CNA Financial (CNA) 10-Q 1 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	6 Months Ended
	Jun. 30, 2016	Jul. 28, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	CNA FINANCIAL CORP
Entity Central Index Key	21,175
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		270,483,164

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues
Net earned premiums	$ 1,730	$ 1,735	$ 3,429	$ 3,422
Net investment income	502	500	937	1,058
Net realized investment gains (losses):
Other-than-temporary impairment losses	(15)	(31)	(38)	(43)
Other net realized investment (losses) gains	31	31	18	53
Net realized investment gains (losses)	16	0	(20)	10
Other revenues	100	92	197	189
Total revenues	2,348	2,327	4,543	4,679
Claims, Benefits and Expenses
Insurance claims and policyholders' benefits	1,339	1,469	2,747	2,808
Amortization of deferred acquisition costs	305	314	612	617
Other operating expenses	378	341	759	699
Interest	38	39	80	78
Total claims, benefits and expenses	2,060	2,163	4,198	4,202
Income (loss) from continuing operations before income tax	288	164	345	477
Income tax benefit (expense)	(79)	(26)	(70)	(106)
Net Income (Loss)	$ 209	$ 138	$ 275	$ 371
Earnings Per Share, Basic	$ 0.77	$ 0.51	$ 1.02	$ 1.37
Earnings Per Share, Diluted	0.77	0.51	1.02	1.37
Dividends declared per share	$ 0.25	$ 0.25	$ 2.50	$ 2.50
Weighted Average Outstanding Common Stock and Common Stock Equivalents
Basic	270.5	270.3	270.4	270.2
Diluted	270.9	270.7	270.9	270.7

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 209	$ 138	$ 275	$ 371
Other Comprehensive Income (Loss), Net of Tax, Changes In:
Net unrealized gains (losses) on investments with other-than-temporary impairments	(1)	(4)	4	(5)
Net unrealized gains (losses) on other investments	310	(365)	544	(253)
Net unrealized gains (losses) on investments	309	(369)	548	(258)
Foreign currency translation adjustment	(48)	49	(34)	(47)
Pension and postretirement benefits	5	42	11	48
Other comprehensive income (loss), net of tax	266	(278)	525	(257)
Total comprehensive income (loss)	$ 475	$ (140)	$ 800	$ 114

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Assets
Fixed maturity securities at fair value (amortized cost of $37,838 and $37,253)	$ 41,857	$ 39,572
Equity securities at fair value (cost of $117 and $191)	123	197
Limited partnership investments	2,542	2,548
Other invested assets	33	44
Mortgage loans	610	678
Short term investments	1,384	1,660
Total investments	46,549	44,699
Cash	289	387
Reinsurance receivables (less allowance for uncollectible receivables of $37 and $38)	4,683	4,453
Insurance receivables (less allowance for uncollectible receivables of $45 and $51)	2,368	2,078
Accrued investment income	400	404
Deferred acquisition costs	620	598
Deferred income taxes	293	638
Property and equipment at cost (less accumulated depreciation of $224 and $382)	276	343
Goodwill	147	150
Other assets (includes $2 and $0 due from Loews Corporation)	1,281	1,295
Total assets	56,906	55,045
Liabilities
Claim and claim adjustment expenses	22,975	22,663
Unearned premiums	3,865	3,671
Future policy benefits	11,140	10,152
Short term debt	0	350
Long term debt	2,708	2,210
Other liabilities (includes $12 and $82 due to Loews Corporation)	4,332	4,243
Total liabilities	45,020	43,289
Stockholders' Equity
Common stock ($2.50 par value; 500,000,000 shares authorized; 273,040,243 shares issued; 273,040,243 and 270,274,361 shares outstanding)	683	683
Additional paid-in capital	2,155	2,153
Retained earnings	8,911	9,313
Accumulated other comprehensive income (loss)	210	(315)
Treasury stock (2,557,079 and 2,765,882 shares), at cost	(73)	(78)
Total stockholders’ equity	11,886	11,756
Total liabilities and stockholders' equity	$ 56,906	$ 55,045

Consolidated Balance Sheet Pare

Consolidated Balance Sheet Parentheticals (Parentheticals) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Fixed maturities securities at amortized cost	$ 37,838	$ 37,253
Equity securities at cost	117	191
Allowance for uncollectible reinsurance receivables	37	38
Allowance for uncollectible insurance receivables	45	51
Accumulated depreciation on property and equipment	224	382
Due from Parent Company	2	0
Due to Parent Company	$ 12	$ 82
Common stock, par value	$ 2.50	$ 2.50
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	273,040,243	273,040,243
Common stock, shares outstanding	270,483,164	270,274,361
Treasury stock, shares	2,557,079	2,765,882

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash Flows from Operating Activities
Net Income (Loss)	$ 275	$ 371
Adjustments to reconcile net income (loss) to net cash flows provided (used) by operating activities:
Deferred income tax expense (benefit)	63	32
Trading portfolio activity	(7)	1
Realized Investment Gains (Losses)	20	(10)
Equity method investees	230	(48)
Amortization of investments	(10)	(13)
Depreciation and amortization	39	39
Changes in:
Receivables, net	(540)	(211)
Accrued investment income	4	8
Deferred acquisition costs	(25)	(8)
Insurance reserves	666	451
Other assets	(106)	(60)
Other liabilities	(27)	(94)
Other, net	31	82
Total adjustments	338	169
Net cash flows provided (used) by operating activities	613	540
Dispositions:
Fixed maturity securities - sales	3,066	2,859
Fixed maturity securities - maturities, calls and redemptions	1,247	2,304
Equity securities	72	33
Limited partnerships	124	85
Mortgage loans	109	19
Purchases:
Fixed maturity securities	(4,874)	(5,029)
Equity securities	0	(30)
Limited partnerships	(206)	(78)
Mortgage loans	(41)	(60)
Change in other investments	11	8
Change in short term investments	281	33
Purchases of property and equipment	(65)	(57)
Disposals of property and equipment	107	0
Other, net	2	0
Net cash flows provided (used) by investing activities	(167)	87
Cash Flows from Financing Activities
Dividends paid to common stockholders	(677)	(676)
Proceeds from the issuance of debt	498	0
Repayment of debt	(358)	0
Other, net	(1)	6
Net cash flows provided (used) by financing activities	(538)	(670)
Effect of foreign exchange rate changes on cash	(6)	(2)
Net change in cash	(98)	(45)
Cash, beginning of year	387	190
Cash, end of period	$ 289	$ 145

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity $ in Millions	USD ($)
Balance, beginning of year at Dec. 31, 2014	$ 683
Balance, end of period at Jun. 30, 2015	683
Balance, beginning of year at Dec. 31, 2014	2,151
Additional Paid-In Capital
Stock-based compensation	(5)
Balance, end of period at Jun. 30, 2015	2,146
Balance, beginning of year at Dec. 31, 2014	9,645
Retained Earnings (Accumulated Deficit)
Dividends paid to common stockholders	(676)
Net Income (Loss)	371
Balance, end of period at Jun. 30, 2015	9,340
Accumulated other comprehensive income (loss), beginning balance at Dec. 31, 2014	400
Accumulated Other Comprehensive Income (Loss)
Other Comprehensive Income (Loss)	(257)
Accumulated other comprehensive income (loss), ending balance at Jun. 30, 2015	143
Balance, beginning of year at Dec. 31, 2014	(84)
Treasury Stock
Stock Based Compensation and Other	6
Balance, end of period at Jun. 30, 2015	(78)
Balance, beginning of year at Dec. 31, 2014	(1)
Notes Receivable for the Issuance of Common Stock
Decrease (increase) in notes receivable for common stock	1
Balance, end of period at Jun. 30, 2015	0
Balance, end of period at Jun. 30, 2015	683
Balance, end of period at Jun. 30, 2015	2,146
Retained Earnings (Accumulated Deficit)
Net Income (Loss)	138
Balance, end of period at Jun. 30, 2015	9,340
Accumulated other comprehensive income (loss), beginning balance at Mar. 31, 2015	421
Accumulated Other Comprehensive Income (Loss)
Other Comprehensive Income (Loss)	(278)
Accumulated other comprehensive income (loss), ending balance at Jun. 30, 2015	143
Balance, end of period at Jun. 30, 2015	(78)
Balance, end of period at Jun. 30, 2015	0
Notes Receivable for the Issuance of Common Stock
Total stockholder's equity	12,234
Total stockholder's equity	11,756
Balance, beginning of year at Dec. 31, 2015	683
Balance, end of period at Jun. 30, 2016	683
Balance, beginning of year at Dec. 31, 2015	2,153
Additional Paid-In Capital
Stock-based compensation	2
Balance, end of period at Jun. 30, 2016	2,155
Balance, beginning of year at Dec. 31, 2015	9,313
Retained Earnings (Accumulated Deficit)
Dividends paid to common stockholders	(677)
Net Income (Loss)	275
Balance, end of period at Jun. 30, 2016	8,911
Accumulated other comprehensive income (loss), beginning balance at Dec. 31, 2015	(315)
Accumulated Other Comprehensive Income (Loss)
Other Comprehensive Income (Loss)	525
Accumulated other comprehensive income (loss), ending balance at Jun. 30, 2016	210
Balance, beginning of year at Dec. 31, 2015	(78)
Treasury Stock
Stock Based Compensation and Other	5
Balance, end of period at Jun. 30, 2016	(73)
Balance, beginning of year at Dec. 31, 2015	0
Notes Receivable for the Issuance of Common Stock
Decrease (increase) in notes receivable for common stock	0
Balance, end of period at Jun. 30, 2016	0
Balance, end of period at Jun. 30, 2016	683
Balance, end of period at Jun. 30, 2016	2,155
Retained Earnings (Accumulated Deficit)
Net Income (Loss)	209
Balance, end of period at Jun. 30, 2016	8,911
Accumulated other comprehensive income (loss), beginning balance at Mar. 31, 2016	(56)
Accumulated Other Comprehensive Income (Loss)
Other Comprehensive Income (Loss)	266
Accumulated other comprehensive income (loss), ending balance at Jun. 30, 2016	210
Balance, end of period at Jun. 30, 2016	(73)
Balance, end of period at Jun. 30, 2016	0
Notes Receivable for the Issuance of Common Stock
Total stockholder's equity	$ 11,886

General

General	6 Months Ended
	Jun. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block]	Note A . General Basis of Presentation The Condensed Consolidated Financial Statements include the accounts of CNA Financial Corporation (CNAF) and its subsidiaries. Collectively, CNAF and its subsidiaries are referred to as CNA or the Company. Loews Corporation (Loews) owned approximately 90% of the outstanding common stock of CNAF as of June 30, 2016 . The accompanying Condensed Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). Intercompany amounts have been eliminated. Certain financial information that is normally included in annual financial statements, including certain financial statement notes, prepared in accordance with GAAP, is not required for interim reporting purposes and has been condensed or omitted. These statements should be read in conjunction with the Consolidated Financial Statements and notes thereto included in CNAF's Annual Report on Form 10-K filed with the Securities and Exchange Commission for the year ended December 31, 2015 , including the summary of significant accounting policies in Note A. The preparation of Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the Condensed Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates. The interim financial data as of June 30, 2016 and for the three and six months ended June 30, 2016 and 2015 is unaudited. However, in the opinion of management, the interim data includes all adjustments, including normal recurring adjustments, necessary for a fair statement of the Company's results for the interim periods. The results of operations for the interim periods are not necessarily indicative of the results to be expected for the full year. Recently Adopted Accounting Standards Updates (ASU) In April 2015, the Financial Accounting Standards Board (FASB) issued ASU No. 2015-03, Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs . The updated accounting guidance requires debt issuance costs to be presented as a deduction from the corresponding debt liability instead of the historical presentation as an unamortized debt issuance asset. As of January 1, 2016, the Company adopted the updated accounting guidance retrospectively. The Company adjusted its previously reported financial information included herein to reflect the change in accounting guidance for debt issuance costs. The impacts of adopting the new accounting standard on the Company’s Consolidated Balance Sheet as of December 31, 2015, were a decrease in Other assets and a decrease in Long term debt of $2 million . In May 2015, the FASB issued ASU No. 2015-07, Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). The updated accounting guidance removes the requirement to categorize assets measured at fair value utilizing the net asset value per share (or equivalent) practical expedient within the fair value hierarchy. As of January 1, 2016, the Company adopted the updated accounting guidance retrospectively. The Company adjusted its previously reported financial information included herein to reflect the change in accounting guidance for assets measured using the net asset value. The impact of adopting the new accounting standard resulted in excluding overseas deposits of $28 million and $27 million from the fair value level disclosure as of June 30, 2016 and December 31, 2015 . Accounting Standards Pending Adoption In May 2015, the FASB issued ASU No. 2015-09, Financial Services-Insurance (Topic 944): Disclosures about Short-Duration Contracts. The updated accounting guidance requires enhanced disclosures to provide additional information about insurance liabilities for short-duration contracts. The guidance is effective for annual periods beginning after December 15, 2015, and interim periods within the annual periods beginning after December 15, 2016. The Company is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures but expects to provide additional incurred and paid claims development information by accident year, quantitative information about claim frequency and the history of claims duration for significant lines of business within the Company’s annual financial statements. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The updated accounting guidance requires changes to the reporting model for financial instruments. The guidance is effective for interim and annual periods beginning after December 15, 2017. The Company is currently evaluating the effect the guidance will have on the Company's financial statements, and expects the primary change for the Company to be the requirement for equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842): Accounting for Leases. The updated accounting guidance requires lessees to recognize on the balance sheet the assets and liabilities for the rights and obligations created by all leases, including those historically accounted for as operating leases. The guidance is effective for interim and annual periods beginning after December 15, 2018. The Company is currently evaluating the effect the updated guidance will have on the Company's financial statements. In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The updated accounting guidance simplifies the accounting for share-based payment award transactions including income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The guidance is effective for annual periods beginning after December 15, 2017, and interim periods within annual periods beginning after December 15, 2018. The Company is currently evaluating the effect the updated guidance will have on the Company’s financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The updated accounting guidance requires changes to the recognition of credit losses on financial instruments not accounted for at fair value through net income. The guidance is effective for interim and annual periods beginning after December 15, 2019. The Company is currently evaluating the effect the guidance will have on the Company's financial statements, but expects the primary changes to be the use of the expected credit loss model for its mortgage loan portfolio and reinsurance receivables and the presentation of credit losses within the available-for-sale fixed maturities portfolio through an allowance method rather than as a direct write-down. The expected credit loss model will require a financial asset to be presented at the net amount expected to be collected. The allowance method for available-for-sale debt securities will allow the Company to record reversals of credit losses when the estimate of credit losses declines.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2016
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Note B . Earnings Per Share Earnings per share is based on the weighted average number of outstanding common shares. Basic earnings (loss) per share excludes the effect of dilutive securities and is computed by dividing Net income (loss) by the weighted average number of common shares outstanding for the period. Diluted earnings (loss) per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock. For the three and six months ended June 30, 2016 , approximately 409 thousand and 473 thousand potential shares attributable to exercises under stock-based employee compensation plans were included in the calculation of diluted earnings per share. For those same periods, approximately 178 thousand and 180 thousand potential shares attributable to exercises under stock-based employee compensation plans were not included in the calculation of diluted earnings per share because the effect would have been antidilutive. For the three and six months ended June 30, 2015 , approximately 423 thousand and 543 thousand potential shares attributable to exercises under stock-based employee compensation plans were included in the calculation of diluted earnings per share. For those same periods, approximately 238 thousand and 208 thousand potential shares attributable to exercises under stock-based employee compensation plans were not included in the calculation of diluted earnings per share because the effect would have been antidilutive.

