, 2014 and 2013 was $179 million, $147 million and $151 million, respectively. A summary of restricted stock units, deferred stock units and performance share activity under the 2014 Incentive Plan and the legacy plans as of and for the year ended December 31, 2015 is as follows: Restricted and Deferred Stock Performance Shares Other Equity Instruments Number Weighted Average Number Weighted Average Nonvested, beginning of year 1,760,971 72.40 1,290,069 79.46 Granted 607,200 106.02 460,855 106.04 Vested (789,538 ) (1) 69.03 (676,177 ) (2) 79.28 Forfeited (142,675 ) 73.57 (31,352 ) 86.41 Performance-based adjustment — — 58,594 (3) 94.06 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nonvested, end of year 1,435,958 88.35 1,101,989 91.27 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Represents awards for which the requisite service has been rendered. (2) Reflects the number of performance shares attributable to the performance goals attained over the completed performance period (three years) and for which service conditions have been met. (3) Represents the current year change in estimated performance shares to reflect the attainment of performance goals for the awards that were granted in each of the years 2013 through 2015. In addition to the nonvested shares presented in the above table, there are related nonvested dividend equivalent shares. The number of nonvested dividend equivalent shares related to deferred stock units was 387 at the beginning of the year and 396 at the end of the year and the number of nonvested dividend equivalent shares related to performance shares was 38,738 at the beginning of the year and 40,663 at the end of the year. The dividend equivalent shares are subject to the same vesting terms as the deferred stock units and performance shares. On February 2, 2016, the Company, under the 2014 Stock Incentive Plan, granted 1,094,685 common stock awards in the form of restricted stock units, deferred stock units and performance share awards to participating officers, non-employee directors and other key employees. The restricted stock units and deferred stock units totaled 618,274 shares while the performance share awards totaled 476,411 shares. The fair value per share attributable to the common stock awards on the date of grant was $106.03. The amount of compensation cost for awards subject to a service condition is based on the number of shares expected to be issued and is recognized over the time period for which service is to be provided (requisite service period). Awards granted to retiree-eligible employees or to employees who become retiree-eligible before an award's vesting date are considered to have met the requisite service condition. The compensation cost for awards subject to a performance condition is based upon the probable outcome of the performance condition, which on the grant date reflects an estimate of attaining 100% of the performance shares granted. The compensation cost reflects an estimated annual forfeiture rate from 3.0% to 4.5% over the requisite service period of the awards. That estimate is revised if subsequent information indicates that the actual number of instruments expected to vest is likely to differ from previous estimates. Compensation costs for awards are recognized on a straight-line basis over the requisite service period. For awards that have graded vesting terms, the compensation cost is recognized on a straight-line basis over the requisite service period for each separate vesting portion of the award as if the award was, in substance, multiple awards. The total compensation cost for all share-based incentive compensation awards recognized in earnings for the years ended December 31, 2015, 2014 and 2013 was $141 million, $138 million and $129 million, respectively. Included in these amounts are compensation cost adjustments of $8 million, $14 million and $8 million, for the years ended December 31, 2015, 2014 and 2013, respectively, that reflected the cost associated with the updated estimate of performance shares due to attaining certain performance levels from the date of the initial grant of the performance awards. The related tax benefits recognized in earnings were $47 million, $47 million and $45 million for the years ended December 31, 2015, 2014 and 2013, respectively. At December 31, 2015, there was $124 million of total unrecognized compensation cost related to all nonvested share-based incentive compensation awards. This includes stock options, restricted and deferred stock units and performance shares granted under the 2014 Incentive Plan and the 2004 Incentive Plan. The unrecognized compensation cost is expected to be recognized over a weighted-average period of 1.7 years. Cash received from the exercise of employee stock options under share-based compensation plans totaled $183 million and $195 million in 2015 and 2014, respectively. The tax benefit realized for tax deductions from employee stock options exercised during 2015 and 2014 totaled $41 million and $40 million, respectively.

Pension Plans, Retirement Benef

Pension Plans, Retirement Benefits and Savings Plans	12 Months Ended
	Dec. 31, 2015
Pension Plans, Retirement Benefits and Savings Plans disclosure
Pension Plans, Retirement Benefits and Savings Plans disclosure [Text Block]	14. PENSION PLANS, RETIREMENT BENEFITS AND SAVINGS PLANS The Company sponsors a qualified non-contributory defined benefit pension plan (the qualified domestic pension plan), which covers substantially all U.S. domestic employees and provides benefits under a cash balance formula, except that employees satisfying certain age and service requirements remain covered by a prior final average pay formula. In addition, the Company sponsors a nonqualified defined benefit pension plan which covers certain highly-compensated employees, pension plans for employees of its foreign subsidiaries, and a postretirement health and life insurance benefit plan for employees satisfying certain age and service requirements and for certain retirees. The following tables summarize the funded status, obligations and amounts recognized in the consolidated balance sheet for the Company's benefit plans. The Company uses a December 31 measurement date for its pension and postretirement benefit plans. Qualified Nonqualified Total (at and for the year ended December 31, in millions) 2015 2014 2015 2014 2015 2014 Change in projected benefit obligation: Benefit obligation at beginning of year 3,385 2,908 227 209 3,612 3,117 Benefits earned 124 104 7 6 131 110 Interest cost on benefit obligation 135 140 9 10 144 150 Actuarial loss (gain) (203 ) 428 2 29 (201 ) 457 Benefits paid (191 ) (187 ) (8 ) (11 ) (199 ) (198 ) Plan amendments — (8 ) — — — (8 ) Curtailment — — — (3 ) — (3 ) Settlement — — — (6 ) — (6 ) Foreign currency exchange rate change — — (9 ) (7 ) (9 ) (7 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefit obligation at end of year 3,250 3,385 228 227 3,478 3,612 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in plan assets: Fair value of plan assets at beginning of year 3,235 3,074 122 129 3,357 3,203 Actual return on plan assets (17 ) 148 3 11 (14 ) 159 Company contributions 100 200 7 7 107 207 Benefits paid (191 ) (187 ) (8 ) (11 ) (199 ) (198 ) Foreign currency exchange rate change — — (9 ) (8 ) (9 ) (8 ) Settlement — — — (6 ) — (6 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at end of year 3,127 3,235 115 122 3,242 3,357 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Funded status of plan at end of year (123 ) (150 ) (113 ) (105 ) (236 ) (255 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in the consolidated balance sheet consist of: Accrued over-funded benefit plan assets — — 4 6 4 6 Accrued under-funded benefit plan liabilities (123 ) (150 ) (117 ) (111 ) (240 ) (261 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total (123 ) (150 ) (113 ) (105 ) (236 ) (255 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in accumulated other comprehensive income consist of: Net actuarial loss 1,079 1,132 52 53 1,131 1,185 Prior service benefit (8 ) (8 ) — — (8 ) (8 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 1,071 1,124 52 53 1,123 1,177 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Postretirement (at and for the year ended December 31, in millions) 2015 2014 Change in projected benefit obligation: Benefit obligation at beginning of year 255 211 Benefits earned — — Interest cost on benefit obligation 10 10 Actuarial loss (gain) (3 ) 51 Benefits paid (13 ) (15 ) Plan amendments (11 ) — Foreign currency exchange rate change (5 ) (2 ) ​ ​ ​ ​ ​ ​ ​ Benefit obligation at end of year 233 255 ​ ​ ​ ​ ​ ​ ​ Change in plan assets: Fair value of plan assets at beginning of year 16 17 Actual return on plan assets — — Company contributions 12 14 Benefits paid (13 ) (15 ) ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at end of year 15 16 ​ ​ ​ ​ ​ ​ ​ Funded status of plan at end of year (218 ) (239 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in the consolidated balance sheet consist of: Accrued under-funded benefit plan liability (218 ) (239 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in accumulated other comprehensive income consist of: Net actuarial loss 4 9 Prior service benefit (35 ) (26 ) ​ ​ ​ ​ ​ ​ ​ Total (31 ) (17 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The total accumulated benefit obligation for the Company's defined benefit pension plans was $3.37 billion and $3.51 billion at December 31, 2015 and 2014, respectively. The qualified domestic pension plan accounted for $3.15 billion and $3.29 billion of the total accumulated benefit obligation at December 31, 2015 and 2014, respectively, whereas the nonqualified and foreign plans accounted for $0.22 billion of the total accumulated benefit obligation at both December 31, 2015 and 2014. For pension plans with an accumulated benefit obligation in excess of plan assets, the aggregate projected benefit obligation was $3.47 billion and $3.53 billion at December 31, 2015 and 2014, respectively, and the aggregate accumulated benefit obligation was $3.36 billion and $3.43 billion at December 31, 2015 and 2014, respectively. The fair value of plan assets for the above plans was $3.23 billion and $3.27 billion at December 31, 2015 and 2014, respectively. The Company has discretion regarding whether to provide additional funding and when to provide such funding to its qualified domestic pension plan. In 2015, 2014 and 2013, there were no required contributions to the qualified domestic pension plan. In 2015 and 2014, the Company voluntarily made contributions totaling $100 million and $200 million, respectively, to the qualified domestic pension plan. In 2013, the Company made no voluntary contributions to the qualified domestic pension plan. There is no required contribution to the qualified domestic pension plan during 2016, and the Company has not determined whether or not additional funding will be made during 2016. With respect to the Company's foreign pension plans, there are no significant required contributions in 2016. The following table summarizes the components of net periodic benefit cost and other amounts recognized in other comprehensive income related to the benefit plans. Pension Plans Postretirement (for the year ended December 31, in millions) 2015 2014 2013 2015 2014 2013 Net Periodic Benefit Cost: Service cost 131 110 118 — — — Interest cost on benefit obligation 144 150 132 10 10 9 Expected return on plan assets (230 ) (218 ) (208 ) — — (1 ) Curtailment — (1 ) — — — — Settlement — 2 — — — — Amortization of unrecognized: Prior service benefit (1 ) — — (3 ) (2 ) (2 ) Net actuarial loss (gain) 96 65 107 1 (3 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net periodic benefit cost 140 108 149 8 5 6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other Changes in Benefit Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income: Prior service benefit — (8 ) — (11 ) — — Net actuarial loss (gain) 43 516 (518 ) (3 ) 50 (24 ) Plan amendments — — — — — — Curtailment — (2 ) — — — — Settlement — (2 ) — — — — Amortization of prior service benefit 1 — — 3 2 2 Amortization of net actuarial gain (loss) (96 ) (65 ) (107 ) (1 ) 3 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total other changes recognized in other comprehensive income (52 ) 439 (625 ) (12 ) 55 (22 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total other changes recognized in net periodic benefit cost and other comprehensive income 88 547 (476 ) (4 ) 60 (16 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the defined benefit pension plans, the estimated net actuarial loss that will be reclassified (amortized) from accumulated other comprehensive income into net income as part of net periodic benefit cost over the next fiscal year is $66 million and the estimated prior service benefit to be amortized over the next fiscal year is $1 million. For the postretirement benefit plans, the estimated net actuarial loss that will be reclassified (amortized) from accumulated other comprehensive income into net income as part of net periodic benefit cost over the next fiscal year is less than $1 million, and the estimated prior service benefit to be amortized over the next fiscal year is $3 million. The following table summarizes assumptions used with regard to the Company's qualified and nonqualified domestic pension plans and the domestic postretirement benefit plans. (at and for the year ended December 31,) 2015 2014 Assumptions used to determine benefit obligations Discount rate: Qualified domestic pension plan 4.50 % 4.10 % Nonqualified domestic pension plan 4.37 % 4.10 % Domestic postretirement benefit plan 4.35 % 4.10 % Future compensation increase rate 4.00 % 4.00 % Assumptions used to determine net periodic benefit cost Discount rate 4.10 % 4.96 % Expected long-term rate of return on assets: Pension plan 7.25 % 7.50 % Postretirement benefit plan 4.00 % 4.00 % Assumed health care cost trend rates Following year: Medical (before age 65) 6.75 % 7.00 % Medical (age 65 and older) 7.50 % 6.50 % Rate to which the cost trend rate is assumed to decline (ultimate trend rate) Year that the rate reaches the ultimate trend rate: Medical (before age 65) 2022 2022 Medical (age 65 and older) 2025 2020 The discount rate assumption used to determine the benefit obligation is based on a yield-curve approach. Under this approach, individual spot rates from the yield curve of a hypothetical portfolio of high quality fixed maturity corporate bonds (rated Aa) available at the year-end valuation date, for which the timing and amount of cash outflows correspond with the timing and amount of the estimated benefit payouts of the Company's benefit plan, are applied to expected future benefits payments in measuring the projected benefit obligation . The discount rate assumption used to determine benefit obligations disclosed above represents the weighted average of the individual spot rates. For 2015, separate discount rate assumptions were used for the qualified domestic pension plan, nonqualified domestic plan and the domestic postretirement plan reflecting the different expected duration of cash flows of each plan to provide a better estimate of the benefit obligation for these plans. The discount rate assumption used to determine the net periodic benefit cost is the single weighted average discount rate derived from the yield curve used to measure the benefit obligation at the beginning of the year. In choosing the expected long-term rate of return on plan assets, the Company selected the rate that was set as the return objective by the Company's Benefit Plans Investment Committee, which had considered the historical returns of equity and fixed maturity markets in conjunction with prevailing economic and financial market conditions. As an indicator of sensitivity, increasing the assumed health care cost trend rate by 1% would have increased the accumulated postretirement benefit obligation by $25 million at December 31, 2015, and the aggregate of the service and interest cost components of net postretirement benefit expense by $1 million for the year ended December 31, 2015. Decreasing the assumed health care cost trend rate by 1% would have decreased the accumulated postretirement benefit obligation at December 31, 2015 by $21 million and the aggregate of the service and interest cost components of net postretirement benefit expense by $1 million for the year ended December 31, 2015. The assumptions made for the Company's foreign pension and foreign postretirement benefit plans are not materially different from those of the Company's qualified domestic pension plan and the domestic postretirement benefit plan. The qualified domestic pension plan assets are invested for the exclusive benefit of the plan participants and beneficiaries and are intended, over time, to satisfy the benefit obligations under the plan. Risk tolerance is established through consideration of plan liabilities, plan funded status and corporate financial position. The asset mix guidelines have been established and are reviewed quarterly. These guidelines are intended to serve as tools to facilitate the investment of plan assets to maximize long-term total return and the ongoing oversight of the plan's investment performance. Investment risk is measured and monitored on an ongoing basis through daily and monthly investment portfolio reviews, annual liability measurements and periodic asset/liability studies. The Company's overall investment strategy for the qualified domestic pension plan is to achieve a mix of approximately 85% to 90% of investments for long-term growth and 10% to 15% for near-term benefit payments with a diversification of asset types, fund strategies and fund managers. The current target allocations for plan assets are 55% to 65% equity securities and 20% to 40% fixed income securities, with the remainder allocated to short-term securities. Equity securities primarily include investments in large, medium and small-cap companies primarily located in the United States. Fixed income securities include corporate bonds of companies from diversified industries, mortgage-backed securities, U.S. Treasury securities and debt securities issued by foreign governments. Other investments include two private equity funds held by the Company's qualified defined benefit pension plan. One private equity fund is focused on financial companies, and the other is focused on real estate-related investments. Assets of the Company's foreign pension plans are not significant. For a discussion of the methods employed by the Company to measure the fair value of invested assets, see note 4. The following discussion of fair value measurements applies exclusively to the Company's pension plans and other postretirement benefit assets. Fair value estimates for equity and bond mutual funds held by the pension plans reflect prices received from an external pricing service that are based on observable market transactions. These estimates are included in Level 1. Short-term securities are carried at fair value which approximates cost plus accrued interest or amortized discount. The fair value or market value of these is periodically compared to this amortized cost and is based on significant observable inputs as determined by an external pricing service. Accordingly, the estimates of fair value for such short-term securities, other than U.S. Treasury securities and money market mutual funds, provided by an external pricing service are included in the amount disclosed in Level 2 of the hierarchy. The estimated fair value of U.S. Treasury securities and money market mutual funds is included in the amount disclosed in Level 1 as the estimates are based on unadjusted market prices. The following tables present the level within the fair value hierarchy at which the financial assets of the Company's pension plans are measured on a recurring basis. (at December 31, 2015, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities Obligations of states, municipalities and political subdivisions 17 — 17 — Debt securities issued by foreign governments 16 — 16 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 16 — 16 — All other corporate bonds 491 — 491 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 540 — 540 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mutual funds Equity mutual funds 1,237 1,231 6 — Bond mutual funds 649 646 3 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total mutual funds 1,886 1,877 9 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities 625 624 1 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other investments(1) 2 — — 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and short-term securities U.S. Treasury securities 25 25 — — Money market mutual funds 23 19 4 — Other 141 20 121 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total cash and short-term securities 189 64 125 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 3,242 2,565 675 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The fair value estimates of the two private equity funds comprising these investments are determined by an external fund manager based on recent filings, operating results, balance sheet stability, growth and other business and market sector fundamentals. Due to the significant unobservable inputs in these valuations, the total fair value estimates are disclosed in Level 3. (at December 31, 2014, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities Obligations of states, municipalities and political subdivisions 19 — 19 — Debt securities issued by foreign governments 17 — 17 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 14 — 14 — All other corporate bonds 474 — 474 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 524 — 524 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mutual funds Equity mutual funds 1,290 1,283 7 — Bond mutual funds 610 607 3 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total mutual funds 1,900 1,890 10 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities 616 615 1 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other investments(1) 2 — — 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and short-term securities Money market mutual funds 22 18 4 — Other 293 29 264 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total cash and short-term securities 315 47 268 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 3,357 2,552 803 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The fair value estimates of the two private equity funds comprising these investments are determined by an external fund manager based on recent filings, operating results, balance sheet stability, growth and other business and market sector fundamentals. Due to the significant unobservable inputs in these valuations, the total fair value estimates are disclosed in Level 3. The balance of Level 3 fair value investments was $2 million at December 31, 2015 and the change in balance from the prior year was insignificant. The Company's overall investment strategy is to achieve a mix of approximately 35% to 65% of investments for long-term growth and 35% to 60% for near-term insurance payments with a wide diversification of asset types, fund strategies and fund managers. The current target allocations for plan assets are 25% to 75% fixed income securities, with the remainder allocated to short-term securities. Fixed income securities include corporate bonds of companies from diversified industries, mortgage-backed securities and U.S. Treasuries. The Company's other postretirement benefit plan had financial assets of $15 million and $16 million at December 31, 2015 and 2014, respectively, which are measured at fair value on a recurring basis. The assets are primarily corporate bonds and short-term securities and categorized as level 2 in the fair value hierarchy. The following table presents the estimated benefits expected to be paid by the Company's pension and postretirement benefit plans for the next ten years (reflecting estimated future employee service). Benefits Expected to be Paid (in millions) Pension Plans Postretirement 2016 215 14 2017 218 14 2018 224 15 2019 231 15 2020 237 15 2021 through 2025 1,215 76 The Company has a savings plan, The Travelers 401(k) Savings Plan (the Savings Plan), in which substantially all U.S. domestic Company employees are eligible to participate. Under the Savings Plan, the Company matches employee contributions up to 5% of eligible pay, with a maximum annual match of $6,000 which becomes 100% vested after three years of service. The Company's matching contribution is made in cash and invested according to the employee's current investment elections and can be reinvested into other investment options in accordance with the terms of the plan. The Company's non-U.S. employees participate in separate savings plans. The total expense related to all of the savings plans was $109 million, $103 million and $100 million for the years ended December 31, 2015, 2014 and 2013, respectively. All common shares held by the Savings Plan are considered outstanding for basic and diluted EPS computations and dividends paid on all shares are charged to retained earnings.

Leases

Leases	12 Months Ended
	Dec. 31, 2015
Leases disclosure
Leases disclosure [Text Block]	15. LEASES Rent expense was $202 million, $215 million and $196 million in 2015, 2014 and 2013, respectively. Future minimum annual rental payments under noncancellable operating leases for 2016, 2017, 2018, 2019 and 2020 are $159 million, $139 million, $102 million, $80 million and $60 million, respectively, and $114 million for 2021 and thereafter. Future sublease rental income aggregating approximately $6 million will partially offset these commitments.

Contingencies, Commitments and

Contingencies, Commitments and Guarantees	12 Months Ended
	Dec. 31, 2015
Contingencies, Commitments and Guarantees disclosure
Contingencies, Commitments and Guarantees disclosure [Text Block]	16. CONTINGENCIES, COMMITMENTS AND GUARANTEES The major pending legal proceedings, other than ordinary routine litigation incidental to the business, to which the Company or any of its subsidiaries is a party or to which any of the Company's properties is subject are described below. In the ordinary course of its insurance business, the Company has received and continues to receive claims for insurance arising under policies issued by the Company asserting alleged injuries and damages from asbestos- and environmental-related exposures that are the subject of related coverage litigation. The Company is defending asbestos- and environmental-related litigation vigorously and believes that it has meritorious defenses; however, the outcomes of these disputes are uncertain. In this regard, the Company employs dedicated specialists and aggressive resolution strategies to manage asbestos and environmental loss exposure, including settling litigation under appropriate circumstances. Currently, it is not possible to predict legal outcomes and their impact on the future development of claims and litigation relating to asbestos and environmental claims. Any such development will be affected by future court decisions and interpretations, as well as changes in applicable legislation. Because of these uncertainties, additional liabilities may arise for amounts in excess of the Company's current reserves. In addition, the Company's estimate of ultimate claims and claim adjustment expenses may change. These additional liabilities or increases in estimates, or a range of either, cannot now be reasonably estimated and could result in income statement charges that could be material to the Company's results of operations in future periods. In October 2001 and April 2002, two purported class action suits ( Wise v. Travelers and Meninger v. Travelers ) were filed against Travelers Property Casualty Corp. (TPC), a wholly-owned subsidiary of the Company, and other insurers (not including The St. Paul Companies, Inc. (SPC), which was acquired by TPC in 2004) in state court in West Virginia. These and other cases subsequently filed in West Virginia were consolidated into a single proceeding in the Circuit Court of Kanawha County, West Virginia. The plaintiffs alleged that the insurer defendants engaged in unfair trade practices in violation of state statutes by inappropriately handling and settling asbestos claims. The plaintiffs sought to reopen large numbers of settled asbestos claims and to impose liability for damages, including punitive damages, directly on insurers. Similar lawsuits alleging inappropriate handling and settling of asbestos claims were filed in Massachusetts and Hawaii state courts. These suits are collectively referred to as the Statutory and Hawaii Actions. In March 2002, the plaintiffs in consolidated asbestos actions pending before a mass tort panel of judges in West Virginia state court amended their complaint to include TPC as a defendant, alleging that TPC and other insurers breached alleged duties to certain users of asbestos products. The plaintiffs sought damages, including punitive damages. Lawsuits seeking similar relief and raising similar allegations, primarily violations of purported common law duties to third parties, were also asserted in various state courts against TPC and SPC. The claims asserted in these suits are collectively referred to as the Common Law Claims. In response to these claims, TPC moved to enjoin the Statutory Actions and the Common Law Claims in the federal bankruptcy court that had presided over the bankruptcy of TPC's former policyholder Johns-Manville Corporation on the ground that the suits violated injunctions entered in connection with confirmation of the Johns-Manville bankruptcy (the 1986 Orders). The bankruptcy court issued a temporary restraining order and referred the parties to mediation. In November 2003, the parties reached a settlement of the Statutory and Hawaii Actions, which included a lump-sum payment of up to $412 million by TPC, subject to a number of significant contingencies. In May 2004, the parties reached a settlement resolving substantially all pending and similar future Common Law Claims against TPC, which included a payment of up to $90 million by TPC, subject to similar contingencies. After the parties reached the settlements of the Statutory and Hawaiian Actions and the Common Law Claims (collectively "the Settlements"), numerous proceedings took place in the bankruptcy, district and appellate courts concerning the approval of the Settlements and their effect on other parties. As a result of certain rulings in those proceedings, TPC concluded that it was not obligated to go forward with the Settlements because certain conditions precedent to the Settlements had not been met. The plaintiffs in the Statutory and Hawaii Actions and the Common Law Claims actions thereafter filed motions in the bankruptcy court to compel TPC to make payment under the settlement agreements, arguing that all conditions precedent to the Settlements had been met. On December 16, 2010, the bankruptcy court granted the plaintiffs' motions and ruled that TPC was required to fund the Settlements. The court entered judgment against TPC on January 20, 2011 in accordance with this ruling and ordered TPC to pay the Settlements plus prejudgment interest. The bankruptcy court's judgment was reversed by the district court on March 1, 2012, the district court having found that the conditions to the Settlements had not been met. The plaintiffs appealed the district court's March 1, 2012 decision to the Second Circuit Court of Appeals. On July 22, 2014, the Second Circuit issued an opinion reversing the district court's decision and reinstating the bankruptcy court's January 20, 2011 order which ordered TPC to pay the Settlements plus prejudgment interest. On August 5, 2014, TPC filed a Petition for Rehearing and Rehearing En Banc with the Second Circuit, which was denied on January 5, 2015. On January 15, 2015, the bankruptcy court entered an order directing TPC to pay $579 million to the plaintiffs, comprising the $502 million settlement amount described above, plus pre-judgment and post-judgment interest totaling $77 million, and the Company made that payment in January 2015. The payment was fully accrued in the Company's financial statements at December 31, 2014. The Company is involved in other lawsuits, including lawsuits alleging extra-contractual damages relating to insurance contracts or reinsurance agreements, that do not arise under insurance contracts or reinsurance agreements. The legal costs associated with such lawsuits are expensed in the period in which the costs are incurred. Based upon currently available information, the Company does not believe it is reasonably possible that any such lawsuit or related lawsuits would be material to the Company's results of operations or would have a material adverse effect on the Company's financial position or liquidity. On August 17, 2010, in a reinsurance dispute in New York state court captioned United States Fidelity & Guaranty Company v. American Re-Insurance Company, et al. , the trial court granted summary judgment for United States Fidelity and Guaranty Company (USF&G), a subsidiary of the Company, and denied summary judgment for American Re-Insurance Company, a subsidiary of Munich Re (American Re), and three other reinsurers. That summary judgment was largely affirmed on appeal, but the Court of Appeals remanded the case for trial on two discrete issues. On June 3, 2015, the trial court entered orders on pretrial motions filed by all parties in advance of the August 3, 2015 trial date and determined that the issues for trial will be limited to the two discrete issues remanded by the Court of Appeals. The reinsurers appealed the trial court's orders to the Appellate Division, First Department and were granted a stay of the trial date pending the outcome of their appeal. On August 12, 2015, USF&G filed a motion to dismiss the reinsurers' appeal. On October 29, 2015, the Appellate Division denied USF&G's motion to dismiss the reinsurers' appeal, but also unanimously ruled in USF&G's favor and affirmed the rulings limiting the issues for trial to the two discrete issues remanded by the Court of Appeals. On October 30, 2015, the reinsurers appealed the Appellate Division's decision to the New York Court of Appeals. On November 9, 2015, the Clerk of the Court of Appeals directed the parties to submit letter briefs addressing whether the Court of Appeals has jurisdiction to decide the reinsurers' appeal. On November 19, 2015, USF&G and the reinsurers filed their respective letter briefs, and the parties await a decision from the Court of Appeals as to whether the reinsurers' appeal may proceed. At December 31, 2015, the claim totaled $509 million, comprising $238 million of reinsurance recoverable plus interest amounting to $271 million as of that date. Interest will continue to accrue at an annual rate of 9% until the claim is paid. The $238 million of reinsurance recoverable owed to USF&G under the terms of the disputed reinsurance contract has been reported as part of reinsurance recoverables in the Company's consolidated balance sheet. The interest that would be owed as part of any judgment ultimately entered in favor of USF&G is treated for accounting purposes as a gain contingency in accordance with FASB Topic 450, Contingencies, and accordingly has not been recognized in the Company's consolidated financial statements. In 2013, the Company favorably resolved a class action lawsuit captioned Safeco Insurance Company of America, et al. v American International Group, Inc. et al. (U.S. District Court, N.D. Ill.). The plaintiffs, including the Company, alleged that the defendants had engaged in the under-reporting of workers' compensation premium in connection with a workers' compensation reinsurance pool in which several subsidiaries of the Company participated. The Company received two payments totaling approximately $93 million, comprising its allocation as a plaintiff class member from the settlement fund, less approximately $2 million remitted to another insurer, resulting in a net gain of $91 million that was reported in "Other revenues" in the Company's consolidated statement of income for the year ended December 31, 2013. Investment Commitments —The Company has unfunded commitments to private equity limited partnerships and real estate partnerships in which it invests. These commitments totaled $1.71 billion and $1.63 billion at December 31, 2015 and 2014, respectively. In the ordinary course of selling businesses to third parties, the Company has agreed to indemnify purchasers for losses arising out of breaches of representations and warranties with respect to the businesses being sold, covenants and obligations of the Company and/or its subsidiaries and, in certain cases, obligations arising from certain liabilities and the imposition of additional taxes due to either a change in the tax law or an adverse interpretation of the tax law. Such indemnification provisions generally are applicable from the closing date to the expiration of the relevant statutes of limitations, although, in some cases, there may be agreed upon term limitations or no term limitations. Certain of these contingent obligations are subject to deductibles which have to be incurred by the obligee before the Company is obligated to make payments. The maximum amount of the Company's contingent obligation for indemnifications related to the sale of businesses that are quantifiable was $391 million at December 31, 2015, of which $2 million was recognized on the balance sheet at that date. The Company also has contingent obligations for guarantees related to certain investments, third-party loans related to certain investments, certain insurance policy obligations of former insurance subsidiaries and various other indemnifications. The Company also provides standard indemnifications to service providers in the normal course of business. The indemnification clauses are often standard contractual terms. The maximum amount of the Company's obligation for guarantees of certain investments and third-party loans related to certain investments that are quantifiable was $150 million at December 31, 2015, approximately $75 million of which is indemnified by a third party. The maximum amount of the Company's obligation related to the guarantee of certain insurance policy obligations of a former insurance subsidiary was $480 million at December 31, 2015, all of which is indemnified by a third party. Certain of the guarantees and indemnifications described above have no stated or notional amounts or limitation to the maximum potential future payments, and, accordingly, the Company is unable to develop an estimate of the maximum potential payments for such arrangements.

Noncash Investing and Financing

Noncash Investing and Financing Activities	12 Months Ended
	Dec. 31, 2015
Noncash Investing and Financing Activities disclosure
Noncash Investing and Financing Activities disclosure [Text Block]	17. NONCASH INVESTING AND FINANCING ACTIVITIES There were no material noncash financing or investing activities during the years ended December 31, 2015, 2014 and 2013.