Investments

Investments	6 Months Ended
	Jun. 30, 2016
Investments [Abstract]
Investments	Note C . Investments The significant components of Net investment income are presented in the following table. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Fixed maturity securities $ 449 $ 452 $ 895 $ 895 Equity securities 4 3 7 6 Limited partnership investments 46 48 32 162 Mortgage loans 13 9 22 17 Short term investments 1 — 4 2 Trading portfolio 4 3 6 5 Gross investment income 517 515 966 1,087 Investment expense (15 ) (15 ) (29 ) (29 ) Net investment income $ 502 $ 500 $ 937 $ 1,058 Net realized investment gains (losses) are presented in the following table. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Net realized investment gains (losses): Fixed maturity securities: Gross realized gains $ 40 $ 36 $ 85 $ 69 Gross realized losses (24 ) (48 ) (86 ) (69 ) Net realized investment gains (losses) on fixed maturity securities 16 (12 ) (1 ) — Equity securities: Gross realized gains 4 — 4 1 Gross realized losses (1 ) (1 ) (6 ) (2 ) Net realized investment gains (losses) on equity securities 3 (1 ) (2 ) (1 ) Derivative financial instruments (6 ) 11 (13 ) 10 Short term investments and other 3 2 (4 ) 1 Net realized investment gains (losses) $ 16 $ — $ (20 ) $ 10 Net realized investment losses for the six months ended June 30, 2016 include $8 million related to the redemption of the Company's $350 million senior notes due August 2016. The components of Net other-than-temporary impairment (OTTI) losses recognized in earnings by asset type are presented in the following table. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Fixed maturity securities available-for-sale: Corporate and other bonds $ 13 $ 11 $ 29 $ 16 States, municipalities and political subdivisions — 13 — 18 Asset-backed: Residential mortgage-backed 1 5 1 6 Other asset-backed 1 1 3 1 Total asset-backed 2 6 4 7 Total fixed maturity securities available-for-sale 15 30 33 41 Equity securities available-for-sale -- Common stock — — 5 1 Short term investments — 1 — 1 OTTI losses recognized in earnings $ 15 $ 31 $ 38 $ 43 The following tables present a summary of fixed maturity and equity securities. June 30, 2016 Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Unrealized OTTI Losses (Gains) (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 17,613 $ 1,684 $ 93 $ 19,204 $ (1 ) States, municipalities and political subdivisions 11,661 2,114 2 13,773 (25 ) Asset-backed: Residential mortgage-backed 4,994 215 20 5,189 (21 ) Commercial mortgage-backed 2,080 91 8 2,163 — Other asset-backed 928 8 5 931 — Total asset-backed 8,002 314 33 8,283 (21 ) U.S. Treasury and obligations of government-sponsored enterprises 81 11 — 92 — Foreign government 438 22 — 460 — Redeemable preferred stock 33 2 — 35 — Total fixed maturity securities available-for-sale 37,828 4,147 128 41,847 $ (47 ) Total fixed maturity securities trading 10 10 Equity securities available-for-sale: Common stock 20 5 2 23 Preferred stock 97 6 3 100 Total equity securities available-for-sale 117 11 5 123 Total $ 37,955 $ 4,158 $ 133 $ 41,980 December 31, 2015 Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Unrealized OTTI Losses (Gains) (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 17,080 $ 1,019 $ 342 $ 17,757 $ — States, municipalities and political subdivisions 11,729 1,453 8 13,174 (4 ) Asset-backed: Residential mortgage-backed 4,935 154 17 5,072 (37 ) Commercial mortgage-backed 2,154 55 12 2,197 — Other asset-backed 923 6 8 921 — Total asset-backed 8,012 215 37 8,190 (37 ) U.S. Treasury and obligations of government-sponsored enterprises 62 5 — 67 — Foreign government 334 13 1 346 — Redeemable preferred stock 33 2 — 35 — Total fixed maturity securities available-for-sale 37,250 2,707 388 39,569 $ (41 ) Total fixed maturity securities trading 3 3 Equity securities available-for-sale: Common stock 46 3 1 48 Preferred stock 145 7 3 149 Total equity securities available-for-sale 191 10 4 197 Total $ 37,444 $ 2,717 $ 392 $ 39,769 The net unrealized gains on investments included in the tables above are recorded as a component of Accumulated other comprehensive income (AOCI). When presented in AOCI, these amounts are net of tax and any required Shadow Adjustments. To the extent that unrealized gains on fixed income securities supporting certain products within the Life & Group Non-Core segment would result in a premium deficiency if realized, a related increase in Insurance reserves is recorded, net of tax, as a reduction of net unrealized gains through Other comprehensive income (loss) (Shadow Adjustments). As of June 30, 2016 and December 31, 2015 , the net unrealized gains on investments included in AOCI were correspondingly reduced by Shadow Adjustments of $1,682 million and $1,111 million . The following tables present the estimated fair value and gross unrealized losses of fixed maturity and equity securities in a gross unrealized loss position by the length of time in which the securities have continuously been in that position. Less than 12 Months 12 Months or Longer Total June 30, 2016 Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 1,032 $ 43 $ 562 $ 50 $ 1,594 $ 93 States, municipalities and political subdivisions 68 2 10 — 78 2 Asset-backed: Residential mortgage-backed 293 8 234 12 527 20 Commercial mortgage-backed 386 7 118 1 504 8 Other asset-backed 306 5 5 — 311 5 Total asset-backed 985 20 357 13 1,342 33 Foreign government 8 — 5 — 13 — Total fixed maturity securities available-for-sale 2,093 65 934 63 3,027 128 Equity securities available-for-sale: Common stock 4 2 — — 4 2 Preferred stock 23 3 — — 23 3 Total equity securities available-for-sale 27 5 — — 27 5 Total $ 2,120 $ 70 $ 934 $ 63 $ 3,054 $ 133 Less than 12 Months 12 Months or Longer Total December 31, 2015 Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 4,882 $ 302 $ 162 $ 40 $ 5,044 $ 342 States, municipalities and political subdivisions 338 8 75 — 413 8 Asset-backed: Residential mortgage-backed 963 9 164 8 1,127 17 Commercial mortgage-backed 652 10 96 2 748 12 Other asset-backed 552 8 5 — 557 8 Total asset-backed 2,167 27 265 10 2,432 37 U.S. Treasury and obligations of government-sponsored enterprises 4 — — — 4 — Foreign government 54 1 — — 54 1 Redeemable preferred stock 3 — — — 3 — Total fixed maturity securities available-for-sale 7,448 338 502 50 7,950 388 Equity securities available-for-sale: Common stock 3 1 — — 3 1 Preferred stock 13 3 — — 13 3 Total equity securities available-for-sale 16 4 — — 16 4 Total $ 7,464 $ 342 $ 502 $ 50 $ 7,966 $ 392 Based on current facts and circumstances, the Company believes the unrealized losses presented in the June 30, 2016 table above, are not indicative of the ultimate collectibility of the current amortized cost of the securities, but rather are attributable to changes in interest rates, credit spreads and other factors. The Company has no current intent to sell securities with unrealized losses, nor is it more likely than not that it will be required to sell prior to recovery of amortized cost; accordingly, the Company has determined that there are no additional OTTI losses to be recorded as of June 30, 2016 . The following table presents the activity related to the pretax credit loss component reflected in Retained earnings on fixed maturity securities still held as of June 30, 2016 and 2015 for which a portion of an OTTI loss was recognized in Other comprehensive income (loss). Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Beginning balance of credit losses on fixed maturity securities $ 48 $ 61 $ 53 $ 62 Reductions for securities sold during the period (7 ) (2 ) (12 ) (3 ) Ending balance of credit losses on fixed maturity securities $ 41 $ 59 $ 41 $ 59 Contractual Maturity The following table presents available-for-sale fixed maturity securities by contractual maturity. June 30, 2016 December 31, 2015 (In millions) Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Due in one year or less $ 1,817 $ 1,855 $ 1,574 $ 1,595 Due after one year through five years 8,616 9,114 7,721 8,070 Due after five years through ten years 14,583 15,466 14,652 14,915 Due after ten years 12,812 15,412 13,303 14,989 Total $ 37,828 $ 41,847 $ 37,250 $ 39,569 Actual maturities may differ from contractual maturities because certain securities may be called or prepaid. Securities not due at a single date are allocated based on weighted average life. Derivative Financial Instruments The Company holds an embedded derivative on funds withheld liability with a notional value of $177 million and $179 million as of June 30, 2016 and December 31, 2015 and a fair value of $8 million and $(5) million as of June 30, 2016 and December 31, 2015 . The embedded derivative on funds withheld liability is accounted for separately and reported with the funds withheld liability in Other liabilities on the Condensed Consolidated Balance Sheets. Investment Commitments As of June 30, 2016 , the Company had committed approximately $365 million to future capital calls from various third-party limited partnership investments in exchange for an ownership interest in the related partnerships. As of June 30, 2016 , the Company had mortgage loan commitments of $59 million representing signed loan applications received and accepted. The Company invests in various privately placed debt securities, including bank loans, as part of its overall investment strategy and has committed to additional future purchases, sales and funding. Purchases and sales of privately placed debt securities are recorded once funded. As of June 30, 2016 , the Company had commitments to purchase or fund additional amounts of $198 million and sell $95 million under the terms of such securities.

Fair Value

Fair Value	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value	Note D . Fair Value Fair value is the price that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The following fair value hierarchy is used in selecting inputs, with the highest priority given to Level 1, as these are the most transparent or reliable. Level 1 - Quoted prices for identical instruments in active markets. Level 2 - Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations in which all significant inputs are observable in active markets. Level 3 - Valuations derived from valuation techniques in which one or more significant inputs are not observable. Prices may fall within Level 1, 2 or 3 depending upon the methodology and inputs used to estimate fair value for each specific security. In general the Company seeks to price securities using third-party pricing services. Securities not priced by pricing services are submitted to independent brokers for valuation and, if those are not available, internally developed pricing models are used to value assets using a methodology and inputs the Company believes market participants would use to value the assets. Prices obtained from third-party pricing services or brokers are not adjusted by the Company. The Company performs control procedures over information obtained from pricing services and brokers to ensure prices received represent a reasonable estimate of fair value and to confirm representations regarding whether inputs are observable or unobservable. Procedures include i) the review of pricing service or broker pricing methodologies, ii) back-testing, where past fair value estimates are compared to actual transactions executed in the market on similar dates, iii) exception reporting, where period-over-period changes in price are reviewed and challenged with the pricing service or broker based on exception criteria, iv) deep dives, where the Company performs an independent analysis of the inputs and assumptions used to price individual securities and v) pricing validation, where prices received are compared to prices independently estimated by the Company. Assets and Liabilities Measured at Fair Value Assets and liabilities measured at fair value on a recurring basis are presented in the following tables. June 30, 2016 Total Assets/Liabilities at Fair Value (In millions) Level 1 Level 2 Level 3 Assets Fixed maturity securities: Corporate and other bonds $ — $ 18,972 $ 242 $ 19,214 States, municipalities and political subdivisions — 13,771 2 13,773 Asset-backed: Residential mortgage-backed — 5,055 134 5,189 Commercial mortgage-backed — 2,152 11 2,163 Other asset-backed — 886 45 931 Total asset-backed — 8,093 190 8,283 U.S. Treasury and obligations of government-sponsored enterprises 91 1 — 92 Foreign government — 460 — 460 Redeemable preferred stock 35 — — 35 Total fixed maturity securities 126 41,297 434 41,857 Equity securities 104 — 19 123 Other invested assets — 5 — 5 Short term investments 339 950 — 1,289 Life settlement contracts, included in Other assets — — 67 67 Total assets $ 569 $ 42,252 $ 520 $ 43,341 Liabilities Other liabilities $ — $ 8 $ — $ 8 Total liabilities $ — $ 8 $ — $ 8 December 31, 2015 Total Assets/Liabilities at Fair Value (In millions) Level 1 Level 2 Level 3 Assets Fixed maturity securities: Corporate and other bonds $ — $ 17,592 $ 168 $ 17,760 States, municipalities and political subdivisions — 13,172 2 13,174 Asset-backed: Residential mortgage-backed — 4,938 134 5,072 Commercial mortgage-backed — 2,175 22 2,197 Other asset-backed — 868 53 921 Total asset-backed — 7,981 209 8,190 U.S. Treasury and obligations of government-sponsored enterprises 66 1 — 67 Foreign government — 346 — 346 Redeemable preferred stock 35 — — 35 Total fixed maturity securities 101 39,092 379 39,572 Equity securities 177 — 20 197 Other invested assets — 17 — 17 Short term investments 448 1,134 — 1,582 Life settlement contracts, included in Other assets — — 74 74 Total assets $ 726 $ 40,243 $ 473 $ 41,442 Liabilities Other liabilities $ — $ (5 ) $ — $ (5 ) Total liabilities $ — $ (5 ) $ — $ (5 ) The tables below present a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3). Level 3 (In millions) Balance as of April 1, 2016 Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in Net income (loss)* Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Balance as of June 30, 2016 Unrealized gains (losses) on Level 3 assets and liabilities held as of June 30, 2016 recognized in Net income (loss)* Fixed maturity securities: Corporate and other bonds $ 193 $ 1 $ 3 $ 94 $ (20 ) $ (7 ) $ — $ (22 ) $ 242 $ — States, municipalities and political subdivisions 2 — — — — — — — 2 — Asset-backed: Residential mortgage-backed 128 1 (1 ) 10 — (4 ) — — 134 — Commercial mortgage-backed 27 — — — — (9 ) 3 (10 ) 11 — Other asset-backed 50 — 2 35 (25 ) (1 ) — (16 ) 45 — Total asset-backed 205 1 1 45 (25 ) (14 ) 3 (26 ) 190 — Total fixed maturity securities 400 2 4 139 (45 ) (21 ) 3 (48 ) 434 — Equity securities 19 — — — — — — — 19 — Life settlement contracts 72 6 — — — (11 ) — — 67 (3 ) Total $ 491 $ 8 $ 4 $ 139 $ (45 ) $ (32 ) $ 3 $ (48 ) $ 520 $ (3 ) Level 3 (In millions) Balance as of April 1, 2015 Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in Net income (loss)* Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Balance as of June 30, 2015 Unrealized gains (losses) on Level 3 assets and liabilities held as of June 30, 2015 recognized in Net income (loss)* Fixed maturity securities: Corporate and other bonds $ 186 $ (2 ) $ (1 ) $ — $ — $ (7 ) $ — $ (35 ) $ 141 $ (3 ) States, municipalities and political subdivisions 86 — — — — (1 ) — — 85 — Asset-backed: Residential mortgage-backed 232 1 (2 ) — — (11 ) — (13 ) 207 — Commercial mortgage-backed 64 1 (1 ) 9 — (1 ) 17 (2 ) 87 — Other asset-backed 553 2 1 47 (90 ) (17 ) — (6 ) 490 — Total asset-backed 849 4 (2 ) 56 (90 ) (29 ) 17 (21 ) 784 — Total fixed maturity securities 1,121 2 (3 ) 56 (90 ) (37 ) 17 (56 ) 1,010 (3 ) Equity securities 13 — 3 — — — — — 16 — Life settlement contracts 79 4 — — — (8 ) — — 75 (2 ) Total $ 1,213 $ 6 $ — $ 56 $ (90 ) $ (45 ) $ 17 $ (56 ) $ 1,101 $ (5 ) Level 3 (In millions) Balance as of January 1, 2016 Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in Net income (loss)* Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Balance as of June 30, 2016 Unrealized gains (losses) on Level 3 assets and liabilities held as of June 30, 2016 recognized in Net income (loss)* Fixed maturity securities: Corporate and other bonds $ 168 $ — $ 7 $ 147 $ (36 ) $ (10 ) $ — $ (34 ) $ 242 $ — States, municipalities and political subdivisions 2 — — — — — — — 2 — Asset-backed: Residential mortgage-backed 134 2 (1 ) 10 — (9 ) — (2 ) 134 — Commercial mortgage-backed 22 — — 9 — (9 ) 3 (14 ) 11 — Other asset-backed 53 — 2 35 (25 ) (1 ) 2 (21 ) 45 — Total asset-backed 209 2 1 54 (25 ) (19 ) 5 (37 ) 190 — Total fixed maturity securities 379 2 8 201 (61 ) (29 ) 5 (71 ) 434 — Equity securities 20 — (1 ) — — — — — 19 — Life settlement contracts 74 10 — — — (17 ) — — 67 (3 ) Total $ 473 $ 12 $ 7 $ 201 $ (61 ) $ (46 ) $ 5 $ (71 ) $ 520 $ (3 ) Level 3 (In millions) Balance as of January 1, 2015 Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in Net income (loss)* Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Balance as of June 30, 2015 Unrealized gains (losses) on Level 3 assets and liabilities held as of June 30, 2015 recognized in Net income (loss)* Fixed maturity securities: Corporate and other bonds $ 162 $ (1 ) $ (1 ) $ 12 $ (12 ) $ (21 ) $ 37 $ (35 ) $ 141 $ (3 ) States, municipalities and political subdivisions 94 1 — — — (10 ) — — 85 — Asset-backed: Residential mortgage-backed 189 2 (2 ) 72 — (21 ) — (33 ) 207 — Commercial mortgage-backed 83 2 — 15 — (2 ) 17 (28 ) 87 — Other asset-backed 655 3 10 82 (234 ) (20 ) — (6 ) 490 — Total asset-backed 927 7 8 169 (234 ) (43 ) 17 (67 ) 784 — Total fixed maturity securities 1,183 7 7 181 (246 ) (74 ) 54 (102 ) 1,010 (3 ) Equity securities 16 — — — — — — — 16 — Life settlement contracts 82 17 — — — (24 ) — — 75 (1 ) Total $ 1,281 $ 24 $ 7 $ 181 $ (246 ) $ (98 ) $ 54 $ (102 ) $ 1,101 $ (4 ) *Net realized and unrealized gains and losses from Level 3 securities and derivatives are reported in Net income (loss) as follows: Major Category of Assets and Liabilities Condensed Consolidated Statements of Operations Line Items Fixed maturity securities available-for-sale (1) Net realized investment gains (losses) Fixed maturity securities trading Net investment income Equity securities (1) Net realized investment gains (losses) Other invested assets - Derivative financial instruments held in a trading portfolio Net investment income Other invested assets - Derivative financial instruments not held in a trading portfolio Net realized investment gains (losses) Life settlement contracts Other revenues Other liabilities - Derivative financial instruments Net realized investment gains (losses) (1) Unrealized gains and losses are reported within AOCI. Securities shown on the previous pages may be transferred in or out of levels within the fair value hierarchy based on the availability of observable market information and quoted prices used to determine the fair value of the security. The availability of observable market information and quoted prices varies based on market conditions and trading volume. During the three and six months ended June 30, 2016 and 2015 there were no transfers between Level 1 and Level 2. The Company's policy is to recognize transfers between levels at the beginning of quarterly reporting periods. Valuation Methodologies and Inputs The following section describes the valuation methodologies and relevant inputs used to measure different financial instruments at fair value, including an indication of the level in the fair value hierarchy in which the instruments are generally classified. Fixed Maturity Securities Level 1 securities include highly liquid and exchange traded bonds and redeemable preferred stock, valued using quoted market prices. Level 2 securities include most other fixed maturity securities as the significant inputs are observable in the marketplace. All classes of Level 2 fixed maturity securities are valued using a methodology based on information generated by market transactions involving identical or comparable assets, a discounted cash flow methodology, or a combination of both when necessary. Common inputs for all classes of fixed maturity securities include prices from recently executed transactions of similar securities, marketplace quotes, benchmark yields, spreads off benchmark yields, interest rates and U.S. Treasury or swap curves. Specifically for asset-backed securities, key inputs include prepayment and default projections based on past performance of the underlying collateral and current market data. Fixed maturity securities are primarily assigned to Level 3 in cases where broker/dealer quotes are significant inputs to the valuation and there is a lack of transparency as to whether these quotes are based on information that is observable in the marketplace. Level 3 securities also include private placement debt securities whose fair value is determined using internal models with inputs that are not market observable. Equity Securities Level 1 equity securities include publicly traded securities valued using quoted market prices. Level 2 securities are primarily non-redeemable preferred stocks and common stocks valued using pricing for similar securities, recently executed transactions and other pricing models utilizing market observable inputs. Level 3 securities are primarily priced using broker/dealer quotes and internal models with inputs that are not market observable. Other invested assets - Federal Home Loan Bank of Chicago (FHLBC) Stock The fair value of FHLBC stock is equal to par because it can only be redeemed by the FHLBC at par or sold to another member of the FHLBC at par and is classified as Level 2. Short Term Investments Securities that are actively traded or have quoted prices are classified as Level 1. These securities include money market funds and treasury bills. Level 2 primarily includes commercial paper, for which all inputs are market observable. Fixed maturity securities purchased within one year of maturity are valued consistent with fixed maturity securities discussed above. Short term investments as presented in the tables above differ from the amounts presented on the Condensed Consolidated Balance Sheets because certain short term investments, such as time deposits, are not measured at fair value. Life Settlement Contracts The fair values of life settlement contracts are determined as the present value of the anticipated death benefits less anticipated premium payments based on contract terms that are distinct for each insured, as well as the Company's own assumptions for mortality, premium expense and the rate of return that a buyer would require on the contracts, as no comparable market pricing data is available. Derivative Financial Investments Level 2 securities primarily include the embedded derivative on funds withheld liability. The embedded derivative on funds withheld liability is valued using the change in fair value of the assets supporting the funds withheld liability, which are fixed maturity securities valued with observable inputs. Other invested assets - Overseas Deposits As of June 30, 2016 and December 31, 2015, there were approximately $28 million and $27 million respectively of overseas deposits, which can be redeemed at net asset value in 90 days or less. Overseas deposits are excluded from the fair value hierarchy because their fair value is recorded using the net asset value per share (or equivalent) practical expedient. Significant Unobservable Inputs The following tables present quantitative information about the significant unobservable inputs utilized by the Company in the fair value measurement of Level 3 assets. Valuations for assets and liabilities not presented in the tables below are primarily based on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of these unobservable inputs is neither provided nor reasonably available to the Company. June 30, 2016 Estimated Fair Value (In millions) Valuation Technique(s) Unobservable Input(s) Range (Weighted Average) Fixed maturity securities $ 226 Discounted cash flow Credit spread 1% - 40% (6%) Life settlement contracts 67 Discounted cash flow Discount rate risk premium 9% Mortality assumption 55% - 1676% (162%) December 31, 2015 Estimated Fair Value Valuation Technique(s) Unobservable Input(s) Range (Weighted Average) Fixed maturity securities $ 138 Discounted cash flow Credit spread 3% - 184% (6%) Life settlement contracts 74 Discounted cash flow Discount rate risk premium 9% Mortality assumption 55% - 1676% (164%) For fixed maturity securities, an increase to the credit spread assumptions would result in a lower fair value measurement. For life settlement contracts, an increase in the discount rate risk premium or decrease in the mortality assumption would result in a lower fair value measurement. Financial Assets and Liabilities Not Measured at Fair Value The carrying amount and estimated fair value of the Company's financial assets and liabilities which are not measured at fair value on the Condensed Consolidated Balance Sheets are presented in the following tables. June 30, 2016 Carrying Amount Estimated Fair Value (In millions) Level 1 Level 2 Level 3 Total Assets Mortgage loans $ 610 $ — $ — $ 638 $ 638 Liabilities Long term debt $ 2,708 $ — $ 3,024 $ — $ 3,024 December 31, 2015 Carrying Estimated Fair Value (In millions) Level 1 Level 2 Level 3 Total Assets Mortgage loans $ 678 $ — $ — $ 688 $ 688 Liabilities Short term debt $ 350 $ — $ 360 $ — $ 360 Long term debt 2,210 — 2,433 — 2,433 The following methods and assumptions were used to estimate the fair value of these financial assets and liabilities. The fair value of Mortgage loans was based on the present value of the expected future cash flows discounted at the current interest rate for origination of similar quality loans, adjusted for specific loan risk. The Company's senior notes and debentures were valued based on observable market prices. The fair value for other debt was estimated using discounted cash flows based on current incremental borrowing rates for similar borrowing arrangements. The carrying amounts reported on the Condensed Consolidated Balance Sheets for Cash, Short term investments not carried at fair value, Accrued investment income and certain Other assets and Other liabilities approximate fair value due to the short term nature of these items. These assets and liabilities are not listed in the tables above.