Consolidating Financial Stateme

Consolidating Financial Statements (Unaudited)	12 Months Ended
	Dec. 31, 2015
Consolidating Financial Statements of The Travelers Companies, Inc. and Subsidiaries (Unaudited) disclosure
Consolidating Financial Statements of The Travelers Companies, Inc. and Subsidiaries (Unaudited) disclosure [Text Block]	18. CONSOLIDATING FINANCIAL STATEMENTS OF THE TRAVELERS COMPANIES, INC. AND SUBSIDIARIES The following consolidating financial statements of the Company have been prepared pursuant to Rule 3-10 of Regulation S-X. These consolidating financial statements have been prepared from the Company's financial information on the same basis of accounting as the consolidated financial statements. The Travelers Companies, Inc. (excluding its subsidiaries, TRV) has fully and unconditionally guaranteed certain debt obligations of Travelers Property Casualty Corp. (TPC), which totaled $700 million at December 31, 2015. Prior to the merger of TPC and The St. Paul Companies, Inc. in 2004, TPC fully and unconditionally guaranteed the payment of all principal, premiums, if any, and interest on certain debt obligations of its wholly-owned subsidiary, Travelers Insurance Group Holdings, Inc. (TIGHI). Concurrent with the merger, TRV fully and unconditionally assumed such guarantee obligations of TPC. TPC is deemed to have no assets or operations independent of TIGHI. Consolidating financial information for TIGHI has not been presented herein because such financial information would be substantially the same as the financial information provided for TPC. CONSOLIDATING STATEMENT OF INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Revenues Premiums 16,254 7,620 — — 23,874 Net investment income 1,612 760 7 — 2,379 Fee income 445 — — — 445 Net realized investment gains (losses)(1) 13 (11 ) 1 — 3 Other revenues 78 21 — — 99 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues 18,402 8,390 8 — 26,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and expenses Claims and claim adjustment expenses 9,208 4,515 — — 13,723 Amortization of deferred acquisition costs 2,627 1,258 — — 3,885 General and administrative expenses 2,838 1,225 16 — 4,079 Interest expense 48 — 325 — 373 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total claims and expenses 14,721 6,998 341 — 22,060 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income (loss) before income taxes 3,681 1,392 (333 ) — 4,740 Income tax expense (benefit) 1,015 394 (108 ) — 1,301 Net income of subsidiaries — — 3,664 (3,664 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 2,666 998 3,439 (3,664 ) 3,439 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Total other-than-temporary impairments (OTTI) for the year ended December 31, 2015, and the amounts comprising total OTTI that were recognized in net realized investment gains (losses) and in other comprehensive income (OCI), were as follows: (in millions) TPC Other TRV Eliminations Consolidated Total OTTI losses (19 ) (35 ) — — (54 ) OTTI losses recognized in net realized investment gains (18 ) (34 ) — — (52 ) OTTI losses recognized in OCI (1 ) (1 ) — — (2 ) CONSOLIDATING STATEMENT OF INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Revenues Premiums 16,097 7,616 — — 23,713 Net investment income 1,874 907 6 — 2,787 Fee income 436 2 — — 438 Net realized investment gains(1) 12 64 3 — 79 Other revenues 125 20 — — 145 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues 18,544 8,609 9 — 27,162 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and expenses Claims and claim adjustment expenses 9,274 4,596 — — 13,870 Amortization of deferred acquisition costs 2,604 1,278 — — 3,882 General and administrative expenses 2,743 1,194 15 — 3,952 Interest expense 48 — 321 — 369 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total claims and expenses 14,669 7,068 336 — 22,073 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income (loss) before income taxes 3,875 1,541 (327 ) — 5,089 Income tax expense (benefit) 1,095 417 (115 ) — 1,397 Net income of subsidiaries — — 3,904 (3,904 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 2,780 1,124 3,692 (3,904 ) 3,692 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Total other-than-temporary impairments (OTTI) for the year ended December 31, 2014, and the amounts comprising total OTTI that were recognized in net realized investment gains and in other comprehensive income (OCI), were as follows: (in millions) TPC Other TRV Eliminations Consolidated Total OTTI losses (16 ) (6 ) — — (22 ) OTTI losses recognized in net realized investment gains (19 ) (7 ) — — (26 ) OTTI gains recognized in OCI 3 1 — — 4 CONSOLIDATING STATEMENT OF INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Revenues Premiums 15,262 7,375 — — 22,637 Net investment income 1,830 879 7 — 2,716 Fee income 393 2 — — 395 Net realized investment gains(1) 126 38 2 — 166 Other revenues 225 52 — — 277 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues 17,836 8,346 9 — 26,191 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and expenses Claims and claim adjustment expenses 8,817 4,490 — — 13,307 Amortization of deferred acquisition costs 2,571 1,250 — — 3,821 General and administrative expenses 2,570 1,174 13 — 3,757 Interest expense 53 — 308 — 361 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total claims and expenses 14,011 6,914 321 — 21,246 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income (loss) before income taxes 3,825 1,432 (312 ) — 4,945 Income tax expense (benefit) 1,054 388 (170 ) — 1,272 Net income of subsidiaries — — 3,815 (3,815 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 2,771 1,044 3,673 (3,815 ) 3,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Total other-than-temporary impairments (OTTI) for the year ended December 31, 2013, and the amounts comprising total OTTI that were recognized in net realized investment gains and in other comprehensive income (loss) (OCI), were as follows: (in millions) TPC Other TRV Eliminations Consolidated Total OTTI losses (8 ) (2 ) — — (10 ) OTTI losses recognized in net realized investment gains (10 ) (5 ) — — (15 ) OTTI gains recognized in OCI 2 3 — — 5 CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Net income 2,666 998 3,439 (3,664 ) 3,439 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss): Changes in net unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income (610 ) (407 ) (3 ) — (1,020 ) Having credit losses recognized in the consolidated statement of income (12 ) (2 ) — — (14 ) Net changes in benefit plan assets and obligations 2 — 64 — 66 Net changes in unrealized foreign currency translation (306 ) (155 ) — — (461 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss) before income taxes and other comprehensive loss of subsidiaries (926 ) (564 ) 61 — (1,429 ) Income tax expense (benefit) (257 ) (156 ) 21 — (392 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss), net of taxes, before other comprehensive loss of subsidiaries (669 ) (408 ) 40 — (1,037 ) Other comprehensive loss of subsidiaries — — (1,077 ) 1,077 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss (669 ) (408 ) (1,037 ) 1,077 (1,037 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive income 1,997 590 2,402 (2,587 ) 2,402 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Net income 2,780 1,124 3,692 (3,904 ) 3,692 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss): Changes in net unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income 681 289 6 — 976 Having credit losses recognized in the consolidated statement of income 9 (7 ) — — 2 Net changes in benefit plan assets and obligations (15 ) (8 ) (471 ) — (494 ) Net changes in unrealized foreign currency translation (173 ) (116 ) — — (289 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss) before income taxes and other comprehensive income of subsidiaries 502 158 (465 ) — 195 Income tax expense (benefit) 207 81 (163 ) — 125 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss), net of taxes, before other comprehensive income of subsidiaries 295 77 (302 ) — 70 Other comprehensive income of subsidiaries — — 372 (372 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income 295 77 70 (372 ) 70 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive income 3,075 1,201 3,762 (4,276 ) 3,762 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Net income 2,771 1,044 3,673 (3,815 ) 3,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss): Changes in net unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income (1,982 ) (771 ) 19 — (2,734 ) Having credit losses recognized in the consolidated statement of income 4 (1 ) — — 3 Net changes in benefit plan assets and obligations 12 19 616 — 647 Net changes in unrealized foreign currency translation (92 ) (20 ) — — (112 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss) before income taxes and other comprehensive loss of subsidiaries (2,058 ) (773 ) 635 — (2,196 ) Income tax expense (benefit) (719 ) (273 ) 222 — (770 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss), net of taxes, before other comprehensive loss of subsidiaries (1,339 ) (500 ) 413 — (1,426 ) Other comprehensive loss of subsidiaries — — (1,839 ) 1,839 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss (1,339 ) (500 ) (1,426 ) 1,839 (1,426 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive income 1,432 544 2,247 (1,976 ) 2,247 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CONSOLIDATING BALANCE SHEET (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Assets Fixed maturities, available for sale, at fair value (amortized cost $58,878) 42,289 18,323 46 — 60,658 Equity securities, available for sale, at fair value (cost $528) 189 375 141 — 705 Real estate investments 56 933 — — 989 Short-term securities 1,947 1,178 1,546 — 4,671 Other investments 2,516 930 1 — 3,447 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total investments 46,997 21,739 1,734 — 70,470 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash 225 153 2 — 380 Investment income accrued 453 185 4 — 642 Premiums receivable 4,336 2,101 — — 6,437 Reinsurance recoverables 5,849 3,061 — — 8,910 Ceded unearned premiums 610 46 — — 656 Deferred acquisition costs 1,660 189 — — 1,849 Deferred taxes 178 83 35 — 296 Contractholder receivables 3,387 987 — — 4,374 Goodwill 2,573 1,000 — — 3,573 Other intangible assets 203 76 — — 279 Investment in subsidiaries — — 27,573 (27,573 ) — Other assets 1,958 344 16 — 2,318 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total assets 68,429 29,964 29,364 (27,573 ) 100,184 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities Claims and claim adjustment expense reserves 31,965 16,330 — — 48,295 Unearned premium reserves 8,335 3,636 — — 11,971 Contractholder payables 3,387 987 — — 4,374 Payables for reinsurance premiums 175 121 — — 296 Debt 693 — 5,651 — 6,344 Other liabilities 3,958 1,221 127 — 5,306 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liabilities 48,513 22,295 5,778 — 76,586 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shareholders' equity Common stock (1,750.0 shares authorized; 295.9 shares issued and outstanding) — 390 22,172 (390 ) 22,172 Additional paid-in capital 11,634 6,499 — (18,133 ) — Retained earnings 7,888 688 29,933 (8,564 ) 29,945 Accumulated other comprehensive income (loss) 394 92 (157 ) (486 ) (157 ) Treasury stock, at cost (467.6 shares) — — (28,362 ) — (28,362 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total shareholders' equity 19,916 7,669 23,586 (27,573 ) 23,598 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liabilities and shareholders' equity 68,429 29,964 29,364 (27,573 ) 100,184 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CONSOLIDATING BALANCE SHEET (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Assets Fixed maturities, available for sale, at fair value (amortized cost $60,801) 43,401 20,043 30 — 63,474 Equity securities, available for sale, at fair value (cost $579) 236 522 141 — 899 Real estate investments 56 882 — — 938 Short-term securities 2,128 706 1,530 — 4,364 Other investments 2,630 955 1 — 3,586 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total investments 48,451 23,108 1,702 — 73,261 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash 221 151 2 — 374 Investment income accrued 468 215 2 — 685 Premiums receivable 4,241 2,057 — — 6,298 Reinsurance recoverables 6,156 3,104 — — 9,260 Ceded unearned premiums 608 70 — — 678 Deferred acquisition costs 1,622 213 — — 1,835 Deferred taxes 23 (40 ) 50 — 33 Contractholder receivables 3,306 1,056 — — 4,362 Goodwill 2,602 1,009 — — 3,611 Other intangible assets 216 88 — — 304 Investment in subsidiaries — — 28,821 (28,821 ) — Other assets 1,931 429 17 — 2,377 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total assets 69,845 31,460 30,594 (28,821 ) 103,078 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities Claims and claim adjustment expense reserves 32,999 16,851 — — 49,850 Unearned premium reserves 8,201 3,638 — — 11,839 Contractholder payables 3,306 1,056 — — 4,362 Payables for reinsurance premiums 194 142 — — 336 Debt 692 — 5,657 — 6,349 Other liabilities 4,084 1,308 114 — 5,506 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liabilities 49,476 22,995 5,771 — 78,242 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shareholders' equity Common stock (1,750.0 shares authorized; 322.2 shares issued and outstanding) — 390 21,843 (390 ) 21,843 Additional paid-in capital 11,634 6,502 — (18,136 ) — Retained earnings 7,673 1,073 27,238 (8,733 ) 27,251 Accumulated other comprehensive income 1,062 500 880 (1,562 ) 880 Treasury stock, at cost (437.3 shares) — — (25,138 ) — (25,138 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total shareholders' equity 20,369 8,465 24,823 (28,821 ) 24,836 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liabilities and shareholders' equity 69,845 31,460 30,594 (28,821 ) 103,078 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CONSOLIDATING STATEMENT OF CASH FLOWS (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Cash flows from operating activities Net income 2,666 998 3,439 (3,664 ) 3,439 Net adjustments to reconcile net income to net cash provided by operating activities (577 ) 414 330 (172 ) (5 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by operating activities 2,089 1,412 3,769 (3,836 ) 3,434 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities Proceeds from maturities of fixed maturities 7,543 3,563 10 — 11,116 Proceeds from sales of investments: Fixed maturities 1,227 723 — — 1,950 Equity securities 25 34 — — 59 Real estate investments — 31 — — 31 Other investments 503 210 — — 713 Purchases of investments: Fixed maturities (8,276 ) (3,787 ) (27 ) — (12,090 ) Equity securities (3 ) (43 ) (3 ) — (49 ) Real estate investments (1 ) (122 ) — — (123 ) Other investments (423 ) (111 ) — — (534 ) Net sales (purchases) of short-term securities 179 (489 ) (16 ) — (326 ) Securities transactions in course of settlement (52 ) (61 ) — — (113 ) Acquisition, net of cash acquired (13 ) — — — (13 ) Other (343 ) 39 — — (304 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) investing activities 366 (13 ) (36 ) — 317 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from financing activities Treasury stock acquired—share repurchase authorization — — (3,150 ) — (3,150 ) Treasury stock acquired—net employee share-based compensation — — (74 ) — (74 ) Dividends paid to shareholders — — (739 ) — (739 ) Payment of debt — — (400 ) — (400 ) Issuance of debt — — 392 — 392 Issuance of common stock—employee share options — — 183 — 183 Excess tax benefits from share-based payment arrangements — — 55 — 55 Dividends paid to parent company (2,450 ) (1,383 ) — 3,833 — Capital contributions, loans and other transactions between subsidiaries — (3 ) — 3 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash used in financing activities (2,450 ) (1,386 ) (3,733 ) 3,836 (3,733 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effect of exchange rate changes on cash (1 ) (11 ) — — (12 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase in cash 4 2 — — 6 Cash at beginning of year 221 151 2 — 374 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash at end of year 225 153 2 — 380 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental disclosure of cash flow information Income taxes paid (received) 1,032 384 (209 ) — 1,207 Interest paid 47 — 318 — 365 CONSOLIDATING STATEMENT OF CASH FLOWS (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Cash flows from operating activities Net income 2,780 1,124 3,692 (3,904 ) 3,692 Net adjustments to reconcile net income to net cash provided by operating activities 343 (293 ) 118 (167 ) 1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by operating activities 3,123 831 3,810 (4,071 ) 3,693 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities Proceeds from maturities of fixed maturities 6,625 4,258 11 — 10,894 Proceeds from sales of investments: Fixed maturities 595 453 1 — 1,049 Equity securities 111 43 4 — 158 Real estate investments 1 14 — — 15 Other investments 477 378 — — 855 Purchases of investments: Fixed maturities (6,856 ) (4,465 ) (4 ) — (11,325 ) Equity securities (3 ) (42 ) (7 ) — (52 ) Real estate investments (22 ) (26 ) — — (48 ) Other investments (405 ) (149 ) — — (554 ) Net purchases of short-term securities (268 ) (223 ) (7 ) — (498 ) Securities transactions in course of settlement 44 38 — — 82 Acquisition, net of cash acquired (9 ) (3 ) — (12 ) Other (350 ) (8 ) — — (358 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) investing activities (60 ) 268 (2 ) — 206 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from financing activities Treasury stock acquired—share repurchase authorization — — (3,275 ) — (3,275 ) Treasury stock acquired—net employee share-based compensation — — (57 ) — (57 ) Dividends paid to shareholders — — (729 ) — (729 ) Issuance of common stock—employee share options — — 195 — 195 Excess tax benefits from share-based payment arrangements — — 57 — 57 Dividends paid to parent company (2,978 ) (1,093 ) — 4,071 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash used in financing activities (2,978 ) (1,093 ) (3,809 ) 4,071 (3,809 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effect of exchange rate changes on cash (1 ) (9 ) — — (10 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase (decrease) in cash 84 (3 ) (1 ) — 80 Cash at beginning of year 137 154 3 — 294 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash at end of year 221 151 2 — 374 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental disclosure of cash flow information Income taxes paid (received) 947 336 (136 ) — 1,147 Interest paid 47 — 318 — 365 CONSOLIDATING STATEMENT OF CASH FLOWS (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Cash flows from operating activities Net income 2,771 1,044 3,673 (3,815 ) 3,673 Net adjustments to reconcile net income to net cash provided by operating activities (497 ) 413 (1,665 ) 1,892 143 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by operating activities 2,274 1,457 2,008 (1,923 ) 3,816 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities Proceeds from maturities of fixed maturities 5,484 2,419 1 — 7,904 Proceeds from sales of investments: Fixed maturities 989 641 5 — 1,635 Equity securities 45 41 — — 86 Real estate investments — 18 — — 18 Other investments 489 273 — — 762 Purchases of investments: Fixed maturities (6,260 ) (3,201 ) (6 ) — (9,467 ) Equity securities (21 ) (34 ) (2 ) — (57 ) Real estate investments (1 ) (106 ) — — (107 ) Other investments (320 ) (126 ) — — (446 ) Net sales (purchases) of short-term securities (272 ) (52 ) 435 — 111 Securities transactions in course of settlement (2 ) 24 (1 ) — 21 Acquisition, net of cash acquired (773 ) (224 ) — (997 ) Other (365 ) (8 ) — — (373 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) investing activities (1,007 ) (335 ) 432 — (910 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from financing activities Treasury stock acquired—share repurchase authorization — — (2,400 ) — (2,400 ) Treasury stock acquired—net employee share-based compensation — — (61 ) — (61 ) Dividends paid to shareholders — — (729 ) — (729 ) Payment of debt (500 ) — — — (500 ) Issuance of debt — — 494 — 494 Issuance of common stock—employee share options — — 206 — 206 Excess tax benefits from share-based payment arrangements — — 51 — 51 Dividends paid to parent company (1,307 ) (1,116 ) — 2,423 — Capital contributions, loans and other transactions between subsidiaries 500 — — (500 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash used in financing activities (1,307 ) (1,116 ) (2,439 ) 1,923 (2,939 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effect of exchange rate changes on cash — (3 ) — — (3 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase (decrease) in cash (40 ) 3 1 — (36 ) Cash at beginning of year 177 151 2 — 330 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash at end of year 137 154 3 — 294 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental disclosure of cash flow information Income taxes paid (received) 942 325 (210 ) — 1,057 Interest paid 60 — 295 — 355

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2015
Selected Quarterly Financial Data (Unaudited) disclosure
Selected Quarterly Financial Data (Unaudited) disclosure [Text Block]	19. SELECTED QUARTERLY FINANCIAL DATA (Unaudited) 2015 (in millions, except per share amounts) First Second Third Fourth Total Total revenues 6,626 6,706 6,794 6,674 26,800 Total expenses 5,478 5,630 5,487 5,465 22,060 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before income taxes 1,148 1,076 1,307 1,209 4,740 Income tax expense 315 264 379 343 1,301 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 833 812 928 866 3,439 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income per share(1): Basic 2.58 2.56 3.00 2.87 10.99 Diluted 2.55 2.53 2.97 2.83 10.88 2014 (in millions, except per share amounts) First Second Third Fourth Total Total revenues 6,708 6,785 6,886 6,783 27,162 Total expenses 5,238 5,884 5,628 5,323 22,073 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before income taxes 1,470 901 1,258 1,460 5,089 Income tax expense 418 218 339 422 1,397 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 1,052 683 919 1,038 3,692 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income per share(1): Basic 2.98 1.98 2.72 3.15 10.82 Diluted 2.95 1.95 2.69 3.11 10.70 (1) Due to the averaging of shares, quarterly earnings per share may not add to the total for the full year.

Schedule II

Schedule II	12 Months Ended
	Dec. 31, 2015
Schedule II
Schedule II [Text Block]	SCHEDULE II THE TRAVELERS COMPANIES, INC. CONDENSED FINANCIAL INFORMATION OF REGISTRANT CONDENSED STATEMENT OF INCOME For the year ended December 31, 2015 2014 2013 Revenues Net investment income 7 6 7 Net realized investment gains(1) 1 3 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues 8 9 9 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expenses Interest 325 321 308 Other 16 15 13 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total expenses 341 336 321 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss before income taxes and net income of subsidiaries (333 ) (327 ) (312 ) Income tax benefit (108 ) (115 ) (170 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss before net income of subsidiaries (225 ) (212 ) (142 ) Net income of subsidiaries 3,664 3,904 3,815 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 3,439 3,692 3,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The parent company had no other-than-temporary impairment gains or losses recognized in net realized investment gains or in other comprehensive income during the years ended December 31, 2015, 2014 and 2013. The condensed financial statements should be read in conjunction with the notes to the condensed financial information of the registrant, as well as the consolidated financial statements and notes thereto. See the accompanying Report of Independent Registered Public Accounting Firm. SCHEDULE II THE TRAVELERS COMPANIES, INC. CONDENSED FINANCIAL INFORMATION OF REGISTRANT CONDENSED STATEMENT OF COMPREHENSIVE INCOME For the year ended December 31, 2015 2014 2013 Consolidated net income 3,439 3,692 3,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss)—parent company: Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income (3 ) 6 19 Net changes in benefit plan assets and obligations 64 (471 ) 616 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss) before income taxes and other comprehensive income (loss) of subsidiaries 61 (465 ) 635 Income tax expense (benefit) 21 (163 ) 222 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries 40 (302 ) 413 Other comprehensive income (loss) of subsidiaries (1,077 ) 372 (1,839 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated other comprehensive income (loss) (1,037 ) 70 (1,426 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated comprehensive income 2,402 3,762 2,247 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The condensed financial statements should be read in conjunction with the notes to the condensed financial information of the registrant, as well as the consolidated financial statements and notes thereto. See the accompanying Report of Independent Registered Public Accounting Firm. SCHEDULE II THE TRAVELERS COMPANIES, INC. CONDENSED FINANCIAL INFORMATION OF REGISTRANT CONDENSED BALANCE SHEET At December 31, 2015 2014 Assets Fixed maturities 46 30 Equity securities 141 141 Short-term securities 1,546 1,530 Investment in subsidiaries 27,573 28,821 Other assets 58 72 ​ ​ ​ ​ ​ ​ ​ Total assets 29,364 30,594 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities Debt 5,651 5,657 Other liabilities 127 114 ​ ​ ​ ​ ​ ​ ​ Total liabilities 5,778 5,771 ​ ​ ​ ​ ​ ​ ​ Shareholders' equity Common stock (1,750.0 shares authorized, 295.9 and 322.2 shares issued and outstanding) 22,172 21,843 Retained earnings 29,933 27,238 Accumulated other comprehensive income (loss) (157 ) 880 Treasury stock, at cost (467.6 and 437.3 shares) (28,362 ) (25,138 ) ​ ​ ​ ​ ​ ​ ​ Total shareholders' equity 23,586 24,823 ​ ​ ​ ​ ​ ​ ​ Total liabilities and shareholders' equity 29,364 30,594 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The condensed financial statements should be read in conjunction with the notes to the condensed financial information of the registrant, as well as the consolidated financial statements and notes thereto. See the accompanying Report of Independent Registered Public Accounting Firm. SCHEDULE II THE TRAVELERS COMPANIES, INC. CONDENSED FINANCIAL INFORMATION OF REGISTRANT CONDENSED STATEMENT OF CASH FLOWS For the year ended December 31, 2015 2014 2013 Cash flows from operating activities Net income 3,439 3,692 3,673 Adjustments to reconcile net income to net cash provided by operating activities: Equity in net income of subsidiaries (3,664 ) (3,904 ) (3,815 ) Dividends received from consolidated subsidiaries 3,833 4,071 2,423 Capital received from (contributed to) subsidiaries 3 — (500 ) Deferred federal income tax expense (benefit) (6 ) 51 (59 ) Change in income taxes payable 51 (87 ) 48 Other 113 (13 ) 238 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by operating activities 3,769 3,810 2,008 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities Net sales (purchases) of short-term securities (16 ) (7 ) 435 Other investments, net (20 ) 5 (3 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) investing activities (36 ) (2 ) 432 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from financing activities Treasury stock acquired—share repurchase authorization (3,150 ) (3,275 ) (2,400 ) Treasury stock acquired—net employee share-based compensation (74 ) (57 ) (61 ) Dividends paid to shareholders (739 ) (729 ) (729 ) Payment of debt (400 ) — — Issuance of debt 392 — 494 Issuance of common stock—employee share options 183 195 206 Other 55 57 51 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash used in financing activities (3,733 ) (3,809 ) (2,439 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase (decrease) in cash — (1 ) 1 Cash at beginning of year 2 3 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash at end of year 2 2 3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental disclosure of cash flow information Cash received during the year for taxes 209 136 210 Cash paid during the year for interest 318 318 295 The condensed financial statements should be read in conjunction with the notes to the condensed financial information of the registrant, as well as the consolidated financial statements and notes thereto. See the accompanying Report of Independent Registered Public Accounting Firm. NOTES TO THE CONDENSED FINANCIAL INFORMATION OF REGISTRANT 1. GUARANTEES In the ordinary course of selling businesses to third parties, The Travelers Companies, Inc. (TRV) has agreed to indemnify purchasers for losses arising out of breaches of representations and warranties with respect to the businesses being sold, covenants and obligations of TRV and/or its subsidiaries, and in certain cases, obligations arising from certain liabilities. Such indemnification provisions generally are applicable from the closing date to the expiration of the relevant statutes of limitations, although, in some cases, there may be agreed upon term limitations or no term limitations. Certain of these contingent obligations are subject to deductibles which have to be incurred by the obligee before TRV is obligated to make payments. The maximum amount of TRV's contingent obligation for indemnifications related to the sale of businesses that are quantifiable was $44 million at December 31, 2015, of which $2 million was recognized on the balance sheet at that date. TRV also has contingent obligations for guarantees related to its subsidiary's debt obligations and various other indemnifications. TRV also provides standard indemnifications to service providers in the normal course of business. The indemnification clauses are often standard contractual terms. Certain of the guarantees and indemnifications described above have no stated or notional amounts or limitation to the maximum potential future payments, and, accordingly, TRV is unable to develop an estimate of the maximum potential payments for such arrangements. TRV fully and unconditionally guarantees the payment of all principal, premiums, if any, and interest on certain debt obligations of its subsidiaries TPC and TIGHI. The guarantees pertain to the $200 million 7.75% notes due 2026 and the $500 million 6.375% notes due 2033.

Schedule III

Schedule III	12 Months Ended
	Dec. 31, 2015
Schedule III
Schedule III [Text Block]	SCHEDULE III THE TRAVELERS COMPANIES, INC. AND SUBSIDIARIES Segment Deferred Claims and Unearned Earned Net Claims and Amortization Other Net 2015 Business and International Insurance 1,072 41,563 7,147 14,521 1,824 8,859 2,329 2,686 14,583 Bond & Specialty Insurance 225 3,157 1,292 2,085 223 643 393 389 2,081 Personal Insurance 552 3,552 3,532 7,268 332 4,221 1,163 973 7,457 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total—Reportable Segments 1,849 48,272 11,971 23,874 2,379 13,723 3,885 4,048 24,121 Other — 23 — — — — — 404 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated 1,849 48,295 11,971 23,874 2,379 13,723 3,885 4,452 24,121 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2014 Business and International Insurance 1,080 42,700 7,208 14,512 2,156 9,145 2,321 2,541 14,636 Bond & Specialty Insurance 222 3,435 1,286 2,076 252 481 388 403 2,103 Personal Insurance 533 3,689 3,345 7,125 379 4,244 1,173 977 7,165 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total—Reportable Segments 1,835 49,824 11,839 23,713 2,787 13,870 3,882 3,921 23,904 Other — 26 — — — — — 400 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated 1,835 49,850 11,839 23,713 2,787 13,870 3,882 4,321 23,904 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2013 Business and International Insurance 1,046 43,181 7,170 13,332 2,087 8,285 2,158 2,369 13,512 Bond & Specialty Insurance 213 3,921 1,264 1,981 260 695 378 388 2,030 Personal Insurance 545 3,763 3,416 7,324 369 4,327 1,285 980 7,225 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total—Reportable Segments 1,804 50,865 11,850 22,637 2,716 13,307 3,821 3,737 22,767 Other — 30 — — — — — 381 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Consolidated 1,804 50,895 11,850 22,637 2,716 13,307 3,821 4,118 22,767 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) See note 2 of notes to the consolidated financial statements herein for discussion of the method used to allocate net investment income and invested assets to the identified segments. (2) Expense allocations are determined in accordance with prescribed statutory accounting practices. These practices make a reasonable allocation of all expenses to those product lines with which they are associated. See the accompanying Report of Independent Registered Public Accounting Firm.

Schedule V

Schedule V	12 Months Ended
	Dec. 31, 2015
Schedule V
Schedule V [Text Block]	SCHEDULE V THE TRAVELERS COMPANIES, INC. AND SUBSIDIARIES Balance at Charged to Charged to Deductions(2) Balance 2015 Reinsurance recoverables 203 — — 46 157 Allowance for uncollectible: Premiums receivable from underwriting activities 70 38 — 43 65 Deductibles 36 3 — 4 35 2014 Reinsurance recoverables 239 — — 36 203 Allowance for uncollectible: Premiums receivable from underwriting activities 75 44 — 49 70 Deductibles 39 — — 3 36 2013 Reinsurance recoverables 258 — 2 21 239 Allowance for uncollectible: Premiums receivable from underwriting activities 76 48 — 49 75 Deductibles 41 1 — 3 39 (1) Amount in 2013 represents allowance for uncollectible reinsurance recoverables acquired November 1, 2013 as part of the Company's acquisition of Dominion. (2) Credited to the related asset account. See the accompanying Report of Independent Registered Public Accounting Firm.

Schedule VI

Schedule VI	12 Months Ended
	Dec. 31, 2015
Schedule VI
Schedule VI [Text Block]	SCHEDULE VI THE TRAVELERS COMPANIES, INC. AND SUBSIDIARIES Claims and Paid Discount From Amortization Affiliation with Registrant(2) Deferred Claims and Unearned Earned Net Current Prior Net 2015 1,849 48,272 1,066 11,971 23,874 2,379 14,412 (897 ) 3,885 14,335 24,121 2014 1,835 49,824 1,080 11,839 23,713 2,787 14,621 (957 ) 3,882 13,927 23,904 2013 1,804 50,865 1,090 11,850 22,637 2,716 14,060 (944 ) 3,821 13,962 22,767 (1) Excludes accident and health insurance business. (2) Consolidated property-casualty insurance operations. (3) For a discussion of types of reserves discounted and discount rates used, see "Item 1—Business—Claims and Claim Adjustment Expense Reserves—Discounting" herein. See the accompanying Report of Independent Registered Public Accounting Firm.