Claim and Claim Adjustment Expe

Claim and Claim Adjustment Expense Reserves	6 Months Ended
	Jun. 30, 2016
Liability for Claims and Claims Adjustment Expense [Abstract]
Claim and Claim Adjustment Expense Reserves	Note E . Claim and Claim Adjustment Expense Reserves The Company's property and casualty insurance claim and claim adjustment expense reserves represent the estimated amounts necessary to resolve all outstanding claims, including incurred but not reported (IBNR) claims as of the reporting date. The Company's reserve projections are based primarily on detailed analysis of the facts in each case, the Company's experience with similar cases and various historical development patterns. Consideration is given to such historical patterns as field reserving trends and claims settlement practices, loss payments, pending levels of unpaid claims and product mix, as well as court decisions, economic conditions including inflation and public attitudes. All of these factors can affect the estimation of claim and claim adjustment expense reserves. Establishing claim and claim adjustment expense reserves, including claim and claim adjustment expense reserves for catastrophic events that have occurred, is an estimation process. Many factors can ultimately affect the final settlement of a claim and, therefore, the necessary reserve. Changes in the law, results of litigation, medical costs, the cost of repair materials and labor rates can all affect ultimate claim costs. In addition, time can be a critical part of reserving determinations since the longer the span between the incidence of a loss and the payment or settlement of the claim, the more variable the ultimate settlement amount can be. Accordingly, short-tail claims, such as property damage claims, tend to be more reasonably estimable than long-tail claims, such as workers' compensation, general liability and professional liability claims. Adjustments to prior year reserve estimates, if necessary, are reflected in the results of operations in the period that the need for such adjustments is determined. There can be no assurance that the Company's ultimate cost for insurance losses will not exceed current estimates. Catastrophes are an inherent risk of the property and casualty insurance business and have contributed to material period-to-period fluctuations in the Company's results of operations and/or equity. The Company reported catastrophe losses, net of reinsurance, of $85 million and $121 million for the three and six months ended June 30, 2016 . Catastrophe losses in 2016 resulted primarily from U.S. weather-related events and the Fort McMurray wildfires. The Company reported catastrophe losses, net of reinsurance, of $60 million and $89 million for the three and six months ended June 30, 2015 . Net Prior Year Development The following tables and discussion present the net prior year development. Three months ended June 30, 2016 (In millions) Specialty Commercial International Corporate & Other Non-Core Total Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development $ (65 ) $ (18 ) $ (15 ) $ — $ (98 ) Pretax (favorable) unfavorable premium development (7 ) (2 ) 1 — (8 ) Total pretax (favorable) unfavorable net prior year development $ (72 ) $ (20 ) $ (14 ) $ — $ (106 ) Three months ended June 30, 2015 (In millions) Specialty Commercial International Corporate & Other Non-Core Total Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development $ (13 ) $ 16 $ (8 ) $ — $ (5 ) Pretax (favorable) unfavorable premium development (2 ) (11 ) (2 ) — (15 ) Total pretax (favorable) unfavorable net prior year development $ (15 ) $ 5 $ (10 ) $ — $ (20 ) Six months ended June 30, 2016 (In millions) Specialty Commercial International Corporate & Other Non-Core Total Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development $ (99 ) $ (32 ) $ (19 ) $ — $ (150 ) Pretax (favorable) unfavorable premium development (18 ) (4 ) — — (22 ) Total pretax (favorable) unfavorable net prior year development $ (117 ) $ (36 ) $ (19 ) $ — $ (172 ) Six months ended June 30, 2015 (In millions) Specialty Commercial International Corporate & Other Non-Core Total Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development $ (11 ) $ 11 $ (12 ) $ — $ (12 ) Pretax (favorable) unfavorable premium development (8 ) (12 ) 14 — (6 ) Total pretax (favorable) unfavorable net prior year development $ (19 ) $ (1 ) $ 2 $ — $ (18 ) Specialty The following table presents further detail of the net prior year claim and allocated claim adjustment expense reserve development (development) recorded for the Specialty segment. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Pretax (favorable) unfavorable development: Medical Professional Liability $ (23 ) $ (6 ) $ (30 ) $ 8 Other Professional Liability and Management Liability (41 ) (1 ) (50 ) (4 ) Surety — — — 1 Warranty 3 1 5 1 Other (4 ) (7 ) (24 ) (17 ) Total pretax (favorable) unfavorable development $ (65 ) $ (13 ) $ (99 ) $ (11 ) Three Months 2016 Favorable development in medical professional liability was due to lower than expected severity for individual healthcare professionals and allied facilities for accident years 2014 and prior. Favorable development in other professional liability and management liability was primarily related to lower than expected frequency of claims in accident years 2010 through 2015, mainly driven by professional services. This was partially offset by unfavorable development in accident year 2015 related to an increase in management liability frequency of larger claims. 2015 Overall, favorable development in medical professional liability was primarily due to lower than expected severity for individual healthcare professionals and allied facilities in accident years 2009 through 2012. Unfavorable development was recorded related to increased claim frequency in the aging services business in accident years 2009 and 2010. Favorable development of $38 million was recorded in other professional liability and management liability related to lower than expected severity for professional services primarily in accident years 2010 and prior. Unfavorable development of $37 million was recorded primarily related to increased claim frequency on public company management liability in accident years 2012 through 2014. Favorable development for other coverages was primarily due to better than expected claim frequency in property coverages provided to Specialty customers in accident year 2014. Six Months 2016 Favorable development for medical professional liability was primarily due to lower than expected severities for individual healthcare professionals, allied facilities, and hospitals in accident years 2011 and prior. This was partially offset by unfavorable development in accident years 2012 and 2013 related to higher than expected large loss emergence in hospitals and higher than expected severity in accident years 2014 and 2015 in our aging services business. Favorable development in other professional liability and management liability was primarily related to lower than expected frequency of claims in accident years 2010 through 2015, mainly driven by professional services. Additional favorable development was related to favorable outcomes on larger claims in 2013 and prior in professional services. This was partially offset by unfavorable development in accident years 2014 and 2015 related to an increase in management liability frequency of larger claims. Favorable development for other coverages was due to better than expected claim frequency in property coverages provided to Specialty customers in accident year 2015. 2015 Overall, unfavorable development for medical professional liability was primarily related to increased claim frequency in the aging services business for accident years 2009 through 2014, partially offset by lower than expected severity in accident years 2010 and prior. Additional favorable development was due to lower than expected severity for individual healthcare professionals and allied facilities in accident years 2009 through 2012. Favorable development of $41 million was recorded in other professional liability and management liability primarily related to lower than expected severity in accident years 2010 and prior for professional services. Unfavorable development of $37 million was recorded primarily related to increased claim frequency on public company management liability in accident years 2012 through 2014. Favorable development for other coverages was primarily due to better than expected claim frequency in property coverages provided to Specialty customers in accident year 2014. Commercial The following table presents further detail of the development recorded for the Commercial segment. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Pretax (favorable) unfavorable development: Commercial Auto $ (20 ) $ 7 $ (35 ) $ 7 General Liability (37 ) 1 (52 ) 5 Workers' Compensation 50 24 54 23 Property and Other (11 ) (16 ) 1 (24 ) Total pretax (favorable) unfavorable development $ (18 ) $ 16 $ (32 ) $ 11 Three Months 2016 Favorable development for commercial auto was primarily due to favorable settlements on claims in accident years 2010 through 2014. Favorable development for general liability was primarily due to better than expected claim settlements in accident years 2012 through 2014 and better than expected severity on umbrella claims in accident years 2010 through 2013. Unfavorable development for workers’ compensation was due to a reduction in estimated recoveries on war hazard claims for Defense Base Act contractors, which was partially offset by favorable development related to lower than expected frequencies for our small and middle market businesses in accident years 2009 through 2014. Favorable development for property and other was primarily due to better than expected loss emergence in accident years 2013 through 2015. 2015 In the aggregate, the unfavorable loss development of $16 million was driven by an extra contractual obligation loss and losses associated with premium development. The reserve development discussed below was largely offsetting. Unfavorable development for workers’ compensation was primarily due to higher than expected severity related to Defense Base Act contractors in accident years 2008 through 2013. Favorable development for property and other was primarily due to better than expected loss emergence from 2012 catastrophe events and better than expected claim frequency of large claims in accident year 2014. Six Months 2016 Favorable development for commercial auto was primarily due to favorable settlements on claims in accident years 2010 through 2014. Favorable development for general liability was primarily due to better than expected claim settlements in accident years 2012 through 2014 and better than expected severity on umbrella claims in accident years 2010 through 2013. Unfavorable development for workers’ compensation was due to a reduction in estimated recoveries on war hazard claims for Defense Base Act contractors, which was partially offset by favorable development related to lower than expected frequencies for our small and middle market businesses in accident years 2009 through 2014. Unfavorable development for property and other was primarily due to higher than expected severity from a 2015 catastrophe event. Favorable development was primarily due to better than expected loss emergence in accident years 2013 through 2015. 2015 In addition to the favorable property development noted in the three month discussion, there was additional favorable development for property related to better than expected loss emergence from 2014 catastrophe events. International The following table presents further detail of the development recorded for the International segment. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Pretax (favorable) unfavorable development: Medical Professional Liability $ (1 ) $ — $ (1 ) $ — Other Professional Liability 18 (5 ) 17 (5 ) Liability (19 ) (2 ) (19 ) (7 ) Property & Marine (3 ) (8 ) (7 ) (14 ) Other (10 ) 7 (9 ) 14 Total pretax (favorable) unfavorable development $ (15 ) $ (8 ) $ (19 ) $ (12 ) Three Months 2016 Unfavorable development for other professional liability was primarily due to higher than expected large loss emergence in accident years 2011 through 2015. Favorable development for liability was primarily due to better than expected severity in accident years 2013 and prior. Favorable development for other coverages was primarily due to better than expected severity in auto liability in accident years 2011 through 2015. 2015 Favorable development in property and marine was due to better than expected emergence in accident years 2012 through 2014. Unfavorable development in other is due to large losses in financial institutions and political risk primarily in accident year 2014. Six Months 2016 Unfavorable development for other professional liability was primarily due to higher than expected large loss emergence in accident years 2011 through 2015. Favorable development for liability was primarily due to better than expected severity in accident years 2013 and prior. Favorable development for other coverages was primarily due to better than expected severity in auto liability in accident years 2011 through 2015. 2015 Favorable development in property and marine was due to better than expected emergence in accident years 2012 through 2014. Unfavorable development in other is due to large losses in financial institutions and political risk primarily in accident year 2014. Asbestos and Environmental Pollution Reserves (A&EP) In 2010, Continental Casualty Company (CCC) together with several of the Company’s insurance subsidiaries completed a transaction with National Indemnity Company (NICO), a subsidiary of Berkshire Hathaway Inc., under which substantially all of the Company’s legacy A&EP liabilities were ceded to NICO through a Loss Portfolio Transfer (LPT). At the effective date of the transaction, the Company ceded approximately $1.6 billion of net A&EP claim and allocated claim adjustment expense reserves to NICO under a retroactive reinsurance agreement with an aggregate limit of $4 billion . The $1.6 billion of claim and allocated claim adjustment expense reserves ceded to NICO was net of $1.2 billion of ceded claim and allocated claim adjustment expense reserves under existing third-party reinsurance contracts. The NICO LPT aggregate reinsurance limit also covers credit risk on the existing third-party reinsurance related to these liabilities. The Company paid NICO a reinsurance premium of $2 billion and transferred to NICO billed third-party reinsurance receivables related to A&EP claims with a net book value of $215 million , resulting in total consideration of $2.2 billion . Through December 31, 2013, the Company recognized $0.9 billion of additional amounts ceded under the LPT. As a result, the cumulative amounts ceded under the LPT exceeded the $2.2 billion consideration paid, resulting in the NICO LPT moving into a gain position, requiring deferred retroactive reinsurance accounting treatment. This deferred gain is recognized in earnings in proportion to actual paid recoveries under the LPT. Over the life of the contract, there is no economic impact as long as any additional losses incurred are within the limit of the LPT. In a period in which a change in the estimate of ceded incurred losses is recognized, the change to the deferred gain is cumulatively recognized in earnings as if the revised estimate was available at the effective date of the LPT. The following table presents the impact of the Loss Portfolio Transfer on the Condensed Consolidated Statements of Operations. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Net A&EP adverse development before consideration of LPT $ — $ 150 $ 200 $ 150 Provision for uncollectible third-party reinsurance on A&EP — — — — Additional amounts ceded under LPT — 150 200 150 Retroactive reinsurance benefit recognized (9 ) (66 ) (82 ) (71 ) Pretax impact of unrecognized deferred retroactive reinsurance benefit $ (9 ) $ 84 $ 118 $ 79 The Company completed its reserve review of A&EP reserves in the first quarter of 2016. Based upon the Company's review, net unfavorable development prior to cessions to the LPT of $200 million was recognized. The unfavorable development was driven by an increase in anticipated future expenses associated with determination of coverage, higher anticipated payouts associated with a limited number of historical accounts having significant asbestos exposures and higher than expected severity on pollution claims. This unfavorable development was ceded to NICO under the LPT; however, the Company’s reported earnings were negatively affected due to the application of retroactive reinsurance accounting, as only a portion of the additional amounts ceded under the LPT were recognized in that quarter. All amounts recognized related to the LPT are recorded within Insurance claims and policyholders’ benefits in the Condensed Consolidated Statement of Operations. As of June 30, 2016 and December 31, 2015 , the cumulative amounts ceded under the LPT were $2.8 billion and $2.6 billion . The unrecognized deferred retroactive reinsurance benefit was $359 million and $241 million as of June 30, 2016 and December 31, 2015 . NICO established a collateral trust account as security for its obligations to the Company. The fair value of the collateral trust account was $2.6 billion and $2.8 billion as of June 30, 2016 and December 31, 2015 . In addition, Berkshire Hathaway Inc. guaranteed the payment obligations of NICO up to the full aggregate reinsurance limit as well as certain of NICO’s performance obligations under the trust agreement. NICO is responsible for claims handling and billing and collection from third-party reinsurers related to the Company’s A&EP claims.

Legal Proceedings and Contingen

Legal Proceedings and Contingent Liabilities	6 Months Ended
	Jun. 30, 2016
Legal Proceedings and Contingent Liabilities [Abstract]
Legal Proceedings and Contingent Liabilities	Note F . Legal Proceedings and Contingent Liabilities The Company is a party to routine litigation incidental to its business, which, based on the facts and circumstances currently known, is not material to the Condensed Consolidated Financial Statements.

Benefit Plans

Benefit Plans	6 Months Ended
	Jun. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Benefit Plans	Note G . Benefit Plans The components of net periodic cost (benefit) are presented in the following table. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Pension cost (benefit) Service cost $ — $ 2 $ — $ 4 Interest cost on projected benefit obligation 28 28 56 56 Expected return on plan assets (40 ) (44 ) (80 ) (87 ) Amortization of net actuarial loss 10 10 19 19 Net periodic pension cost (benefit) $ (2 ) $ (4 ) $ (5 ) $ (8 ) In the second quarter of 2015 , the Company eliminated future benefit accruals associated with the CNA Retirement Plan (Plan) effective June 30, 2015 . Employees who were continuing to accrue under this Plan up until that date are entitled to an accrued benefit payable based on their eligible compensation and accrued service through June 30, 2015 , in accordance with the terms of the Plan. Starting with the first pay period after July 1, 2015, affected employees began receiving enhanced employer contributions in the CNA 401(k) Plus Plan similar to employees who elected to cease accruals effective December 31, 1999. Employees who elected to cease accruals effective December 31, 1999 are not affected by this curtailment. This curtailment resulted in a $55 million decrease in the Plan benefit obligation liability and a reduction of the unrecognized actuarial losses included in AOCI. In connection with the curtailment, the Company remeasured the plan benefit obligation which resulted in an increase in the discount rate used to determine the benefit obligation from 3.85% to 4.00% .

Commitments and Contingencies,

Commitments and Contingencies, and Guarantees	6 Months Ended
	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments Contingencies and Guarantees [Text Block]	Note H . Commitments, Contingencies and Guarantees Commitments and Contingencies The Company holds an investment in a real estate joint venture in which the Company, on a joint and several basis with the other unrelated shareholders guaranteed to fund operating deficits of the joint venture and an operating lease for an office building entered into by the venture. The lease was terminated in March 2016. In the event that the other parties to the joint venture are unable to meet their commitments in funding this joint venture, the Company would be required to assume future obligations, primarily related to the wind-down of the lease and joint venture. The Company does not believe it is likely that it will be required to do so. However, as of June 30, 2016 , the maximum potential loss that the Company could be required to pay under this guarantee, in excess of amounts already recorded, was approximately $16 million . If the Company were required to assume future obligations, the Company would have the right to pursue reimbursement from the other shareholders. Guarantees As of June 30, 2016 and December 31, 2015 , the Company had recorded liabilities of approximately $5 million related to guarantee and indemnification agreements and management believes that it is not likely that any future indemnity claims will be significantly greater than the amounts recorded. In the course of selling business entities and assets to third parties, the Company agreed to guarantee the performance of certain obligations of a previously owned subsidiary and to indemnify purchasers for losses arising out of breaches of representation and warranties with respect to the business entities or assets sold, including, in certain cases, losses arising from undisclosed liabilities or certain named litigation. Such guarantee and indemnification agreements in effect for sales of business entities, assets and third-party loans may include provisions that survive indefinitely. As of June 30, 2016 , the aggregate amount related to quantifiable guarantees was $375 million and the aggregate amount related to indemnification agreements was $259 million . Should the Company be required to make payments under the guarantee, it would have the right to seek reimbursement in certain cases from an affiliate of a previously owned subsidiary. In addition, the Company has agreed to provide indemnification to third-party purchasers for certain losses associated with sold business entities or assets that are not limited by a contractual monetary amount. As of June 30, 2016 , the Company had outstanding unlimited indemnifications in connection with the sales of certain of its business entities or assets that included tax liabilities arising prior to a purchaser's ownership of an entity or asset, defects in title at the time of sale, employee claims arising prior to closing and in some cases losses arising from certain litigation and undisclosed liabilities. Certain provisions of the indemnification agreements survive indefinitely, while others survive until the applicable statutes of limitation expire, or until the agreed-upon contract terms expire. The Company also provided guarantees, if the primary obligor fails to perform, to holders of structured settlement annuities provided by a previously owned subsidiary. As of June 30, 2016 , the potential amount of future payments the Company could be required to pay under these guarantees was approximately $2.0 billion , which will be paid over the lifetime of the annuitants. The Company does not believe any payment is likely under these guarantees, as the Company is the beneficiary of a trust that must be maintained at a level that approximates the discounted reserves for these annuities.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss) by Component	6 Months Ended
	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss) by Component	Note I . Accumulated Other Comprehensive Income (Loss) by Component The table below displays the changes in Accumulated other comprehensive income (loss) by component. (In millions) Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment Total Balance as of April 1, 2016 $ 32 $ 624 $ (642 ) $ (70 ) $ (56 ) Other comprehensive income (loss) before reclassifications (1 ) 323 — (48 ) 274 Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $-, $(6), $3, $- and $(3) — 13 (5 ) — 8 Other comprehensive income (loss) net of tax (expense) benefit of $1, $(157), $(3), $- and $(159) (1 ) 310 5 (48 ) 266 Balance as of June 30, 2016 $ 31 $ 934 $ (637 ) $ (118 ) $ 210 (In millions) Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment Total Balance as of April 1, 2015 $ 35 $ 1,054 $ (627 ) $ (41 ) $ 421 Other comprehensive income (loss) before reclassifications (4 ) (372 ) 36 49 (291 ) Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $-, $5, $4, $- and $9 — (7 ) (6 ) — (13 ) Other comprehensive income (loss) net of tax (expense) benefit of $2, $181, $(23), $- and $160 (4 ) (365 ) 42 49 (278 ) Balance as of June 30, 2015 $ 31 $ 689 $ (585 ) $ 8 $ 143 (In millions) Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment Total Balance as of January 1, 2016 $ 27 $ 390 $ (648 ) $ (84 ) $ (315 ) Other comprehensive income (loss) before reclassifications 2 546 — (34 ) 514 Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $1, $1, $6, $- and $8 (2 ) 2 (11 ) — (11 ) Other comprehensive income (loss) net of tax (expense) benefit of $(2), $(273), $(6), $- and $(281) 4 544 11 (34 ) 525 Balance as of June 30, 2016 $ 31 $ 934 $ (637 ) $ (118 ) $ 210 (In millions) Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment Total Balance as of January 1, 2015 $ 36 $ 942 $ (633 ) $ 55 $ 400 Other comprehensive income (loss) before reclassifications (5 ) (251 ) 36 (47 ) (267 ) Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $-, $5, $7, $- and $12 — 2 (12 ) — (10 ) Other comprehensive income (loss) net of tax (expense) benefit of $2, $119, $(26), $- and $95 (5 ) (253 ) 48 (47 ) (257 ) Balance as of June 30, 2015 $ 31 $ 689 $ (585 ) $ 8 $ 143 Amounts reclassified from Accumulated other comprehensive income (loss) shown above are reported in Net income (loss) as follows: Component of AOCI Condensed Consolidated Statements of Operations Line Item Affected by Reclassifications Net unrealized gains (losses) on investments with OTTI losses Net realized investment gains (losses) Net unrealized gains (losses) on other investments Net realized investment gains (losses) Pension and postretirement benefits Other operating expenses

Business Segments

Business Segments	6 Months Ended
	Jun. 30, 2016
Segment Reporting [Abstract]
Business Segments	Note J . Business Segments The Company's core property and casualty commercial insurance operations are aggregated and reported in three business segments: Specialty, Commercial and International. The Company's non-core operations are managed and reported in two segments: Life & Group Non-Core and Corporate & Other Non-Core. The accounting policies of the segments are the same as those described in Note A to the Consolidated Financial Statements within CNAF's Annual Report on Form 10-K for the year ended December 31, 2015 . The Company manages most of its assets on a legal entity basis, while segment operations are generally conducted across legal entities. As such, only Insurance and Reinsurance receivables, Insurance reserves, Deferred acquisition costs and Goodwill are readily identifiable for all individual segments. Distinct investment portfolios are not maintained for every individual segment; accordingly, allocation of assets to each segment is not performed. Therefore, a significant portion of Net investment income and Realized investment gains or losses are allocated primarily based on each segment's net carried insurance reserves, as adjusted. All significant intersegment income and expense has been eliminated. Income taxes have been allocated on the basis of the taxable income of the segments. In the following tables, certain financial measures are presented to provide information used by management to monitor the Company's operating performance. Management utilizes these financial measures to monitor the Company's insurance operations and investment portfolio. Net operating income (loss), which is derived from certain income statement amounts, is used by management to monitor performance of the Company's insurance operations. The Company's investment portfolio is monitored by management through analysis of various factors including unrealized gains and losses on securities, portfolio duration and exposure to market and credit risk. Based on such analyses, the Company may recognize an OTTI loss on an investment security in accordance with its policy, or sell a security, which may produce realized gains and losses. Net operating income (loss) is calculated by excluding from net income (loss) the after-tax effects of i) net realized investment gains (losses) ii) income or loss from discontinued operations and iii) any cumulative effects of changes in accounting guidance. The calculation of net operating income excludes net realized investment gains (losses) because net realized investment gains (losses) are largely discretionary, except for some losses related to OTTI, and are generally driven by economic factors that are not necessarily consistent with key drivers of underwriting performance, and are therefore not considered an indication of trends in insurance operations. The Company's results of operations and selected balance sheet items by segment are presented in the following tables. Three months ended June 30, 2016 Specialty Commercial International Life & Group Non-Core Corporate & Other Non-Core (In millions) Eliminations Total Operating revenues Net earned premiums $ 702 $ 696 $ 197 $ 136 $ — $ (1 ) $ 1,730 Net investment income 133 164 13 188 4 — 502 Other revenues 89 8 — 3 — — 100 Total operating revenues 924 868 210 327 4 (1 ) 2,332 Claims, Benefits and Expenses Net incurred claims and benefits 377 469 157 340 (8 ) — 1,335 Policyholders’ dividends 1 3 — — — — 4 Amortization of deferred acquisition costs 148 117 40 — — — 305 Other insurance related expenses 73 130 37 31 — (1 ) 270 Other expenses 79 11 7 2 47 — 146 Total claims, benefits and expenses 678 730 241 373 39 (1 ) 2,060 Operating income (loss) before income tax 246 138 (31 ) (46 ) (35 ) — 272 Income tax (expense) benefit on operating income (loss) (82 ) (46 ) 4 42 11 — (71 ) Net operating income (loss) 164 92 (27 ) (4 ) (24 ) — 201 Net realized investment gains (losses) 4 8 4 (2 ) 2 — 16 Income tax (expense) benefit on net realized investment gains (losses) (2 ) (3 ) (1 ) (3 ) 1 — (8 ) Net realized investment gains (losses), after tax 2 5 3 (5 ) 3 — 8 Net income (loss) $ 166 $ 97 $ (24 ) $ (9 ) $ (21 ) $ — $ 209 Three months ended June 30, 2015 Specialty Commercial International Life & Group Non-Core Corporate & Other Non-Core (In millions) Eliminations Total Operating revenues Net earned premiums $ 689 $ 703 $ 207 $ 137 $ — $ (1 ) $ 1,735 Net investment income 134 169 13 179 5 — 500 Other revenues 81 9 (1 ) — 3 — 92 Total operating revenues 904 881 219 316 8 (1 ) 2,327 Claims, Benefits and Expenses Net incurred claims and benefits 416 507 114 344 85 — 1,466 Policyholders’ dividends 1 2 — — — — 3 Amortization of deferred acquisition costs 146 117 45 6 — — 314 Other insurance related expenses 66 130 31 34 (1 ) (1 ) 259 Other expenses 69 5 (5 ) 5 47 — 121 Total claims, benefits and expenses 698 761 185 389 131 (1 ) 2,163 Operating income (loss) before income tax 206 120 34 (73 ) (123 ) — 164 Income tax (expense) benefit on operating income (loss) (69 ) (42 ) (12 ) 49 42 — (32 ) Net operating income (loss) 137 78 22 (24 ) (81 ) — 132 Net realized investment gains (losses) — 2 1 (5 ) 2 — — Income tax (expense) benefit on net realized investment gains (losses) — 2 (1 ) 6 (1 ) — 6 Net realized investment gains (losses), after tax — 4 — 1 1 — 6 Net income (loss) $ 137 $ 82 $ 22 $ (23 ) $ (80 ) $ — $ 138 Six months ended June 30, 2016 Specialty Commercial International Life & Group Non-Core Corporate & Other Non-Core (In millions) Eliminations Total Operating revenues Net earned premiums $ 1,384 $ 1,384 $ 395 $ 267 $ — $ (1 ) $ 3,429 Net investment income 240 290 25 375 7 — 937 Other revenues 176 14 1 3 3 — 197 Total operating revenues 1,800 1,688 421 645 10 (1 ) 4,563 Claims, Benefits and Expenses Net incurred claims and benefits 767 911 278 663 120 — 2,739 Policyholders’ dividends 2 6 — — — — 8 Amortization of deferred acquisition costs 292 233 87 — — — 612 Other insurance related expenses 148 271 65 64 — (1 ) 547 Other expenses 154 16 16 5 101 — 292 Total claims, benefits and expenses 1,363 1,437 446 732 221 (1 ) 4,198 Operating income (loss) before income tax 437 251 (25 ) (87 ) (211 ) — 365 Income tax (expense) benefit on operating income (loss) (146 ) (85 ) 4 81 73 — (73 ) Net operating income (loss) 291 166 (21 ) (6 ) (138 ) — 292 Net realized investment gains (losses) (7 ) (10 ) 8 (5 ) (6 ) — (20 ) Income tax (expense) benefit on net realized investment gains (losses) 2 3 (2 ) (3 ) 3 — 3 Net realized investment gains (losses), after tax (5 ) (7 ) 6 (8 ) (3 ) — (17 ) Net income (loss) $ 286 $ 159 $ (15 ) $ (14 ) $ (141 ) $ — $ 275 June 30, 2016 (In millions) Reinsurance receivables $ 856 $ 621 $ 128 $ 492 $ 2,623 $ — $ 4,720 Insurance receivables 1,005 1,120 274 11 3 — 2,413 Deferred acquisition costs 308 228 84 — — — 620 Goodwill 117 — 30 — — — 147 Insurance reserves Claim and claim adjustment expenses 6,414 8,973 1,409 3,382 2,797 — 22,975 Unearned premiums 1,871 1,417 450 128 — (1 ) 3,865 Future policy benefits — — — 11,140 — — 11,140 Six months ended June 30, 2015 Specialty Commercial International Life & Group Non-Core Corporate & Other Non-Core (In millions) Eliminations Total Operating revenues Net earned premiums $ 1,369 $ 1,381 $ 398 $ 275 $ — $ (1 ) $ 3,422 Net investment income 289 373 27 358 11 — 1,058 Other revenues 159 18 (1 ) 9 5 (1 ) 189 Total operating revenues 1,817 1,772 424 642 16 (2 ) 4,669 Claims, Benefits and Expenses Net incurred claims and benefits 845 961 230 684 81 — 2,801 Policyholders’ dividends 2 5 — — — — 7 Amortization of deferred acquisition costs 290 234 80 13 — — 617 Other insurance related expenses 135 257 68 69 (1 ) (1 ) 527 Other expenses 136 13 — 9 93 (1 ) 250 Total claims, benefits and expenses 1,408 1,470 378 775 173 (2 ) 4,202 Operating income (loss) before income tax 409 302 46 (133 ) (157 ) — 467 Income tax (expense) benefit on operating income (loss) (137 ) (104 ) (15 ) 92 54 — (110 ) Net operating income (loss) 272 198 31 (41 ) (103 ) — 357 Net realized investment gains (losses) 4 6 2 (4 ) 2 — 10 Income tax (expense) benefit on net realized investment gains (losses) (1 ) (1 ) (1 ) 8 (1 ) — 4 Net realized investment gains (losses), after tax 3 5 1 4 1 — 14 Net income (loss) $ 275 $ 203 $ 32 $ (37 ) $ (102 ) $ — $ 371 December 31, 2015 (In millions) Reinsurance receivables $ 724 $ 639 $ 144 $ 497 $ 2,487 $ — $ 4,491 Insurance receivables 890 993 233 11 2 — 2,129 Deferred acquisition costs 307 213 78 — — — 598 Goodwill 117 — 33 — — — 150 Insurance reserves Claim and claim adjustment expenses 6,269 9,183 1,347 3,220 2,644 — 22,663 Unearned premiums 1,839 1,297 415 120 — — 3,671 Future policy benefits — — — 10,152 — — 10,152 The following table presents revenue by line of business for each reportable segment. Revenues are comprised of Operating revenues and Net realized investment gains and losses. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Specialty Management & Professional Liability $ 659 $ 674 $ 1,277 $ 1,371 Surety 133 125 260 245 Warranty & Alternative Risks 136 105 256 205 Specialty revenues 928 904 1,793 1,821 Commercial Middle Market 434 412 835 821 Small Business 151 158 294 323 Other Commercial Insurance 291 313 549 634 Commercial revenues 876 883 1,678 1,778 International Canada 51 54 101 109 CNA Europe 81 77 159 154 Hardy 82 89 169 163 International revenues 214 220 429 426 Life & Group Non-Core revenues 325 311 640 638 Corporate & Other Non-Core revenues 6 10 4 18 Eliminations (1 ) (1 ) (1 ) (2 ) Total revenues $ 2,348 $ 2,327 $ 4,543 $ 4,679

General Summary of Significant

General Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
Accounting Policies [Abstract]
Consolidation, Policy [Policy Text Block]	The accompanying Condensed Consolidated Financial Statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP).
Use of Estimates, Policy [Policy Text Block]	The preparation of Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the Condensed Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Actual results may differ from those estimates.
New Accounting Pronouncements and Changes in Accounting Principles, Policies [Text Block]	Recently Adopted Accounting Standards Updates (ASU) In April 2015, the Financial Accounting Standards Board (FASB) issued ASU No. 2015-03, Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs . The updated accounting guidance requires debt issuance costs to be presented as a deduction from the corresponding debt liability instead of the historical presentation as an unamortized debt issuance asset. As of January 1, 2016, the Company adopted the updated accounting guidance retrospectively. The Company adjusted its previously reported financial information included herein to reflect the change in accounting guidance for debt issuance costs. The impacts of adopting the new accounting standard on the Company’s Consolidated Balance Sheet as of December 31, 2015, were a decrease in Other assets and a decrease in Long term debt of $2 million . In May 2015, the FASB issued ASU No. 2015-07, Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent). The updated accounting guidance removes the requirement to categorize assets measured at fair value utilizing the net asset value per share (or equivalent) practical expedient within the fair value hierarchy. As of January 1, 2016, the Company adopted the updated accounting guidance retrospectively. The Company adjusted its previously reported financial information included herein to reflect the change in accounting guidance for assets measured using the net asset value. The impact of adopting the new accounting standard resulted in excluding overseas deposits of $28 million and $27 million from the fair value level disclosure as of June 30, 2016 and December 31, 2015 .
New Accounting Pronouncements, Policy [Policy Text Block]	Accounting Standards Pending Adoption In May 2015, the FASB issued ASU No. 2015-09, Financial Services-Insurance (Topic 944): Disclosures about Short-Duration Contracts. The updated accounting guidance requires enhanced disclosures to provide additional information about insurance liabilities for short-duration contracts. The guidance is effective for annual periods beginning after December 15, 2015, and interim periods within the annual periods beginning after December 15, 2016. The Company is currently evaluating the effect the updated guidance will have on the Company's financial statement disclosures but expects to provide additional incurred and paid claims development information by accident year, quantitative information about claim frequency and the history of claims duration for significant lines of business within the Company’s annual financial statements. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. The updated accounting guidance requires changes to the reporting model for financial instruments. The guidance is effective for interim and annual periods beginning after December 15, 2017. The Company is currently evaluating the effect the guidance will have on the Company's financial statements, and expects the primary change for the Company to be the requirement for equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842): Accounting for Leases. The updated accounting guidance requires lessees to recognize on the balance sheet the assets and liabilities for the rights and obligations created by all leases, including those historically accounted for as operating leases. The guidance is effective for interim and annual periods beginning after December 15, 2018. The Company is currently evaluating the effect the updated guidance will have on the Company's financial statements. In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting. The updated accounting guidance simplifies the accounting for share-based payment award transactions including income tax consequences, classification of awards as either equity or liabilities and classification on the statement of cash flows. The guidance is effective for annual periods beginning after December 15, 2017, and interim periods within annual periods beginning after December 15, 2018. The Company is currently evaluating the effect the updated guidance will have on the Company’s financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The updated accounting guidance requires changes to the recognition of credit losses on financial instruments not accounted for at fair value through net income. The guidance is effective for interim and annual periods beginning after December 15, 2019. The Company is currently evaluating the effect the guidance will have on the Company's financial statements, but expects the primary changes to be the use of the expected credit loss model for its mortgage loan portfolio and reinsurance receivables and the presentation of credit losses within the available-for-sale fixed maturities portfolio through an allowance method rather than as a direct write-down. The expected credit loss model will require a financial asset to be presented at the net amount expected to be collected. The allowance method for available-for-sale debt securities will allow the Company to record reversals of credit losses when the estimate of credit losses declines.