Summary of Significant Accoun32

Summary of Significant Accounting Policies (policies)	12 Months Ended
	Dec. 31, 2015
Summary of Significant Accounting Policies disclosure
Accounting Policies, Basis of Presentation [Policy Text Block]	The consolidated financial statements include the accounts of The Travelers Companies, Inc. (together with its subsidiaries, the Company). The preparation of the consolidated financial statements in conformity with U.S. generally accepted accounting principles (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and claims and expenses during the reporting period. Actual results could differ from those estimates. Certain reclassifications have been made to the 2014 and 2013 financial statements to conform to the 2015 presentation. All material intercompany transactions and balances have been eliminated.
Accounting Policies, Acquisition [Policy Text Block]	On November 1, 2013, the Company acquired all of the issued and outstanding shares of The Dominion of Canada General Insurance Company (Dominion) for an aggregate purchase price of approximately $1.035 billion. Dominion primarily markets personal lines and small commercial insurance business in Canada. At the acquisition date, the Company recorded at fair value $3.91 billion of assets acquired and $2.88 billion of liabilities assumed as part of purchase accounting, including $16 million of identifiable intangible assets and $273 million of goodwill. Dominion is included in the Company's Business and International Insurance segment. The unearned premium reserve related to the acquired insurance and reinsurance contracts was carried over and included in the Company's unearned premium reserve. Premium revenue from the acquired business is recognized on a pro rata basis beginning with the acquisition date over the remaining policy terms in accordance with the Company's accounting policy. The Company recognized an intangible asset for the value of business acquired (VOBA) of $76 million at the acquisition date. VOBA represented the present value of future gross profits of the business acquired from Dominion, was reported as part of the Company's deferred acquisition costs, and was amortized in proportion to the premium revenue recognized from the acquired business.
Accounting Policies, Adoption of Accounting Standards [Policy Text Block]	Adoption of Accounting Standards In April 2014, the Financial Accounting Standards Board (FASB) issued revised guidance to reduce diversity in practice for reporting discontinued operations. Under the previous guidance, any component of an entity that was a reportable segment, an operating segment, a reporting unit, a subsidiary or an asset group was eligible for discontinued operations presentation. The revised guidance only allows disposals of components of an entity that represent a strategic shift (e.g., disposal of a major geographical area, a major line of business, a major equity method investment or other major parts of an entity) and that have a major effect on a reporting entity's operations and financial results to be reported as discontinued operations. The revised guidance also requires expanded disclosure in the financial statements for discontinued operations as well as for disposals of significant components of an entity that do not qualify for discontinued operations presentation. The updated guidance was effective for the quarter ending March 31, 2015. The adoption of this guidance did not have any effect on the Company's results of operations, financial position or liquidity.
Accounting Policies, Investments [Policy Text Block]	Investments Fixed maturities include bonds, notes and redeemable preferred stocks. Fixed maturities, including instruments subject to securities lending agreements, are classified as available for sale and are reported at fair value, with unrealized investment gains and losses, net of income taxes, charged or credited directly to other comprehensive income. Equity securities, which include public common and non-redeemable preferred stocks, are classified as available for sale with changes in fair value, net of income taxes, charged or credited directly to other comprehensive income. The Company's real estate investments include warehouses, office buildings and other commercial land and properties that are directly owned. Real estate is recorded on the purchase date at the purchase price, which generally represents fair value, and is supported by internal analysis or external appraisals that use discounted cash flow analyses and other acceptable valuation techniques. Real estate held for investment purposes is subsequently carried at cost less accumulated depreciation. Buildings are depreciated on a straight-line basis over the shorter of the expected useful life of the building or 39 years. Real estate held for sale is carried at lower of cost or fair value, less estimated costs to sell. Short-term securities have an original maturity of less than one year and are carried at amortized cost, which approximates fair value. Investments in Private Equity Limited Partnerships, Hedge Funds and Real Estate Partnerships The Company uses the equity method of accounting for investments in private equity limited partnerships, hedge funds and real estate partnerships. The partnerships and the hedge funds generally report investments on their balance sheet at fair value. The financial statements prepared by the investee are received by the Company on a lag basis, with the lag period generally dependent upon the type of underlying investments. The private equity and real estate partnerships provide financial information quarterly which is generally available to investors, including the Company, within three to six months following the date of the reporting period. The hedge funds provide financial information monthly, which is generally available to investors within one month following the date of the reporting period. The Company regularly requests financial information from the partnerships prior to the receipt of the partnerships' financial statements and records any material information obtained from these requests in its consolidated financial statements. Other Also included in other investments are non-public common equities, preferred equities and derivatives. Non-public common equities and preferred equities are reported at fair value with changes in fair value, net of income taxes, charged or credited directly to other comprehensive income. The Company's derivative financial instruments are carried at fair value, with the changes in fair value reflected in the consolidated statement of income in net realized investment gains (losses). For a further discussion of the derivatives used by the Company, see note 3.
Accounting Policies, Net Investment Income [Policy Text Block]	Net Investment Income Investment income from fixed maturities is recognized based on the constant effective yield method which includes an adjustment for estimated principal pre-payments, if any. The effective yield used to determine amortization for fixed maturities subject to prepayment risk (e.g., asset-backed, loan-backed and structured securities) is recalculated and adjusted periodically based upon actual historical and/or projected future cash flows, which are obtained from a widely-accepted securities data provider. The adjustments to the yield for highly rated prepayable fixed maturities are accounted for using the retrospective method. The adjustments to the yield for non-highly rated prepayable fixed maturities are accounted for using the prospective method. Dividends on equity securities (including those with transfer restrictions) are recognized in income when declared. Rental income on real estate is recognized on a straight-line basis over the lease term. See note 3 for further discussion. Investments in private equity limited partnerships, hedge funds, real estate partnerships and joint ventures are accounted for using the equity method of accounting, whereby the Company's share of the investee's earnings or losses in the fund is reported in net investment income. Accrual of income is suspended on non-securitized fixed maturities that are in default, or on which it is likely that future payments will not be made as scheduled. Interest income on investments in default is recognized only when payments are received. Investments included in the consolidated balance sheet that were not income-producing for the preceding 12 months were not material. For fixed maturities where the Company records an other-than-temporary impairment, a determination is made as to the cause of the impairment and whether the Company expects a recovery in the value. For fixed maturities where the Company expects a recovery in value, not necessarily to par, the constant effective yield method is utilized, and the investment is amortized to the expected recovery amount.
Accounting Policies, Investment Gains and Losses [Policy Text Block]	Investment Gains and Losses Net realized investment gains and losses are included as a component of pretax revenues based upon specific identification of the investments sold on the trade date. Included in net realized investment gains (losses) are other-than-temporary impairment losses on invested assets other than those investments accounted for using the equity method of accounting as described in the "Investment Impairments" section that follows.
Accounting Policies, Investment Impairments [Policy Text Block]	Investment Impairments The Company conducts a periodic review to identify and evaluate invested assets having other-than-temporary impairments. Some of the factors considered in identifying other-than-temporary impairments include: (1) for fixed maturity investments, whether the Company intends to sell the investment or whether it is more likely than not that the Company will be required to sell the investment prior to an anticipated recovery in value; (2) for non-fixed maturity investments, the Company's ability and intent to retain the investment for a reasonable period of time sufficient to allow for an anticipated recovery in value; (3) the likelihood of the recoverability of principal and interest for fixed maturity securities (i.e., whether there is a credit loss) or cost for equity securities; (4) the length of time and extent to which the fair value has been less than amortized cost for fixed maturity securities or cost for equity securities; and (5) the financial condition, near-term and long-term prospects for the issuer, including the relevant industry conditions and trends, and implications of rating agency actions and offering prices. For fixed maturity investments that the Company does not intend to sell or for which it is more likely than not that the Company would not be required to sell before an anticipated recovery in value, the Company separates the credit loss component of the impairment from the amount related to all other factors and reports the credit loss component in net realized investment gains (losses). The impairment related to all other factors is reported in other comprehensive income. For equity securities (including public common and non-redeemable preferred stock) and for fixed maturity investments the Company intends to sell or for which it is more likely than not that the Company will be required to sell before an anticipated recovery in value, the full amount of the impairment is included in net realized investment gains (losses). Upon recognizing an other-than-temporary impairment, the new cost basis of the investment is the previous amortized cost basis less the other-than-temporary impairment recognized in net realized investment gains (losses). The new cost basis is not adjusted for any subsequent recoveries in fair value; however, for fixed maturity investments the difference between the new cost basis and the expected cash flows is accreted on a quarterly basis to net investment income over the remaining expected life of the investment. The Company determines the credit loss component of fixed maturity investments by utilizing discounted cash flow modeling to determine the present value of the security and comparing the present value with the amortized cost of the security. If the amortized cost is greater than the present value of the expected cash flows, the difference is considered a credit loss and recognized in net realized investment gains (losses). For non-structured fixed maturities (U.S. Treasury securities, obligations of U.S. government and government agencies and authorities, obligations of states, municipalities and political subdivisions, debt securities issued by foreign governments and certain corporate debt), the estimate of expected cash flows is determined by projecting a recovery value and a recovery time frame and assessing whether further principal and interest will be received. The determination of recovery value incorporates an issuer valuation assumption utilizing one or a combination of valuation methods as deemed appropriate by the Company. The Company determines the undiscounted recovery value by allocating the estimated value of the issuer to the Company's assessment of the priority of claims. The present value of the cash flows is determined by applying the effective yield of the security at the date of acquisition (or the most recent implied rate used to accrete the security if the implied rate has changed as a result of a previous impairment) and an estimated recovery time frame. Generally, that time frame for securities for which the issuer is in bankruptcy is 12 months. For securities for which the issuer is financially troubled but not in bankruptcy, that time frame is generally 24 months. Included in the present value calculation are expected principal and interest payments; however, for securities for which the issuer is classified as bankrupt or in default, the present value calculation assumes no interest payments and a single recovery amount. In estimating the recovery value, significant judgment is involved in the development of assumptions relating to a myriad of factors related to the issuer including, but not limited to, revenue, margin and earnings projections, the likely market or liquidation values of assets, potential additional debt to be incurred pre- or post-bankruptcy/restructuring, the ability to shift existing or new debt to different priority layers, the amount of restructuring/bankruptcy expenses, the size and priority of unfunded pension obligations, litigation or other contingent claims, the treatment of intercompany claims and the likely outcome with respect to inter-creditor conflicts. For structured fixed maturity securities (primarily residential and commercial mortgage-backed securities and asset-backed securities), the Company estimates the present value of the security by projecting future cash flows of the assets underlying the securitization, allocating the flows to the various tranches based on the structure of the securitization and determining the present value of the cash flows using the effective yield of the security at the date of acquisition (or the most recent implied rate used to accrete the security if the implied rate has changed as a result of a previous impairment or changes in expected cash flows). The Company incorporates levels of delinquencies, defaults and severities as well as credit attributes of the remaining assets in the securitization, along with other economic data, to arrive at its best estimate of the parameters applied to the assets underlying the securitization. In order to project cash flows, the following assumptions are applied to the assets underlying the securitization: (1) voluntary prepayment rates, (2) default rates and (3) loss severity. The key assumptions made for the Prime, Alt-A and first-lien Sub-Prime mortgage-backed securities at December 31, 2015 were as follows: (at December 31, 2015) Prime Alt-A Sub-Prime Voluntary prepayment rates 1% - 33% 3% - 18% 2% - 10% Percentage of remaining pool liquidated due to defaults 1% - 46% 8% - 62% 22% - 61% Loss severity 30% - 65% 55% - 120% 70% - 120% On at least an annual basis, the Company obtains independent appraisals for substantially all of its real estate investments. In addition, the carrying value of all real estate investments is reviewed for impairment on a quarterly basis or when events or changes in circumstances indicate that the carrying amount may not be recoverable. The review for impairment considers the valuation from the independent appraisal, when applicable, and incorporates an estimate of the undiscounted cash flows expected to result from the use and eventual disposition of the real estate property. An impairment loss is recognized if the expected future undiscounted cash flows are less than the carrying value of the real estate property. The impairment loss is the amount by which the carrying amount exceeds fair value. The Company reviews its investments in private equity limited partnerships, hedge funds and real estate partnerships for impairment no less frequently than quarterly and monitors the performance throughout the year through discussions with the managers/general partners. If the Company becomes aware of an impairment of a partnership's investments at the balance sheet date prior to receiving the partnership's financial statements, it will recognize an impairment by recording a reduction in the carrying value of the partnership with a corresponding charge to net investment income. The Company may, from time to time, sell invested assets subsequent to the balance sheet date that it did not intend to sell at the balance sheet date. Conversely, the Company may not sell invested assets that it asserted that it intended to sell at the balance sheet date. Such changes in intent are due to events occurring subsequent to the balance sheet date. The types of events that may result in a change in intent include, but are not limited to, significant changes in the economic facts and circumstances related to the invested asset (e.g., a downgrade or upgrade from a rating agency), significant unforeseen changes in liquidity needs, or changes in tax laws or the regulatory environment.
Accounting Policies, Securities Lending [Policy Text Block]	Securities Lending The Company has engaged in securities lending activities from which it generates net investment income by lending certain of its investments to other institutions for short periods of time. Borrowers of these securities provide collateral equal to at least 102% of the market value of the loaned securities plus accrued interest. This collateral is held by a third-party custodian, and the Company has the right to access the collateral only in the event that the institution borrowing the Company's securities is in default under the lending agreement. Therefore, the Company does not recognize the receipt of the collateral held by the third-party custodian or the obligation to return the collateral. The loaned securities remain a recorded asset of the Company. The Company accepts only cash as collateral for securities on loan and restricts the manner in which that cash is invested.
Accounting Policies, Reinsurance Recoverables [Policy Text Block]	Reinsurance Recoverables Amounts recoverable from reinsurers are estimated in a manner consistent with the associated claim liability. The Company reports its reinsurance recoverables net of an allowance for estimated uncollectible reinsurance recoverables. The allowance is based upon the Company's ongoing review of amounts outstanding, length of collection periods, changes in reinsurer credit standing, disputes, applicable coverage defenses and other relevant factors. Amounts deemed to be uncollectible, including amounts due from known insolvent reinsurers, are written off against the allowance for estimated uncollectible reinsurance recoverables. Any subsequent collections of amounts previously written off are reported as part of claims and claim adjustment expenses. The Company evaluates and monitors the financial condition of its reinsurers under voluntary reinsurance arrangements to minimize its exposure to significant losses from reinsurer insolvencies.
Accounting Policies, Deferred Acquisition Costs [Policy Text Block]	Deferred Acquisition Costs Incremental direct costs of acquired, new and renewal insurance contracts, consisting of commissions (other than contingent commissions) and premium-related taxes, are capitalized and charged to expense pro rata over the contract periods in which the related premiums are earned. Deferred acquisition costs are reviewed to determine if they are recoverable from future income and, if not, are charged to expense. Future investment income attributable to related premiums is taken into account in measuring the recoverability of the carrying value of this asset. All other acquisition expenses are charged to operations as incurred.
Accounting Policies, Contractholder Receivables and Payables [Policy Text Block]	Contractholder Receivables and Payables Under certain workers' compensation insurance contracts with deductible features, the Company is obligated to pay the claimant for the full amount of the claim. The Company is subsequently reimbursed by the policyholder for the deductible amount. These amounts are included on a gross basis in the consolidated balance sheet in contractholder payables and contractholder receivables, respectively.
Accounting Policies, Goodwill and Other Intangible Assets [Policy Text Block]	Goodwill and Other Intangible Assets The Company performs a review, on at least an annual basis, of goodwill held by the reporting units which are the Company's three operating and reportable segments: Business and International Insurance; Bond & Specialty Insurance; and Personal Insurance. The Company estimates the fair value of its reporting units and compares it to their carrying value, including goodwill. If the carrying values of the reporting units were to exceed their fair value, the amount of the impairment would be calculated and goodwill adjusted accordingly. The Company uses a discounted cash flow model to estimate the fair value of its reporting units. The discounted cash flow model is an income approach to valuation that is based on a detailed cash flow analysis for deriving a current fair value of reporting units and is representative of the Company's reporting units' current and expected future financial performance. The discount rate assumptions reflect the Company's assessment of the risks inherent in the projected future cash flows and the Company's weighted-average cost of capital, and are compared against available market data for reasonableness. Other indefinite-lived intangible assets held by the Company are also reviewed for impairment on at least an annual basis. The classification of the asset as indefinite-lived is reassessed and an impairment is recognized if the carrying amount of the asset exceeds its fair value. Intangible assets that are deemed to have a finite useful life are amortized over their useful lives. The carrying amount of intangible assets with a finite useful life is regularly reviewed for indicators of impairment in value. Impairment is recognized only if the carrying amount of the intangible asset is not recoverable from its undiscounted cash flows and is measured as the difference between the carrying amount and the fair value of the asset. As a result of the reviews performed for the years ended December 31, 2015, 2014 and 2013, the Company determined that the estimated fair value substantially exceeded the respective carrying value of its reporting units for those years and that goodwill was not impaired. The Company also determined during its reviews for each year that its other indefinite-lived intangible assets and finite-lived intangible assets were not impaired.
Accounting Policies, Claims and Claim Adjustment Expense Reserves [Policy Text Block]	Claims and Claim Adjustment Expense Reserves Claims and claim adjustment expense reserves represent estimates for the ultimate cost of unpaid reported and unreported claims incurred and related expenses. The reserves are adjusted regularly based upon experience. Included in the claims and claim adjustment expense reserves in the consolidated balance sheet are certain reserves discounted to the present value of estimated future payments. The liabilities for losses for most long-term disability and annuity claim payments, primarily arising from workers' compensation insurance and workers' compensation excess insurance policies, were discounted using a rate of 5% at both December 31, 2015 and 2014. These discounted reserves totaled $2.13 billion and $2.01 billion at December 31, 2015 and 2014, respectively. The Company performs a continuing review of its claims and claim adjustment expense reserves, including its reserving techniques and the impact of reinsurance. The reserves are also reviewed regularly by qualified actuaries employed by the Company. Since the reserves are based on estimates, the ultimate liability may be more or less than such reserves. The effects of changes in such estimated reserves are included in the results of operations in the period in which the estimates are changed. Such changes in estimates could occur in a future period and may be material to the Company's results of operations and financial position in such period.
Accounting Policies, Other Liabilities [Policy Text Block]	Other Liabilities Included in other liabilities in the consolidated balance sheet is the Company's estimate of its liability for guaranty fund and other insurance-related assessments. The liability for expected state guaranty fund and other premium-based assessments is recognized as the Company writes or becomes obligated to write or renew the premiums on which the assessments are expected to be based. The liability for loss-based assessments is recognized as the related losses are incurred. At December 31, 2015 and 2014, the Company had a liability of $241 million and $245 million, respectively, for guaranty fund and other insurance-related assessments and related recoverables of $18 million and $15 million, respectively. The liability for such assessments and the related recoverables are not discounted for the time value of money. The loss-based assessments are expected to be paid over a period ranging from one year to the life expectancy of certain workers' compensation claimants and the recoveries are expected to occur over the same period of time. Also included in other liabilities is an accrual for policyholder dividends. Certain insurance contracts, primarily workers' compensation, are participating whereby dividends are paid to policyholders in accordance with contract provisions. Net written premiums for participating dividend policies were approximately 2%, 1% and 1% of total net written premiums for the years ended December 31, 2015, 2014 and 2013, respectively. Policyholder dividends are accrued against earnings using best available estimates of amounts to be paid. The liability accrued for policyholder dividends totaled $57 million and $54 million at December 31, 2015 and 2014, respectively.
Accounting Policies, Treasury Stock [Policy Text Block]	Treasury Stock The cost of common stock repurchased by the Company is reported as treasury stock and represents authorized and unissued shares of the Company under the Minnesota Business Corporation Act.
Accounting Policies, Statutory Accounting Practices [Policy Text Block]	Statutory Accounting Practices The Company's U.S. insurance subsidiaries, domiciled principally in the State of Connecticut, are required to prepare statutory financial statements in accordance with the accounting practices prescribed or permitted by the insurance departments of the states of domicile. Prescribed statutory accounting practices are those practices that are incorporated directly or by reference in state laws, regulations, and general administrative rules applicable to all insurance enterprises domiciled in a particular state. The State of Connecticut requires insurers domiciled in Connecticut to prepare their statutory financial statements in accordance with National Association of Insurance Commissioners' (NAIC) statutory accounting practices. Permitted statutory accounting practices are those practices that differ either from state-prescribed statutory accounting practices or NAIC statutory accounting practices. The Company does not apply any statutory accounting practices that would be considered a prescribed or permitted statutory accounting practice that differs from NAIC statutory accounting practices. The Company's non-U.S. insurance subsidiaries file financial statements prepared in accordance with the regulatory reporting requirements of their respective local jurisdiction.
Accounting Policies, Premiums and Unearned Premium Reserves [Policy Text Block]	Premiums and Unearned Premium Reserves Premiums are recognized as revenues pro rata over the policy period. Unearned premium reserves represent the unexpired portion of policy premiums. Accrued retrospective premiums are included in premium balances receivable. Premium balances receivable are reported net of an allowance for estimated uncollectible premium amounts. Ceded premiums are charged to income over the applicable term of the various reinsurance contracts with third party reinsurers. Prepaid reinsurance premiums represent the unexpired portion of premiums ceded to reinsurers and are reported as part of other assets.
Accounting Policies, Fee Income [Policy Text Block]	Fee Income Fee income includes servicing fees from carriers and revenues from large deductible policies and service contracts and is recognized pro rata over the contract or policy periods.
Accounting Policies, Other Revenues [Policy Text Block]	Other Revenues Other revenues include revenues from premium installment charges, which are recognized as collected, revenues of noninsurance subsidiaries other than fee income and gains and losses on dispositions of assets and redemption of debt, and other miscellaneous revenues.
Accounting Policies, Income Taxes [Policy Text Block]	Income Taxes The Company recognizes deferred income tax assets and liabilities for the expected future tax effects attributable to temporary differences between the financial statement and tax return bases of assets and liabilities, based on enacted tax rates and other provisions of the tax law. The effect of a change in tax laws or rates on deferred tax assets and liabilities is recognized in income in the period in which such change is enacted. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that all or some portion of the deferred tax assets will not be realized.
Accounting Policies, Foreign Currency Translation [Policy Text Block]	Foreign Currency Translation The Company assigns functional currencies to its foreign operations, which are generally the currencies of the local operating environment. Foreign currency amounts are remeasured to the functional currency, and the resulting foreign exchange gains or losses are reflected in earnings. Functional currency amounts are then translated into U.S. dollars. The foreign currency remeasurement and translation are calculated using current exchange rates for items reported in the balance sheets and average exchange rates for items recorded in earnings. The change in unrealized foreign currency translation gain or loss during the year, net of tax, is a component of other comprehensive income.
Accounting Policies, Share-Based Compensation [Policy Text Block]	Share-Based Compensation The Company has an employee stock incentive compensation plan that permits grants of nonqualified stock options, incentive stock options, stock appreciation rights, restricted stock, deferred stock, stock units, performance awards and other share-based or share-denominated awards with respect to the Company's common stock. Compensation cost is measured based on the grant-date fair value of an award, utilizing the assumptions discussed in note 13. Compensation cost is recognized for financial reporting purposes over the period in which the employee is required to provide service in exchange for the award (generally the vesting period). In connection with certain share-based awards, participants are entitled to receive dividends during the vesting period, either in cash or dividend equivalent shares, commensurate with the dividends paid to common shareholders. Dividends and dividend equivalent shares on awards that are expected to vest are recorded in retained earnings. Dividends paid on awards that are not expected to vest as part of the Company's forfeiture estimate are recorded as compensation expense.

Summary of Significant Accoun33

Summary of Significant Accounting Policies (table)	12 Months Ended
	Dec. 31, 2015
Summary of Significant Accounting Policies disclosure
Key assumptions used in estimation of present value of structured fixed maturity securities [Table Text Block]	(at December 31, 2015) Prime Alt-A Sub-Prime Voluntary prepayment rates 1% - 33% 3% - 18% 2% - 10% Percentage of remaining pool liquidated due to defaults 1% - 46% 8% - 62% 22% - 61% Loss severity 30% - 65% 55% - 120% 70% - 120%

Segment Information (tables)

Segment Information (tables)	12 Months Ended
	Dec. 31, 2015
Segment Information disclosure
Company's revenues and operating income by segment [Table Text Block]	(for the year ended December 31, in millions) Business and Bond & Personal Total 2015 Premiums 14,521 2,085 7,268 23,874 Net investment income 1,824 223 332 2,379 Fee income 445 — — 445 Other revenues 23 22 48 93 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating revenues(1) 16,813 2,330 7,648 26,791 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization and depreciation 2,907 467 1,322 4,696 Income tax expense 769 272 402 1,443 Operating income(1) 2,170 633 889 3,692 2014 Premiums 14,512 2,076 7,125 23,713 Net investment income 2,156 252 379 2,787 Fee income 438 — — 438 Other revenues 46 19 80 145 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating revenues(1) 17,152 2,347 7,584 27,083 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization and depreciation 2,909 482 1,347 4,738 Income tax expense 798 348 366 1,512 Operating income(1) 2,347 727 824 3,898 2013 Premiums 13,332 1,981 7,324 22,637 Net investment income 2,087 260 369 2,716 Fee income 395 — — 395 Other revenues 160 20 103 283 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating revenues(1) 15,974 2,261 7,796 26,031 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amortization and depreciation 2,751 473 1,461 4,685 Income tax expense 758 227 366 1,351 Operating income(1) 2,404 573 838 3,815 (1) Operating revenues for reportable business segments exclude net realized investment gains. Operating income for reportable business segments equals net income excluding the after-tax impact of net realized investment gains.
Net written premiums by market [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 Business and International Insurance: Domestic: Select Accounts 2,716 2,707 2,724 Middle Market 6,325 6,108 5,862 National Accounts 1,048 1,047 1,010 First Party 1,564 1,579 1,552 Specialized Distribution 1,111 1,074 1,085 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Domestic 12,764 12,515 12,233 International 1,819 2,121 1,279 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Business and International Insurance 14,583 14,636 13,512 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Bond & Specialty Insurance 2,081 2,103 2,030 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Personal Insurance: Automobile 3,700 3,390 3,370 Homeowners and Other 3,757 3,775 3,855 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Personal Insurance 7,457 7,165 7,225 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total consolidated net written premiums 24,121 23,904 22,767 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Business segment reconciliations of revenue and income, net of tax [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 Revenue reconciliation Earned premiums Business and International Insurance: Domestic: Workers' compensation 3,868 3,713 3,560 Commercial automobile 1,925 1,901 1,904 Commercial property 1,772 1,756 1,698 General liability 1,914 1,852 1,790 Commercial multi-peril 3,132 3,070 3,093 Other 39 42 39 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Domestic 12,650 12,334 12,084 International 1,871 2,178 1,248 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Business and International Insurance 14,521 14,512 13,332 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Bond & Specialty Insurance: Fidelity and surety 954 936 913 General liability 955 963 891 Other 176 177 177 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Bond & Specialty Insurance 2,085 2,076 1,981 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Personal Insurance: Automobile 3,512 3,316 3,431 Homeowners and Other 3,756 3,809 3,893 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Personal Insurance 7,268 7,125 7,324 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total earned premiums 23,874 23,713 22,637 Net investment income 2,379 2,787 2,716 Fee income 445 438 395 Other revenues 93 145 283 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating revenues for reportable segments 26,791 27,083 26,031 Other revenues 6 — (6 ) Net realized investment gains 3 79 166 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total consolidated revenues 26,800 27,162 26,191 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income reconciliation, net of tax Total operating income for reportable segments 3,692 3,898 3,815 Interest Expense and Other(1) (255 ) (257 ) (248 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total operating income 3,437 3,641 3,567 Net realized investment gains 2 51 106 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total consolidated net income 3,439 3,692 3,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The primary component of Interest Expense and Other was after-tax interest expense of $242 million, $240 million and $235 million in 2015, 2014 and 2013, respectively.
Asset reconciliation [Table Text Block]	(at December 31, in millions) 2015 2014 Asset reconciliation: Business and International Insurance 79,692 82,310 Bond & Specialty Insurance 7,360 7,525 Personal Insurance 12,748 12,798 ​ ​ ​ ​ ​ ​ ​ Total assets for reportable segments 99,800 102,633 Other assets(1) 384 445 ​ ​ ​ ​ ​ ​ ​ Total consolidated assets 100,184 103,078 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The primary components of other assets at December 31, 2015 and 2014 were other intangible assets and deferred taxes.
Revenues of the Company's operations based on location [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 U.S. 25,112 25,091 25,138 Non-U.S.: Canada 1,202 1,474 529 Other Non-U.S. 486 597 524 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total Non-U.S. 1,688 2,071 1,053 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues 26,800 27,162 26,191 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Investments (tables)

Investments (tables)	12 Months Ended
	Dec. 31, 2015
Investments disclosure
Amortized cost and fair value of investments in fixed maturities [Table Text Block]	Gross Unrealized Amortized (at December 31, 2015, in millions) Gains Losses Fair Value U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 2,202 8 16 2,194 Obligations of states, municipalities and political subdivisions: Local general obligation 12,744 577 3 13,318 Revenue 9,492 472 4 9,960 State general obligation 1,978 97 2 2,073 Pre-refunded 5,813 247 — 6,060 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total obligations of states, municipalities and political subdivisions 30,027 1,393 9 31,411 Debt securities issued by foreign governments 1,829 45 1 1,873 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,863 124 6 1,981 All other corporate bonds 22,854 523 288 23,089 Redeemable preferred stock 103 7 — 110 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 58,878 2,100 320 60,658 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Unrealized Amortized (at December 31, 2014, in millions) Gains Losses Fair Value U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 2,022 36 5 2,053 Obligations of states, municipalities and political subdivisions: Local general obligation 12,366 644 5 13,005 Revenue 9,833 575 4 10,404 State general obligation 2,467 137 1 2,603 Pre-refunded 7,229 332 — 7,561 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total obligations of states, municipalities and political subdivisions 31,895 1,688 10 33,573 Debt securities issued by foreign governments 2,320 48 — 2,368 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 2,052 165 4 2,213 All other corporate bonds 22,390 844 99 23,135 Redeemable preferred stock 122 10 — 132 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 60,801 2,791 118 63,474 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Amortized cost and fair value of fixed maturities by contractual maturity [Table Text Block]	(at December 31, 2015, in millions) Amortized Fair Due in one year or less 6,240 6,324 Due after 1 year through 5 years 16,741 17,296 Due after 5 years through 10 years 16,008 16,260 Due after 10 years 18,026 18,797 ​ ​ ​ ​ ​ ​ ​ 57,015 58,677 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,863 1,981 ​ ​ ​ ​ ​ ​ ​ Total 58,878 60,658 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Cost and fair value of investments in equity securities [Table Text Block]	Gross Fair (at December 31, 2015, in millions) Cost Gains Losses Public common stock 386 164 7 543 Non-redeemable preferred stock 142 26 6 162 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 528 190 13 705 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross Fair (at December 31, 2014, in millions) Cost Gains Losses Public common stock 400 295 4 691 Non-redeemable preferred stock 179 31 2 208 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 579 326 6 899 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Unrealized investment losses [Table Text Block]	Less than 12 months 12 months or longer Total (at December 31, 2015, in millions) Fair Gross Fair Gross Fair Gross Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 1,820 15 28 1 1,848 16 Obligations of states, municipalities and political subdivisions 928 7 142 2 1,070 9 Debt securities issued by foreign governments 172 1 — — 172 1 Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 473 4 57 2 530 6 All other corporate bonds 7,725 197 710 91 8,435 288 Redeemable preferred stock 8 — — — 8 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 11,126 224 937 96 12,063 320 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities Public common stock 48 6 33 1 81 7 Non-redeemable preferred stock 47 3 38 3 85 6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total equity securities 95 9 71 4 166 13 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 11,221 233 1,008 100 12,229 333 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 12 months 12 months or longer Total (at December 31, 2014, in millions) Fair Gross Fair Gross Fair Gross Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 180 2 125 3 305 5 Obligations of states, municipalities and political subdivisions 173 1 797 9 970 10 Debt securities issued by foreign governments 50 — 24 — 74 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 68 — 192 4 260 4 All other corporate bonds 2,148 38 2,355 61 4,503 99 Redeemable preferred stock — — — — — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 2,619 41 3,493 77 6,112 118 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities Public common stock 81 4 1 — 82 4 Non-redeemable preferred stock 44 1 42 1 86 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total equity securities 125 5 43 1 168 6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 2,744 46 3,536 78 6,280 124 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Securities continuously in an unrealized loss position of greater than 20% of amortized cost by length of time [Table Text Block]	Period For Which Fair Value Is Less Than 80% of Amortized Cost (in millions) 3 Months Greater Than Greater Than Greater Than Total Fixed maturities Mortgage-backed securities — — — — — Other 51 17 6 7 81 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 51 17 6 7 81 Equity securities 3 1 — — 4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 54 18 6 7 85 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Impairment charges included in net realized investment gains [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities — — — Obligations of states, municipalities and political subdivisions — — — Debt securities issued by foreign governments — — — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities — 1 2 All other corporate bonds 13 15 3 Redeemable preferred stock — — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 13 16 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities Public common stock 37 9 5 Non-redeemable preferred stock — — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total equity securities 37 9 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other investments 2 1 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 52 26 15 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Cumulative amount of and the changes during the reporting period in the credit losses of other-than-temporary impairments (OTTI) on fixed maturities recognized in the consolidated statement of income for which a portion of the OTTI was recognized in other comprehensive income [Table Text Block]	Year ended December 31, 2015 Cumulative Additions for Additions for Reductions Adjustments to Cumulative OTTI Fixed maturities Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 40 — — (6 ) (2 ) 32 All other corporate bonds 59 2 — (4 ) (6 ) 51 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 99 2 — (10 ) (8 ) 83 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year ended December 31, 2014 Cumulative Additions for Additions for Reductions Adjustments to Cumulative OTTI Fixed maturities Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 53 — 1 (5 ) (9 ) 40 All other corporate bonds 65 — 3 (6 ) (3 ) 59 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 118 — 4 (11 ) (12 ) 99 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Net investment income [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 Gross investment income Fixed maturities 2,091 2,244 2,310 Equity securities 39 40 31 Short-term securities 12 9 11 Real estate investments 48 44 37 Other investments 230 489 364 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Gross investment income 2,420 2,826 2,753 Investment expenses 41 39 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net investment income 2,379 2,787 2,716 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Changes in net unrealized investment gains [Table Text Block]	(at and for the year ended December 31, in millions) 2015 2014 2013 Changes in net unrealized investment gains Fixed maturities (893 ) 913 (2,804 ) Equity securities (143 ) 63 74 Other investments 2 2 (1 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in net pretax unrealized gains on investment securities (1,034 ) 978 (2,731 ) Related tax expense (benefit) (357 ) 334 (950 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in net unrealized gains on investment securities (677 ) 644 (1,781 ) Balance, beginning of year 1,966 1,322 3,103 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, end of year 1,289 1,966 1,322 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Fair Value Measurements (tables

Fair Value Measurements (tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Measurements disclosure
Level within the fair value hierarchy at which the Company's financial assets and financial liabilities reported at fair value are measured [Table Text Block]	(at December 31, 2015, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 2,194 2,194 — — Obligations of states, municipalities and political subdivisions 31,411 — 31,398 13 Debt securities issued by foreign governments 1,873 — 1,873 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 1,981 — 1,957 24 All other corporate bonds 23,089 — 22,915 174 Redeemable preferred stock 110 3 100 7 —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Total fixed maturities 60,658 2,197 58,243 218 —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Equity securities Public common stock 543 543 — — Non-redeemable preferred stock 162 55 107 — —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Total equity securities 705 598 107 — —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Other investments 56 18 — 38 —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Total 61,419 2,813 58,350 256 —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ (at December 31, 2014, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities U.S. Treasury securities and obligations of U.S. government and government agencies and authorities 2,053 2,049 4 — Obligations of states, municipalities and political subdivisions 33,573 — 33,560 13 Debt securities issued by foreign governments 2,368 — 2,368 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 2,213 — 2,203 10 All other corporate bonds 23,135 — 22,934 201 Redeemable preferred stock 132 2 122 8 —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Total fixed maturities 63,474 2,051 61,191 232 —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Equity securities Public common stock 691 691 — — Non-redeemable preferred stock 208 82 126 — —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Total equity securities 899 773 126 — —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Other investments 55 19 — 36 —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ Total 64,428 2,843 61,317 268 —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹ —‹
Changes in the Level 3 fair value category [Table Text Block]	(in millions) Fixed Other Total Balance at December 31, 2014 232 36 268 Total realized and unrealized investment gains (losses): Reported in net realized investment gains(1) 1 2 3 Reported in increases (decreases) in other comprehensive income (4 ) 1 (3 ) Purchases, sales and settlements/maturities: Purchases 202 1 203 Sales (7 ) (2 ) (9 ) Settlements/maturities (41 ) — (41 ) Gross transfers into Level 3 21 — 21 Gross transfers out of Level 3 (186 ) — (186 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at December 31, 2015 218 38 256 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date — (1 ) (1 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Includes impairments on investments held at the end of the period as well as amortization on fixed maturities. (in millions) Fixed Other Total Balance at December 31, 2013 255 34 289 Total realized and unrealized investment gains (losses): Reported in net realized investment gains(1) 3 1 4 Reported in increases (decreases) in other comprehensive income (2 ) 1 (1 ) Purchases, sales and settlements/maturities: Purchases 232 1 233 Sales (1 ) (1 ) (2 ) Settlements/maturities (90 ) — (90 ) Gross transfers into Level 3 18 — 18 Gross transfers out of Level 3 (183 ) — (183 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at December 31, 2014 232 36 268 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date — — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Includes impairments on investments held at the end of the period as well as amortization on fixed maturities.
Carrying value and fair value of financial instruments disclosed, but not carried, at fair value and the level within the fair value hierarchy at which such financial instruments are categorized [Table Text Block]	(at December 31, 2015, in millions) Carrying Fair Level 1 Level 2 Level 3 Financial assets: Short-term securities 4,671 4,671 1,685 2,958 28 Financial liabilities: Debt 6,244 7,180 — 7,180 — Commercial paper 100 100 — 100 — (at December 31, 2014, in millions) Carrying Fair Level 1 Level 2 Level 3 Financial assets: Short-term securities 4,364 4,364 1,283 3,042 39 Financial liabilities: Debt 6,249 7,522 — 7,522 — Commercial paper 100 100 — 100 —

Reinsurance (tables)

Reinsurance (tables)	12 Months Ended
	Dec. 31, 2015
Reinsurance disclosure
Summary of reinsurance financial data [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 Written premiums Direct 24,939 24,844 23,952 Assumed 843 788 705 Ceded (1,661 ) (1,728 ) (1,890 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total net written premiums 24,121 23,904 22,767 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Earned premiums Direct 24,740 24,810 23,891 Assumed 814 743 717 Ceded (1,680 ) (1,840 ) (1,971 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total net earned premiums 23,874 23,713 22,637 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Percentage of assumed earned premiums to net earned premiums 3.4 % 3.1 % 3.2 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Ceded claims and claim adjustment expenses incurred 1,034 953 1,019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Reinsurance recoverables [Table Text Block]	(at December 31, in millions) 2015 2014 Gross reinsurance recoverables on paid and unpaid claims and claim adjustment expenses 3,848 4,270 Allowance for uncollectible reinsurance (157 ) (203 ) ​ ​ ​ ​ ​ ​ ​ Net reinsurance recoverables 3,691 4,067 Mandatory pools and associations 2,015 1,909 Structured settlements 3,204 3,284 ​ ​ ​ ​ ​ ​ ​ Total reinsurance recoverables 8,910 9,260 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Goodwill and Other Intangible38

Goodwill and Other Intangible Assets (tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Other Intangible Assets disclosure
Goodwill by segment [Table Text Block]	(at December 31, in millions) 2015 2014 Business and International Insurance(1) 2,439 2,477 Bond & Specialty Insurance 496 496 Personal Insurance 612 612 Other 26 26 ​ ​ ​ ​ ​ ​ ​ Total 3,573 3,611 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Includes goodwill associated with the Company's international business which is subject to the impact of changes in foreign currency exchange rates.
Other intangible assets [Table Text Block]	(at December 31, 2015, in millions) Gross Accumulated Net Subject to amortization(1) 210 148 62 Not subject to amortization 217 — 217 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 427 148 279 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (at December 31, 2014, in millions) Gross Accumulated Net Subject to amortization(1) 669 582 87 Not subject to amortization 217 — 217 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 886 582 304 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Intangible assets subject to amortization are comprised of fair value adjustments on claims and claim adjustment expense reserves, reinsurance recoverables and other contract and customer-related intangibles. At December 31, 2014, the Company had certain customer-related intangibles with a gross carrying amount of $460 million and accumulated amortization of $446 million which became fully amortized during the second quarter of 2015. Fair value adjustments of $5 million and $191 million were recorded in connection with the acquisition of Dominion in 2013 and in connection with the merger of The St. Paul Companies, Inc. and Travelers Property Casualty Corp. in 2004, respectively, and were based on management's estimate of nominal claims and claim adjustment expense reserves and reinsurance recoverables. The method used calculated a risk adjustment to a risk-free discounted reserve that would, if reserves ran off as expected, produce results that yielded the assumed cost-of-capital on the capital supporting the loss reserves. The fair value adjustments are reported as other intangible assets on the consolidated balance sheet, and the amounts measured in accordance with the acquirer's accounting policies for insurance contracts have been reported as part of the claims and claim adjustment expense reserves and reinsurance recoverables. The intangible assets are being recognized into income over the expected payment pattern. Because the time value of money and the risk adjustment (cost of capital) components of the intangible assets run off at different rates, the amount recognized in income may be a net benefit in some periods and a net expense in other periods. Additionally, $5 million of contract-related intangibles were recorded related to operating leases in connection with the acquisition of Dominion in 2013.