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2016
Investments [Abstract]
Net investment income	The significant components of Net investment income are presented in the following table. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Fixed maturity securities $ 449 $ 452 $ 895 $ 895 Equity securities 4 3 7 6 Limited partnership investments 46 48 32 162 Mortgage loans 13 9 22 17 Short term investments 1 — 4 2 Trading portfolio 4 3 6 5 Gross investment income 517 515 966 1,087 Investment expense (15 ) (15 ) (29 ) (29 ) Net investment income $ 502 $ 500 $ 937 $ 1,058
Net realized investment gains (losses)	Net realized investment gains (losses) are presented in the following table. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Net realized investment gains (losses): Fixed maturity securities: Gross realized gains $ 40 $ 36 $ 85 $ 69 Gross realized losses (24 ) (48 ) (86 ) (69 ) Net realized investment gains (losses) on fixed maturity securities 16 (12 ) (1 ) — Equity securities: Gross realized gains 4 — 4 1 Gross realized losses (1 ) (1 ) (6 ) (2 ) Net realized investment gains (losses) on equity securities 3 (1 ) (2 ) (1 ) Derivative financial instruments (6 ) 11 (13 ) 10 Short term investments and other 3 2 (4 ) 1 Net realized investment gains (losses) $ 16 $ — $ (20 ) $ 10
Components of net other than temporary impairment losses recognized in earnings by asset type	The components of Net other-than-temporary impairment (OTTI) losses recognized in earnings by asset type are presented in the following table. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Fixed maturity securities available-for-sale: Corporate and other bonds $ 13 $ 11 $ 29 $ 16 States, municipalities and political subdivisions — 13 — 18 Asset-backed: Residential mortgage-backed 1 5 1 6 Other asset-backed 1 1 3 1 Total asset-backed 2 6 4 7 Total fixed maturity securities available-for-sale 15 30 33 41 Equity securities available-for-sale -- Common stock — — 5 1 Short term investments — 1 — 1 OTTI losses recognized in earnings $ 15 $ 31 $ 38 $ 43
Summary of fixed maturity and equity securities	The following tables present a summary of fixed maturity and equity securities. June 30, 2016 Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Unrealized OTTI Losses (Gains) (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 17,613 $ 1,684 $ 93 $ 19,204 $ (1 ) States, municipalities and political subdivisions 11,661 2,114 2 13,773 (25 ) Asset-backed: Residential mortgage-backed 4,994 215 20 5,189 (21 ) Commercial mortgage-backed 2,080 91 8 2,163 — Other asset-backed 928 8 5 931 — Total asset-backed 8,002 314 33 8,283 (21 ) U.S. Treasury and obligations of government-sponsored enterprises 81 11 — 92 — Foreign government 438 22 — 460 — Redeemable preferred stock 33 2 — 35 — Total fixed maturity securities available-for-sale 37,828 4,147 128 41,847 $ (47 ) Total fixed maturity securities trading 10 10 Equity securities available-for-sale: Common stock 20 5 2 23 Preferred stock 97 6 3 100 Total equity securities available-for-sale 117 11 5 123 Total $ 37,955 $ 4,158 $ 133 $ 41,980 December 31, 2015 Cost or Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Unrealized OTTI Losses (Gains) (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 17,080 $ 1,019 $ 342 $ 17,757 $ — States, municipalities and political subdivisions 11,729 1,453 8 13,174 (4 ) Asset-backed: Residential mortgage-backed 4,935 154 17 5,072 (37 ) Commercial mortgage-backed 2,154 55 12 2,197 — Other asset-backed 923 6 8 921 — Total asset-backed 8,012 215 37 8,190 (37 ) U.S. Treasury and obligations of government-sponsored enterprises 62 5 — 67 — Foreign government 334 13 1 346 — Redeemable preferred stock 33 2 — 35 — Total fixed maturity securities available-for-sale 37,250 2,707 388 39,569 $ (41 ) Total fixed maturity securities trading 3 3 Equity securities available-for-sale: Common stock 46 3 1 48 Preferred stock 145 7 3 149 Total equity securities available-for-sale 191 10 4 197 Total $ 37,444 $ 2,717 $ 392 $ 39,769
Securities in a gross unrealized loss position	The following tables present the estimated fair value and gross unrealized losses of fixed maturity and equity securities in a gross unrealized loss position by the length of time in which the securities have continuously been in that position. Less than 12 Months 12 Months or Longer Total June 30, 2016 Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 1,032 $ 43 $ 562 $ 50 $ 1,594 $ 93 States, municipalities and political subdivisions 68 2 10 — 78 2 Asset-backed: Residential mortgage-backed 293 8 234 12 527 20 Commercial mortgage-backed 386 7 118 1 504 8 Other asset-backed 306 5 5 — 311 5 Total asset-backed 985 20 357 13 1,342 33 Foreign government 8 — 5 — 13 — Total fixed maturity securities available-for-sale 2,093 65 934 63 3,027 128 Equity securities available-for-sale: Common stock 4 2 — — 4 2 Preferred stock 23 3 — — 23 3 Total equity securities available-for-sale 27 5 — — 27 5 Total $ 2,120 $ 70 $ 934 $ 63 $ 3,054 $ 133 Less than 12 Months 12 Months or Longer Total December 31, 2015 Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses Estimated Fair Value Gross Unrealized Losses (In millions) Fixed maturity securities available-for-sale: Corporate and other bonds $ 4,882 $ 302 $ 162 $ 40 $ 5,044 $ 342 States, municipalities and political subdivisions 338 8 75 — 413 8 Asset-backed: Residential mortgage-backed 963 9 164 8 1,127 17 Commercial mortgage-backed 652 10 96 2 748 12 Other asset-backed 552 8 5 — 557 8 Total asset-backed 2,167 27 265 10 2,432 37 U.S. Treasury and obligations of government-sponsored enterprises 4 — — — 4 — Foreign government 54 1 — — 54 1 Redeemable preferred stock 3 — — — 3 — Total fixed maturity securities available-for-sale 7,448 338 502 50 7,950 388 Equity securities available-for-sale: Common stock 3 1 — — 3 1 Preferred stock 13 3 — — 13 3 Total equity securities available-for-sale 16 4 — — 16 4 Total $ 7,464 $ 342 $ 502 $ 50 $ 7,966 $ 392
Activity related to the pretax fixed maturity credit loss component reflected within retained earnings for securities still held for which a portion of an OTTI loss was recognized in OCI	The following table presents the activity related to the pretax credit loss component reflected in Retained earnings on fixed maturity securities still held as of June 30, 2016 and 2015 for which a portion of an OTTI loss was recognized in Other comprehensive income (loss). Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Beginning balance of credit losses on fixed maturity securities $ 48 $ 61 $ 53 $ 62 Reductions for securities sold during the period (7 ) (2 ) (12 ) (3 ) Ending balance of credit losses on fixed maturity securities $ 41 $ 59 $ 41 $ 59
Contractual maturity	The following table presents available-for-sale fixed maturity securities by contractual maturity. June 30, 2016 December 31, 2015 (In millions) Amortized Cost Estimated Fair Value Amortized Cost Estimated Fair Value Due in one year or less $ 1,817 $ 1,855 $ 1,574 $ 1,595 Due after one year through five years 8,616 9,114 7,721 8,070 Due after five years through ten years 14,583 15,466 14,652 14,915 Due after ten years 12,812 15,412 13,303 14,989 Total $ 37,828 $ 41,847 $ 37,250 $ 39,569

Fair Value (Tables)

Fair Value (Tables)	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Assets and liabilities measured at fair value on a recurring basis	Assets and liabilities measured at fair value on a recurring basis are presented in the following tables. June 30, 2016 Total Assets/Liabilities at Fair Value (In millions) Level 1 Level 2 Level 3 Assets Fixed maturity securities: Corporate and other bonds $ — $ 18,972 $ 242 $ 19,214 States, municipalities and political subdivisions — 13,771 2 13,773 Asset-backed: Residential mortgage-backed — 5,055 134 5,189 Commercial mortgage-backed — 2,152 11 2,163 Other asset-backed — 886 45 931 Total asset-backed — 8,093 190 8,283 U.S. Treasury and obligations of government-sponsored enterprises 91 1 — 92 Foreign government — 460 — 460 Redeemable preferred stock 35 — — 35 Total fixed maturity securities 126 41,297 434 41,857 Equity securities 104 — 19 123 Other invested assets — 5 — 5 Short term investments 339 950 — 1,289 Life settlement contracts, included in Other assets — — 67 67 Total assets $ 569 $ 42,252 $ 520 $ 43,341 Liabilities Other liabilities $ — $ 8 $ — $ 8 Total liabilities $ — $ 8 $ — $ 8 December 31, 2015 Total Assets/Liabilities at Fair Value (In millions) Level 1 Level 2 Level 3 Assets Fixed maturity securities: Corporate and other bonds $ — $ 17,592 $ 168 $ 17,760 States, municipalities and political subdivisions — 13,172 2 13,174 Asset-backed: Residential mortgage-backed — 4,938 134 5,072 Commercial mortgage-backed — 2,175 22 2,197 Other asset-backed — 868 53 921 Total asset-backed — 7,981 209 8,190 U.S. Treasury and obligations of government-sponsored enterprises 66 1 — 67 Foreign government — 346 — 346 Redeemable preferred stock 35 — — 35 Total fixed maturity securities 101 39,092 379 39,572 Equity securities 177 — 20 197 Other invested assets — 17 — 17 Short term investments 448 1,134 — 1,582 Life settlement contracts, included in Other assets — — 74 74 Total assets $ 726 $ 40,243 $ 473 $ 41,442 Liabilities Other liabilities $ — $ (5 ) $ — $ (5 ) Total liabilities $ — $ (5 ) $ — $ (5 )
Table of reconciliation for assets and liablities measured at fair value on a recurring basis using significant unobservable inputs	The tables below present a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3). Level 3 (In millions) Balance as of April 1, 2016 Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in Net income (loss)* Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Balance as of June 30, 2016 Unrealized gains (losses) on Level 3 assets and liabilities held as of June 30, 2016 recognized in Net income (loss)* Fixed maturity securities: Corporate and other bonds $ 193 $ 1 $ 3 $ 94 $ (20 ) $ (7 ) $ — $ (22 ) $ 242 $ — States, municipalities and political subdivisions 2 — — — — — — — 2 — Asset-backed: Residential mortgage-backed 128 1 (1 ) 10 — (4 ) — — 134 — Commercial mortgage-backed 27 — — — — (9 ) 3 (10 ) 11 — Other asset-backed 50 — 2 35 (25 ) (1 ) — (16 ) 45 — Total asset-backed 205 1 1 45 (25 ) (14 ) 3 (26 ) 190 — Total fixed maturity securities 400 2 4 139 (45 ) (21 ) 3 (48 ) 434 — Equity securities 19 — — — — — — — 19 — Life settlement contracts 72 6 — — — (11 ) — — 67 (3 ) Total $ 491 $ 8 $ 4 $ 139 $ (45 ) $ (32 ) $ 3 $ (48 ) $ 520 $ (3 ) Level 3 (In millions) Balance as of April 1, 2015 Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in Net income (loss)* Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Balance as of June 30, 2015 Unrealized gains (losses) on Level 3 assets and liabilities held as of June 30, 2015 recognized in Net income (loss)* Fixed maturity securities: Corporate and other bonds $ 186 $ (2 ) $ (1 ) $ — $ — $ (7 ) $ — $ (35 ) $ 141 $ (3 ) States, municipalities and political subdivisions 86 — — — — (1 ) — — 85 — Asset-backed: Residential mortgage-backed 232 1 (2 ) — — (11 ) — (13 ) 207 — Commercial mortgage-backed 64 1 (1 ) 9 — (1 ) 17 (2 ) 87 — Other asset-backed 553 2 1 47 (90 ) (17 ) — (6 ) 490 — Total asset-backed 849 4 (2 ) 56 (90 ) (29 ) 17 (21 ) 784 — Total fixed maturity securities 1,121 2 (3 ) 56 (90 ) (37 ) 17 (56 ) 1,010 (3 ) Equity securities 13 — 3 — — — — — 16 — Life settlement contracts 79 4 — — — (8 ) — — 75 (2 ) Total $ 1,213 $ 6 $ — $ 56 $ (90 ) $ (45 ) $ 17 $ (56 ) $ 1,101 $ (5 ) Level 3 (In millions) Balance as of January 1, 2016 Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in Net income (loss)* Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Balance as of June 30, 2016 Unrealized gains (losses) on Level 3 assets and liabilities held as of June 30, 2016 recognized in Net income (loss)* Fixed maturity securities: Corporate and other bonds $ 168 $ — $ 7 $ 147 $ (36 ) $ (10 ) $ — $ (34 ) $ 242 $ — States, municipalities and political subdivisions 2 — — — — — — — 2 — Asset-backed: Residential mortgage-backed 134 2 (1 ) 10 — (9 ) — (2 ) 134 — Commercial mortgage-backed 22 — — 9 — (9 ) 3 (14 ) 11 — Other asset-backed 53 — 2 35 (25 ) (1 ) 2 (21 ) 45 — Total asset-backed 209 2 1 54 (25 ) (19 ) 5 (37 ) 190 — Total fixed maturity securities 379 2 8 201 (61 ) (29 ) 5 (71 ) 434 — Equity securities 20 — (1 ) — — — — — 19 — Life settlement contracts 74 10 — — — (17 ) — — 67 (3 ) Total $ 473 $ 12 $ 7 $ 201 $ (61 ) $ (46 ) $ 5 $ (71 ) $ 520 $ (3 ) Level 3 (In millions) Balance as of January 1, 2015 Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in Net income (loss)* Net change in unrealized appreciation (depreciation) included in Other comprehensive income (loss) Purchases Sales Settlements Transfers into Level 3 Transfers out of Level 3 Balance as of June 30, 2015 Unrealized gains (losses) on Level 3 assets and liabilities held as of June 30, 2015 recognized in Net income (loss)* Fixed maturity securities: Corporate and other bonds $ 162 $ (1 ) $ (1 ) $ 12 $ (12 ) $ (21 ) $ 37 $ (35 ) $ 141 $ (3 ) States, municipalities and political subdivisions 94 1 — — — (10 ) — — 85 — Asset-backed: Residential mortgage-backed 189 2 (2 ) 72 — (21 ) — (33 ) 207 — Commercial mortgage-backed 83 2 — 15 — (2 ) 17 (28 ) 87 — Other asset-backed 655 3 10 82 (234 ) (20 ) — (6 ) 490 — Total asset-backed 927 7 8 169 (234 ) (43 ) 17 (67 ) 784 — Total fixed maturity securities 1,183 7 7 181 (246 ) (74 ) 54 (102 ) 1,010 (3 ) Equity securities 16 — — — — — — — 16 — Life settlement contracts 82 17 — — — (24 ) — — 75 (1 ) Total $ 1,281 $ 24 $ 7 $ 181 $ (246 ) $ (98 ) $ 54 $ (102 ) $ 1,101 $ (4 )
Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets	The following tables present quantitative information about the significant unobservable inputs utilized by the Company in the fair value measurement of Level 3 assets. Valuations for assets and liabilities not presented in the tables below are primarily based on broker/dealer quotes for which there is a lack of transparency as to inputs used to develop the valuations. The quantitative detail of these unobservable inputs is neither provided nor reasonably available to the Company. June 30, 2016 Estimated Fair Value (In millions) Valuation Technique(s) Unobservable Input(s) Range (Weighted Average) Fixed maturity securities $ 226 Discounted cash flow Credit spread 1% - 40% (6%) Life settlement contracts 67 Discounted cash flow Discount rate risk premium 9% Mortality assumption 55% - 1676% (162%) December 31, 2015 Estimated Fair Value Valuation Technique(s) Unobservable Input(s) Range (Weighted Average) Fixed maturity securities $ 138 Discounted cash flow Credit spread 3% - 184% (6%) Life settlement contracts 74 Discounted cash flow Discount rate risk premium 9% Mortality assumption 55% - 1676% (164%)
Carrying amount and estimated fair value of financial instrument assets and liabilities not measured at fair value	The carrying amount and estimated fair value of the Company's financial assets and liabilities which are not measured at fair value on the Condensed Consolidated Balance Sheets are presented in the following tables. June 30, 2016 Carrying Amount Estimated Fair Value (In millions) Level 1 Level 2 Level 3 Total Assets Mortgage loans $ 610 $ — $ — $ 638 $ 638 Liabilities Long term debt $ 2,708 $ — $ 3,024 $ — $ 3,024 December 31, 2015 Carrying Estimated Fair Value (In millions) Level 1 Level 2 Level 3 Total Assets Mortgage loans $ 678 $ — $ — $ 688 $ 688 Liabilities Short term debt $ 350 $ — $ 360 $ — $ 360 Long term debt 2,210 — 2,433 — 2,433