Insurance Claim Reserves (table

Insurance Claim Reserves (tables)	12 Months Ended
	Dec. 31, 2015
Insurance Claim Reserves disclosure
Claims and claim adjustment expense reserves [Table Text Block]	(at December 31, in millions) 2015 2014 Property-casualty 48,272 49,824 Accident and health 23 26 ​ ​ ​ ​ ​ ​ ​ Total 48,295 49,850 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Reconciliation of beginning and ending property casualty reserve balances for claims and claim adjustment expenses [Table Text Block]	(at and for the year ended December 31, in millions) 2015 2014 2013 Claims and claim adjustment expense reserves at beginning of year 49,824 50,865 50,888 Less reinsurance recoverables on unpaid losses 8,788 9,280 10,254 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net reserves at beginning of year 41,036 41,585 40,634 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated claims and claim adjustment expenses for claims arising in the current year 14,412 14,621 14,060 Estimated decrease in claims and claim adjustment expenses for claims arising in prior years (897 ) (957 ) (944 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total increases 13,515 13,664 13,116 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and claim adjustment expense payments for claims arising in: Current year 5,666 5,828 5,485 Prior years 8,669 8,099 8,477 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total payments 14,335 13,927 13,962 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Acquisitions(1) 2 — 1,792 Unrealized foreign exchange (gain) loss (395 ) (286 ) 5 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net reserves at end of year 39,823 41,036 41,585 Plus reinsurance recoverables on unpaid losses 8,449 8,788 9,280 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and claim adjustment expense reserves at end of year 48,272 49,824 50,865 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Amount in 2015 represents acquired net claims and claim adjustment expense reserves of Travelers Participações em Seguros Brasil S.A. at October 1, 2015. Amount in 2013 represents acquired net claims and claim adjustment expense reserves of Dominion at November 1, 2013. Dominion's gross reserves on that date were $2,144 million. Dominion's reinsurance recoverables on unpaid losses on that date were $352 million.

Debt (tables)

Debt (tables)	12 Months Ended
	Dec. 31, 2015
Debt disclosure
Debt outstanding [Table Text Block]	(at December 31, in millions) 2015 2014 Short-term: Commercial paper 100 100 6.25% Senior notes due June 20, 2016 400 — 5.50% Senior notes due December 1, 2015 — 400 ​ ​ ​ ​ ​ ​ ​ Total short-term debt 500 500 ​ ​ ​ ​ ​ ​ ​ Long-term: 6.25% Senior notes due June 20, 2016 — 400 5.75% Senior notes due December 15, 2017 450 450 5.80% Senior notes due May 15, 2018 500 500 5.90% Senior notes due June 2, 2019 500 500 3.90% Senior notes due November 1, 2020 500 500 7.75% Senior notes due April 15, 2026 200 200 7.625% Junior subordinated debentures due December 15, 2027 125 125 6.375% Senior notes due March 15, 2033 500 500 6.75% Senior notes due June 20, 2036 400 400 6.25% Senior notes due June 15, 2037 800 800 5.35% Senior notes due November 1, 2040 750 750 4.60% Senior notes due August 1, 2043 500 500 4.30% Senior notes due August 25, 2045 400 — 8.50% Junior subordinated debentures due December 15, 2045 56 56 8.312% Junior subordinated debentures due July 1, 2046 73 73 6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 107 107 ​ ​ ​ ​ ​ ​ ​ Total long-term debt 5,861 5,861 ​ ​ ​ ​ ​ ​ ​ Total debt principal 6,361 6,361 Unamortized fair value adjustment 49 50 Unamortized debt issuance costs (66 ) (62 ) ​ ​ ​ ​ ​ ​ ​ Total debt 6,344 6,349 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Merger-related unamortized fair value adjustments and the related effective interest rate [Table Text Block]	Unamortized Effective (in millions) Issue Rate Maturity Date 2015 2014 Subordinated debentures 7.625 % Dec. 2027 15 16 6.147 % 8.500 % Dec. 2045 15 15 6.362 % 8.312 % Jul. 2046 19 19 6.362 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 49 50 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Shareholders' Equity and Divi41

Shareholders' Equity and Dividend Availability (table)	12 Months Ended
	Dec. 31, 2015
Shareholders' Equity and Dividend Availability disclosure
Share repurchase activity and remaining repurchase capacity under the share repurchase authorization [Table Text Block]	Quarterly Period Ending Number of Cost of Average price Remaining capacity March 31, 2015 5.6 600 106.97 884 June 30, 2015 7.9 800 101.62 5,084 September 30, 2015 7.3 750 102.81 4,334 December 31, 2015 8.8 1,000 113.47 3,334 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 29.6 3,150 106.46 3,334 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Other Comprehensive Income an42

Other Comprehensive Income and Accumulated Other Comprehensive Income (tables)	12 Months Ended
	Dec. 31, 2015
Other Comprehensive Income and Accumulated Other Comprehensive Income disclosure
Changes in accumulated other comprehensive income (AOCI) [Table Text Block]	(in millions) Changes in Net Changes in Net Net Benefit Plan Net Total Balance, December 31, 2012 2,908 195 (857 ) (10 ) 2,236 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss) (OCI) before reclassifications (1,740 ) (2 ) 358 (79 ) (1,463 ) Amounts reclassified from AOCI (43 ) 4 68 8 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net OCI, current period (1,783 ) 2 426 (71 ) (1,426 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2013 1,125 197 (431 ) (81 ) 810 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ OCI before reclassifications 667 (2 ) (363 ) (250 ) 52 Amounts reclassified from AOCI (24 ) 3 39 — 18 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net OCI, current period 643 1 (324 ) (250 ) 70 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2014 1,768 198 (755 ) (331 ) 880 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ OCI before reclassifications (641 ) (11 ) (18 ) (419 ) (1,089 ) Amounts reclassified from AOCI (27 ) 2 60 17 52 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net OCI, current period (668 ) (9 ) 42 (402 ) (1,037 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, December 31, 2015 1,100 189 (713 ) (733 ) (157 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Pretax components of other comprehensive income (loss) and the related income tax expense (benefit) for each component [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 Changes in net unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income (1,020 ) 976 (2,734 ) Income tax expense (benefit) (352 ) 333 (951 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes (668 ) 643 (1,783 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Having credit losses recognized in the consolidated statement of income (14 ) 2 3 Income tax expense (benefit) (5 ) 1 1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes (9 ) 1 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net changes in benefit plan assets and obligations 66 (494 ) 647 Income tax expense (benefit) 24 (170 ) 221 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes 42 (324 ) 426 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net changes in unrealized foreign currency translation (461 ) (289 ) (112 ) Income tax benefit (59 ) (39 ) (41 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes (402 ) (250 ) (71 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total other comprehensive income (loss) (1,429 ) 195 (2,196 ) Total income tax expense (benefit) (392 ) 125 (770 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total other comprehensive income (loss), net of taxes (1,037 ) 70 (1,426 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Pretax components of the amounts reclassified from accumulated other comprehensive income and the related income tax (expense) benefit for each component [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 Reclassification adjustments related to unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income(1) (42 ) (36 ) (66 ) Income tax expense(2) (15 ) (12 ) (23 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes (27 ) (24 ) (43 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Having credit losses recognized in the consolidated statement of income(1) 2 4 5 Income tax benefit(2) — 1 1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes 2 3 4 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reclassification adjustment related to benefit plan assets and obligations(3) 93 60 105 Income tax benefit(2) 33 21 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes 60 39 68 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Reclassification adjustment related to foreign currency translation(1) 26 — 8 Income tax benefit(2) 9 — — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net of taxes 17 — 8 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications 79 28 52 Total income tax benefit 27 10 15 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total reclassifications, net of taxes 52 18 37 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) (Increases) decreases net realized investment gains on the consolidated statement of income. (2) (Increases) decreases income tax expense on the consolidated statement of income. (3) Increases (decreases) general and administrative expenses on the consolidated statement of income.

Earnings per Share (table)

Earnings per Share (table)	12 Months Ended
	Dec. 31, 2015
Earnings per Share disclosure
Earnings per share reconciliation [Table Text Block]	(for the year ended December 31, in millions, except per share amounts) 2015 2014 2013 Basic and Diluted Net income, as reported 3,439 3,692 3,673 Participating share-based awards—allocated income (25 ) (27 ) (27 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income available to common shareholders—basic and diluted 3,414 3,665 3,646 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Common Shares Basic Weighted average shares outstanding 310.6 338.8 370.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted Weighted average shares outstanding 310.6 338.8 370.3 Weighted average effects of dilutive securities: Stock options and performance shares 3.3 3.7 4.0 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 313.9 342.5 374.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income Per Common Share Basic 10.99 10.82 9.84 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted 10.88 10.70 9.74 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Income Taxes (tables)

Income Taxes (tables)	12 Months Ended
	Dec. 31, 2015
Income Taxes disclosure
Composition of income tax expense included in consolidated statement of income and shareholders' equity [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 Composition of income tax expense included in the consolidated statement of income Current expense: Federal 1,144 1,216 1,059 Foreign 29 28 30 State 9 10 6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total current tax expense 1,182 1,254 1,095 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred expense: Federal 117 121 167 Foreign 2 22 10 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total deferred tax expense 119 143 177 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total income tax expense included in the consolidated statement of income 1,301 1,397 1,272 Composition of income tax expense (benefit) included in shareholders' equity Expense (benefit) relating to share-based compensation, the changes in unrealized gain on investments, unrealized loss on foreign exchange and other items in other comprehensive income (448 ) 68 (822 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total income tax expense included in the consolidated financial statements 853 1,465 450 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Effective tax rate [Table Text Block]	(for the year ended December 31, in millions) 2015 2014 2013 Income before income taxes U.S. 4,621 4,899 4,804 Foreign 119 190 141 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total income before income taxes 4,740 5,089 4,945 Effective tax rate Statutory tax rate 35 % 35 % 35 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Expected federal income tax expense 1,659 1,781 1,731 Tax effect of: Nontaxable investment income (345 ) (379 ) (409 ) Other, net (13 ) (5 ) (50 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total income tax expense 1,301 1,397 1,272 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effective tax rate 27 % 27 % 26 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Deferred tax assets and liabilities [Table Text Block]	(at December 31, in millions) 2015 2014 Deferred tax assets Claims and claim adjustment expense reserves 691 768 Unearned premium reserves 731 709 Compensation-related liabilities 326 345 Other 320 346 ​ ​ ​ ​ ​ ​ ​ Total gross deferred tax assets 2,068 2,168 ​ ​ ​ ​ ​ ​ ​ Deferred tax liabilities Deferred acquisition costs 580 565 Investments 867 1,267 Internally developed software 134 130 Other 191 173 ​ ​ ​ ​ ​ ​ ​ Total gross deferred tax liabilities 1,772 2,135 ​ ​ ​ ​ ​ ​ ​ Net deferred tax asset 296 33 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Net operating loss amounts by jurisdiction and year of expiration [Table Text Block]	(in millions) Amount Year of United States 4 2018 Brazil 1 None United Kingdom 200 None
Reconciliation of unrecognized tax benefits [Table Text Block]	(in millions) 2015 2014 Balance at January 1 23 21 Additions for tax positions of prior years 2 2 Reductions for tax positions of prior years (9 ) — Additions based on tax positions related to current year — — ​ ​ ​ ​ ​ ​ ​ Balance at December 31 16 23 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Share-Based Incentive Compens45

Share-Based Incentive Compensation (tables)	12 Months Ended
	Dec. 31, 2015
Share-Based Incentive Compensation disclosure
Assumptions used in estimating fair value of options on grant date [Table Text Block]	(for the year ended December 31,) 2015 2014 2013 Assumptions used in estimating fair value of options on grant date Expected term of stock options 6 years 6 years 6 years Expected volatility of Company's stock 19.29% 27.2% - 27.5% 28.7% - 28.8% Weighted average volatility 19.29% 27.5% 28.8% Expected annual dividend per share $2.20 $2.00 - $2.20 $1.84 Risk-free rate 1.31% 1.81% - 1.82% 1.11% - 1.14%
Additional information regarding option grants [Table Text Block]	(for the year ended December 31,) 2015 2014 2013 Additional information Weighted average grant-date fair value of options granted (per share) $15.78 $17.22 $17.09 Total intrinsic value of options exercised during the year (in millions) $120 $117 $122 ​ ​ ​ ​ ​ ​
Summary of stock option activity under the Company's 2014 Incentive Plan and legacy share-based incentive compensation plans [Table Text Block]	Stock Options Number Weighted Weighted Aggregate Outstanding, beginning of year 10,024,860 63.08 Original grants 2,244,464 106.04 Exercised (2,310,548 ) 55.16 Forfeited or expired (94,521 ) 87.17 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding, end of year 9,864,255 74.48 6.6 years 379 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Vested at end of year(1) 7,226,516 68.80 6.0 years 318 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Exercisable at end of year 4,155,912 53.51 4.3 years 247 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Represents awards for which the requisite service has been rendered, including those that are retirement eligible.
Summary of restricted stock units, deferred stock units and performance share activity [Table Text Block]	Restricted and Deferred Stock Performance Shares Other Equity Instruments Number Weighted Average Number Weighted Average Nonvested, beginning of year 1,760,971 72.40 1,290,069 79.46 Granted 607,200 106.02 460,855 106.04 Vested (789,538 ) (1) 69.03 (676,177 ) (2) 79.28 Forfeited (142,675 ) 73.57 (31,352 ) 86.41 Performance-based adjustment — — 58,594 (3) 94.06 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nonvested, end of year 1,435,958 88.35 1,101,989 91.27 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Represents awards for which the requisite service has been rendered. (2) Reflects the number of performance shares attributable to the performance goals attained over the completed performance period (three years) and for which service conditions have been met. (3) Represents the current year change in estimated performance shares to reflect the attainment of performance goals for the awards that were granted in each of the years 2013 through 2015.

Pension Plans, Retirement Ben46

Pension Plans, Retirement Benefits and Savings Plans (tables)	12 Months Ended
	Dec. 31, 2015
Pension Plans, Retirement Benefits and Savings Plans disclosure
Summary of the funded status, obligations and amounts recognized in the consolidated balance sheet for the Company's benefit plans [Table Text Block]	Qualified Nonqualified Total (at and for the year ended December 31, in millions) 2015 2014 2015 2014 2015 2014 Change in projected benefit obligation: Benefit obligation at beginning of year 3,385 2,908 227 209 3,612 3,117 Benefits earned 124 104 7 6 131 110 Interest cost on benefit obligation 135 140 9 10 144 150 Actuarial loss (gain) (203 ) 428 2 29 (201 ) 457 Benefits paid (191 ) (187 ) (8 ) (11 ) (199 ) (198 ) Plan amendments — (8 ) — — — (8 ) Curtailment — — — (3 ) — (3 ) Settlement — — — (6 ) — (6 ) Foreign currency exchange rate change — — (9 ) (7 ) (9 ) (7 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Benefit obligation at end of year 3,250 3,385 228 227 3,478 3,612 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Change in plan assets: Fair value of plan assets at beginning of year 3,235 3,074 122 129 3,357 3,203 Actual return on plan assets (17 ) 148 3 11 (14 ) 159 Company contributions 100 200 7 7 107 207 Benefits paid (191 ) (187 ) (8 ) (11 ) (199 ) (198 ) Foreign currency exchange rate change — — (9 ) (8 ) (9 ) (8 ) Settlement — — — (6 ) — (6 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at end of year 3,127 3,235 115 122 3,242 3,357 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Funded status of plan at end of year (123 ) (150 ) (113 ) (105 ) (236 ) (255 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in the consolidated balance sheet consist of: Accrued over-funded benefit plan assets — — 4 6 4 6 Accrued under-funded benefit plan liabilities (123 ) (150 ) (117 ) (111 ) (240 ) (261 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total (123 ) (150 ) (113 ) (105 ) (236 ) (255 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in accumulated other comprehensive income consist of: Net actuarial loss 1,079 1,132 52 53 1,131 1,185 Prior service benefit (8 ) (8 ) — — (8 ) (8 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 1,071 1,124 52 53 1,123 1,177 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Postretirement (at and for the year ended December 31, in millions) 2015 2014 Change in projected benefit obligation: Benefit obligation at beginning of year 255 211 Benefits earned — — Interest cost on benefit obligation 10 10 Actuarial loss (gain) (3 ) 51 Benefits paid (13 ) (15 ) Plan amendments (11 ) — Foreign currency exchange rate change (5 ) (2 ) ​ ​ ​ ​ ​ ​ ​ Benefit obligation at end of year 233 255 ​ ​ ​ ​ ​ ​ ​ Change in plan assets: Fair value of plan assets at beginning of year 16 17 Actual return on plan assets — — Company contributions 12 14 Benefits paid (13 ) (15 ) ​ ​ ​ ​ ​ ​ ​ Fair value of plan assets at end of year 15 16 ​ ​ ​ ​ ​ ​ ​ Funded status of plan at end of year (218 ) (239 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in the consolidated balance sheet consist of: Accrued under-funded benefit plan liability (218 ) (239 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Amounts recognized in accumulated other comprehensive income consist of: Net actuarial loss 4 9 Prior service benefit (35 ) (26 ) ​ ​ ​ ​ ​ ​ ​ Total (31 ) (17 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Summary of the components of net periodic benefit cost and other amounts recognized in other comprehensive income related to the benefit plans [Table Text Block]	Pension Plans Postretirement (for the year ended December 31, in millions) 2015 2014 2013 2015 2014 2013 Net Periodic Benefit Cost: Service cost 131 110 118 — — — Interest cost on benefit obligation 144 150 132 10 10 9 Expected return on plan assets (230 ) (218 ) (208 ) — — (1 ) Curtailment — (1 ) — — — — Settlement — 2 — — — — Amortization of unrecognized: Prior service benefit (1 ) — — (3 ) (2 ) (2 ) Net actuarial loss (gain) 96 65 107 1 (3 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net periodic benefit cost 140 108 149 8 5 6 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other Changes in Benefit Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income: Prior service benefit — (8 ) — (11 ) — — Net actuarial loss (gain) 43 516 (518 ) (3 ) 50 (24 ) Plan amendments — — — — — — Curtailment — (2 ) — — — — Settlement — (2 ) — — — — Amortization of prior service benefit 1 — — 3 2 2 Amortization of net actuarial gain (loss) (96 ) (65 ) (107 ) (1 ) 3 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total other changes recognized in other comprehensive income (52 ) 439 (625 ) (12 ) 55 (22 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total other changes recognized in net periodic benefit cost and other comprehensive income 88 547 (476 ) (4 ) 60 (16 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Benefit obligations assumptions, net periodic benefit cost assumptions and health care cost trend rates [Table Text Block]	(at and for the year ended December 31,) 2015 2014 Assumptions used to determine benefit obligations Discount rate: Qualified domestic pension plan 4.50 % 4.10 % Nonqualified domestic pension plan 4.37 % 4.10 % Domestic postretirement benefit plan 4.35 % 4.10 % Future compensation increase rate 4.00 % 4.00 % Assumptions used to determine net periodic benefit cost Discount rate 4.10 % 4.96 % Expected long-term rate of return on assets: Pension plan 7.25 % 7.50 % Postretirement benefit plan 4.00 % 4.00 % Assumed health care cost trend rates Following year: Medical (before age 65) 6.75 % 7.00 % Medical (age 65 and older) 7.50 % 6.50 % Rate to which the cost trend rate is assumed to decline (ultimate trend rate) Year that the rate reaches the ultimate trend rate: Medical (before age 65) 2022 2022 Medical (age 65 and older) 2025 2020
Level within the fair value hierarchy at which the financial assets of the Company's pension plans are measured [Table Text Block]	(at December 31, 2015, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities Obligations of states, municipalities and political subdivisions 17 — 17 — Debt securities issued by foreign governments 16 — 16 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 16 — 16 — All other corporate bonds 491 — 491 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 540 — 540 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mutual funds Equity mutual funds 1,237 1,231 6 — Bond mutual funds 649 646 3 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total mutual funds 1,886 1,877 9 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities 625 624 1 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other investments(1) 2 — — 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and short-term securities U.S. Treasury securities 25 25 — — Money market mutual funds 23 19 4 — Other 141 20 121 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total cash and short-term securities 189 64 125 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 3,242 2,565 675 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The fair value estimates of the two private equity funds comprising these investments are determined by an external fund manager based on recent filings, operating results, balance sheet stability, growth and other business and market sector fundamentals. Due to the significant unobservable inputs in these valuations, the total fair value estimates are disclosed in Level 3. (at December 31, 2014, in millions) Total Level 1 Level 2 Level 3 Invested assets: Fixed maturities Obligations of states, municipalities and political subdivisions 19 — 19 — Debt securities issued by foreign governments 17 — 17 — Mortgage-backed securities, collateralized mortgage obligations and pass-through securities 14 — 14 — All other corporate bonds 474 — 474 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total fixed maturities 524 — 524 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Mutual funds Equity mutual funds 1,290 1,283 7 — Bond mutual funds 610 607 3 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total mutual funds 1,900 1,890 10 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Equity securities 616 615 1 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other investments(1) 2 — — 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash and short-term securities Money market mutual funds 22 18 4 — Other 293 29 264 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total cash and short-term securities 315 47 268 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total 3,357 2,552 803 2 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) The fair value estimates of the two private equity funds comprising these investments are determined by an external fund manager based on recent filings, operating results, balance sheet stability, growth and other business and market sector fundamentals. Due to the significant unobservable inputs in these valuations, the total fair value estimates are disclosed in Level 3.
Estimated future benefit payments [Table Text Block]	Benefits Expected to be Paid (in millions) Pension Plans Postretirement 2016 215 14 2017 218 14 2018 224 15 2019 231 15 2020 237 15 2021 through 2025 1,215 76

Consolidating Financial State47

Consolidating Financial Statements (Unaudited) (tables)	12 Months Ended
	Dec. 31, 2015
Consolidating Financial Statements of The Travelers Companies, Inc. and Subsidiaries (Unaudited) disclosure
Consolidating Statement of Income (Unaudited) [Table Text Block]	CONSOLIDATING STATEMENT OF INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Revenues Premiums 16,254 7,620 — — 23,874 Net investment income 1,612 760 7 — 2,379 Fee income 445 — — — 445 Net realized investment gains (losses)(1) 13 (11 ) 1 — 3 Other revenues 78 21 — — 99 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues 18,402 8,390 8 — 26,800 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and expenses Claims and claim adjustment expenses 9,208 4,515 — — 13,723 Amortization of deferred acquisition costs 2,627 1,258 — — 3,885 General and administrative expenses 2,838 1,225 16 — 4,079 Interest expense 48 — 325 — 373 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total claims and expenses 14,721 6,998 341 — 22,060 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income (loss) before income taxes 3,681 1,392 (333 ) — 4,740 Income tax expense (benefit) 1,015 394 (108 ) — 1,301 Net income of subsidiaries — — 3,664 (3,664 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 2,666 998 3,439 (3,664 ) 3,439 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Total other-than-temporary impairments (OTTI) for the year ended December 31, 2015, and the amounts comprising total OTTI that were recognized in net realized investment gains (losses) and in other comprehensive income (OCI), were as follows: (in millions) TPC Other TRV Eliminations Consolidated Total OTTI losses (19 ) (35 ) — — (54 ) OTTI losses recognized in net realized investment gains (18 ) (34 ) — — (52 ) OTTI losses recognized in OCI (1 ) (1 ) — — (2 ) CONSOLIDATING STATEMENT OF INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Revenues Premiums 16,097 7,616 — — 23,713 Net investment income 1,874 907 6 — 2,787 Fee income 436 2 — — 438 Net realized investment gains(1) 12 64 3 — 79 Other revenues 125 20 — — 145 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues 18,544 8,609 9 — 27,162 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and expenses Claims and claim adjustment expenses 9,274 4,596 — — 13,870 Amortization of deferred acquisition costs 2,604 1,278 — — 3,882 General and administrative expenses 2,743 1,194 15 — 3,952 Interest expense 48 — 321 — 369 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total claims and expenses 14,669 7,068 336 — 22,073 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income (loss) before income taxes 3,875 1,541 (327 ) — 5,089 Income tax expense (benefit) 1,095 417 (115 ) — 1,397 Net income of subsidiaries — — 3,904 (3,904 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 2,780 1,124 3,692 (3,904 ) 3,692 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Total other-than-temporary impairments (OTTI) for the year ended December 31, 2014, and the amounts comprising total OTTI that were recognized in net realized investment gains and in other comprehensive income (OCI), were as follows: (in millions) TPC Other TRV Eliminations Consolidated Total OTTI losses (16 ) (6 ) — — (22 ) OTTI losses recognized in net realized investment gains (19 ) (7 ) — — (26 ) OTTI gains recognized in OCI 3 1 — — 4 CONSOLIDATING STATEMENT OF INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Revenues Premiums 15,262 7,375 — — 22,637 Net investment income 1,830 879 7 — 2,716 Fee income 393 2 — — 395 Net realized investment gains(1) 126 38 2 — 166 Other revenues 225 52 — — 277 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total revenues 17,836 8,346 9 — 26,191 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Claims and expenses Claims and claim adjustment expenses 8,817 4,490 — — 13,307 Amortization of deferred acquisition costs 2,571 1,250 — — 3,821 General and administrative expenses 2,570 1,174 13 — 3,757 Interest expense 53 — 308 — 361 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total claims and expenses 14,011 6,914 321 — 21,246 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income (loss) before income taxes 3,825 1,432 (312 ) — 4,945 Income tax expense (benefit) 1,054 388 (170 ) — 1,272 Net income of subsidiaries — — 3,815 (3,815 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 2,771 1,044 3,673 (3,815 ) 3,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (1) Total other-than-temporary impairments (OTTI) for the year ended December 31, 2013, and the amounts comprising total OTTI that were recognized in net realized investment gains and in other comprehensive income (loss) (OCI), were as follows: (in millions) TPC Other TRV Eliminations Consolidated Total OTTI losses (8 ) (2 ) — — (10 ) OTTI losses recognized in net realized investment gains (10 ) (5 ) — — (15 ) OTTI gains recognized in OCI 2 3 — — 5
Consolidating Statement of Comprehensive Income (Unaudited) [Table Text Block]	CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Net income 2,666 998 3,439 (3,664 ) 3,439 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss): Changes in net unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income (610 ) (407 ) (3 ) — (1,020 ) Having credit losses recognized in the consolidated statement of income (12 ) (2 ) — — (14 ) Net changes in benefit plan assets and obligations 2 — 64 — 66 Net changes in unrealized foreign currency translation (306 ) (155 ) — — (461 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss) before income taxes and other comprehensive loss of subsidiaries (926 ) (564 ) 61 — (1,429 ) Income tax expense (benefit) (257 ) (156 ) 21 — (392 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss), net of taxes, before other comprehensive loss of subsidiaries (669 ) (408 ) 40 — (1,037 ) Other comprehensive loss of subsidiaries — — (1,077 ) 1,077 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss (669 ) (408 ) (1,037 ) 1,077 (1,037 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive income 1,997 590 2,402 (2,587 ) 2,402 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Net income 2,780 1,124 3,692 (3,904 ) 3,692 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss): Changes in net unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income 681 289 6 — 976 Having credit losses recognized in the consolidated statement of income 9 (7 ) — — 2 Net changes in benefit plan assets and obligations (15 ) (8 ) (471 ) — (494 ) Net changes in unrealized foreign currency translation (173 ) (116 ) — — (289 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss) before income taxes and other comprehensive income of subsidiaries 502 158 (465 ) — 195 Income tax expense (benefit) 207 81 (163 ) — 125 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss), net of taxes, before other comprehensive income of subsidiaries 295 77 (302 ) — 70 Other comprehensive income of subsidiaries — — 372 (372 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income 295 77 70 (372 ) 70 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive income 3,075 1,201 3,762 (4,276 ) 3,762 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CONSOLIDATING STATEMENT OF COMPREHENSIVE INCOME (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Net income 2,771 1,044 3,673 (3,815 ) 3,673 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss): Changes in net unrealized gains on investment securities: Having no credit losses recognized in the consolidated statement of income (1,982 ) (771 ) 19 — (2,734 ) Having credit losses recognized in the consolidated statement of income 4 (1 ) — — 3 Net changes in benefit plan assets and obligations 12 19 616 — 647 Net changes in unrealized foreign currency translation (92 ) (20 ) — — (112 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss) before income taxes and other comprehensive loss of subsidiaries (2,058 ) (773 ) 635 — (2,196 ) Income tax expense (benefit) (719 ) (273 ) 222 — (770 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive income (loss), net of taxes, before other comprehensive loss of subsidiaries (1,339 ) (500 ) 413 — (1,426 ) Other comprehensive loss of subsidiaries — — (1,839 ) 1,839 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Other comprehensive loss (1,339 ) (500 ) (1,426 ) 1,839 (1,426 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Comprehensive income 1,432 544 2,247 (1,976 ) 2,247 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Consolidating Balance Sheet (Unaudited) [Table Text Block]	CONSOLIDATING BALANCE SHEET (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Assets Fixed maturities, available for sale, at fair value (amortized cost $58,878) 42,289 18,323 46 — 60,658 Equity securities, available for sale, at fair value (cost $528) 189 375 141 — 705 Real estate investments 56 933 — — 989 Short-term securities 1,947 1,178 1,546 — 4,671 Other investments 2,516 930 1 — 3,447 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total investments 46,997 21,739 1,734 — 70,470 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash 225 153 2 — 380 Investment income accrued 453 185 4 — 642 Premiums receivable 4,336 2,101 — — 6,437 Reinsurance recoverables 5,849 3,061 — — 8,910 Ceded unearned premiums 610 46 — — 656 Deferred acquisition costs 1,660 189 — — 1,849 Deferred taxes 178 83 35 — 296 Contractholder receivables 3,387 987 — — 4,374 Goodwill 2,573 1,000 — — 3,573 Other intangible assets 203 76 — — 279 Investment in subsidiaries — — 27,573 (27,573 ) — Other assets 1,958 344 16 — 2,318 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total assets 68,429 29,964 29,364 (27,573 ) 100,184 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities Claims and claim adjustment expense reserves 31,965 16,330 — — 48,295 Unearned premium reserves 8,335 3,636 — — 11,971 Contractholder payables 3,387 987 — — 4,374 Payables for reinsurance premiums 175 121 — — 296 Debt 693 — 5,651 — 6,344 Other liabilities 3,958 1,221 127 — 5,306 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liabilities 48,513 22,295 5,778 — 76,586 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shareholders' equity Common stock (1,750.0 shares authorized; 295.9 shares issued and outstanding) — 390 22,172 (390 ) 22,172 Additional paid-in capital 11,634 6,499 — (18,133 ) — Retained earnings 7,888 688 29,933 (8,564 ) 29,945 Accumulated other comprehensive income (loss) 394 92 (157 ) (486 ) (157 ) Treasury stock, at cost (467.6 shares) — — (28,362 ) — (28,362 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total shareholders' equity 19,916 7,669 23,586 (27,573 ) 23,598 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liabilities and shareholders' equity 68,429 29,964 29,364 (27,573 ) 100,184 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ CONSOLIDATING BALANCE SHEET (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Assets Fixed maturities, available for sale, at fair value (amortized cost $60,801) 43,401 20,043 30 — 63,474 Equity securities, available for sale, at fair value (cost $579) 236 522 141 — 899 Real estate investments 56 882 — — 938 Short-term securities 2,128 706 1,530 — 4,364 Other investments 2,630 955 1 — 3,586 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total investments 48,451 23,108 1,702 — 73,261 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash 221 151 2 — 374 Investment income accrued 468 215 2 — 685 Premiums receivable 4,241 2,057 — — 6,298 Reinsurance recoverables 6,156 3,104 — — 9,260 Ceded unearned premiums 608 70 — — 678 Deferred acquisition costs 1,622 213 — — 1,835 Deferred taxes 23 (40 ) 50 — 33 Contractholder receivables 3,306 1,056 — — 4,362 Goodwill 2,602 1,009 — — 3,611 Other intangible assets 216 88 — — 304 Investment in subsidiaries — — 28,821 (28,821 ) — Other assets 1,931 429 17 — 2,377 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total assets 69,845 31,460 30,594 (28,821 ) 103,078 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities Claims and claim adjustment expense reserves 32,999 16,851 — — 49,850 Unearned premium reserves 8,201 3,638 — — 11,839 Contractholder payables 3,306 1,056 — — 4,362 Payables for reinsurance premiums 194 142 — — 336 Debt 692 — 5,657 — 6,349 Other liabilities 4,084 1,308 114 — 5,506 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liabilities 49,476 22,995 5,771 — 78,242 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Shareholders' equity Common stock (1,750.0 shares authorized; 322.2 shares issued and outstanding) — 390 21,843 (390 ) 21,843 Additional paid-in capital 11,634 6,502 — (18,136 ) — Retained earnings 7,673 1,073 27,238 (8,733 ) 27,251 Accumulated other comprehensive income 1,062 500 880 (1,562 ) 880 Treasury stock, at cost (437.3 shares) — — (25,138 ) — (25,138 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total shareholders' equity 20,369 8,465 24,823 (28,821 ) 24,836 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Total liabilities and shareholders' equity 69,845 31,460 30,594 (28,821 ) 103,078 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​
Consolidating Statement of Cash Flows (Unaudited) [Table Text Block]	CONSOLIDATING STATEMENT OF CASH FLOWS (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Cash flows from operating activities Net income 2,666 998 3,439 (3,664 ) 3,439 Net adjustments to reconcile net income to net cash provided by operating activities (577 ) 414 330 (172 ) (5 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by operating activities 2,089 1,412 3,769 (3,836 ) 3,434 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities Proceeds from maturities of fixed maturities 7,543 3,563 10 — 11,116 Proceeds from sales of investments: Fixed maturities 1,227 723 — — 1,950 Equity securities 25 34 — — 59 Real estate investments — 31 — — 31 Other investments 503 210 — — 713 Purchases of investments: Fixed maturities (8,276 ) (3,787 ) (27 ) — (12,090 ) Equity securities (3 ) (43 ) (3 ) — (49 ) Real estate investments (1 ) (122 ) — — (123 ) Other investments (423 ) (111 ) — — (534 ) Net sales (purchases) of short-term securities 179 (489 ) (16 ) — (326 ) Securities transactions in course of settlement (52 ) (61 ) — — (113 ) Acquisition, net of cash acquired (13 ) — — — (13 ) Other (343 ) 39 — — (304 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) investing activities 366 (13 ) (36 ) — 317 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from financing activities Treasury stock acquired—share repurchase authorization — — (3,150 ) — (3,150 ) Treasury stock acquired—net employee share-based compensation — — (74 ) — (74 ) Dividends paid to shareholders — — (739 ) — (739 ) Payment of debt — — (400 ) — (400 ) Issuance of debt — — 392 — 392 Issuance of common stock—employee share options — — 183 — 183 Excess tax benefits from share-based payment arrangements — — 55 — 55 Dividends paid to parent company (2,450 ) (1,383 ) — 3,833 — Capital contributions, loans and other transactions between subsidiaries — (3 ) — 3 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash used in financing activities (2,450 ) (1,386 ) (3,733 ) 3,836 (3,733 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effect of exchange rate changes on cash (1 ) (11 ) — — (12 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase in cash 4 2 — — 6 Cash at beginning of year 221 151 2 — 374 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash at end of year 225 153 2 — 380 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental disclosure of cash flow information Income taxes paid (received) 1,032 384 (209 ) — 1,207 Interest paid 47 — 318 — 365 CONSOLIDATING STATEMENT OF CASH FLOWS (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Cash flows from operating activities Net income 2,780 1,124 3,692 (3,904 ) 3,692 Net adjustments to reconcile net income to net cash provided by operating activities 343 (293 ) 118 (167 ) 1 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by operating activities 3,123 831 3,810 (4,071 ) 3,693 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities Proceeds from maturities of fixed maturities 6,625 4,258 11 — 10,894 Proceeds from sales of investments: Fixed maturities 595 453 1 — 1,049 Equity securities 111 43 4 — 158 Real estate investments 1 14 — — 15 Other investments 477 378 — — 855 Purchases of investments: Fixed maturities (6,856 ) (4,465 ) (4 ) — (11,325 ) Equity securities (3 ) (42 ) (7 ) — (52 ) Real estate investments (22 ) (26 ) — — (48 ) Other investments (405 ) (149 ) — — (554 ) Net purchases of short-term securities (268 ) (223 ) (7 ) — (498 ) Securities transactions in course of settlement 44 38 — — 82 Acquisition, net of cash acquired (9 ) (3 ) — (12 ) Other (350 ) (8 ) — — (358 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) investing activities (60 ) 268 (2 ) — 206 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from financing activities Treasury stock acquired—share repurchase authorization — — (3,275 ) — (3,275 ) Treasury stock acquired—net employee share-based compensation — — (57 ) — (57 ) Dividends paid to shareholders — — (729 ) — (729 ) Issuance of common stock—employee share options — — 195 — 195 Excess tax benefits from share-based payment arrangements — — 57 — 57 Dividends paid to parent company (2,978 ) (1,093 ) — 4,071 — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash used in financing activities (2,978 ) (1,093 ) (3,809 ) 4,071 (3,809 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effect of exchange rate changes on cash (1 ) (9 ) — — (10 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase (decrease) in cash 84 (3 ) (1 ) — 80 Cash at beginning of year 137 154 3 — 294 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash at end of year 221 151 2 — 374 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental disclosure of cash flow information Income taxes paid (received) 947 336 (136 ) — 1,147 Interest paid 47 — 318 — 365 CONSOLIDATING STATEMENT OF CASH FLOWS (Unaudited) (in millions) TPC Other TRV Eliminations Consolidated Cash flows from operating activities Net income 2,771 1,044 3,673 (3,815 ) 3,673 Net adjustments to reconcile net income to net cash provided by operating activities (497 ) 413 (1,665 ) 1,892 143 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by operating activities 2,274 1,457 2,008 (1,923 ) 3,816 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from investing activities Proceeds from maturities of fixed maturities 5,484 2,419 1 — 7,904 Proceeds from sales of investments: Fixed maturities 989 641 5 — 1,635 Equity securities 45 41 — — 86 Real estate investments — 18 — — 18 Other investments 489 273 — — 762 Purchases of investments: Fixed maturities (6,260 ) (3,201 ) (6 ) — (9,467 ) Equity securities (21 ) (34 ) (2 ) — (57 ) Real estate investments (1 ) (106 ) — — (107 ) Other investments (320 ) (126 ) — — (446 ) Net sales (purchases) of short-term securities (272 ) (52 ) 435 — 111 Securities transactions in course of settlement (2 ) 24 (1 ) — 21 Acquisition, net of cash acquired (773 ) (224 ) — (997 ) Other (365 ) (8 ) — — (373 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash provided by (used in) investing activities (1,007 ) (335 ) 432 — (910 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash flows from financing activities Treasury stock acquired—share repurchase authorization — — (2,400 ) — (2,400 ) Treasury stock acquired—net employee share-based compensation — — (61 ) — (61 ) Dividends paid to shareholders — — (729 ) — (729 ) Payment of debt (500 ) — — — (500 ) Issuance of debt — — 494 — 494 Issuance of common stock—employee share options — — 206 — 206 Excess tax benefits from share-based payment arrangements — — 51 — 51 Dividends paid to parent company (1,307 ) (1,116 ) — 2,423 — Capital contributions, loans and other transactions between subsidiaries 500 — — (500 ) — ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net cash used in financing activities (1,307 ) (1,116 ) (2,439 ) 1,923 (2,939 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Effect of exchange rate changes on cash — (3 ) — — (3 ) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net increase (decrease) in cash (40 ) 3 1 — (36 ) Cash at beginning of year 177 151 2 — 330 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash at end of year 137 154 3 — 294 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Supplemental disclosure of cash flow information Income taxes paid (received) 942 325 (210 ) — 1,057 Interest paid 60 — 295 — 355