Claim and Claim Adjustment Ex21

Claim and Claim Adjustment Expense Reserves (Tables)	6 Months Ended
	Jun. 30, 2016
Liability for Claims and Claims Adjustment Expense [Abstract]
Net prior year development	The following tables and discussion present the net prior year development. Three months ended June 30, 2016 (In millions) Specialty Commercial International Corporate & Other Non-Core Total Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development $ (65 ) $ (18 ) $ (15 ) $ — $ (98 ) Pretax (favorable) unfavorable premium development (7 ) (2 ) 1 — (8 ) Total pretax (favorable) unfavorable net prior year development $ (72 ) $ (20 ) $ (14 ) $ — $ (106 ) Three months ended June 30, 2015 (In millions) Specialty Commercial International Corporate & Other Non-Core Total Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development $ (13 ) $ 16 $ (8 ) $ — $ (5 ) Pretax (favorable) unfavorable premium development (2 ) (11 ) (2 ) — (15 ) Total pretax (favorable) unfavorable net prior year development $ (15 ) $ 5 $ (10 ) $ — $ (20 ) Six months ended June 30, 2016 (In millions) Specialty Commercial International Corporate & Other Non-Core Total Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development $ (99 ) $ (32 ) $ (19 ) $ — $ (150 ) Pretax (favorable) unfavorable premium development (18 ) (4 ) — — (22 ) Total pretax (favorable) unfavorable net prior year development $ (117 ) $ (36 ) $ (19 ) $ — $ (172 ) Six months ended June 30, 2015 (In millions) Specialty Commercial International Corporate & Other Non-Core Total Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development $ (11 ) $ 11 $ (12 ) $ — $ (12 ) Pretax (favorable) unfavorable premium development (8 ) (12 ) 14 — (6 ) Total pretax (favorable) unfavorable net prior year development $ (19 ) $ (1 ) $ 2 $ — $ (18 )
Net prior year claim and allocated claim adjustment expense reserve development for Specialty segment	The following table presents further detail of the net prior year claim and allocated claim adjustment expense reserve development (development) recorded for the Specialty segment. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Pretax (favorable) unfavorable development: Medical Professional Liability $ (23 ) $ (6 ) $ (30 ) $ 8 Other Professional Liability and Management Liability (41 ) (1 ) (50 ) (4 ) Surety — — — 1 Warranty 3 1 5 1 Other (4 ) (7 ) (24 ) (17 ) Total pretax (favorable) unfavorable development $ (65 ) $ (13 ) $ (99 ) $ (11 )
Net prior year claim and allocated claim adjustment expense reserve development for Commercial segment	The following table presents further detail of the development recorded for the Commercial segment. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Pretax (favorable) unfavorable development: Commercial Auto $ (20 ) $ 7 $ (35 ) $ 7 General Liability (37 ) 1 (52 ) 5 Workers' Compensation 50 24 54 23 Property and Other (11 ) (16 ) 1 (24 ) Total pretax (favorable) unfavorable development $ (18 ) $ 16 $ (32 ) $ 11
Net prior year claim and allocated claim adjustment expense reserve development for International segment	The following table presents further detail of the development recorded for the International segment. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Pretax (favorable) unfavorable development: Medical Professional Liability $ (1 ) $ — $ (1 ) $ — Other Professional Liability 18 (5 ) 17 (5 ) Liability (19 ) (2 ) (19 ) (7 ) Property & Marine (3 ) (8 ) (7 ) (14 ) Other (10 ) 7 (9 ) 14 Total pretax (favorable) unfavorable development $ (15 ) $ (8 ) $ (19 ) $ (12 )
Impact Of Loss Portfolio Transfer On Consolidated Statements Of Operations [Table Text Block]	The following table presents the impact of the Loss Portfolio Transfer on the Condensed Consolidated Statements of Operations. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Net A&EP adverse development before consideration of LPT $ — $ 150 $ 200 $ 150 Provision for uncollectible third-party reinsurance on A&EP — — — — Additional amounts ceded under LPT — 150 200 150 Retroactive reinsurance benefit recognized (9 ) (66 ) (82 ) (71 ) Pretax impact of unrecognized deferred retroactive reinsurance benefit $ (9 ) $ 84 $ 118 $ 79

Benefit Plans (Tables)

Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Components of net periodic cost (benefit)	The components of net periodic cost (benefit) are presented in the following table. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Pension cost (benefit) Service cost $ — $ 2 $ — $ 4 Interest cost on projected benefit obligation 28 28 56 56 Expected return on plan assets (40 ) (44 ) (80 ) (87 ) Amortization of net actuarial loss 10 10 19 19 Net periodic pension cost (benefit) $ (2 ) $ (4 ) $ (5 ) $ (8 )

Accumulated Other Comprehensi23

Accumulated Other Comprehensive Income (Loss) by Component (Tables)	6 Months Ended
	Jun. 30, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss) by Component	The table below displays the changes in Accumulated other comprehensive income (loss) by component. (In millions) Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment Total Balance as of April 1, 2016 $ 32 $ 624 $ (642 ) $ (70 ) $ (56 ) Other comprehensive income (loss) before reclassifications (1 ) 323 — (48 ) 274 Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $-, $(6), $3, $- and $(3) — 13 (5 ) — 8 Other comprehensive income (loss) net of tax (expense) benefit of $1, $(157), $(3), $- and $(159) (1 ) 310 5 (48 ) 266 Balance as of June 30, 2016 $ 31 $ 934 $ (637 ) $ (118 ) $ 210 (In millions) Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment Total Balance as of April 1, 2015 $ 35 $ 1,054 $ (627 ) $ (41 ) $ 421 Other comprehensive income (loss) before reclassifications (4 ) (372 ) 36 49 (291 ) Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $-, $5, $4, $- and $9 — (7 ) (6 ) — (13 ) Other comprehensive income (loss) net of tax (expense) benefit of $2, $181, $(23), $- and $160 (4 ) (365 ) 42 49 (278 ) Balance as of June 30, 2015 $ 31 $ 689 $ (585 ) $ 8 $ 143 (In millions) Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment Total Balance as of January 1, 2016 $ 27 $ 390 $ (648 ) $ (84 ) $ (315 ) Other comprehensive income (loss) before reclassifications 2 546 — (34 ) 514 Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $1, $1, $6, $- and $8 (2 ) 2 (11 ) — (11 ) Other comprehensive income (loss) net of tax (expense) benefit of $(2), $(273), $(6), $- and $(281) 4 544 11 (34 ) 525 Balance as of June 30, 2016 $ 31 $ 934 $ (637 ) $ (118 ) $ 210 (In millions) Net unrealized gains (losses) on investments with OTTI losses Net unrealized gains (losses) on other investments Pension and postretirement benefits Cumulative foreign currency translation adjustment Total Balance as of January 1, 2015 $ 36 $ 942 $ (633 ) $ 55 $ 400 Other comprehensive income (loss) before reclassifications (5 ) (251 ) 36 (47 ) (267 ) Amounts reclassified from accumulated other comprehensive income (loss) net of tax (expense) benefit of $-, $5, $7, $- and $12 — 2 (12 ) — (10 ) Other comprehensive income (loss) net of tax (expense) benefit of $2, $119, $(26), $- and $95 (5 ) (253 ) 48 (47 ) (257 ) Balance as of June 30, 2015 $ 31 $ 689 $ (585 ) $ 8 $ 143

Business Segments (Tables)