Selected Quarterly Financial 48

Selected Quarterly Financial Data (Unaudited) (table)	12 Months Ended
	Dec. 31, 2015
Selected Quarterly Financial Data (Unaudited) disclosure
Selected Quarterly Financial Data (Unaudited) disclosure [Table Text Block]	2015 (in millions, except per share amounts) First Second Third Fourth Total Total revenues 6,626 6,706 6,794 6,674 26,800 Total expenses 5,478 5,630 5,487 5,465 22,060 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before income taxes 1,148 1,076 1,307 1,209 4,740 Income tax expense 315 264 379 343 1,301 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 833 812 928 866 3,439 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income per share(1): Basic 2.58 2.56 3.00 2.87 10.99 Diluted 2.55 2.53 2.97 2.83 10.88 2014 (in millions, except per share amounts) First Second Third Fourth Total Total revenues 6,708 6,785 6,886 6,783 27,162 Total expenses 5,238 5,884 5,628 5,323 22,073 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Income before income taxes 1,470 901 1,258 1,460 5,089 Income tax expense 418 218 339 422 1,397 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income 1,052 683 919 1,038 3,692 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income per share(1): Basic 2.98 1.98 2.72 3.15 10.82 Diluted 2.95 1.95 2.69 3.11 10.70 (1) Due to the averaging of shares, quarterly earnings per share may not add to the total for the full year.

Summary of Significant Accoun49

Summary of Significant Accounting Policies (details)	12 Months Ended
	Dec. 31, 2015
Summary of Significant Accounting Policies disclosure
Maximum useful life for buildings held in real estate investments	39 years
Maximum original maturity of short-term securities	1 year
Availability of financial information provided by private equity and real estate partnerships following the date of the reporting, minimum	3 months
Availability of financial information provided by private equity and real estate partnerships following the date of the reporting, maximum	6 months
Availability of financial information provided by hedge funds following the date of the reporting	1 month
Estimated recovery time for securities for which the issuer is in bankruptcy	12 months
Estimated recovery time for securities for which the issuer is financially troubled but not in bankruptcy	24 months

Summary of Significant Accoun50

Summary of Significant Accounting Policies (details) - Acquisition - USD ($) $ in Millions	Nov. 01, 2013	Dec. 31, 2015	Oct. 01, 2015	Dec. 31, 2014
Business Acquisition
Goodwill acquired		$ 3,573		$ 3,611
Dominion [Member]
Business Acquisition
Purchase price	$ 1,035
Assets acquired	3,910
Liabilities assumed	2,880
Intangible assets acquired	16
Goodwill acquired	273
Value of business acquired (VOBA)	$ 76
Travelers Participacoes em Seguros Brasil S.A. [Member]
Business Acquisition
Percentage of common stock acquired			100.00%

Summary of Significant Accoun51

Summary of Significant Accounting Policies (details) - Key Assumptions	12 Months Ended
	Dec. 31, 2015
Prime [Member] | Minimum [Member]
Key assumptions used in estimation of present value of structured fixed maturity securities
Voluntary prepayment rates	1.00%
Percentage of remaining pool liquidated due to defaults	1.00%
Loss severity	30.00%
Prime [Member] | Maxiumum [Member]
Key assumptions used in estimation of present value of structured fixed maturity securities
Voluntary prepayment rates	33.00%
Percentage of remaining pool liquidated due to defaults	46.00%
Loss severity	65.00%
Alt-A [Member] | Minimum [Member]
Key assumptions used in estimation of present value of structured fixed maturity securities
Voluntary prepayment rates	3.00%
Percentage of remaining pool liquidated due to defaults	8.00%
Loss severity	55.00%
Alt-A [Member] | Maxiumum [Member]
Key assumptions used in estimation of present value of structured fixed maturity securities
Voluntary prepayment rates	18.00%
Percentage of remaining pool liquidated due to defaults	62.00%
Loss severity	120.00%
Sub-Prime [Member] | Minimum [Member]
Key assumptions used in estimation of present value of structured fixed maturity securities
Voluntary prepayment rates	2.00%
Percentage of remaining pool liquidated due to defaults	22.00%
Loss severity	70.00%
Sub-Prime [Member] | Maxiumum [Member]
Key assumptions used in estimation of present value of structured fixed maturity securities
Voluntary prepayment rates	10.00%
Percentage of remaining pool liquidated due to defaults	61.00%
Loss severity	120.00%

Summary of Significant Accoun52

Summary of Significant Accounting Policies (details) - Additional Details $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)item	Dec. 31, 2014USD ($)	Dec. 31, 2013
Summary of Significant Accounting Policies disclosure
Minimum collateral provided by borrowers of securities, as a percentage of the market value of the loaned securities plus accrued interest	102.00%
Number of reportable business segments | item	3
Liabilities for losses for most long-term disability and annuity claim payments primarily arising from workers' compensation insurance and workers' compensation excess insurance policies, discount rate (percent)	5.00%	5.00%
Liabilities for losses for most long-term disability and annuity claim payments primarily arising from workers' compensation insurance and workers' compensation excess insurance policies	$ 2,130	$ 2,010
Liability for guaranty fund and other insurance-related assessments	241	245
Recoverables for liability for guaranty fund and other insurance-related assessments	$ 18	$ 15
Minimum expected payment period for loss-based assessments and recoveries	1 year	1 year
Net written premiums for participating dividend policies as a percent of total Company net written premiums	2.00%	1.00%	1.00%
Liability accrued for policyholder dividends	$ 57	$ 54
Percentage of capital provided by International for its syndicate at Lloyd's	100.00%
Number of principal business units through which the Company's syndicate at Lloyd's writes business | item	5

Summary of Significant Accoun53

Summary of Significant Accounting Policies (details) - Equity Method Investment	Dec. 31, 2015
JMalucelli - Brazilian joint venture [Member]
Equity method investment
Percent of common stock owned	49.50%
J. Malucelli Latam S.A. [Member]
Equity method investment
Percent of common stock owned	49.50%

Segment Information (details)

Segment Information (details) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2015USD ($)item	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Segment reporting information
Number of reportable business segments | item										3
Premiums										$ 23,874	$ 23,713	$ 22,637
Net investment income										2,379	2,787	2,716
Fee income										445	438	395
Other revenues										99	145	277
Income tax expense		$ 343	$ 379	$ 264	$ 315	$ 422	$ 339	$ 218	$ 418	1,301	1,397	1,272
Operating income (loss)										3,437	3,641	3,567
Net realized investment gains	[1]									3	79	166
Total revenues		6,674	6,794	6,706	6,626	6,783	6,886	6,785	6,708	26,800	27,162	26,191
Net realized investment gains, net of tax										2	51	106
Net income		$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	3,439	3,692	3,673
Property casualty [Member]
Segment reporting information
Premiums										23,874	23,713	22,637
Net investment income										2,379	2,787	2,716
Domestic [Member]
Segment reporting information
Total revenues										25,112	25,091	25,138
International [Member]
Segment reporting information
Total revenues										1,688	2,071	1,053
Reportable Segments [Member]
Segment reporting information
Premiums										23,874	23,713	22,637
Net investment income										2,379	2,787	2,716
Fee income										445	438	395
Other revenues										93	145	283
Total operating revenues										26,791	27,083	26,031
Amortization and depreciation										4,696	4,738	4,685
Income tax expense										1,443	1,512	1,351
Operating income (loss)										3,692	3,898	3,815
Reportable Segments [Member] | Business and International Insurance [Member]
Segment reporting information
Premiums										14,521	14,512	13,332
Net investment income										1,824	2,156	2,087
Fee income										445	438	395
Other revenues										23	46	160
Total operating revenues										16,813	17,152	15,974
Amortization and depreciation										2,907	2,909	2,751
Income tax expense										769	798	758
Operating income (loss)										2,170	2,347	2,404
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member]
Segment reporting information
Premiums										12,650	12,334	12,084
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Workers' compensation [Member]
Segment reporting information
Premiums										3,868	3,713	3,560
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Automobile [Member]
Segment reporting information
Premiums										1,925	1,901	1,904
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Commercial Property [Member]
Segment reporting information
Premiums										1,772	1,756	1,698
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | General Liability [Member]
Segment reporting information
Premiums										1,914	1,852	1,790
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Commercial multi-peril [Member]
Segment reporting information
Premiums										3,132	3,070	3,093
Reportable Segments [Member] | Business and International Insurance [Member] | Domestic [Member] | Other [Member]
Segment reporting information
Premiums										39	42	39
Reportable Segments [Member] | Business and International Insurance [Member] | International [Member]
Segment reporting information
Premiums										1,871	2,178	1,248
Reportable Segments [Member] | Bond & Specialty Insurance [Member]
Segment reporting information
Premiums										2,085	2,076	1,981
Net investment income										223	252	260
Other revenues										22	19	20
Total operating revenues										2,330	2,347	2,261
Amortization and depreciation										467	482	473
Income tax expense										272	348	227
Operating income (loss)										633	727	573
Reportable Segments [Member] | Bond & Specialty Insurance [Member] | General Liability [Member]
Segment reporting information
Premiums										955	963	891
Reportable Segments [Member] | Bond & Specialty Insurance [Member] | Fidelity and surety [Member]
Segment reporting information
Premiums										954	936	913
Reportable Segments [Member] | Bond & Specialty Insurance [Member] | Other [Member]
Segment reporting information
Premiums										176	177	177
Reportable Segments [Member] | Personal Insurance [Member]
Segment reporting information
Premiums										7,268	7,125	7,324
Net investment income										332	379	369
Other revenues										48	80	103
Total operating revenues										7,648	7,584	7,796
Amortization and depreciation										1,322	1,347	1,461
Income tax expense										402	366	366
Operating income (loss)										889	824	838
Reportable Segments [Member] | Personal Insurance [Member] | Automobile [Member]
Segment reporting information
Premiums										3,512	3,316	3,431
Reportable Segments [Member] | Personal Insurance [Member] | Homeowners and other [Member]
Segment reporting information
Premiums										3,756	3,809	3,893
Other [Member]
Segment reporting information
Other revenues										6		(6)
Operating income (loss)										(255)	(257)	(248)
After-tax interest expense										$ 242	$ 240	$ 235
[1]	Total other-than-temporary impairment (OTTI) losses were $(54) million, $(22) million and $(10) million for the years ended December 31, 2015, 2014 and 2013, respectively. Of total OTTI, credit losses of $(52) million, $(26) million and $(15) million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(2) million, $4 million and $5 million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.

Segment Information (details) -

Segment Information (details) - Net Written Premiums - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment reporting information
Net written premiums	$ 24,121	$ 23,904	$ 22,767
Business and International Insurance [Member]
Segment reporting information
Net written premiums	14,583	14,636	13,512
Business and International Insurance [Member] | Domestic [Member]
Segment reporting information
Net written premiums	12,764	12,515	12,233
Business and International Insurance [Member] | Domestic [Member] | Select Accounts [Member]
Segment reporting information
Net written premiums	2,716	2,707	2,724
Business and International Insurance [Member] | Domestic [Member] | Middle Market [Member]
Segment reporting information
Net written premiums	6,325	6,108	5,862
Business and International Insurance [Member] | Domestic [Member] | National Accounts [Member]
Segment reporting information
Net written premiums	1,048	1,047	1,010
Business and International Insurance [Member] | Domestic [Member] | First Party [Member]
Segment reporting information
Net written premiums	1,564	1,579	1,552
Business and International Insurance [Member] | Domestic [Member] | Specialized Distribution [Member]
Segment reporting information
Net written premiums	1,111	1,074	1,085
Business and International Insurance [Member] | International [Member]
Segment reporting information
Net written premiums	1,819	2,121	1,279
Bond & Specialty Insurance [Member]
Segment reporting information
Net written premiums	2,081	2,103	2,030
Personal Insurance [Member]
Segment reporting information
Net written premiums	7,457	7,165	7,225
Personal Insurance [Member] | Automobile [Member]
Segment reporting information
Net written premiums	3,700	3,390	3,370
Personal Insurance [Member] | Homeowners and other [Member]
Segment reporting information
Net written premiums	$ 3,757	$ 3,775	$ 3,855

Segment Information (details)56

Segment Information (details) - Assets by Segment - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Assets by segment
Total assets	$ 100,184	$ 103,078
Reportable Segments [Member]
Assets by segment
Total assets	99,800	102,633
Reportable Segments [Member] | Business and International Insurance [Member]
Assets by segment
Total assets	79,692	82,310
Reportable Segments [Member] | Bond & Specialty Insurance [Member]
Assets by segment
Total assets	7,360	7,525
Reportable Segments [Member] | Personal Insurance [Member]
Assets by segment
Total assets	12,748	12,798
Other assets [Member]
Assets by segment
Total assets	$ 384	$ 445

Segment Information (details)57

Segment Information (details) - Enterprise-Wide Disclosures - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues based on location
Benchmark percentage of revenue transactions from a single customer									10.00%	10.00%	10.00%
Total revenues	$ 6,674	$ 6,794	$ 6,706	$ 6,626	$ 6,783	$ 6,886	$ 6,785	$ 6,708	$ 26,800	$ 27,162	$ 26,191
U.S. [Member]
Revenues based on location
Total revenues									25,112	25,091	25,138
Non-U.S. [Member]
Revenues based on location
Total revenues									1,688	2,071	1,053
Canada [Member]
Revenues based on location
Total revenues									1,202	1,474	529
Other Non-U.S. [Member]
Revenues based on location
Total revenues									$ 486	$ 597	$ 524

Investments (details)

Investments (details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments disclosure
Fixed maturities, due in one year or less, amortized cost	$ 6,240
Fixed maturities, due after 1 year through 5 years, amortized cost	16,741
Fixed maturities, due after 5 years through 10 years, amortized cost	16,008
Fixed maturities, due after 10 years, amortized cost	18,026
Fixed maturities excluding mortgage-backed securities, collateralized mortgage obligations and pass-through securities, amortized cost	57,015
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities, amortized cost	1,863
Fixed maturities, amortized cost	58,878	$ 60,801
Fixed maturities, due in one year or less, fair value	6,324
Fixed maturities, due after 1 year through 5 years, fair value	17,296
Fixed maturities, due after 5 years through 10 years, fair value	16,260
Fixed maturities, due after 10 years, fair value	18,797
Fixed maturities excluding mortgage-backed securities, collateralized mortgage obligations and pass-through securities, fair value	58,677
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities, fair value	1,981
Fixed maturities, at fair value	60,658	63,474
Securities on loan as part of a tri-party lending agreement	269	296
Proceeds from sales of fixed maturities classified as available for sale	1,950	1,049	$ 1,635
Insurance subsidiaries' securities on deposit at financial institutions in certain states pursuant to the respective states' insurance regulatory requirements	4,660	4,780
Fair value of funds deposited with third parties to be used as collateral to secure various liabilities on behalf of insureds, cedants and other creditors	28	39
Fair value of other investments pledged as collateral securing outstanding letters of credit	21	22
Fair value of owned securities held by an insurance subsidiary pledged into a Lloyd's trust account to support capital requirements for the Company's operations at Lloyd's	140	151
Proceeds from sales of equity securities	59	158	86
Proceeds from sale of real estate investments	31	15	$ 18
Real estate held for sale	0	0
Accumulated depreciation on real estate held for investment purposes	320	290
Future minimum rental income expected on operating leases relating to the Company's real estate properties for 2016	92
Future minimum rental income expected on operating leases relating to the Company's real estate properties for 2017	74
Future minimum rental income expected on operating leases relating to the Company's real estate properties for 2018	61
Future minimum rental income expected on operating leases relating to the Company's real estate properties for 2019	49
Future minimum rental income expected on operating leases relating to the Company's real estate properties for 2020	36
Future minimum rental income expected on operating leases relating to the Company's real estate properties for 2021 and thereafter	$ 59
Maximum original maturity of short-term securities	1 year
Combined average days to maturity of short-term securities (in days)	67 days
Amortized cost of short-term securities (which approximates fair value)	$ 4,670	$ 4,360

Investments (details) - Investm

Investments (details) - Investment Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investment disclosure details
Fixed maturities, amortized cost	$ 58,878	$ 60,801
Gross unrealized gains	2,100	2,791
Gross unrealized losses	320	118
Fixed maturities, at fair value	60,658	63,474
Equity securities, cost	528	579
Gross unrealized gains	190	326
Gross unrealized losses	13	6
Equity securities, at fair value	705	899
Continuous unrealized loss position less than 12 months, fair value	11,221	2,744
Continuous unrealized loss position less than 12 months, gross unrealized losses	233	46
Continuous unrealized loss position 12 months or longer, fair value	1,008	3,536
Continuous unrealized loss position 12 months or longer, gross unrealized losses	100	78
Continuous unrealized loss position, total, fair value	12,229	6,280
Continuous unrealized loss position, total, gross unrealized losses	333	124
Available-for-sale securities for which fair value is less than 80% of amortized cost, 3 months or less	54
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 3 months, 6 months or less	18
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less	6
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 12 months	7
Available-for-sale securities for which fair value is less than 80% of amortized cost, total	$ 85
Maxiumum [Member]
Investment disclosure details
Unrealized investment losses for securities for which fair value is less than 80% of amortized cost, as a percentage of the combined fixed maturity and equity security portfolios on a pretax basis	1.00%
Unrealized investment losses for securities for which fair value is less than 80% of amortized cost, as a percentage of shareholders' equity on an after-tax basis	1.00%
Fixed maturities [Member]
Investment disclosure details
Gross realized gains	$ 95	44	$ 66
Gross realized losses	14	12	25
Continuous unrealized loss position less than 12 months, fair value	11,126	2,619
Continuous unrealized loss position less than 12 months, gross unrealized losses	224	41
Continuous unrealized loss position 12 months or longer, fair value	937	3,493
Continuous unrealized loss position 12 months or longer, gross unrealized losses	96	77
Continuous unrealized loss position, total, fair value	12,063	6,112
Continuous unrealized loss position, total, gross unrealized losses	320	118
Available-for-sale securities for which fair value is less than 80% of amortized cost, 3 months or less	51
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 3 months, 6 months or less	17
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less	6
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 12 months	7
Available-for-sale securities for which fair value is less than 80% of amortized cost, total	81
Fixed maturities [Member] | Below investment grade [Member]
Investment disclosure details
Fixed maturities, at fair value	1,710	1,910
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Investment disclosure details
Fixed maturities, amortized cost	2,202	2,022
Gross unrealized gains	8	36
Gross unrealized losses	16	5
Fixed maturities, at fair value	2,194	2,053
Continuous unrealized loss position less than 12 months, fair value	1,820	180
Continuous unrealized loss position less than 12 months, gross unrealized losses	15	2
Continuous unrealized loss position 12 months or longer, fair value	28	125
Continuous unrealized loss position 12 months or longer, gross unrealized losses	1	3
Continuous unrealized loss position, total, fair value	1,848	305
Continuous unrealized loss position, total, gross unrealized losses	16	5
Obligations of states, municipalities and political subdivisions [Member]
Investment disclosure details
Fixed maturities, amortized cost	30,027	31,895
Gross unrealized gains	1,393	1,688
Gross unrealized losses	9	10
Fixed maturities, at fair value	31,411	33,573
Continuous unrealized loss position less than 12 months, fair value	928	173
Continuous unrealized loss position less than 12 months, gross unrealized losses	7	1
Continuous unrealized loss position 12 months or longer, fair value	142	797
Continuous unrealized loss position 12 months or longer, gross unrealized losses	2	9
Continuous unrealized loss position, total, fair value	1,070	970
Continuous unrealized loss position, total, gross unrealized losses	9	10
Obligations of states, municipalities and political subdivisions, local general obligation [Member]
Investment disclosure details
Fixed maturities, amortized cost	12,744	12,366
Gross unrealized gains	577	644
Gross unrealized losses	3	5
Fixed maturities, at fair value	13,318	13,005
Obligations of states, municipalities and political subdivisions, revenue [Member]
Investment disclosure details
Fixed maturities, amortized cost	9,492	9,833
Gross unrealized gains	472	575
Gross unrealized losses	4	4
Fixed maturities, at fair value	9,960	10,404
Obligations of states, municipalities and political subdivisions, state general obligation [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,978	2,467
Gross unrealized gains	97	137
Gross unrealized losses	2	1
Fixed maturities, at fair value	2,073	2,603
Obligations of states, municipalities and political subdivisions, pre-refunded [Member]
Investment disclosure details
Fixed maturities, amortized cost	5,813	7,229
Gross unrealized gains	247	332
Fixed maturities, at fair value	6,060	7,561
Debt securities issued by foreign governments [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,829	2,320
Gross unrealized gains	45	48
Gross unrealized losses	1
Fixed maturities, at fair value	1,873	2,368
Continuous unrealized loss position less than 12 months, fair value	172	50
Continuous unrealized loss position less than 12 months, gross unrealized losses	1
Continuous unrealized loss position 12 months or longer, fair value		24
Continuous unrealized loss position, total, fair value	172	74
Continuous unrealized loss position, total, gross unrealized losses	1
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Investment disclosure details
Fixed maturities, amortized cost	1,863	2,052
Gross unrealized gains	124	165
Gross unrealized losses	6	4
Fixed maturities, at fair value	1,981	2,213
Continuous unrealized loss position less than 12 months, fair value	473	68
Continuous unrealized loss position less than 12 months, gross unrealized losses	4
Continuous unrealized loss position 12 months or longer, fair value	57	192
Continuous unrealized loss position 12 months or longer, gross unrealized losses	2	4
Continuous unrealized loss position, total, fair value	530	260
Continuous unrealized loss position, total, gross unrealized losses	6	4
Residential mortgage-backed pass-through securities classified as available-for-sale, GNMA, FNMA, FHLMC and Canadian Government [Member]
Investment disclosure details
Fixed maturities, at fair value	676	872
Residential collateralized mortgage obligations [Member]
Investment disclosure details
Fixed maturities, at fair value	$ 1,300	$ 1,340
Percent guaranteed by or fully collateralized by securities issued by GNMA, FNMA or FHLMC	48.00%	46.00%
Non-guaranteed residential collateralized mortgage obligations [Member]
Investment disclosure details
Fixed maturities, at fair value	$ 683	$ 725
All other corporate bonds [Member]
Investment disclosure details
Fixed maturities, amortized cost	22,854	22,390
Gross unrealized gains	523	844
Gross unrealized losses	288	99
Fixed maturities, at fair value	23,089	23,135
Continuous unrealized loss position less than 12 months, fair value	7,725	2,148
Continuous unrealized loss position less than 12 months, gross unrealized losses	197	38
Continuous unrealized loss position 12 months or longer, fair value	710	2,355
Continuous unrealized loss position 12 months or longer, gross unrealized losses	91	61
Continuous unrealized loss position, total, fair value	8,435	4,503
Continuous unrealized loss position, total, gross unrealized losses	288	99
Commercial mortgage-backed securities [Member]
Investment disclosure details
Fixed maturities, at fair value	865	715
Commercial mortgage-backed securities, containing guarantees by the U.S. government or a government-sponsored enterprise [Member]
Investment disclosure details
Fixed maturities, at fair value	303	202
Commercial mortgage-backed securities, non-guaranteed securities [Member]
Investment disclosure details
Fixed maturities, at fair value	562	513
Other fixed maturities [Member]
Investment disclosure details
Available-for-sale securities for which fair value is less than 80% of amortized cost, 3 months or less	51
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 3 months, 6 months or less	17
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 6 months, 12 months or less	6
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 12 months	7
Available-for-sale securities for which fair value is less than 80% of amortized cost, total	81
Redeemable preferred stock [Member]
Investment disclosure details
Fixed maturities, amortized cost	103	122
Gross unrealized gains	7	10
Fixed maturities, at fair value	110	132
Continuous unrealized loss position less than 12 months, fair value	8
Continuous unrealized loss position, total, fair value	8
Equity securities [Member]
Investment disclosure details
Gross realized gains	16	27	16
Gross realized losses	10	3	1
Continuous unrealized loss position less than 12 months, fair value	95	125
Continuous unrealized loss position less than 12 months, gross unrealized losses	9	5
Continuous unrealized loss position 12 months or longer, fair value	71	43
Continuous unrealized loss position 12 months or longer, gross unrealized losses	4	1
Continuous unrealized loss position, total, fair value	166	168
Continuous unrealized loss position, total, gross unrealized losses	13	6
Available-for-sale securities for which fair value is less than 80% of amortized cost, 3 months or less	3
Available-for-sale securities for which fair value is less than 80% of amortized cost, greater than 3 months, 6 months or less	1
Available-for-sale securities for which fair value is less than 80% of amortized cost, total	4
Public common stock [Member]
Investment disclosure details
Equity securities, cost	386	400
Gross unrealized gains	164	295
Gross unrealized losses	7	4
Equity securities, at fair value	543	691
Continuous unrealized loss position less than 12 months, fair value	48	81
Continuous unrealized loss position less than 12 months, gross unrealized losses	6	4
Continuous unrealized loss position 12 months or longer, fair value	33	1
Continuous unrealized loss position 12 months or longer, gross unrealized losses	1
Continuous unrealized loss position, total, fair value	81	82
Continuous unrealized loss position, total, gross unrealized losses	7	4
Non-redeemable preferred stock [Member]
Investment disclosure details
Equity securities, cost	142	179
Gross unrealized gains	26	31
Gross unrealized losses	6	2
Equity securities, at fair value	162	208
Continuous unrealized loss position less than 12 months, fair value	47	44
Continuous unrealized loss position less than 12 months, gross unrealized losses	3	1
Continuous unrealized loss position 12 months or longer, fair value	38	42
Continuous unrealized loss position 12 months or longer, gross unrealized losses	3	1
Continuous unrealized loss position, total, fair value	85	86
Continuous unrealized loss position, total, gross unrealized losses	6	2
Real estate [Member]
Investment disclosure details
Gross realized gains	4	6	7
Gross realized losses	$ 0	$ 0	$ 0

Investments (details) - Impairm

Investments (details) - Impairment Charges - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Impairment charges
Impairment charges	$ 52	$ 26	$ 15
Fixed maturities [Member]
Impairment charges
Impairment charges	13	16	5
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Impairment charges
Impairment charges		1	2
All other corporate bonds [Member]
Impairment charges
Impairment charges	13	15	3
Equity securities [Member]
Impairment charges
Impairment charges	37	9	5
Public common stock [Member]
Impairment charges
Impairment charges	37	9	5
Other investments [Member]
Impairment charges
Impairment charges	$ 2	$ 1	$ 5

Investments (details) - OTTI Ro

Investments (details) - OTTI Rollforward - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Roll-forward of the credit component of other-than-temporary impairments on fixed maturities recognized in the consolidated statement of income for which a portion of the other-than-temporary impairment was recognized in other comprehensive income [Roll Forward]
Cumulative OTTI credit losses recognized for securities held, beginning of period	$ 99	$ 118
Additions for OTTI securities where no credit losses were previously recognized	2
Additions for OTTI securities where credit losses have been previously recognized		4
Reductions due to sales/defaults of credit-impaired securities	(10)	(11)
Adjustments to book value of credit-impaired securities due to changes in cash flows	(8)	(12)
Cumulative OTTI credit losses recognized for securities still held, end of period	83	99
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Roll-forward of the credit component of other-than-temporary impairments on fixed maturities recognized in the consolidated statement of income for which a portion of the other-than-temporary impairment was recognized in other comprehensive income [Roll Forward]
Cumulative OTTI credit losses recognized for securities held, beginning of period	40	53
Additions for OTTI securities where credit losses have been previously recognized		1
Reductions due to sales/defaults of credit-impaired securities	(6)	(5)
Adjustments to book value of credit-impaired securities due to changes in cash flows	(2)	(9)
Cumulative OTTI credit losses recognized for securities still held, end of period	32	40
All other corporate bonds [Member]
Roll-forward of the credit component of other-than-temporary impairments on fixed maturities recognized in the consolidated statement of income for which a portion of the other-than-temporary impairment was recognized in other comprehensive income [Roll Forward]
Cumulative OTTI credit losses recognized for securities held, beginning of period	59	65
Additions for OTTI securities where no credit losses were previously recognized	2
Additions for OTTI securities where credit losses have been previously recognized		3
Reductions due to sales/defaults of credit-impaired securities	(4)	(6)
Adjustments to book value of credit-impaired securities due to changes in cash flows	(6)	(3)
Cumulative OTTI credit losses recognized for securities still held, end of period	$ 51	$ 59

Investments (details) - Concent

Investments (details) - Concentrations and Credit Quality - Credit Concentration Risk [Member] - Stockholders' Equity, Total [Member] - Minimum [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Investment disclosure details
Concentration risk as a percentage of shareholders' equity	5.00%	5.00%
Obligations of the Canadian government [Member]
Investment disclosure details
Concentration risk as a percentage of shareholders' equity	5.00%	5.00%

Investments (details) - Net Inv

Investments (details) - Net Investment Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net investment income
Gross investment income	$ 2,420	$ 2,826	$ 2,753
Investment expenses	41	39	37
Net investment income	2,379	2,787	2,716
Fixed maturities [Member]
Net investment income
Gross investment income	2,091	2,244	2,310
Equity securities [Member]
Net investment income
Gross investment income	39	40	31
Short-term securities [Member]
Net investment income
Gross investment income	12	9	11
Real estate [Member]
Net investment income
Gross investment income	48	44	37
Other investments [Member]
Net investment income
Gross investment income	$ 230	$ 489	$ 364

Investments (details) - Changes

Investments (details) - Changes in Net Unrealized Investment Gains - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes in net unrealized investment gains [Roll Forward]
Changes in net unrealized investment gains	$ (1,429)	$ 195	$ (2,196)
Income tax expense (benefit)	(392)	125	(770)
Change in net unrealized gain on investment securities, net of tax	(1,037)	70	(1,426)
Balance, beginning of year	880
Balance, end of year	(157)	880
Accumulated Other Comprehensive Income (Loss) [Member]
Changes in net unrealized investment gains [Roll Forward]
Changes in net unrealized investment gains	(1,429)	195	(2,196)
Income tax expense (benefit)	(392)	125	(770)
Change in net unrealized gain on investment securities, net of tax	(1,037)	70	(1,426)
Changes in Net Unrealized Gains on Investment Securities [Member]
Changes in net unrealized investment gains [Roll Forward]
Changes in net unrealized investment gains	(1,034)	978	(2,731)
Income tax expense (benefit)	(357)	334	(950)
Change in net unrealized gain on investment securities, net of tax	(677)	644	(1,781)
Balance, beginning of year	1,966	1,322	3,103
Balance, end of year	1,289	1,966	1,322
Changes in Net Unrealized Gains on Investment Securities [Member] | Fixed maturities [Member]
Changes in net unrealized investment gains [Roll Forward]
Changes in net unrealized investment gains	(893)	913	(2,804)
Changes in Net Unrealized Gains on Investment Securities [Member] | Equity securities [Member]
Changes in net unrealized investment gains [Roll Forward]
Changes in net unrealized investment gains	(143)	63	74
Changes in Net Unrealized Gains on Investment Securities [Member] | Other investments [Member]
Changes in net unrealized investment gains [Roll Forward]
Changes in net unrealized investment gains	$ 2	$ 2	$ (1)

Investments (details) - Derivat

Investments (details) - Derivatives - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivatives
Net realized investment gains (losses)	[1]	$ 3	$ 79	$ 166
Futures [Member] | U.S. Treasury notes contracts [Member]
Derivatives
Notional value of open contracts		400	350
Net realized investment gains (losses)		$ (5)	$ (1)	$ 115
[1]	Total other-than-temporary impairment (OTTI) losses were $(54) million, $(22) million and $(10) million for the years ended December 31, 2015, 2014 and 2013, respectively. Of total OTTI, credit losses of $(52) million, $(26) million and $(15) million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(2) million, $4 million and $5 million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.

Fair Value Measurements (detail

Fair Value Measurements (details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Fair Value Measurements disclosure
Percent of fixed maturities for which a pricing service estimates fair value	98.00%	98.00%
Fair value of the fixed maturities for which the Company used an internal pricing matrix	$ 101	$ 92
Fair value of the fixed maturities for which the Company received a broker quote	$ 117	$ 140
Percent of short-term securities for which a pricing service estimates fair value	99.00%	98.00%
Percent of debt, including commercial paper, for which a pricing service estimates fair value	100.00%	100.00%

Fair Value Measurements (deta67

Fair Value Measurements (details) - Fair Value Hierarchy - Recurring basis [Member] - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	$ 61,419	$ 64,428
Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	2,813	2,843
Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	58,350	61,317
Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	256	268
Fixed maturities [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	60,658	63,474
Fixed maturities [Member] | Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	2,197	2,051
Fixed maturities [Member] | Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	58,243	61,191
Convertible bonds held containing embedded conversion options that are valued separately from the host bond contract and disclosed in Level 2	2	4
Fixed maturities [Member] | Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	218	232
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	2,194	2,053
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member] | Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	2,194	2,049
U.S. Treasury securities and obligations of U.S. government and government agencies and authorities [Member] | Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis		4
Obligations of states, municipalities and political subdivisions [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	31,411	33,573
Obligations of states, municipalities and political subdivisions [Member] | Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	31,398	33,560
Obligations of states, municipalities and political subdivisions [Member] | Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	13	13
Debt securities issued by foreign governments [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	1,873	2,368
Debt securities issued by foreign governments [Member] | Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	1,873	2,368
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	1,981	2,213
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member] | Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	1,957	2,203
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member] | Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	24	10
All other corporate bonds [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	23,089	23,135
All other corporate bonds [Member] | Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	22,915	22,934
All other corporate bonds [Member] | Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	174	201
Redeemable preferred stock [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	110	132
Redeemable preferred stock [Member] | Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	3	2
Redeemable preferred stock [Member] | Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	100	122
Redeemable preferred stock [Member] | Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	7	8
Equity securities [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	705	899
Equity securities [Member] | Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	598	773
Equity securities [Member] | Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	107	126
Public common stock [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	543	691
Public common stock [Member] | Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	543	691
Non-redeemable preferred stock [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	162	208
Non-redeemable preferred stock [Member] | Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	55	82
Non-redeemable preferred stock [Member] | Level 2 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	107	126
Other investments [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	56	55
Other investments [Member] | Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	18	19
Other investments [Member] | Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	38	36
Investments in various publicly-traded securities, including mutual funds and other small holdings disclosed in Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	18	19
Investments in various publicly-traded securities, including mutual funds and other small holdings disclosed in Level 1 [Member] | Level 1 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	18	19
Investment in non-public common and preferred equity securities where the fair value estimate is determined either internally or by an external fund manager and therefore disclosed in Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	38	36
Investment in non-public common and preferred equity securities where the fair value estimate is determined either internally or by an external fund manager and therefore disclosed in Level 3 [Member] | Level 3 [Member]
Level within the fair value hierarchy at which the Company's financial assets are measured
Total invested assets measured on a recurring basis	$ 38	$ 36

Fair Value Measurements (deta68

Fair Value Measurements (details) - Changes in Level 3 - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Changes in Level 3 fair value category [Roll Forward]
Level 3 fair value category, beginning balance	$ 268	$ 289
Level 3 fair value category, total realized and unrealized investment gains (losses) reported in net realized investment gains	3	4
Level 3 fair value category, total unrealized investment gains (losses) reported in increases (decreases) in other comprehensive income	(3)	(1)
Level 3 fair value category purchases	203	233
Level 3 fair value category sales	(9)	(2)
Level 3 fair value category settlements/maturities	(41)	(90)
Gross transfers into Level 3	21	18
Gross transfers out of Level 3	(186)	(183)
Level 3 fair value category, ending balance	256	268
Level 3 fair value category, amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date	(1)
Fixed maturities [Member]
Changes in Level 3 fair value category [Roll Forward]
Level 3 fair value category, beginning balance	232	255
Level 3 fair value category, total realized and unrealized investment gains (losses) reported in net realized investment gains	1	3
Level 3 fair value category, total unrealized investment gains (losses) reported in increases (decreases) in other comprehensive income	(4)	(2)
Level 3 fair value category purchases	202	232
Level 3 fair value category sales	(7)	(1)
Level 3 fair value category settlements/maturities	(41)	(90)
Gross transfers into Level 3	21	18
Gross transfers out of Level 3	(186)	(183)
Level 3 fair value category, ending balance	218	232
Other investments [Member]
Changes in Level 3 fair value category [Roll Forward]
Level 3 fair value category, beginning balance	36	34
Level 3 fair value category, total realized and unrealized investment gains (losses) reported in net realized investment gains	2	1
Level 3 fair value category, total unrealized investment gains (losses) reported in increases (decreases) in other comprehensive income	1	1
Level 3 fair value category purchases	1	1
Level 3 fair value category sales	(2)	(1)
Level 3 fair value category, ending balance	38	$ 36
Level 3 fair value category, amount of total realized investment gains (losses) for the period included in the consolidated statement of income attributable to changes in the fair value of assets still held at the reporting date	$ (1)

Fair Value Measurements Footnot

Fair Value Measurements Footnote (details) - Financial Instruments - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Financial Instruments
Short-term securities	$ 4,671	$ 4,364
Commercial paper amount	100	100
Fair Value [Member]
Financial Instruments
Short-term securities	4,671	4,364
Debt	7,180	7,522
Commercial paper amount	100	100
Fair Value [Member] | Level 1 [Member]
Financial Instruments
Short-term securities	1,685	1,283
Fair Value [Member] | Level 2 [Member]
Financial Instruments
Short-term securities	2,958	3,042
Debt	7,180	7,522
Commercial paper amount	100	100
Fair Value [Member] | Level 3 [Member]
Financial Instruments
Short-term securities	28	39
Carrying Value [Member]
Financial Instruments
Short-term securities	4,671	4,364
Debt	6,244	6,249
Commercial paper amount	$ 100	$ 100

Reinsurance (details)

Reinsurance (details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reinsurance disclosure
Percentage of residual market business written directly by the Company for mandatory pools and associations and then ceded to the mandatory pool	100.00%
Written premiums, direct	$ 24,939	$ 24,844	$ 23,952
Written premiums, assumed	843	788	705
Written premiums, ceded	(1,661)	(1,728)	(1,890)
Total net written premiums	24,121	23,904	22,767
Earned premiums, direct	24,740	24,810	23,891
Earned premiums, assumed	814	743	717
Earned premiums, ceded	(1,680)	(1,840)	(1,971)
Total net earned premiums	$ 23,874	$ 23,713	$ 22,637
Percentage of assumed earned premiums to net earned premiums	3.40%	3.10%	3.20%
Ceded claims and claim adjustment expenses incurred	$ 1,034	$ 953	$ 1,019
Gross reinsurance recoverables on paid and unpaid claims and claim adjustment expenses	3,848	4,270
Allowance for uncollectible reinsurance	(157)	(203)
Net reinsurance recoverables	3,691	4,067
Reinsurance recoverables, mandatory pools and associations	2,015	1,909
Reinsurance recoverables, structured settlements	3,204	3,284
Total reinsurance recoverables	8,910	$ 9,260
Terrorism Risk Insurance Program, annual aggregate industry loss minimum in order for a loss to be covered, next fiscal year	120
Terrorism Risk Insurance Program, ultimate annual aggregate industry loss minimum in order for a loss to be covered	$ 200
Terrorism Risk Insurance Program, percentage of subject losses reimbursed by the Federal Government, after insurer deductible, subject to annual cap, next fiscal year	84.00%
Terrorism Risk Insurance Program, remaining life of the program (in years)	5 years
Terrorism Risk Insurance Program, ultimate percentage of subject losses reimbursed by the Federal Government, after insurer deductible, subject to annual cap	80.00%
Terrorism Risk Insurance Program, percentage of insurer's direct earned premiums for covered lines for the preceding calendar year at which the deductible is set	20.00%
Terrorism Risk Insurance Program, Company's estimated deductible for the year following the date of this report	$ 2,430
Terrorism Risk Insurance Program, annual cap limiting amount of aggregate subject losses for all participating insurers	$ 100,000

Goodwill (details)

Goodwill (details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Goodwill by segment
Goodwill	$ 3,573	$ 3,611
Reportable Segments [Member] | Business and International Insurance [Member]
Goodwill by segment
Goodwill	2,439	2,477
Reportable Segments [Member] | Bond & Specialty Insurance [Member]
Goodwill by segment
Goodwill	496	496
Reportable Segments [Member] | Personal Insurance [Member]
Goodwill by segment
Goodwill	612	612
Other [Member]
Goodwill by segment
Goodwill	$ 26	$ 26

Goodwill (details) - Other Inta

Goodwill (details) - Other Intangible Assets - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 01, 2013	Apr. 01, 2004
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	$ 210	$ 669
Intangible assets subject to amortization, accumulated amortization	148	582
Intangible assets subject to amortization, net	62	87
Amortization expense for other intangible assets	26	46	$ 46
Estimated intangible asset amortization expense, 2016	11
Estimated intangible asset amortization expense, 2017	9
Estimated intangible asset amortization expense, 2018	8
Estimated intangible asset amortization expense, 2019	6
Estimated intangible asset amortization expense, 2020	$ 5
Customer-related [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount		460
Intangible assets subject to amortization, accumulated amortization		$ 446
Dominion [Member] | Fair value adjustment on claims and claim adjustment expense reserves and reinsurance recoverables [Member]
Other intangible assets by major asset class
Intangible assets acquired				$ 5
Dominion [Member] | Contract-related [Member]
Other intangible assets by major asset class
Intangible assets acquired				$ 5
Travelers Property Casualty Corp. [Member] | Fair value adjustment on claims and claim adjustment expense reserves and reinsurance recoverables [Member]
Other intangible assets by major asset class
Intangible assets acquired					$ 191

Goodwill (details) - Total Inta

Goodwill (details) - Total Intangibles - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Goodwill and Other Intangible Assets disclosure
Intangible assets not subject to amortization	$ 217	$ 217
Total other intangible assets, gross carrying amount	427	886
Total other intangible assets, accumulated amortization	148	582
Total other intangible assets, net	$ 279	$ 304

Insurance Claim Reserves (detai

Insurance Claim Reserves (details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Insurance Claim Reserves disclosure
Amount of decrease in gross claims and claim adjustment expense reserves	$ 1,550	$ 1,040
Amount of decline in reinsurance recoverables on unpaid losses	339	492
Accretion of discount	51	50	$ 48
Asbestos and environmental claims reserves, balance	$ 2,170	$ 2,700

Insurance Claim Reserves (det75

Insurance Claim Reserves (details) - Reserve Detail for Claims and Claim Adjustment Expenses - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of beginning and ending reserve balances for claims and claim adjustment expenses [Roll Forward]
Claims and claim adjustment expense reserves at beginning of year	$ 49,850	$ 50,895
Claims and claim adjustment expense reserves at end of year	48,295	49,850	$ 50,895
Property casualty [Member]
Reconciliation of beginning and ending reserve balances for claims and claim adjustment expenses [Roll Forward]
Claims and claim adjustment expense reserves at beginning of year	49,824	50,865	50,888
Reinsurance recoverables on unpaid losses	8,788	9,280	10,254
Net reserves at beginning of year	41,036	41,585	40,634
Estimated claims and claim adjustment expenses for claims arising in the current year	14,412	14,621	14,060
Estimated decrease in claims and claim adjustment expenses for claims arising in prior years	(897)	(957)	(944)
Total increases	13,515	13,664	13,116
Claims and claim adjustment expense payments for claims arising in current year	5,666	5,828	5,485
Claims and claim adjustment expense payments for claims arising in prior years	8,669	8,099	8,477
Total payments	14,335	13,927	13,962
Acquisitions	2		1,792
Unrealized foreign exchange (gain) loss	(395)	(286)	5
Net reserves at end of year	39,823	41,036	41,585
Reinsurance recoverables on unpaid losses	8,449	8,788	9,280
Claims and claim adjustment expense reserves at end of year	48,272	49,824	$ 50,865
Accident and health [Member]
Reconciliation of beginning and ending reserve balances for claims and claim adjustment expenses [Roll Forward]
Claims and claim adjustment expense reserves at beginning of year	26
Claims and claim adjustment expense reserves at end of year	$ 23	$ 26

Insurance Claim Reserves (det76

Insurance Claim Reserves (details) - Reserve Detail for Claims and Claim Adjustment Expenses Acquisitions - USD ($) $ in Millions	Dec. 31, 2015	Oct. 01, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 01, 2013	Dec. 31, 2012
Liability for claims and claim adjustment expense
Claims and claim adjustment expense reserves	$ 48,295		$ 49,850	$ 50,895
Property casualty [Member]
Liability for claims and claim adjustment expense
Net reserves	39,823		41,036	41,585		$ 40,634
Reinsurance recoverables on unpaid losses	8,449		8,788	9,280		10,254
Claims and claim adjustment expense reserves	$ 48,272		$ 49,824	$ 50,865		$ 50,888
Dominion [Member] | Property casualty [Member]
Liability for claims and claim adjustment expense
Net reserves					$ 1,792
Reinsurance recoverables on unpaid losses					352
Claims and claim adjustment expense reserves					$ 2,144
Travelers Participacoes em Seguros Brasil S.A. [Member] | Property casualty [Member]
Liability for claims and claim adjustment expense
Net reserves		$ 2

Insurance Claim Reserves Footno

Insurance Claim Reserves Footnote (details) - Asbestos Payment - Asbestos Direct Action Litigation [Member] $ in Millions	Jan. 15, 2015USD ($)
Loss Contingencies [Line Items]
Payment related to the settlement of the Asbestos Direct Action Litigation impacting gross claims and claim adjustment expense reserves	$ 579
Settlement amount	$ 502

Insurance Claim Reserves (det78

Insurance Claim Reserves (details) - Prior Year Reserve Development by Segment - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Liability for claims and claim adjustment expense
Net favorable prior year reserve development impacting the Company's results of operations	$ 941	$ 941	$ 840
Business and International Insurance [Member]
Liability for claims and claim adjustment expense
Net favorable prior year reserve development impacting the Company's results of operations	405	322	399
Increase to net favorable prior year reserve development related to workers' compensation reinsurance pool for accident years 1996 and prior		162
Reduction to net favorable prior year reserve development precipitated by legislation in New York related to the New York Fund for Reopened Cases for workers' compensation			42
Reduction to net favorable prior year reserve development due to interest awarded as part of damages relating to a legal matter		77
Bond & Specialty Insurance [Member]
Liability for claims and claim adjustment expense
Net favorable prior year reserve development impacting the Company's results of operations	258	450	232
Personal Insurance [Member]
Liability for claims and claim adjustment expense
Net favorable prior year reserve development impacting the Company's results of operations	$ 278	$ 169	$ 209

Insurance Claim Reserves (det79

Insurance Claim Reserves (details) Asbestos and Environmental Reserves - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Asbestos reserves [Member]
Liability for claims and claim adjustment expense
Increase (decrease) to asbestos and environmental reserves	$ 224	$ 250	$ 190
Net losses paid	$ 770	$ 242	$ 218
Percent of total asbestos net paid losses related to policyholders with whom the Company had entered into settlement agreements limiting the Company's liability	69.00%	8.00%	1.00%
Environmental reserves [Member]
Liability for claims and claim adjustment expense
Increase (decrease) to asbestos and environmental reserves	$ 72	$ 87	$ 65
Business and International Insurance [Member] | Asbestos reserves [Member]
Liability for claims and claim adjustment expense
Increase (decrease) to asbestos and environmental reserves	224	250	190
Business and International Insurance [Member] | Environmental reserves [Member]
Liability for claims and claim adjustment expense
Increase (decrease) to asbestos and environmental reserves	$ 72	$ 87	$ 65

Debt (details)

Debt (details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 01, 2015	Dec. 31, 2014
Debt disclosure
Commercial paper amount	$ 100		$ 100
Total short-term debt	500		500
Schedule of debt
Total long-term debt	5,861		5,861
Total debt principal	6,361		6,361
Unamortized fair value adjustment, debt	49		50
Unamortized debt issuance costs	(66)		(62)
Total debt	6,344		6,349
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	700
5.50% Senior notes due December 1, 2015 [Member]
Schedule of debt
Current maturities of long-term debt			$ 400
Interest rate (percent)		5.50%	5.50%
6.25% Senior notes due June 20, 2016 [Member]
Schedule of debt
Current maturities of long-term debt	$ 400
Total long-term debt			$ 400
Interest rate (percent)	6.25%		6.25%
5.75% Senior notes due December 15, 2017 [Member]
Schedule of debt
Total long-term debt	$ 450		$ 450
Interest rate (percent)	5.75%		5.75%
5.80% Senior notes due May 15, 2018 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	5.80%		5.80%
5.90% Senior notes due June 2, 2019 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	5.90%		5.90%
3.90% Senior notes due November 1, 2020 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	3.90%		3.90%
7.75% Senior notes due April 15, 2026 [Member]
Schedule of debt
Total long-term debt	$ 200		$ 200
Interest rate (percent)	7.75%		7.75%
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 200
7.625% Junior subordinated debentures due December 15, 2027 [Member]
Schedule of debt
Total long-term debt	125		$ 125
Unamortized fair value adjustment, debt	$ 15		$ 16
Interest rate (percent)	7.625%		7.625%
6.375% Senior notes due March 15, 2033 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	6.375%		6.375%
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 500
6.75% Senior notes due June 20, 2036 [Member]
Schedule of debt
Total long-term debt	$ 400		$ 400
Interest rate (percent)	6.75%		6.75%
6.25% Senior notes due June 15, 2037 [Member]
Schedule of debt
Total long-term debt	$ 800		$ 800
Interest rate (percent)	6.25%		6.25%
5.35% Senior notes due November 1, 2040 [Member]
Schedule of debt
Total long-term debt	$ 750		$ 750
Interest rate (percent)	5.35%		5.35%
4.60% Senior notes due August 1, 2043 [Member]
Schedule of debt
Total long-term debt	$ 500		$ 500
Interest rate (percent)	4.60%		4.60%
4.30% Senior notes due August 25, 2045 [Member]
Schedule of debt
Total long-term debt	$ 400
Interest rate (percent)	4.30%
8.50% Junior subordinated debentures due December 15, 2045 [Member]
Schedule of debt
Total long-term debt	$ 56		$ 56
Unamortized fair value adjustment, debt	$ 15		$ 15
Interest rate (percent)	8.50%		8.50%
8.312% Junior subordinated debentures due July 1, 2046 [Member]
Schedule of debt
Total long-term debt	$ 73		$ 73
Unamortized fair value adjustment, debt	$ 19		$ 19
Interest rate (percent)	8.312%		8.312%
6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 [Member]
Schedule of debt
Total long-term debt	$ 107		$ 107
Interest rate (percent)	6.25%		6.25%

Debt (details) - Debt Issuance

Debt (details) - Debt Issuance - USD ($) $ in Millions	Aug. 25, 2015	Jul. 25, 2013	Dec. 31, 2015	Dec. 31, 2013
Debt Instrument
Net proceeds of issuance, after original issuance discount and deduction of underwriting expenses and commissions and other expenses			$ 392	$ 494
Senior notes [Member]
Debt Instrument
Debt, principal amount	$ 400	$ 500
Interest rate (percent)	4.30%	4.60%
Net proceeds of issuance, after original issuance discount and deduction of underwriting expenses and commissions and other expenses	$ 392	$ 494
Percentage of principal amount at which redemption price may be set	100.00%	100.00%
Basis points added to current treasury rate used in calculation of alternative redemption price	0.25%	0.15%

Debt (details) - Repayment

Debt (details) - Repayment - USD ($) $ in Millions	Dec. 01, 2015	Mar. 15, 2013	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2014
Debt Instrument
Debt, principal amount repaid			$ 400	$ 500
5.50% Senior notes due December 1, 2015 [Member]
Debt Instrument
Debt, principal amount repaid	$ 400
Interest rate (percent)	5.50%				5.50%
5.00% Senior notes due March 15, 2013 [Member]
Debt Instrument
Debt, principal amount repaid		$ 500
Interest rate (percent)		5.00%

Debt (details) - Junior Sub Deb

Debt (details) - Junior Sub Debt $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)item	Dec. 31, 2014USD ($)
Debt Instrument
Unamortized fair value adjustment, debt	$ 49	$ 50
Junior subordinated debt [Member]
Debt Instrument
Number of junior subordinated debentures that are not fixed-to-floating rate debentures | item	3
Number of separate trusts that issued preferred securities and used proceeds to purchase the Company's subordinated debentures that are not fixed-to-floating rate | item	3
Impact of amortization of the fair value adjustment on interest expense	$ 1	$ 1
7.625% Junior subordinated debentures due December 15, 2027 [Member]
Debt Instrument
Interest rate (percent)	7.625%	7.625%
Debt, effective interest rate (percent)	6.147%	6.147%
Unamortized fair value adjustment, debt	$ 15	$ 16
8.50% Junior subordinated debentures due December 15, 2045 [Member]
Debt Instrument
Interest rate (percent)	8.50%	8.50%
Debt, effective interest rate (percent)	6.362%	6.362%
Unamortized fair value adjustment, debt	$ 15	$ 15
8.312% Junior subordinated debentures due July 1, 2046 [Member]
Debt Instrument
Interest rate (percent)	8.312%	8.312%
Debt, effective interest rate (percent)	6.362%	6.362%
Unamortized fair value adjustment, debt	$ 19	$ 19
6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 [Member]
Debt Instrument
Number of consecutive years before Company is required to settle deferred interest	5 years
Number of consecutive years Company may defer interest without giving rise to an event of default	10 years
Interest rate (percent)	6.25%	6.25%
6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 [Member] | Minimum [Member]
Debt Instrument
Number of occasions the Company may defer payment of interest | item	1
6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 [Member] | Period from issuance to March 14, 2017 [Member]
Debt Instrument
Interest rate (percent)	6.25%
6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 [Member] | Period from March 15, 2017 until redemption [Member]
Debt Instrument
Percentage of principal amount at which redemption price may be set	100.00%
6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 [Member] | Period from March 15, 2017 until redemption [Member] | LIBOR [Member]
Debt Instrument
Maturity of LIBOR rate used	three-month LIBOR
Basis spread on variable rate	2.215%
6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 [Member] | Period from March 15, 2037 until redemption [Member]
Debt Instrument
Days in period during which Company will be required to raise proceeds to repay debentures if Company chooses not to redeem the debentures	180 days
6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 [Member] | Period from March 15, 2037 until redemption [Member] | Minimum [Member]
Debt Instrument
Days before scheduled maturity date that Company's 180-day period must end	10 days
6.25% Fixed-to-floating rate junior subordinated debentures due March 15, 2067 [Member] | Period from March 15, 2037 until redemption [Member] | Maxiumum [Member]
Debt Instrument
Days before scheduled maturity date that Company's 180-day period must end	15 days

Debt (details) - Maturities

Debt (details) - Maturities $ in Millions	Dec. 31, 2015USD ($)
Maturities of long-term debt
Amount of debt obligations, other than commercial paper, due in 2016	$ 400
Amount of debt obligations, other than commercial paper, due in 2017	450
Amount of debt obligations, other than commercial paper, due in 2018	500
Amount of debt obligations, other than commercial paper, due in 2019	500
Amount of debt obligations, other than commercial paper, due in 2020	$ 500

Debt (details) - Line of Credit

Debt (details) - Line of Credit - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Line of credit [Member]
Line of credit
Credit agreement, term (in years)	5 years
Credit agreement, maximum borrowing capacity	$ 1,000
Credit agreement, covenant terms	Pursuant to the credit agreement covenants, the Company must maintain a minimum consolidated net worth, defined as shareholders' equity determined in accordance with GAAP plus (a) trust preferred securities (not to exceed 15% of total capital) and (b) mandatorily convertible securities (combined with trust preferred securities, not to exceed 25% of total capital) less goodwill and other intangible assets, of $13.73 billion. In addition, the credit agreement contains other customary restrictive covenants as well as certain customary events of default, including with respect to a change in control, which is defined to include the acquisition of 35% or more of the Company's voting stock and certain changes in the composition of the Company's board of directors.
Credit agreement, threshold of consolidated net worth	$ 13,730
Credit agreement, compliance	At December 31, 2015, the Company was in compliance with these covenants.
Line of credit [Member] | Minimum [Member]
Line of credit
Percentage of Company's voting stock acquired by outside entity that would be considered a change in control	35.00%
Line of credit [Member] | Maxiumum [Member]
Line of credit
Maximum percentage of trust preferred securities relative to total capital in determining consolidated net worth	15.00%
Maximum percentage of trust preferred securities and mandatorily convertible securities relative to total capital in determining consolidated net worth	25.00%
Line of credit [Member] | LIBOR [Member]
Line of credit
Credit agreement, cost of borrowing, basis points above LIBOR	1.125%
Line of credit [Member] | LIBOR [Member] | Minimum [Member]
Line of credit
Credit agreement, cost of borrowing, basis points above LIBOR	0.875%
Line of credit [Member] | LIBOR [Member] | Maxiumum [Member]
Line of credit
Credit agreement, cost of borrowing, basis points above LIBOR	1.50%
Commercial Paper [Member]
Line of credit
Credit agreement, maximum borrowing capacity	$ 800
Commercial Paper [Member] | Minimum [Member]
Line of credit
Interest rate on commercial paper	0.09%	0.08%
Commercial Paper [Member] | Maxiumum [Member]
Line of credit
Interest rate on commercial paper	0.30%	0.15%

Shareholders' Equity and Divi86

Shareholders' Equity and Dividend Availability (details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Apr. 30, 2015	May. 31, 2013
Shareholders' Equity and Dividend Availability disclosure
Number of authorized shares	1,755				1,755
Number of authorized shares, voting common stock	1,745				1,745
Number of authorized shares, preferred shares	5				5			5
Number of authorized shares, undesignated shares	5				5
Additional share repurchase authorization							$ 5,000
Number of shares purchased (in shares)	8.8	7.3	7.9	5.6	29.6
Cost of shares repurchased	$ 1,000	$ 750	$ 800	$ 600	$ 3,150
Average price paid per share	$ 113.47	$ 102.81	$ 101.62	$ 106.97	$ 106.46
Remaining capacity under share repurchase authorization	$ 3,334	$ 4,334	$ 5,084	$ 884	$ 3,334
Shares acquired to cover tax withholding costs and exercise costs					$ 74	$ 58

Shareholders' Equity and Divi87

Shareholders' Equity and Dividend Availability (details) - Dividend Availability $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)item$ / shares	Dec. 31, 2014USD ($)item$ / shares	Dec. 31, 2013USD ($)item$ / shares
Statutory accounting principals
Dividends received by TRV and its two non-insurance holding companies from their U.S. insurance subsidiaries	$ 3,750	$ 4,100	$ 2,900
Cash dividends declared per common share | $ / shares	$ 2.38	$ 2.15	$ 1.96
Cash dividends paid	$ 739	$ 729	$ 729
Insurance subsidiaries [Member]
Statutory accounting principals
Statutory net income of the Company's domestic and international insurance subsidiaries	3,800	3,970	$ 4,180
Statutory capital and surplus of the Company's domestic and international insurance subsidiaries	$ 20,570	$ 21,050
Travelers [Member]
Statutory accounting principals
Number of non-insurance holding companies underneath TRV | item	2	2	2
Cash dividends declared per common share | $ / shares	$ 2.38	$ 2.15	$ 1.96
Cash dividends paid	$ 739	$ 729	$ 729
Connecticut Insurance Department [Member] | Insurance subsidiaries [Member]
Statutory accounting principals
Maximum amount of dividends available to be paid by subsidiaries to their parent without prior approval of the Connecticut Insurance Department	$ 3,810

Other Comprehensive Income an88

Other Comprehensive Income and Accumulated Other Comprehensive Income (details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated other comprehensive income [Roll Forward]
Shareholders' equity, beginning of year	$ 24,836	$ 24,796
Other comprehensive income (loss), net of taxes	(1,037)	70	$ (1,426)
Shareholders' equity, end of year	23,598	24,836	24,796
Pretax components of other comprehensive income (loss) and related tax expense (benefit)
Other comprehensive income (loss) before income taxes	(1,429)	195	(2,196)
Income tax expense (benefit), other comprehensive income (loss)	(392)	125	(770)
Other comprehensive income (loss), net of taxes	(1,037)	70	(1,426)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated other comprehensive income [Roll Forward]
Shareholders' equity, beginning of year	880	810	2,236
Other comprehensive income (loss) before reclassifications	(1,089)	52	(1,463)
Amounts reclassified from accumulated other comprehensive income	52	18	37
Other comprehensive income (loss), net of taxes	(1,037)	70	(1,426)
Shareholders' equity, end of year	(157)	880	810
Pretax components of other comprehensive income (loss) and related tax expense (benefit)
Other comprehensive income (loss) before income taxes	(1,429)	195	(2,196)
Income tax expense (benefit), other comprehensive income (loss)	(392)	125	(770)
Other comprehensive income (loss), net of taxes	(1,037)	70	(1,426)
Changes in Net Unrealized Gains on Investment Securities Having No Credit Losses Recognized in the Consolidated Statement of Income [Member]
Accumulated other comprehensive income [Roll Forward]
Shareholders' equity, beginning of year	1,768	1,125	2,908
Other comprehensive income (loss) before reclassifications	(641)	667	(1,740)
Amounts reclassified from accumulated other comprehensive income	(27)	(24)	(43)
Other comprehensive income (loss), net of taxes	(668)	643	(1,783)
Shareholders' equity, end of year	1,100	1,768	1,125
Pretax components of other comprehensive income (loss) and related tax expense (benefit)
Other comprehensive income (loss) before income taxes	(1,020)	976	(2,734)
Income tax expense (benefit), other comprehensive income (loss)	(352)	333	(951)
Other comprehensive income (loss), net of taxes	(668)	643	(1,783)
Changes in Net Unrealized Gains on Investment Securities Having Credit Losses Recognized in the Consolidated Statement of Income [Member]
Accumulated other comprehensive income [Roll Forward]
Shareholders' equity, beginning of year	198	197	195
Other comprehensive income (loss) before reclassifications	(11)	(2)	(2)
Amounts reclassified from accumulated other comprehensive income	2	3	4
Other comprehensive income (loss), net of taxes	(9)	1	2
Shareholders' equity, end of year	189	198	197
Pretax components of other comprehensive income (loss) and related tax expense (benefit)
Other comprehensive income (loss) before income taxes	(14)	2	3
Income tax expense (benefit), other comprehensive income (loss)	(5)	1	1
Other comprehensive income (loss), net of taxes	(9)	1	2
Net Benefit Plan Assets and Obligations Recognized in Shareholders' Equity [Member]
Accumulated other comprehensive income [Roll Forward]
Shareholders' equity, beginning of year	(755)	(431)	(857)
Other comprehensive income (loss) before reclassifications	(18)	(363)	358
Amounts reclassified from accumulated other comprehensive income	60	39	68
Other comprehensive income (loss), net of taxes	42	(324)	426
Shareholders' equity, end of year	(713)	(755)	(431)
Pretax components of other comprehensive income (loss) and related tax expense (benefit)
Other comprehensive income (loss) before income taxes	66	(494)	647
Income tax expense (benefit), other comprehensive income (loss)	24	(170)	221
Other comprehensive income (loss), net of taxes	42	(324)	426
Net Unrealized Foreign Currency Translation [Member]
Accumulated other comprehensive income [Roll Forward]
Shareholders' equity, beginning of year	(331)	(81)	(10)
Other comprehensive income (loss) before reclassifications	(419)	(250)	(79)
Amounts reclassified from accumulated other comprehensive income	17		8
Other comprehensive income (loss), net of taxes	(402)	(250)	(71)
Shareholders' equity, end of year	(733)	(331)	(81)
Pretax components of other comprehensive income (loss) and related tax expense (benefit)
Other comprehensive income (loss) before income taxes	(461)	(289)	(112)
Income tax expense (benefit), other comprehensive income (loss)	(59)	(39)	(41)
Other comprehensive income (loss), net of taxes	$ (402)	$ (250)	$ (71)

Other Comprehensive Income an89

Other Comprehensive Income and Accumulated Other Comprehensive Income (details) - Reclassifications - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting realized gains on the income statement	[1]									$ (3)	$ (79)	$ (166)
Reclassification adjustment impacting general and administrative expense on the income statement										4,079	3,952	3,757
Total reclassifications		$ (1,209)	$ (1,307)	$ (1,076)	$ (1,148)	$ (1,460)	$ (1,258)	$ (901)	$ (1,470)	(4,740)	(5,089)	(4,945)
Income tax benefit		(343)	(379)	(264)	(315)	(422)	(339)	(218)	(418)	(1,301)	(1,397)	(1,272)
Amounts reclassified from accumulated other comprehensive income, net of taxes		$ (866)	$ (928)	$ (812)	$ (833)	$ (1,038)	$ (919)	$ (683)	$ (1,052)	(3,439)	(3,692)	(3,673)
Accumulated Other Comprehensive Income (Loss) [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Total reclassifications										79	28	52
Income tax benefit										27	10	15
Amounts reclassified from accumulated other comprehensive income, net of taxes										52	18	37
Changes in Net Unrealized Gains on Investment Securities Having No Credit Losses Recognized in the Consolidated Statement of Income [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting realized gains on the income statement										(42)	(36)	(66)
Income tax benefit										(15)	(12)	(23)
Amounts reclassified from accumulated other comprehensive income, net of taxes										(27)	(24)	(43)
Changes in Net Unrealized Gains on Investment Securities Having Credit Losses Recognized in the Consolidated Statement of Income [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting realized gains on the income statement										2	4	5
Income tax benefit											1	1
Amounts reclassified from accumulated other comprehensive income, net of taxes										2	3	4
Net Benefit Plan Assets and Obligations Recognized in Shareholders' Equity [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting general and administrative expense on the income statement										93	60	105
Income tax benefit										33	21	37
Amounts reclassified from accumulated other comprehensive income, net of taxes										60	$ 39	68
Net Unrealized Foreign Currency Translation [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income
Reclassification adjustment impacting realized gains on the income statement										26		8
Income tax benefit										9
Amounts reclassified from accumulated other comprehensive income, net of taxes										$ 17		$ 8
[1]	Total other-than-temporary impairment (OTTI) losses were $(54) million, $(22) million and $(10) million for the years ended December 31, 2015, 2014 and 2013, respectively. Of total OTTI, credit losses of $(52) million, $(26) million and $(15) million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(2) million, $4 million and $5 million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.

Earnings per Share (details)

Earnings per Share (details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings per Share disclosure
Net income	$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	$ 3,439	$ 3,692	$ 3,673
Participating share-based awards - allocated income									(25)	(27)	(27)
Net income available to common shareholders -- basic									3,414	3,665	3,646
Net income available to common shareholders -- diluted									$ 3,414	$ 3,665	$ 3,646
Weighted average shares outstanding, basic									310.6	338.8	370.3
Weighted average effects of dilutive securities, stock options and performance shares (in shares)									3.3	3.7	4
Weighted average shares outstanding, diluted									313.9	342.5	374.3
Net income per common share, basic	$ 2.87	$ 3	$ 2.56	$ 2.58	$ 3.15	$ 2.72	$ 1.98	$ 2.98	$ 10.99	$ 10.82	$ 9.84
Net income per common share, diluted	$ 2.83	$ 2.97	$ 2.53	$ 2.55	$ 3.11	$ 2.69	$ 1.95	$ 2.95	$ 10.88	$ 10.70	$ 9.74

Income Taxes (details)

Income Taxes (details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Taxes disclosure
Current income tax expense included in consolidated statement of income, federal									$ 1,144	$ 1,216	$ 1,059
Current income tax expense included in consolidated statement of income, foreign									29	28	30
Current income tax expense included in consolidated statement of income, state									9	10	6
Total current tax expense									1,182	1,254	1,095
Deferred income tax expense included in consolidated statement of income, federal									117	121	167
Deferred income tax expense included in consolidated statement of income, foreign									2	22	10
Total deferred tax expense									119	143	177
Total income tax expense included in consolidated statement of income	$ 343	$ 379	$ 264	$ 315	$ 422	$ 339	$ 218	$ 418	1,301	1,397	1,272
Expense (benefit) relating to share-based compensation, the changes in unrealized gain on investments, unrealized loss on foreign exchange and other items in other comprehensive income									(448)	68	(822)
Total income tax expense included in consolidated financial statements									853	1,465	450
U.S. income before income taxes									4,621	4,899	4,804
Foreign income before income taxes									119	190	141
Income before income taxes	1,209	$ 1,307	$ 1,076	$ 1,148	1,460	$ 1,258	$ 901	$ 1,470	$ 4,740	$ 5,089	$ 4,945
Statutory tax rate (percent)									35.00%	35.00%	35.00%
Expected federal income tax expense									$ 1,659	$ 1,781	$ 1,731
Tax effect of nontaxable investment income									(345)	(379)	(409)
Tax effect of other, net									$ (13)	$ (5)	$ (50)
Effective tax rate (percent)									27.00%	27.00%	26.00%
Income taxes paid									$ 1,207	$ 1,147	$ 1,057
Current income tax payable	50				139				50	139
Deferred tax assets, claims and claim adjustment expense reserves	691				768				691	768
Deferred tax assets, unearned premium reserves	731				709				731	709
Deferred tax assets, compensation-related liabilities	326				345				326	345
Deferred tax assets, other	320				346				320	346
Total gross deferred tax assets	2,068				2,168				2,068	2,168
Deferred tax liabilities, deferred acquisition costs	580				565				580	565
Deferred tax liabilities, investments	867				1,267				867	1,267
Deferred tax liabilities, internally-developed software	134				130				134	130
Deferred tax liabilities, other	191				173				191	173
Total gross deferred tax liabilities	1,772				2,135				1,772	2,135
Net deferred tax asset	296				$ 33				296	$ 33
Amount of the Company's foreign operations' undistributed earnings for which U.S. income taxes have not been recognized	$ 383								$ 383

Income Taxes (details) - NOL Ca

Income Taxes (details) - NOL Carryforwards $ in Millions	Dec. 31, 2015USD ($)
United States [Member]
Net Operating Loss Carryforward
Net operating loss carryforward	$ 4
Brazil [Member]
Net Operating Loss Carryforward
Net operating loss carryforward	1
United Kingdom [Member]
Net Operating Loss Carryforward
Net operating loss carryforward	$ 200

Income Taxes (details) - Additi

Income Taxes (details) - Additional Tax Details - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of unrecognized tax benefits [Roll Forward]
Unrecognized tax benefits, balance at January 1	$ 23	$ 21
Additions for tax positions of prior years	2	2
Reductions for tax positions of prior years	(9)
Unrecognized tax benefits, balance at December 31	16	23	$ 21
Unrecognized tax benefits that, if recognized, would affect the annual effective tax rate	4	2
Amount of unrecognized tax benefits that are tax positions for which the ultimate deductibility is certain, but for which there is uncertainty about the timing of deductibility	12	21
Amount of interest recognized on unrecognized tax benefits in income taxes		31
Amount of interest benefit recognized on unrecognized tax benefits in income taxes	(32)		$ (67)
Accrued payment of interest balance for unrecognized tax benefits	$ 26	$ 58

Share-Based Incentive Compens94

Share-Based Incentive Compensation (details) - USD ($) $ / shares in Units, $ in Millions	Feb. 02, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	May. 31, 2014
Summary of stock option activity
Stock options outstanding, beginning of year, number (in shares)		10,024,860
Granted (in shares)		2,244,464
Stock options exercised, number (in shares)		(2,310,548)
Stock options forfeited or expired, number (in shares)		(94,521)
Stock options outstanding, end of year, number (in shares)		9,864,255	10,024,860
Stock options outstanding, beginning of year, weighted average exercise price (per share)		$ 63.08
Stock options granted, weighted average exercise price (per share)		106.04
Stock options exercised, weighted average exercise price (per share)		55.16
Stock options forfeited or expired, weighted average exercise price (per share)		87.17
Stock options outstanding, end of year, weighted average exercise price (per share)		$ 74.48	$ 63.08
Stock options outstanding, weighted average contractual life remaining		6 years 7 months 6 days
Stock options outstanding, aggregate intrinsic value		$ 379
Stock options vested at end of year, number (in shares)		7,226,516
Stock options vested at end of year, weighted average exercise price (per share)		$ 68.80
Stock options vested at end of year, weighted average contractual life remaining		6 years
Stock options vested at end of year, aggregate intrinsic value		$ 318
Stock options exercisable at end of year, number (in shares)		4,155,912
Stock options exercisable at end of year, weighted average exercise price (per share)		$ 53.51
Stock options exercisable at end of year, weighted average contractual life remaining		4 years 3 months 18 days
Stock options exercisable at end of year, aggregate intrinsic value		$ 247
Stock option grants [Member]
Assumptions used in estimating fair value of options
Expected term of stock options		6 years	6 years	6 years
Expected volatility of the Company's stock (percent)		19.29%
Weighted average volatility (percent)		19.29%	27.50%	28.80%
Expected annual dividend per share		$ 2.20		$ 1.84
Risk-free rate		1.31%
Summary of stock option activity
Stock options granted, weighted average grant-date fair value of options granted (per share)		$ 15.78	$ 17.22	$ 17.09
Total intrinsic value of options exercised during the year		$ 120	$ 117	$ 122
Stock option grants [Member] | Minimum [Member]
Assumptions used in estimating fair value of options
Expected volatility of the Company's stock (percent)			27.20%	28.70%
Expected annual dividend per share			$ 2
Risk-free rate			1.81%	1.11%
Stock option grants [Member] | Maxiumum [Member]
Assumptions used in estimating fair value of options
Expected volatility of the Company's stock (percent)			27.50%	28.80%
Expected annual dividend per share			$ 2.20
Risk-free rate			1.82%	1.14%
The Travelers Companies, Inc 2014 Stock Incentive Plan [Member]
Share-based compensation plan description
Number of shares of the Company's common stock authorized for grant under the 2014 Incentive Plan					10,000,000
The Travelers Companies, Inc 2014 Stock Incentive Plan [Member] | Stock option grants [Member]
Share-based compensation plan description
Option term		10 years
Vesting period		3 years
The Travelers Companies, Inc 2014 Stock Incentive Plan [Member] | Stock option grants [Member] | Subsequent Event [Member]
Summary of stock option activity
Granted (in shares)	2,808,558
Stock options granted, weighted average exercise price (per share)	$ 106.03
Stock options granted, weighted average grant-date fair value of options granted (per share)	$ 13.26
The Travelers Companies, Inc 2014 Stock Incentive Plan [Member] | Director deferred stock awards [Member]
Share-based compensation plan description
Number of days prior to date of annual meeting in year following date of grant in which annual deferred stock awards vest in full		1 day
Number of months after termination of service as a director before distributions of deferreed stock awards begin		6 months

Share-Based Incentive Compens95

Share-Based Incentive Compensation (details) - Restricted Stock - USD ($) $ / shares in Units, $ in Millions	Feb. 02, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restricted stock units, deferred stock units and performance share awards [Member]
Share-based compensation
Fair value of shares that vested during the year		$ 179	$ 147	$ 151
Restricted stock units, deferred stock units and performance share awards [Member] | Subsequent Event [Member]
Summary of other equity instruments [Roll Forward]
Other equity instruments, granted, number	1,094,685
Other equity instruments, granted, weighted average grant-date fair value	$ 106.03
Restricted and deferred stock units [Member]
Summary of other equity instruments [Roll Forward]
Other equity instruments, nonvested, number, beginning of year		1,760,971
Other equity instruments, granted, number		607,200
Other equity instruments, vested, number		(789,538)
Other equity instruments, forfeited, number		(142,675)
Other equity instruments, nonvested, number, end of year		1,435,958	1,760,971
Other equity instruments, nonvested, weighted average grant-date fair value, beginning of year		$ 72.40
Other equity instruments, granted, weighted average grant-date fair value		106.02
Other equity instruments, vested, weighted average grant-date fair value		69.03
Other equity instruments, forfeited, weighted average grant-date fair value		73.57
Other equity instruments, nonvested, weighted average grant-date fair value, end of year		$ 88.35	$ 72.40
Other equity instruments, nonvested dividend equivalents, number, beginning of year		387
Other equity instruments, nonvested dividend equivalents, number, end of year		396	387
Restricted and deferred stock units [Member] | Subsequent Event [Member]
Summary of other equity instruments [Roll Forward]
Other equity instruments, granted, number	618,274
Restricted stock units [Member]
Share-based compensation
Award vesting period		3 years
Performance shares [Member]
Share-based compensation
Award vesting period		3 years
Peformance period		3 years
Summary of other equity instruments [Roll Forward]
Other equity instruments, nonvested, number, beginning of year		1,290,069
Other equity instruments, granted, number		460,855
Other equity instruments, vested, number		(676,177)
Other equity instruments, forfeited, number		(31,352)
Other equity instruments, performance-based adjustment, number		58,594
Other equity instruments, nonvested, number, end of year		1,101,989	1,290,069
Other equity instruments, nonvested, weighted average grant-date fair value, beginning of year		$ 79.46
Other equity instruments, granted, weighted average grant-date fair value		106.04
Other equity instruments, vested, weighted average grant-date fair value		79.28
Other equity instruments, forfeited, weighted average grant-date fair value		86.41
Other equity instruments, performance-based adjustment, weighted average grant-date fair value		94.06
Other equity instruments, nonvested, weighted average grant-date fair value, end of year		$ 91.27	$ 79.46
Other equity instruments, nonvested dividend equivalents, number, beginning of year		38,738
Other equity instruments, nonvested dividend equivalents, number, end of year		40,663	38,738
Performance shares [Member] | Subsequent Event [Member]
Summary of other equity instruments [Roll Forward]
Other equity instruments, granted, number	476,411
Performance shares [Member] | Feburary 2014, 2015 and 2016 Awards [Member] | Minimum [Member]
Share-based compensation
Percentage of of performance shares to vest		50.00%
Performance shares [Member] | Feburary 2014, 2015 and 2016 Awards [Member] | Maxiumum [Member]
Share-based compensation
Percentage of of performance shares to vest		150.00%

Share-Based Incentive Compensta

Share-Based Incentive Compenstaion (details) - Cost Recognition - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based compensation
Total compensation cost recognized in earnings for all share-based incentive compensation awards	$ 141	$ 138	$ 129
Tax benefit recognized in earnings related to compensation costs	47	47	45
Total unrecognized compensation cost related to all nonvested share-based incentive compensation awards	$ 124
Weighted-average period of recognition for unrecognized compensation cost (in years)	1 year 8 months 12 days
Cash received from the exercise of employee stock options under share-based compensation plans	$ 183	195	206
Tax benefit realized for tax deductions from employee stock options	$ 41	40
Minimum [Member]
Share-based compensation
Estimated annual forfeiture rate reflected in share-based compensation cost (percent)	3.00%
Maxiumum [Member]
Share-based compensation
Estimated annual forfeiture rate reflected in share-based compensation cost (percent)	4.50%
Performance shares [Member]
Share-based compensation
Estimated attainment of performance shares at grant date (percent)	100.00%
Compensation cost adjustments for the updated estimate of performance shares due to attaining certain performance levels	$ 8	$ 14	$ 8

Pension Plans, Retirement Ben97

Pension Plans, Retirement Benefits and Savings Plans (details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plans [Member]
Change in projected benefit obligation [Roll Forward]
Benefit obligation, balance, beginning of year	$ 3,612	$ 3,117
Benefits earned	131	110	$ 118
Interest cost on benefit obligation	144	150	132
Actuarial loss (gain)	(201)	457
Benefits paid	(199)	(198)
Plan amendments		(8)
Curtailment		(3)
Settlement		(6)
Foreign currency exchange rate change, change in projected benefit obligation	(9)	(7)
Benefit obligation, balance, end of year	3,478	3,612	3,117
Change in plan assets [Roll Forward]
Fair value of plan assets, balance, beginning of year	3,357	3,203
Actual return on plan assets	(14)	159
Company contributions	107	207
Benefits paid	(199)	(198)
Foreign currency exchange rate change, change in plan assets	(9)	(8)
Settlement		(6)
Fair value of plan assets, balance, end of year	3,242	3,357	3,203
Funded status of plan at end of year	(236)	(255)
Amounts recognized in the consolidated balance sheet consist of:
Accrued over-funded benefit plan assets	4	6
Accrued under-funded benefit plan liabilities	(240)	(261)
Total amount recognized in the consolidated balance sheet	(236)	(255)
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss	1,131	1,185
Prior service benefit	(8)	(8)
Total amount recognized in accumulated other comprehensive income	1,123	1,177
Qualified Domestic Pension Plan [Member]
Change in projected benefit obligation [Roll Forward]
Benefit obligation, balance, beginning of year	3,385	2,908
Benefits earned	124	104
Interest cost on benefit obligation	135	140
Actuarial loss (gain)	(203)	428
Benefits paid	(191)	(187)
Plan amendments		(8)
Benefit obligation, balance, end of year	3,250	3,385	2,908
Change in plan assets [Roll Forward]
Fair value of plan assets, balance, beginning of year	3,235	3,074
Actual return on plan assets	(17)	148
Company contributions	100	200	0
Benefits paid	(191)	(187)
Fair value of plan assets, balance, end of year	3,127	3,235	3,074
Funded status of plan at end of year	(123)	(150)
Amounts recognized in the consolidated balance sheet consist of:
Accrued under-funded benefit plan liabilities	(123)	(150)
Total amount recognized in the consolidated balance sheet	(123)	(150)
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss	1,079	1,132
Prior service benefit	(8)	(8)
Total amount recognized in accumulated other comprehensive income	1,071	1,124
Nonqualified and Foreign Pension Plans [Member]
Change in projected benefit obligation [Roll Forward]
Benefit obligation, balance, beginning of year	227	209
Benefits earned	7	6
Interest cost on benefit obligation	9	10
Actuarial loss (gain)	2	29
Benefits paid	(8)	(11)
Curtailment		(3)
Settlement		(6)
Foreign currency exchange rate change, change in projected benefit obligation	(9)	(7)
Benefit obligation, balance, end of year	228	227	209
Change in plan assets [Roll Forward]
Fair value of plan assets, balance, beginning of year	122	129
Actual return on plan assets	3	11
Company contributions	7	7
Benefits paid	(8)	(11)
Foreign currency exchange rate change, change in plan assets	(9)	(8)
Settlement		(6)
Fair value of plan assets, balance, end of year	115	122	129
Funded status of plan at end of year	(113)	(105)
Amounts recognized in the consolidated balance sheet consist of:
Accrued over-funded benefit plan assets	4	6
Accrued under-funded benefit plan liabilities	(117)	(111)
Total amount recognized in the consolidated balance sheet	(113)	(105)
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss	52	53
Total amount recognized in accumulated other comprehensive income	52	53
Postretirement Benefit Plans [Member]
Change in projected benefit obligation [Roll Forward]
Benefit obligation, balance, beginning of year	255	211
Interest cost on benefit obligation	10	10	9
Actuarial loss (gain)	(3)	51
Benefits paid	(13)	(15)
Plan amendments	(11)
Foreign currency exchange rate change, change in projected benefit obligation	(5)	(2)
Benefit obligation, balance, end of year	233	255	211
Change in plan assets [Roll Forward]
Fair value of plan assets, balance, beginning of year	16	17
Company contributions	12	14
Benefits paid	(13)	(15)
Fair value of plan assets, balance, end of year	15	16	$ 17
Funded status of plan at end of year	(218)	(239)
Amounts recognized in the consolidated balance sheet consist of:
Accrued under-funded benefit plan liabilities	(218)	(239)
Total amount recognized in the consolidated balance sheet	(218)	(239)
Amounts recognized in accumulated other comprehensive income consist of:
Net actuarial loss	4	9
Prior service benefit	(35)	(26)
Total amount recognized in accumulated other comprehensive income	$ (31)	$ (17)

Pension Plans, Retirement Ben98

Pension Plans, Retirement Benefits and Savings Plans (details) - Additional Pension Disclosures - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income:
Total other changes in benefit plan assets and benefit obligations recognized in other comprehensive income	$ (66)	$ 494	$ (647)
Pension Plans [Member]
Defined benefit plan disclosure
Total accumulated benefit obligation	3,370	3,510
Aggregate projected benefit obligation for pension plans with an accumulated benefit obligation in excess of plan assets	3,470	3,530
Aggregate accumulated benefit obligation for pension plans with an accumulated benefit obligation in excess of plan assets	3,360	3,430
Fair value of plan assets for pension plans with an accumulated benefit obligation in excess of plan assets	3,230	3,270
Components of net periodic benefit cost
Service cost	131	110	118
Interest cost on benefit obligation	144	150	132
Expected return on plan assets	(230)	(218)	(208)
Net periodic benefit cost, curtailment		(1)
Net periodic benefit cost, settlement		2
Net periodic benefit cost, amortization of unrecognized prior service benefit	(1)
Net periodic benefit cost, amortization of unrecognized net actuarial loss (gain)	96	65	107
Net periodic benefit cost	140	108	149
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income:
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, prior service benefit		(8)
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, net actuarial loss (gain)	43	516	(518)
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, curtailment		(2)
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, settlement		(2)
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, amortization of prior service benefit	1
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, amortization of net actuarial gain (loss)	(96)	(65)	(107)
Total other changes in benefit plan assets and benefit obligations recognized in other comprehensive income	(52)	439	(625)
Total other changes recognized in net periodic benefit cost and other comprehensive income	88	547	(476)
Estimated net actuarial loss that will be amortized from other comprehensive income into net periodic benefit cost over the next fiscal year	66
Estimated prior service benefit to be amortized over the next fiscal year	1
Qualified Domestic Pension Plan [Member]
Defined benefit plan disclosure
Total accumulated benefit obligation	3,150	3,290
Required contributions made	0	0	0
Required contributions during next fiscal year	0
Components of net periodic benefit cost
Service cost	124	104
Interest cost on benefit obligation	135	140
Nonqualified and Foreign Pension Plans [Member]
Defined benefit plan disclosure
Total accumulated benefit obligation	220	220
Components of net periodic benefit cost
Service cost	7	6
Interest cost on benefit obligation	9	10
Foreign Pension Plan [Member]
Defined benefit plan disclosure
Required contributions during next fiscal year	0
Postretirement Benefit Plans [Member]
Components of net periodic benefit cost
Interest cost on benefit obligation	10	10	9
Expected return on plan assets			(1)
Net periodic benefit cost, amortization of unrecognized prior service benefit	(3)	(2)	(2)
Net periodic benefit cost, amortization of unrecognized net actuarial loss (gain)	1	(3)
Net periodic benefit cost	8	5	6
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income:
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, prior service benefit	(11)
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, net actuarial loss (gain)	(3)	50	(24)
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, amortization of prior service benefit	3	2	2
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income, amortization of net actuarial gain (loss)	(1)	3
Total other changes in benefit plan assets and benefit obligations recognized in other comprehensive income	(12)	55	(22)
Total other changes recognized in net periodic benefit cost and other comprehensive income	(4)	$ 60	$ (16)
Estimated prior service benefit to be amortized over the next fiscal year	3
Postretirement Benefit Plans [Member] | Maxiumum [Member]
Other changes in benefit plan assets and benefit obligations recognized in other comprehensive income:
Estimated net actuarial loss that will be amortized from other comprehensive income into net periodic benefit cost over the next fiscal year	$ 1

Pension Plans, Retirement Ben99

Pension Plans, Retirement Benefits and Savings Plans (details) - Assumptions - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined benefit plan disclosure
Assumptions used to determine benefit obligations, future compensation increase rate (percent)	4.00%	4.00%
Assumptions used to determine net periodic benefit cost, discount rate (percent)	4.10%	4.96%
Pension Plans [Member]
Defined benefit plan disclosure
Assumptions used to determine net periodic benefit cost, expected long-term rate of return on assets (percent)	7.25%	7.50%
Qualified Domestic Pension Plan [Member]
Defined benefit plan disclosure
Assumptions used to determine benefit obligations, discount rate (percent)	4.50%	4.10%
Nonqualified Domestic Pension Plan [Member]
Defined benefit plan disclosure
Assumptions used to determine benefit obligations, discount rate (percent)	4.37%	4.10%
Postretirement Benefit Plans [Member]
Defined benefit plan disclosure
Impact to accumulated postretirement benefit obligation from increasing the assumed health care cost trend rate by 1%	$ 25
Impact to the aggregate of the service and interest cost components of net postretirement benefit expense from increasing the assumed health care cost trend rate by 1%	1
Impact to accumulated postretirement benefit obligation from decreasing the assumed health care cost trend rate by 1%	21
Impact to the aggregate of the service and interest cost components of net postretirement benefit expense from decreasing the assumed health care cost trend rate by 1%	$ 1
Domestic Postretirement Benefit Plans [Member]
Defined benefit plan disclosure
Assumptions used to determine benefit obligations, discount rate (percent)	4.35%	4.10%
Assumptions used to determine net periodic benefit cost, expected long-term rate of return on assets (percent)	4.00%	4.00%
Assumed health care cost trend rates, rate to which the cost trend rate is assumed to decline (ultimate trend rate) (percent)	5.00%	5.00%
Postretirement Benefit Plan Before Age 65 [Member]
Defined benefit plan disclosure
Assumed health care cost trend rates, medical, following year (percent)	6.75%	7.00%
Assumed health care cost trend rates, medical, year that the rate reaches the ultimate trend rate	2,022	2,022
Postretirement Benefit Plan Age 65 and Older [Member]
Defined benefit plan disclosure
Assumed health care cost trend rates, medical, following year (percent)	7.50%	6.50%
Assumed health care cost trend rates, medical, year that the rate reaches the ultimate trend rate	2,025	2,020

Pension Plans, Retirement Be100

Pension Plans, Retirement Benefits and Savings Plans (details) - Miscellaneous Fair Value Disclosures - item	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Qualified Domestic Pension Plan [Member] | Equity securities [Member]
Defined benefit plan disclosure
Minimum investment in class of securities (as a percentage)	55.00%
Maximum investment in class of securities (as a percentage)	65.00%
Qualified Domestic Pension Plan [Member] | Fixed income securities [Member]
Defined benefit plan disclosure
Minimum investment in class of securities (as a percentage)	20.00%
Maximum investment in class of securities (as a percentage)	40.00%
Qualified Domestic Pension Plan [Member] | Private equity funds [Member]
Defined benefit plan disclosure
Number of private equity funds included in pension plan assets	2	2
Number of private equity funds included in pension plan assets focused on financial companies	1
Qualified Domestic Pension Plan [Member] | Long-term growth [Member]
Defined benefit plan disclosure
Minimum investment in class of securities (as a percentage)	85.00%
Maximum investment in class of securities (as a percentage)	90.00%
Qualified Domestic Pension Plan [Member] | Near-term benefit payments [Member]
Defined benefit plan disclosure
Minimum investment in class of securities (as a percentage)	10.00%
Maximum investment in class of securities (as a percentage)	15.00%
Postretirement Benefit Plans [Member] | Fixed income securities [Member]
Defined benefit plan disclosure
Minimum investment in class of securities (as a percentage)	25.00%
Maximum investment in class of securities (as a percentage)	75.00%
Postretirement Benefit Plans [Member] | Long-term growth [Member]
Defined benefit plan disclosure
Minimum investment in class of securities (as a percentage)	35.00%
Maximum investment in class of securities (as a percentage)	65.00%
Postretirement Benefit Plans [Member] | Near-term benefit payments [Member]
Defined benefit plan disclosure
Minimum investment in class of securities (as a percentage)	35.00%
Maximum investment in class of securities (as a percentage)	60.00%

Pension Plans, Retirement Be101

Pension Plans, Retirement Benefits and Savings Plans (details) - Fair Value - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	$ 3,242	$ 3,357	$ 3,203
Postretirement Benefit Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	15	16	$ 17
Level 1 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	2,565	2,552
Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	675	803
Level 2 [Member] | Postretirement Benefit Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	15	16
Level 3 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	2	2
Fixed maturities [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	540	524
Fixed maturities [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	540	524
Obligations of states, municipalities and political subdivisions [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	17	19
Obligations of states, municipalities and political subdivisions [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	17	19
Debt securities issued by foreign governments [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	16	17
Debt securities issued by foreign governments [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	16	17
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	16	14
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	16	14
All other corporate bonds [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	491	474
All other corporate bonds [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	491	474
Total mutual funds [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	1,886	1,900
Total mutual funds [Member] | Level 1 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	1,877	1,890
Total mutual funds [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	9	10
Equity mutual funds [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	1,237	1,290
Equity mutual funds [Member] | Level 1 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	1,231	1,283
Equity mutual funds [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	6	7
Bond mutual funds [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	649	610
Bond mutual funds [Member] | Level 1 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	646	607
Bond mutual funds [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	3	3
Equity securities [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	625	616
Equity securities [Member] | Level 1 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	624	615
Equity securities [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	1	1
Other investments [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	2	2
Other investments [Member] | Level 3 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	2	2
Cash and short-term securities [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	189	315
Cash and short-term securities [Member] | Level 1 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	64	47
Cash and short-term securities [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	125	268
Cash and short-term securities, U.S. Treasury securities [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	25
Cash and short-term securities, U.S. Treasury securities [Member] | Level 1 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	25
Money market mutual funds [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	23	22
Money market mutual funds [Member] | Level 1 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	19	18
Money market mutual funds [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	4	4
Cash and short-term securities, other [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	141	293
Cash and short-term securities, other [Member] | Level 1 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	20	29
Cash and short-term securities, other [Member] | Level 2 [Member] | Pension Plans [Member]
Defined benefit plan disclosure
Fair value of plan assets	$ 121	$ 264

Pension Plans Retirement Benefi

Pension Plans Retirement Benefits and Savings Plans (details) - Future Payments $ in Millions	Dec. 31, 2015USD ($)
Pension Plans [Member]
Estimated Future Benefit Payments
Benefits expected to be paid, 2016	$ 215
Benefits expected to be paid, 2017	218
Benefits expected to be paid, 2018	224
Benefits expected to be paid, 2019	231
Benefits expected to be paid, 2020	237
Benefits expected to be paid, 2021 through 2025	1,215
Postretirement Benefit Plans [Member]
Estimated Future Benefit Payments
Benefits expected to be paid, 2016	14
Benefits expected to be paid, 2017	14
Benefits expected to be paid, 2018	15
Benefits expected to be paid, 2019	15
Benefits expected to be paid, 2020	15
Benefits expected to be paid, 2021 through 2025	$ 76

Pension Plans, Retirement Be103

Pension Plans, Retirement Benefits and Savings Plan (details) - Savings Plan - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Savings Plan
Expense related to all savings plans	$ 109,000,000	$ 103,000,000	$ 100,000,000
The Travelers 401(k) Savings Plan [Member]
Savings Plan
Maximum annual match	$ 6,000
Vesting percentage of employer match after vesting period	100.00%
Vesting period	3 years
The Travelers 401(k) Savings Plan [Member] | Maxiumum [Member]
Savings Plan
Matching contribution as a percent of eligible pay	5.00%

Leases (details)

Leases (details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Leases disclosure
Rent expense	$ 202	$ 215	$ 196
Future minimum annual rental payments due for 2016	159
Future minimum annual rental payments due for 2017	139
Future minimum annual rental payments due for 2018	102
Future minimum annual rental payments due for 2019	80
Future minimum annual rental payments due for 2020	60
Future minimum annual rental payments due for 2021 and thereafter	114
Approximate aggregate future sublease rental income that will partially offset the lease commitments	$ 6

Contingencies, Commitments a105

Contingencies, Commitments and Guarantees (details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Contingencies and Commitments disclosure
Unfunded commitments to private equity limited partnerships and real estate partnerships	$ 1,710	$ 1,630

Contingencies, Commitments a106

Contingencies, Commitments and Guarantees (details) - Loss Contingencies $ in Millions	Jan. 15, 2015USD ($)	May. 31, 2004USD ($)	Nov. 30, 2003USD ($)	Apr. 30, 2002item
Asbestos Direct Action Litigation [Member]
Loss Contingencies
Number of purported class action suits filed against TPC and other insurers in state court in West Virginia relative to asbestos direct action litigation | item				2
Settlement amount	$ 502
Total settlement amount	579
Interest related to settlement award	$ 77
Statutory and Hawaii Actions [Member] | Maxiumum [Member]
Loss Contingencies
Settlement amount			$ 412
Common Law Claims [Member] | Maxiumum [Member]
Loss Contingencies
Settlement amount		$ 90

Contingencies, Commitments a107

Contingencies, Commitments and Guarantees (details) - Gain Contingencies $ in Millions	12 Months Ended	64 Months Ended
	Dec. 31, 2013USD ($)item	Dec. 31, 2015USD ($)item	Aug. 17, 2010item
United States Fidelity & Guaranty Company v. American Re-Insurance Company, et al. [Member]
Gain Contingencies
Number of other reinsurers beside American Re against which judgment was entered in a reinsurance dispute | item			3
Number of discrete issues modified in part by the summary judgment in reinsurance dispute | item		2
Total settlement amount		$ 509
Settlement amount		238
Interest related to settlement award		$ 271
Annual interest rate accruing on judgment not yet paid		9.00%
Safeco Insurance Company of America, et al v American International Group, Inc, et al [Member]
Gain Contingencies
Total settlement amount	$ 91
Number of payments received in settlement of workers' compensation matter | item	2
Payment received from settlement fund	$ 93
Amount of settlement fund payment received that was remitted to another insurer	$ 2

Contingencies, Commitments a108

Contingencies, Commitments and Guarantees (details) - Guarantees $ in Millions	Dec. 31, 2015USD ($)
Indemnifications related to the sale of businesses [Member]
Guarantor obligations
Maximum amount of contingent obligation	$ 391
Amount recognized on balance sheet for contingent obligation	2
Guarantees of certain investments and third-party loans [Member]
Guarantor obligations
Maximum amount of contingent obligation	150
Amount indemnified by a third party	75
Guarantees of certain insurance policy obligations [Member]
Guarantor obligations
Maximum amount of contingent obligation	480
Amount indemnified by a third party	$ 480

Consolidating Financial Stat109

Consolidating Financial Statements (Unaudited) (details) $ in Millions	Dec. 31, 2015USD ($)
Consolidating Financial Statements of The Travelers Companies, Inc. and Subsidiaries (Unaudited) disclosure
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 700

Consolidating Financial Stat110

Consolidating Financial Statements (details) - Consolidating Statement of Income (Unaudited) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidating Statement of Income
Premiums										$ 23,874	$ 23,713	$ 22,637
Net investment income										2,379	2,787	2,716
Fee income										445	438	395
Net realized investment gains (losses)	[1]									3	79	166
Other revenues										99	145	277
Total revenues		$ 6,674	$ 6,794	$ 6,706	$ 6,626	$ 6,783	$ 6,886	$ 6,785	$ 6,708	26,800	27,162	26,191
Claims and claim adjustment expenses										13,723	13,870	13,307
Amortization of deferred acquisition costs										3,885	3,882	3,821
General and administrative expenses										4,079	3,952	3,757
Interest expense										373	369	361
Total claims and expenses		5,465	5,487	5,630	5,478	5,323	5,628	5,884	5,238	22,060	22,073	21,246
Income before income taxes		1,209	1,307	1,076	1,148	1,460	1,258	901	1,470	4,740	5,089	4,945
Income tax expense (benefit)		343	379	264	315	422	339	218	418	1,301	1,397	1,272
Net income		$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	3,439	3,692	3,673
Total other-than-temporary impairment losses										(54)	(22)	(10)
Other-than-temporary impairment losses recognized in net realized investment gains										(52)	(26)	(15)
Other-than-temporary impairment gains (losses) recognized in other comprehensive income										(2)	4	5
TPC [Member]
Consolidating Statement of Income
Premiums										16,254	16,097	15,262
Net investment income										1,612	1,874	1,830
Fee income										445	436	393
Net realized investment gains (losses)										13	12	126
Other revenues										78	125	225
Total revenues										18,402	18,544	17,836
Claims and claim adjustment expenses										9,208	9,274	8,817
Amortization of deferred acquisition costs										2,627	2,604	2,571
General and administrative expenses										2,838	2,743	2,570
Interest expense										48	48	53
Total claims and expenses										14,721	14,669	14,011
Income before income taxes										3,681	3,875	3,825
Income tax expense (benefit)										1,015	1,095	1,054
Net income										2,666	2,780	2,771
Total other-than-temporary impairment losses										(19)	(16)	(8)
Other-than-temporary impairment losses recognized in net realized investment gains										(18)	(19)	(10)
Other-than-temporary impairment gains (losses) recognized in other comprehensive income										(1)	3	2
Other Subsidiaries [Member]
Consolidating Statement of Income
Premiums										7,620	7,616	7,375
Net investment income										760	907	879
Fee income											2	2
Net realized investment gains (losses)										(11)	64	38
Other revenues										21	20	52
Total revenues										8,390	8,609	8,346
Claims and claim adjustment expenses										4,515	4,596	4,490
Amortization of deferred acquisition costs										1,258	1,278	1,250
General and administrative expenses										1,225	1,194	1,174
Total claims and expenses										6,998	7,068	6,914
Income before income taxes										1,392	1,541	1,432
Income tax expense (benefit)										394	417	388
Net income										998	1,124	1,044
Total other-than-temporary impairment losses										(35)	(6)	(2)
Other-than-temporary impairment losses recognized in net realized investment gains										(34)	(7)	(5)
Other-than-temporary impairment gains (losses) recognized in other comprehensive income										(1)	1	3
Travelers [Member]
Consolidating Statement of Income
Net investment income										7	6	7
Net realized investment gains (losses)										1	3	2
Total revenues										8	9	9
General and administrative expenses										16	15	13
Interest expense										325	321	308
Total claims and expenses										341	336	321
Income before income taxes										(333)	(327)	(312)
Income tax expense (benefit)										(108)	(115)	(170)
Net income of subsidiaries										3,664	3,904	3,815
Net income										3,439	3,692	3,673
Other-than-temporary impairment losses recognized in net realized investment gains										0	0	0
Other-than-temporary impairment gains (losses) recognized in other comprehensive income										0	0	0
Eliminations [Member]
Consolidating Statement of Income
Net income of subsidiaries										(3,664)	(3,904)	(3,815)
Net income										$ (3,664)	$ (3,904)	$ (3,815)
[1]	Total other-than-temporary impairment (OTTI) losses were $(54) million, $(22) million and $(10) million for the years ended December 31, 2015, 2014 and 2013, respectively. Of total OTTI, credit losses of $(52) million, $(26) million and $(15) million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(2) million, $4 million and $5 million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.

Consolidating Financial Stat111

Consolidating Financial Statements (details) - Consolidating Statement of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidating Statement of Comprehensive Income
Net income	$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	$ 3,439	$ 3,692	$ 3,673
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income									(1,020)	976	(2,734)
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income									(14)	2	3
Net changes in benefit plan assets and obligations									66	(494)	647
Net changes in unrealized foreign currency translation									(461)	(289)	(112)
Other comprehensive income (loss) before income taxes									(1,429)	195	(2,196)
Income tax expense (benefit)									(392)	125	(770)
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries									(1,037)	70	(1,426)
Other comprehensive income (loss), net of taxes									(1,037)	70	(1,426)
Comprehensive income									2,402	3,762	2,247
TPC [Member]
Consolidating Statement of Comprehensive Income
Net income									2,666	2,780	2,771
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income									(610)	681	(1,982)
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income									(12)	9	4
Net changes in benefit plan assets and obligations									2	(15)	12
Net changes in unrealized foreign currency translation									(306)	(173)	(92)
Other comprehensive income (loss) before income taxes									(926)	502	(2,058)
Income tax expense (benefit)									(257)	207	(719)
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries									(669)	295	(1,339)
Other comprehensive income (loss), net of taxes									(669)	295	(1,339)
Comprehensive income									1,997	3,075	1,432
Other Subsidiaries [Member]
Consolidating Statement of Comprehensive Income
Net income									998	1,124	1,044
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income									(407)	289	(771)
Changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income									(2)	(7)	(1)
Net changes in benefit plan assets and obligations										(8)	19
Net changes in unrealized foreign currency translation									(155)	(116)	(20)
Other comprehensive income (loss) before income taxes									(564)	158	(773)
Income tax expense (benefit)									(156)	81	(273)
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries									(408)	77	(500)
Other comprehensive income (loss), net of taxes									(408)	77	(500)
Comprehensive income									590	1,201	544
Travelers [Member]
Consolidating Statement of Comprehensive Income
Net income									3,439	3,692	3,673
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income									(3)	6	19
Net changes in benefit plan assets and obligations									64	(471)	616
Other comprehensive income (loss) before income taxes									61	(465)	635
Income tax expense (benefit)									21	(163)	222
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries									40	(302)	413
Other comprehensive income (loss) of subsidiaries									(1,077)	372	(1,839)
Other comprehensive income (loss), net of taxes									(1,037)	70	(1,426)
Comprehensive income									2,402	3,762	2,247
Eliminations [Member]
Consolidating Statement of Comprehensive Income
Net income									(3,664)	(3,904)	(3,815)
Other comprehensive income (loss) of subsidiaries									1,077	(372)	1,839
Other comprehensive income (loss), net of taxes									1,077	(372)	1,839
Comprehensive income									$ (2,587)	$ (4,276)	$ (1,976)

Consolidating Financial Stat112

Consolidating Financial Statements (details) - Consolidating Balance Sheet (Unaudited) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	$ 60,658	$ 63,474
Equity securities, available for sale, at fair value	705	899
Real estate investments	989	938
Short-term securities	4,671	4,364
Other investments	3,447	3,586
Total investments	70,470	73,261
Cash	380	374	$ 294	$ 330
Investment income accrued	642	685
Premiums receivable	6,437	6,298
Reinsurance recoverables	8,910	9,260
Ceded unearned premiums	656	678
Deferred acquisition costs	1,849	1,835	1,804
Deferred taxes	296	33
Contractholder receivables	4,374	4,362
Goodwill	3,573	3,611
Other intangible assets	279	304
Other assets	2,318	2,377
Total assets	100,184	103,078
Claims and claim adjustment expense reserves	48,295	49,850	50,895
Unearned premium reserves	11,971	11,839	11,850
Contractholder payables	4,374	4,362
Payables for reinsurance premiums	296	336
Debt	6,344	6,349
Other liabilities	5,306	5,506
Total liabilities	76,586	78,242
Common stock	22,172	21,843
Retained earnings	29,945	27,251
Accumulated other comprehensive income (loss)	(157)	880
Treasury stock, at cost	(28,362)	(25,138)
Total shareholders' equity	23,598	24,836	24,796
Total liabilities and shareholders' equity	100,184	103,078
Fixed maturities, available for sale, amortized cost	58,878	60,801
Equity securities, available for sale, cost	$ 528	$ 579
Common stock, shares authorized	1,750	1,750
Common stock, shares issued	295.9	322.2
Common stock, shares outstanding	295.9	322.2
Treasury stock, at cost, shares	467.6	437.3
TPC [Member]
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	$ 42,289	$ 43,401
Equity securities, available for sale, at fair value	189	236
Real estate investments	56	56
Short-term securities	1,947	2,128
Other investments	2,516	2,630
Total investments	46,997	48,451
Cash	225	221	137	177
Investment income accrued	453	468
Premiums receivable	4,336	4,241
Reinsurance recoverables	5,849	6,156
Ceded unearned premiums	610	608
Deferred acquisition costs	1,660	1,622
Deferred taxes	178	23
Contractholder receivables	3,387	3,306
Goodwill	2,573	2,602
Other intangible assets	203	216
Other assets	1,958	1,931
Total assets	68,429	69,845
Claims and claim adjustment expense reserves	31,965	32,999
Unearned premium reserves	8,335	8,201
Contractholder payables	3,387	3,306
Payables for reinsurance premiums	175	194
Debt	693	692
Other liabilities	3,958	4,084
Total liabilities	48,513	49,476
Additional paid-in capital	11,634	11,634
Retained earnings	7,888	7,673
Accumulated other comprehensive income (loss)	394	1,062
Total shareholders' equity	19,916	20,369
Total liabilities and shareholders' equity	68,429	69,845
Other Subsidiaries [Member]
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	18,323	20,043
Equity securities, available for sale, at fair value	375	522
Real estate investments	933	882
Short-term securities	1,178	706
Other investments	930	955
Total investments	21,739	23,108
Cash	153	151	154	151
Investment income accrued	185	215
Premiums receivable	2,101	2,057
Reinsurance recoverables	3,061	3,104
Ceded unearned premiums	46	70
Deferred acquisition costs	189	213
Deferred taxes	83	(40)
Contractholder receivables	987	1,056
Goodwill	1,000	1,009
Other intangible assets	76	88
Other assets	344	429
Total assets	29,964	31,460
Claims and claim adjustment expense reserves	16,330	16,851
Unearned premium reserves	3,636	3,638
Contractholder payables	987	1,056
Payables for reinsurance premiums	121	142
Other liabilities	1,221	1,308
Total liabilities	22,295	22,995
Common stock	390	390
Additional paid-in capital	6,499	6,502
Retained earnings	688	1,073
Accumulated other comprehensive income (loss)	92	500
Total shareholders' equity	7,669	8,465
Total liabilities and shareholders' equity	29,964	31,460
Travelers [Member]
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	46	30
Equity securities, available for sale, at fair value	141	141
Short-term securities	1,546	1,530
Other investments	1	1
Total investments	1,734	1,702
Cash	2	2	$ 3	$ 2
Investment income accrued	4	2
Deferred taxes	35	50
Investment in subsidiaries	27,573	28,821
Other assets	16	17
Total assets	29,364	30,594
Debt	5,651	5,657
Other liabilities	127	114
Total liabilities	5,778	5,771
Common stock	22,172	21,843
Retained earnings	29,933	27,238
Accumulated other comprehensive income (loss)	(157)	880
Treasury stock, at cost	(28,362)	(25,138)
Total shareholders' equity	23,586	24,823
Total liabilities and shareholders' equity	$ 29,364	$ 30,594
Common stock, shares authorized	1,750	1,750
Common stock, shares issued	295.9	322.2
Common stock, shares outstanding	295.9	322.2
Treasury stock, at cost, shares	467.6	437.3
Eliminations [Member]
Consolidating Balance Sheet
Investment in subsidiaries	$ (27,573)	$ (28,821)
Total assets	(27,573)	(28,821)
Common stock	(390)	(390)
Additional paid-in capital	(18,133)	(18,136)
Retained earnings	(8,564)	(8,733)
Accumulated other comprehensive income (loss)	(486)	(1,562)
Total shareholders' equity	(27,573)	(28,821)
Total liabilities and shareholders' equity	$ (27,573)	$ (28,821)

Consolidating Financial Stat113

Consolidating Financial Statements (details) - Consolidating Statement of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Consolidating Statement of Cash Flows
Net income	$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	$ 3,439	$ 3,692	$ 3,673
Net adjustments to reconcile net income to net cash provided by operating activities									(5)	1	143
Net cash provided by operating activities									3,434	3,693	3,816
Proceeds from maturities of fixed maturities									11,116	10,894	7,904
Proceeds from sales of investments, fixed maturities									1,950	1,049	1,635
Proceeds from sales of investments, equity securities									59	158	86
Proceeds from sales of investments, real estate investments									31	15	18
Proceeds from sales of investments, other investments									713	855	762
Purchases of investments, fixed maturities									(12,090)	(11,325)	(9,467)
Purchases of investments, equity securities									(49)	(52)	(57)
Purchases of investments, real estate investments									(123)	(48)	(107)
Purchases of investments, other investments									(534)	(554)	(446)
Net sales (purchases) of short-term securities									(326)	(498)	111
Securities transactions in course of settlement									(113)	82	21
Acquisition, net of cash acquired									(13)	(12)	(997)
Other investing activities									(304)	(358)	(373)
Net cash provided by (used in) investing activities									317	206	(910)
Treasury stock acquired - share repurchase authorization									(3,150)	(3,275)	(2,400)
Treasury stock acquired - net employee share-based compensation									(74)	(57)	(61)
Dividends paid to shareholders									(739)	(729)	(729)
Payment of debt									(400)		(500)
Issuance of debt									392		494
Issuance of common stock - employee share options									183	195	206
Excess tax benefits from share-based payment arrangements									55	57	51
Net cash used in financing activities									(3,733)	(3,809)	(2,939)
Effect of exchange rate changes on cash									(12)	(10)	(3)
Net increase (decrease) in cash									6	80	(36)
Cash at beginning of year				374				294	374	294	330
Cash at end of year	380				374				380	374	294
Income taxes paid (received)									1,207	1,147	1,057
Interest paid									365	365	355
TPC [Member]
Consolidating Statement of Cash Flows
Net income									2,666	2,780	2,771
Net adjustments to reconcile net income to net cash provided by operating activities									(577)	343	(497)
Net cash provided by operating activities									2,089	3,123	2,274
Proceeds from maturities of fixed maturities									7,543	6,625	5,484
Proceeds from sales of investments, fixed maturities									1,227	595	989
Proceeds from sales of investments, equity securities									25	111	45
Proceeds from sales of investments, real estate investments										1
Proceeds from sales of investments, other investments									503	477	489
Purchases of investments, fixed maturities									(8,276)	(6,856)	(6,260)
Purchases of investments, equity securities									(3)	(3)	(21)
Purchases of investments, real estate investments									(1)	(22)	(1)
Purchases of investments, other investments									(423)	(405)	(320)
Net sales (purchases) of short-term securities									179	(268)	(272)
Securities transactions in course of settlement									(52)	44	(2)
Acquisition, net of cash acquired									(13)	(9)	(773)
Other investing activities									(343)	(350)	(365)
Net cash provided by (used in) investing activities									366	(60)	(1,007)
Payment of debt											(500)
Dividends paid to parent company									(2,450)	(2,978)	(1,307)
Capital contributions, loans and other transactions between subsidiaries											500
Net cash used in financing activities									(2,450)	(2,978)	(1,307)
Effect of exchange rate changes on cash									(1)	(1)
Net increase (decrease) in cash									4	84	(40)
Cash at beginning of year				221				137	221	137	177
Cash at end of year	225				221				225	221	137
Income taxes paid (received)									1,032	947	942
Interest paid									47	47	60
Other Subsidiaries [Member]
Consolidating Statement of Cash Flows
Net income									998	1,124	1,044
Net adjustments to reconcile net income to net cash provided by operating activities									414	(293)	413
Net cash provided by operating activities									1,412	831	1,457
Proceeds from maturities of fixed maturities									3,563	4,258	2,419
Proceeds from sales of investments, fixed maturities									723	453	641
Proceeds from sales of investments, equity securities									34	43	41
Proceeds from sales of investments, real estate investments									31	14	18
Proceeds from sales of investments, other investments									210	378	273
Purchases of investments, fixed maturities									(3,787)	(4,465)	(3,201)
Purchases of investments, equity securities									(43)	(42)	(34)
Purchases of investments, real estate investments									(122)	(26)	(106)
Purchases of investments, other investments									(111)	(149)	(126)
Net sales (purchases) of short-term securities									(489)	(223)	(52)
Securities transactions in course of settlement									(61)	38	24
Acquisition, net of cash acquired										(3)	(224)
Other investing activities									39	(8)	(8)
Net cash provided by (used in) investing activities									(13)	268	(335)
Dividends paid to parent company									(1,383)	(1,093)	(1,116)
Capital contributions, loans and other transactions between subsidiaries									(3)
Net cash used in financing activities									(1,386)	(1,093)	(1,116)
Effect of exchange rate changes on cash									(11)	(9)	(3)
Net increase (decrease) in cash									2	(3)	3
Cash at beginning of year				151				154	151	154	151
Cash at end of year	153				151				153	151	154
Income taxes paid (received)									384	336	325
Travelers [Member]
Consolidating Statement of Cash Flows
Net income									3,439	3,692	3,673
Net adjustments to reconcile net income to net cash provided by operating activities									330	118	(1,665)
Net cash provided by operating activities									3,769	3,810	2,008
Proceeds from maturities of fixed maturities									10	11	1
Proceeds from sales of investments, fixed maturities										1	5
Proceeds from sales of investments, equity securities										4
Purchases of investments, fixed maturities									(27)	(4)	(6)
Purchases of investments, equity securities									(3)	(7)	(2)
Net sales (purchases) of short-term securities									(16)	(7)	435
Securities transactions in course of settlement											(1)
Net cash provided by (used in) investing activities									(36)	(2)	432
Treasury stock acquired - share repurchase authorization									(3,150)	(3,275)	(2,400)
Treasury stock acquired - net employee share-based compensation									(74)	(57)	(61)
Dividends paid to shareholders									(739)	(729)	(729)
Payment of debt									(400)
Issuance of debt									392		494
Issuance of common stock - employee share options									183	195	206
Excess tax benefits from share-based payment arrangements									55	57	51
Net cash used in financing activities									(3,733)	(3,809)	(2,439)
Net increase (decrease) in cash										(1)	1
Cash at beginning of year				$ 2				$ 3	2	3	2
Cash at end of year	$ 2				$ 2				2	2	3
Income taxes paid (received)									(209)	(136)	(210)
Interest paid									318	318	295
Eliminations [Member]
Consolidating Statement of Cash Flows
Net income									(3,664)	(3,904)	(3,815)
Net adjustments to reconcile net income to net cash provided by operating activities									(172)	(167)	1,892
Net cash provided by operating activities									(3,836)	(4,071)	(1,923)
Dividends paid to parent company									3,833	4,071	2,423
Capital contributions, loans and other transactions between subsidiaries									3		(500)
Net cash used in financing activities									$ 3,836	$ 4,071	$ 1,923

Selected Quarterly Financial114

Selected Quarterly Financial Data (Unaudited) (details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Data (Unaudited) disclosure
Total revenues	$ 6,674	$ 6,794	$ 6,706	$ 6,626	$ 6,783	$ 6,886	$ 6,785	$ 6,708	$ 26,800	$ 27,162	$ 26,191
Total expenses	5,465	5,487	5,630	5,478	5,323	5,628	5,884	5,238	22,060	22,073	21,246
Income before income taxes	1,209	1,307	1,076	1,148	1,460	1,258	901	1,470	4,740	5,089	4,945
Income tax expense	343	379	264	315	422	339	218	418	1,301	1,397	1,272
Net income	$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	$ 3,439	$ 3,692	$ 3,673
Net income per share, basic	$ 2.87	$ 3	$ 2.56	$ 2.58	$ 3.15	$ 2.72	$ 1.98	$ 2.98	$ 10.99	$ 10.82	$ 9.84
Net income per share, diluted	$ 2.83	$ 2.97	$ 2.53	$ 2.55	$ 3.11	$ 2.69	$ 1.95	$ 2.95	$ 10.88	$ 10.70	$ 9.74

Schedule II (details) - Condens

Schedule II (details) - Condensed Income Statement - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Statement of Income
Net investment income										$ 2,379	$ 2,787	$ 2,716
Net realized investment gains	[1]									3	79	166
Total revenues		$ 6,674	$ 6,794	$ 6,706	$ 6,626	$ 6,783	$ 6,886	$ 6,785	$ 6,708	26,800	27,162	26,191
Interest expense										373	369	361
Expenses, other										4,079	3,952	3,757
Total claims and expenses		5,465	5,487	5,630	5,478	5,323	5,628	5,884	5,238	22,060	22,073	21,246
Income before income taxes		1,209	1,307	1,076	1,148	1,460	1,258	901	1,470	4,740	5,089	4,945
Income tax expense (benefit)		343	379	264	315	422	339	218	418	1,301	1,397	1,272
Net income		$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	3,439	3,692	3,673
Other-than-temporary impairment losses recognized in net realized investment gains										(52)	(26)	(15)
Other-than-temporary impairment gains (losses) recognized in other comprehensive income										(2)	4	5
Travelers [Member]
Condensed Statement of Income
Net investment income										7	6	7
Net realized investment gains										1	3	2
Total revenues										8	9	9
Interest expense										325	321	308
Expenses, other										16	15	13
Total claims and expenses										341	336	321
Income before income taxes										(333)	(327)	(312)
Income tax expense (benefit)										(108)	(115)	(170)
Loss before net income of subsidiaries										(225)	(212)	(142)
Net income of subsidiaries										3,664	3,904	3,815
Net income										3,439	3,692	3,673
Other-than-temporary impairment losses recognized in net realized investment gains										0	0	0
Other-than-temporary impairment gains (losses) recognized in other comprehensive income										$ 0	$ 0	$ 0
[1]	Total other-than-temporary impairment (OTTI) losses were $(54) million, $(22) million and $(10) million for the years ended December 31, 2015, 2014 and 2013, respectively. Of total OTTI, credit losses of $(52) million, $(26) million and $(15) million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(2) million, $4 million and $5 million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.

Schedule II (details) - Cond116

Schedule II (details) - Condensed Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Statement of Comprehensive Income
Net income	$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	$ 3,439	$ 3,692	$ 3,673
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income									(1,020)	976	(2,734)
Net changes in benefit plan assets and obligations									66	(494)	647
Other comprehensive income (loss) before income taxes									(1,429)	195	(2,196)
Income tax expense (benefit)									(392)	125	(770)
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries									(1,037)	70	(1,426)
Other comprehensive income (loss), net of taxes									(1,037)	70	(1,426)
Comprehensive income									2,402	3,762	2,247
Travelers [Member]
Condensed Statement of Comprehensive Income
Net income									3,439	3,692	3,673
Changes in net unrealized gains on investment securities having no credit losses recognized in the consolidated statement of income									(3)	6	19
Net changes in benefit plan assets and obligations									64	(471)	616
Other comprehensive income (loss) before income taxes									61	(465)	635
Income tax expense (benefit)									21	(163)	222
Other comprehensive income (loss), net of taxes, before other comprehensive income (loss) of subsidiaries									40	(302)	413
Other comprehensive income (loss) of subsidiaries									(1,077)	372	(1,839)
Other comprehensive income (loss), net of taxes									(1,037)	70	(1,426)
Comprehensive income									$ 2,402	$ 3,762	$ 2,247

Schedule II (details) - Cond117

Schedule II (details) - Condensed Balance Sheet - USD ($) shares in Millions, $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Balance Sheet
Fixed maturities, at fair value	$ 60,658	$ 63,474
Equity securities	705	899
Short-term securities	4,671	4,364
Total assets	100,184	103,078
Debt	6,344	6,349
Total liabilities	76,586	78,242
Common stock (1,750.0 shares authorized; 295.9 and 322.2 shares issued and outstanding)	22,172	21,843
Retained earnings	29,945	27,251
Accumulated other comprehensive income (loss)	(157)	880
Treasury stock, at cost (467.6 and 437.3 shares)	(28,362)	(25,138)
Total shareholders' equity	23,598	24,836	$ 24,796
Total liabilities and shareholders' equity	$ 100,184	$ 103,078
Common stock, shares authorized	1,750	1,750
Common stock, shares issued	295.9	322.2
Common stock, shares outstanding	295.9	322.2
Treasury stock, at cost, shares	467.6	437.3
Travelers [Member]
Condensed Balance Sheet
Fixed maturities, at fair value	$ 46	$ 30
Equity securities	141	141
Short-term securities	1,546	1,530
Investment in subsidiaries	27,573	28,821
Other assets	58	72
Total assets	29,364	30,594
Debt	5,651	5,657
Other liabilities	127	114
Total liabilities	5,778	5,771
Common stock (1,750.0 shares authorized; 295.9 and 322.2 shares issued and outstanding)	22,172	21,843
Retained earnings	29,933	27,238
Accumulated other comprehensive income (loss)	(157)	880
Treasury stock, at cost (467.6 and 437.3 shares)	(28,362)	(25,138)
Total shareholders' equity	23,586	24,823
Total liabilities and shareholders' equity	$ 29,364	$ 30,594
Common stock, shares authorized	1,750	1,750
Common stock, shares issued	295.9	322.2
Common stock, shares outstanding	295.9	322.2
Treasury stock, at cost, shares	467.6	437.3

Schedule II (details) - Cond118

Schedule II (details) - Condensed Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Statement of Cash Flows
Net income	$ 866	$ 928	$ 812	$ 833	$ 1,038	$ 919	$ 683	$ 1,052	$ 3,439	$ 3,692	$ 3,673
Deferred federal income tax expense (benefit)									117	121	167
Other operating activities									56	63	262
Net cash provided by operating activities									3,434	3,693	3,816
Net sales (purchases) of short-term securities									(326)	(498)	111
Net cash provided by (used in) investing activities									317	206	(910)
Treasury stock acquired - share repurchase authorization									(3,150)	(3,275)	(2,400)
Treasury stock acquired - net employee share-based compensation									(74)	(57)	(61)
Dividends paid to shareholders									(739)	(729)	(729)
Payment of debt									(400)		(500)
Issuance of debt									392		494
Issuance of common stock - employee share options									183	195	206
Net cash used in financing activities									(3,733)	(3,809)	(2,939)
Net increase (decrease) in cash									6	80	(36)
Cash at beginning of year				374				294	374	294	330
Cash at end of year	380				374				380	374	294
Cash received during the year for taxes									(1,207)	(1,147)	(1,057)
Cash paid during the year for interest									365	365	355
Travelers [Member]
Condensed Statement of Cash Flows
Net income									3,439	3,692	3,673
Equity in net income of subsidiaries									(3,664)	(3,904)	(3,815)
Dividends received from consolidated subsidiaries									3,833	4,071	2,423
Capital received from (contributed to) subsidiaries									3		(500)
Deferred federal income tax expense (benefit)									(6)	51	(59)
Change in income taxes payable									51	(87)	48
Other operating activities									113	(13)	238
Net cash provided by operating activities									3,769	3,810	2,008
Net sales (purchases) of short-term securities									(16)	(7)	435
Other investments, net									(20)	5	(3)
Net cash provided by (used in) investing activities									(36)	(2)	432
Treasury stock acquired - share repurchase authorization									(3,150)	(3,275)	(2,400)
Treasury stock acquired - net employee share-based compensation									(74)	(57)	(61)
Dividends paid to shareholders									(739)	(729)	(729)
Payment of debt									(400)
Issuance of debt									392		494
Issuance of common stock - employee share options									183	195	206
Other financing activities									55	57	51
Net cash used in financing activities									(3,733)	(3,809)	(2,439)
Net increase (decrease) in cash										(1)	1
Cash at beginning of year				$ 2				$ 3	2	3	2
Cash at end of year	$ 2				$ 2				2	2	3
Cash received during the year for taxes									209	136	210
Cash paid during the year for interest									$ 318	$ 318	$ 295

Schedule II (details) - Guarant

Schedule II (details) - Guarantees Footnote	12 Months Ended
	Dec. 31, 2015
Schedule II
Schedule II Guarantees Footnote [Text Block]	NOTES TO THE CONDENSED FINANCIAL INFORMATION OF REGISTRANT 1. GUARANTEES In the ordinary course of selling businesses to third parties, The Travelers Companies, Inc. (TRV) has agreed to indemnify purchasers for losses arising out of breaches of representations and warranties with respect to the businesses being sold, covenants and obligations of TRV and/or its subsidiaries, and in certain cases, obligations arising from certain liabilities. Such indemnification provisions generally are applicable from the closing date to the expiration of the relevant statutes of limitations, although, in some cases, there may be agreed upon term limitations or no term limitations. Certain of these contingent obligations are subject to deductibles which have to be incurred by the obligee before TRV is obligated to make payments. The maximum amount of TRV's contingent obligation for indemnifications related to the sale of businesses that are quantifiable was $44 million at December 31, 2015, of which $2 million was recognized on the balance sheet at that date. TRV also has contingent obligations for guarantees related to its subsidiary's debt obligations and various other indemnifications. TRV also provides standard indemnifications to service providers in the normal course of business. The indemnification clauses are often standard contractual terms. Certain of the guarantees and indemnifications described above have no stated or notional amounts or limitation to the maximum potential future payments, and, accordingly, TRV is unable to develop an estimate of the maximum potential payments for such arrangements. TRV fully and unconditionally guarantees the payment of all principal, premiums, if any, and interest on certain debt obligations of its subsidiaries TPC and TIGHI. The guarantees pertain to the $200 million 7.75% notes due 2026 and the $500 million 6.375% notes due 2033.

Schedule II (details) - Guar120

Schedule II (details) - Guarantees Footnote (details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 700
7.75% Senior notes due April 15, 2026 [Member]
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 200
Interest rate (percent)	7.75%	7.75%
6.375% Senior notes due March 15, 2033 [Member]
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 500
Interest rate (percent)	6.375%	6.375%
Indemnifications related to the sale of businesses [Member]
Guarantor obligations
Maximum amount of contingent obligation	$ 391
Amount recognized on balance sheet for contingent obligation	2
Indemnifications related to the sale of businesses [Member] | Travelers [Member]
Guarantor obligations
Maximum amount of contingent obligation	44
Amount recognized on balance sheet for contingent obligation	2
Guarantees on payment of principal, premiums and interest on certain debt obligations [Member] | Travelers [Member] | 7.75% Senior notes due April 15, 2026 [Member]
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 200
Interest rate (percent)	7.75%
Guarantees on payment of principal, premiums and interest on certain debt obligations [Member] | Travelers [Member] | 6.375% Senior notes due March 15, 2033 [Member]
Guarantor obligations
Amount of certain debt obligations of TPC that are unconditionally guaranteed by The Travelers Companies, Inc.	$ 500
Interest rate (percent)	6.375%

Schedule III (details)

Schedule III (details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule III
Deferred acquisition costs	$ 1,849	$ 1,835	$ 1,804
Claims and claim adjustment expense reserves	48,295	49,850	50,895
Unearned premiums	11,971	11,839	11,850
Earned premiums	23,874	23,713	22,637
Net investment income	2,379	2,787	2,716
Claims and claim adjustment expenses	13,723	13,870	13,307
Amortization of deferred acquisition costs	3,885	3,882	3,821
Other operating expenses	4,452	4,321	4,118
Net written premiums	24,121	23,904	22,767
Business and International Insurance [Member]
Schedule III
Net written premiums	14,583	14,636	13,512
Bond & Specialty Insurance [Member]
Schedule III
Net written premiums	2,081	2,103	2,030
Personal Insurance [Member]
Schedule III
Net written premiums	7,457	7,165	7,225
Reportable Segments [Member]
Schedule III
Deferred acquisition costs	1,849	1,835	1,804
Claims and claim adjustment expense reserves	48,272	49,824	50,865
Unearned premiums	11,971	11,839	11,850
Earned premiums	23,874	23,713	22,637
Net investment income	2,379	2,787	2,716
Claims and claim adjustment expenses	13,723	13,870	13,307
Amortization of deferred acquisition costs	3,885	3,882	3,821
Other operating expenses	4,048	3,921	3,737
Net written premiums	24,121	23,904	22,767
Reportable Segments [Member] | Business and International Insurance [Member]
Schedule III
Deferred acquisition costs	1,072	1,080	1,046
Claims and claim adjustment expense reserves	41,563	42,700	43,181
Unearned premiums	7,147	7,208	7,170
Earned premiums	14,521	14,512	13,332
Net investment income	1,824	2,156	2,087
Claims and claim adjustment expenses	8,859	9,145	8,285
Amortization of deferred acquisition costs	2,329	2,321	2,158
Other operating expenses	2,686	2,541	2,369
Net written premiums	14,583	14,636	13,512
Reportable Segments [Member] | Bond & Specialty Insurance [Member]
Schedule III
Deferred acquisition costs	225	222	213
Claims and claim adjustment expense reserves	3,157	3,435	3,921
Unearned premiums	1,292	1,286	1,264
Earned premiums	2,085	2,076	1,981
Net investment income	223	252	260
Claims and claim adjustment expenses	643	481	695
Amortization of deferred acquisition costs	393	388	378
Other operating expenses	389	403	388
Net written premiums	2,081	2,103	2,030
Reportable Segments [Member] | Personal Insurance [Member]
Schedule III
Deferred acquisition costs	552	533	545
Claims and claim adjustment expense reserves	3,552	3,689	3,763
Unearned premiums	3,532	3,345	3,416
Earned premiums	7,268	7,125	7,324
Net investment income	332	379	369
Claims and claim adjustment expenses	4,221	4,244	4,327
Amortization of deferred acquisition costs	1,163	1,173	1,285
Other operating expenses	973	977	980
Net written premiums	7,457	7,165	7,225
Other [Member]
Schedule III
Claims and claim adjustment expense reserves	23	26	30
Other operating expenses	$ 404	$ 400	$ 381

Schedule V (details)

Schedule V (details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reinsurance recoverables [Member]
Schedule V [Roll Forward]
Valuation and qualifying accounts, balance at beginning of period	$ 203	$ 239	$ 258
Valuation and qualifying accounts, charged to other accounts			2
Valuation and qualifying accounts, deductions	46	36	21
Valuation and qualifying accounts, balance at end of period	157	203	239
Allowance for uncollectible premiums receivable from underwriting activities [Member]
Schedule V [Roll Forward]
Valuation and qualifying accounts, balance at beginning of period	70	75	76
Valuation and qualifying accounts, charged to costs and expenses	38	44	48
Valuation and qualifying accounts, deductions	43	49	49
Valuation and qualifying accounts, balance at end of period	65	70	75
Allowance for uncollectible deductibles [Member]
Schedule V [Roll Forward]
Valuation and qualifying accounts, balance at beginning of period	36	39	41
Valuation and qualifying accounts, charged to costs and expenses	3		1
Valuation and qualifying accounts, deductions	4	3	3
Valuation and qualifying accounts, balance at end of period	$ 35	$ 36	$ 39

Schedule VI (details)

Schedule VI (details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplementary Information Concerning Property-Casualty Insurance Operations
Deferred acquisition costs	$ 1,849	$ 1,835	$ 1,804
Claims and claim adjustment expense reserves	48,295	49,850	50,895
Unearned premiums	11,971	11,839	11,850
Earned premiums	23,874	23,713	22,637
Net investment income	2,379	2,787	2,716
Amortization of deferred acquisition costs	3,885	3,882	3,821
Net written premiums	24,121	23,904	22,767
Property casualty [Member]
Supplementary Information Concerning Property-Casualty Insurance Operations
Deferred acquisition costs	1,849	1,835	1,804
Claims and claim adjustment expense reserves	48,272	49,824	50,865	$ 50,888
Discount from reserves for unpaid claims	1,066	1,080	1,090
Unearned premiums	11,971	11,839	11,850
Earned premiums	23,874	23,713	22,637
Net investment income	2,379	2,787	2,716
Claims and claim adjustment expenses incurred related to current year	14,412	14,621	14,060
Claims and claim adjustment expenses incurred related to prior year	(897)	(957)	(944)
Amortization of deferred acquisition costs	3,885	3,882	3,821
Paid claims and claim adjustment expenses	14,335	13,927	13,962
Net written premiums	$ 24,121	$ 23,904	$ 22,767