Business Segments (Tables)	6 Months Ended
	Jun. 30, 2016
Segment Reporting [Abstract]
Significant components of the Company's continuing operations and selected balance sheet items	The Company's results of operations and selected balance sheet items by segment are presented in the following tables. Three months ended June 30, 2016 Specialty Commercial International Life & Group Non-Core Corporate & Other Non-Core (In millions) Eliminations Total Operating revenues Net earned premiums $ 702 $ 696 $ 197 $ 136 $ — $ (1 ) $ 1,730 Net investment income 133 164 13 188 4 — 502 Other revenues 89 8 — 3 — — 100 Total operating revenues 924 868 210 327 4 (1 ) 2,332 Claims, Benefits and Expenses Net incurred claims and benefits 377 469 157 340 (8 ) — 1,335 Policyholders’ dividends 1 3 — — — — 4 Amortization of deferred acquisition costs 148 117 40 — — — 305 Other insurance related expenses 73 130 37 31 — (1 ) 270 Other expenses 79 11 7 2 47 — 146 Total claims, benefits and expenses 678 730 241 373 39 (1 ) 2,060 Operating income (loss) before income tax 246 138 (31 ) (46 ) (35 ) — 272 Income tax (expense) benefit on operating income (loss) (82 ) (46 ) 4 42 11 — (71 ) Net operating income (loss) 164 92 (27 ) (4 ) (24 ) — 201 Net realized investment gains (losses) 4 8 4 (2 ) 2 — 16 Income tax (expense) benefit on net realized investment gains (losses) (2 ) (3 ) (1 ) (3 ) 1 — (8 ) Net realized investment gains (losses), after tax 2 5 3 (5 ) 3 — 8 Net income (loss) $ 166 $ 97 $ (24 ) $ (9 ) $ (21 ) $ — $ 209 Three months ended June 30, 2015 Specialty Commercial International Life & Group Non-Core Corporate & Other Non-Core (In millions) Eliminations Total Operating revenues Net earned premiums $ 689 $ 703 $ 207 $ 137 $ — $ (1 ) $ 1,735 Net investment income 134 169 13 179 5 — 500 Other revenues 81 9 (1 ) — 3 — 92 Total operating revenues 904 881 219 316 8 (1 ) 2,327 Claims, Benefits and Expenses Net incurred claims and benefits 416 507 114 344 85 — 1,466 Policyholders’ dividends 1 2 — — — — 3 Amortization of deferred acquisition costs 146 117 45 6 — — 314 Other insurance related expenses 66 130 31 34 (1 ) (1 ) 259 Other expenses 69 5 (5 ) 5 47 — 121 Total claims, benefits and expenses 698 761 185 389 131 (1 ) 2,163 Operating income (loss) before income tax 206 120 34 (73 ) (123 ) — 164 Income tax (expense) benefit on operating income (loss) (69 ) (42 ) (12 ) 49 42 — (32 ) Net operating income (loss) 137 78 22 (24 ) (81 ) — 132 Net realized investment gains (losses) — 2 1 (5 ) 2 — — Income tax (expense) benefit on net realized investment gains (losses) — 2 (1 ) 6 (1 ) — 6 Net realized investment gains (losses), after tax — 4 — 1 1 — 6 Net income (loss) $ 137 $ 82 $ 22 $ (23 ) $ (80 ) $ — $ 138 Six months ended June 30, 2016 Specialty Commercial International Life & Group Non-Core Corporate & Other Non-Core (In millions) Eliminations Total Operating revenues Net earned premiums $ 1,384 $ 1,384 $ 395 $ 267 $ — $ (1 ) $ 3,429 Net investment income 240 290 25 375 7 — 937 Other revenues 176 14 1 3 3 — 197 Total operating revenues 1,800 1,688 421 645 10 (1 ) 4,563 Claims, Benefits and Expenses Net incurred claims and benefits 767 911 278 663 120 — 2,739 Policyholders’ dividends 2 6 — — — — 8 Amortization of deferred acquisition costs 292 233 87 — — — 612 Other insurance related expenses 148 271 65 64 — (1 ) 547 Other expenses 154 16 16 5 101 — 292 Total claims, benefits and expenses 1,363 1,437 446 732 221 (1 ) 4,198 Operating income (loss) before income tax 437 251 (25 ) (87 ) (211 ) — 365 Income tax (expense) benefit on operating income (loss) (146 ) (85 ) 4 81 73 — (73 ) Net operating income (loss) 291 166 (21 ) (6 ) (138 ) — 292 Net realized investment gains (losses) (7 ) (10 ) 8 (5 ) (6 ) — (20 ) Income tax (expense) benefit on net realized investment gains (losses) 2 3 (2 ) (3 ) 3 — 3 Net realized investment gains (losses), after tax (5 ) (7 ) 6 (8 ) (3 ) — (17 ) Net income (loss) $ 286 $ 159 $ (15 ) $ (14 ) $ (141 ) $ — $ 275 June 30, 2016 (In millions) Reinsurance receivables $ 856 $ 621 $ 128 $ 492 $ 2,623 $ — $ 4,720 Insurance receivables 1,005 1,120 274 11 3 — 2,413 Deferred acquisition costs 308 228 84 — — — 620 Goodwill 117 — 30 — — — 147 Insurance reserves Claim and claim adjustment expenses 6,414 8,973 1,409 3,382 2,797 — 22,975 Unearned premiums 1,871 1,417 450 128 — (1 ) 3,865 Future policy benefits — — — 11,140 — — 11,140 Six months ended June 30, 2015 Specialty Commercial International Life & Group Non-Core Corporate & Other Non-Core (In millions) Eliminations Total Operating revenues Net earned premiums $ 1,369 $ 1,381 $ 398 $ 275 $ — $ (1 ) $ 3,422 Net investment income 289 373 27 358 11 — 1,058 Other revenues 159 18 (1 ) 9 5 (1 ) 189 Total operating revenues 1,817 1,772 424 642 16 (2 ) 4,669 Claims, Benefits and Expenses Net incurred claims and benefits 845 961 230 684 81 — 2,801 Policyholders’ dividends 2 5 — — — — 7 Amortization of deferred acquisition costs 290 234 80 13 — — 617 Other insurance related expenses 135 257 68 69 (1 ) (1 ) 527 Other expenses 136 13 — 9 93 (1 ) 250 Total claims, benefits and expenses 1,408 1,470 378 775 173 (2 ) 4,202 Operating income (loss) before income tax 409 302 46 (133 ) (157 ) — 467 Income tax (expense) benefit on operating income (loss) (137 ) (104 ) (15 ) 92 54 — (110 ) Net operating income (loss) 272 198 31 (41 ) (103 ) — 357 Net realized investment gains (losses) 4 6 2 (4 ) 2 — 10 Income tax (expense) benefit on net realized investment gains (losses) (1 ) (1 ) (1 ) 8 (1 ) — 4 Net realized investment gains (losses), after tax 3 5 1 4 1 — 14 Net income (loss) $ 275 $ 203 $ 32 $ (37 ) $ (102 ) $ — $ 371 December 31, 2015 (In millions) Reinsurance receivables $ 724 $ 639 $ 144 $ 497 $ 2,487 $ — $ 4,491 Insurance receivables 890 993 233 11 2 — 2,129 Deferred acquisition costs 307 213 78 — — — 598 Goodwill 117 — 33 — — — 150 Insurance reserves Claim and claim adjustment expenses 6,269 9,183 1,347 3,220 2,644 — 22,663 Unearned premiums 1,839 1,297 415 120 — — 3,671 Future policy benefits — — — 10,152 — — 10,152
Revenues by line of business	The following table presents revenue by line of business for each reportable segment. Revenues are comprised of Operating revenues and Net realized investment gains and losses. Periods ended June 30 Three Months Six Months (In millions) 2016 2015 2016 2015 Specialty Management & Professional Liability $ 659 $ 674 $ 1,277 $ 1,371 Surety 133 125 260 245 Warranty & Alternative Risks 136 105 256 205 Specialty revenues 928 904 1,793 1,821 Commercial Middle Market 434 412 835 821 Small Business 151 158 294 323 Other Commercial Insurance 291 313 549 634 Commercial revenues 876 883 1,678 1,778 International Canada 51 54 101 109 CNA Europe 81 77 159 154 Hardy 82 89 169 163 International revenues 214 220 429 426 Life & Group Non-Core revenues 325 311 640 638 Corporate & Other Non-Core revenues 6 10 4 18 Eliminations (1 ) (1 ) (1 ) (2 ) Total revenues $ 2,348 $ 2,327 $ 4,543 $ 4,679

General (Narrative) (Details)

General (Narrative) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Cumulative Effect of New Accounting Principle in Period of Adoption on Long Term Debt		$ (2)
Cumulative Effect of New Accounting Principle in Period of Adoption on Other Assets		(2)
Other Invested Assets Overseas Deposit	$ 28	$ 27

Earnings Per Share Narrative (D

Earnings Per Share Narrative (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	409	423	473	543
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	178	238	180	208

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Investments [Abstract]
Gains (Losses) on Extinguishment of Debt	$ 8
Reduction of net unrealized gains on investments included in AOCI due to shadow adjustments	1,682	$ 1,111
Derivative, Notional Amount	177	179
Derivative Asset, Fair Value, Gross Asset	8
Derivative Liability, Fair Value, Gross Liability		$ (5)
Future Capital Call Commitments	365
Mortgage Loan Commitments	59
Commitments To Purchase Or Fund Additional Amounts	198
Commitments To Sell Various Privately Placed Debt Securities	$ 95

Investments (Net investment inc

Investments (Net investment income) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net Investment Income [Line Items]
Gross investment income	$ 517	$ 515	$ 966	$ 1,087
Investment expense	(15)	(15)	(29)	(29)
Net investment income	502	500	937	1,058
Fixed maturity securities [Member]
Net Investment Income [Line Items]
Gross investment income	449	452	895	895
Total equity securities available-for-sale [Member]
Net Investment Income [Line Items]
Gross investment income	4	3	7	6
Limited partnership investments [Member]
Net Investment Income [Line Items]
Gross investment income	46	48	32	162
Mortgage loans [Member]
Net Investment Income [Line Items]
Gross investment income	13	9	22	17
Short term investments [Member]
Net Investment Income [Line Items]
Gross investment income	1	0	4	2
Trading portfolio [Member]
Net Investment Income [Line Items]
Gross investment income	$ 4	$ 3	$ 6	$ 5

Investments (Net realized inves

Investments (Net realized investment gains (losses)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net realized investment gains (losses)	$ 16	$ 0	$ (20)	$ 10
Fixed maturity securities [Member]
Gross realized gains	40	36	85	69
Gross realized losses	(24)	(48)	(86)	(69)
Net realized investment gains (losses)	16	(12)	(1)	0
Total equity securities available-for-sale [Member]
Gross realized gains	4	0	4	1
Gross realized losses	(1)	(1)	(6)	(2)
Net realized investment gains (losses)	3	(1)	(2)	(1)
Derivative [Member]
Net realized investment gains (losses)	(6)	11	(13)	10
Short term investments and other [Member]
Net realized investment gains (losses)	$ 3	$ 2	$ (4)	$ 1

Investments (Components of othe

Investments (Components of other-than-temporary impairment losses recognized in earnings) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other-than-temporary impairment losses recognized in earnings	$ 15	$ 31	$ 38	$ 43
Corporate and other bonds [Member]
Other-than-temporary impairment losses recognized in earnings	13	11	29	16
States, municipalities and political subdivisions [Member]
Other-than-temporary impairment losses recognized in earnings	0	13	0	18
Residential mortgage-backed [Member]
Other-than-temporary impairment losses recognized in earnings	1	5	1	6
Other asset-backed [Member]
Other-than-temporary impairment losses recognized in earnings	1	1	3	1
Total asset-backed [Member]
Other-than-temporary impairment losses recognized in earnings	2	6	4	7
Total fixed maturity securities available-for-sale [Member]
Other-than-temporary impairment losses recognized in earnings	15	30	33	41
Common stock [Member]
Other-than-temporary impairment losses recognized in earnings	0	0	5	1
Short term investments [Member]
Other-than-temporary impairment losses recognized in earnings	$ 0	$ 1	$ 0	$ 1

Investments (Summary of fixed m

Investments (Summary of fixed maturity and equity securities) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Cost or Amortized Cost	$ 37,955	$ 37,444
Gross Unrealized Gain	4,158	2,717
Gross Unrealized Loss	133	392
Estimated fair value	41,980	39,769
Corporate and other bonds [Member]
Cost or Amortized Cost	17,613	17,080
Gross Unrealized Gain	1,684	1,019
Gross Unrealized Loss	93	342
Estimated fair value	19,204	17,757
Unrealized OTTI Losses (Gains)	(1)	0
States, municipalities and political subdivisions [Member]
Cost or Amortized Cost	11,661	11,729
Gross Unrealized Gain	2,114	1,453
Gross Unrealized Loss	2	8
Estimated fair value	13,773	13,174
Unrealized OTTI Losses (Gains)	(25)	(4)
Residential mortgage-backed [Member]
Cost or Amortized Cost	4,994	4,935
Gross Unrealized Gain	215	154
Gross Unrealized Loss	20	17
Estimated fair value	5,189	5,072
Unrealized OTTI Losses (Gains)	(21)	(37)
Commercial mortgage-backed [Member]
Cost or Amortized Cost	2,080	2,154
Gross Unrealized Gain	91	55
Gross Unrealized Loss	8	12
Estimated fair value	2,163	2,197
Unrealized OTTI Losses (Gains)	0	0
Other asset-backed [Member]
Cost or Amortized Cost	928	923
Gross Unrealized Gain	8	6
Gross Unrealized Loss	5	8
Estimated fair value	931	921
Unrealized OTTI Losses (Gains)	0	0
Total asset-backed [Member]
Cost or Amortized Cost	8,002	8,012
Gross Unrealized Gain	314	215
Gross Unrealized Loss	33	37
Estimated fair value	8,283	8,190
Unrealized OTTI Losses (Gains)	(21)	(37)
U.S. Treasury and obligations of government-sponsored enterprises [Member]
Cost or Amortized Cost	81	62
Gross Unrealized Gain	11	5
Gross Unrealized Loss	0	0
Estimated fair value	92	67
Unrealized OTTI Losses (Gains)	0	0
Foreign Government Debt Securities [Member]
Cost or Amortized Cost	438	334
Gross Unrealized Gain	22	13
Gross Unrealized Loss	0	1
Estimated fair value	460	346
Unrealized OTTI Losses (Gains)	0	0
Redeemable preferred stock [Member]
Cost or Amortized Cost	33	33
Gross Unrealized Gain	2	2
Gross Unrealized Loss	0	0
Estimated fair value	35	35
Unrealized OTTI Losses (Gains)	0	0
Total fixed maturity securities available-for-sale [Member]
Cost or Amortized Cost	37,828	37,250
Gross Unrealized Gain	4,147	2,707
Gross Unrealized Loss	128	388
Estimated fair value	41,847	39,569
Unrealized OTTI Losses (Gains)	(47)	(41)
Total fixed maturity securities trading [Member]
Cost or Amortized Cost, Trading Securities	10	3
Estimated Fair Value, Trading Securities	10	3
Common stock [Member]
Cost or Amortized Cost	20	46
Gross Unrealized Gain	5	3
Gross Unrealized Loss	2	1
Estimated fair value	23	48
Preferred stock [Member]
Cost or Amortized Cost	97	145
Gross Unrealized Gain	6	7
Gross Unrealized Loss	3	3
Estimated fair value	100	149
Total equity securities available-for-sale [Member]
Cost or Amortized Cost	117	191
Gross Unrealized Gain	11	10
Gross Unrealized Loss	5	4
Estimated fair value	$ 123	$ 197

Investments (Securities in a gr

Investments (Securities in a gross unrealized loss position) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	$ 2,120	$ 7,464
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	70	342
Estimated Fair Value, 12 Months or Longer	934	502
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	63	50
Estimated Fair Value, Total	3,054	7,966
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	133	392
Corporate and other bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	1,032	4,882
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	43	302
Estimated Fair Value, 12 Months or Longer	562	162
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	50	40
Estimated Fair Value, Total	1,594	5,044
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	93	342
States, municipalities and political subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	68	338
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2	8
Estimated Fair Value, 12 Months or Longer	10	75
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Estimated Fair Value, Total	78	413
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	2	8
Residential mortgage-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	293	963
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	8	9
Estimated Fair Value, 12 Months or Longer	234	164
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	12	8
Estimated Fair Value, Total	527	1,127
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	20	17
Commercial mortgage-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	386	652
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	7	10
Estimated Fair Value, 12 Months or Longer	118	96
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1	2
Estimated Fair Value, Total	504	748
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	8	12
Other asset-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	306	552
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	5	8
Estimated Fair Value, 12 Months or Longer	5	5
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Estimated Fair Value, Total	311	557
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	5	8
Total asset-backed [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	985	2,167
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	20	27
Estimated Fair Value, 12 Months or Longer	357	265
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	13	10
Estimated Fair Value, Total	1,342	2,432
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	33	37
U.S. Treasury and obligations of government-sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months		4
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0
Estimated Fair Value, 12 Months or Longer		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Estimated Fair Value, Total		4
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		0
Foreign Government Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	8	54
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	1
Estimated Fair Value, 12 Months or Longer	5	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Estimated Fair Value, Total	13	54
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	0	1
Redeemable preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months		3
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0
Estimated Fair Value, 12 Months or Longer		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Estimated Fair Value, Total		3
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss		0
Total fixed maturity securities available-for-sale [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	2,093	7,448
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	65	338
Estimated Fair Value, 12 Months or Longer	934	502
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	63	50
Estimated Fair Value, Total	3,027	7,950
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	128	388
Common stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	4	3
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2	1
Estimated Fair Value, 12 Months or Longer	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Estimated Fair Value, Total	4	3
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	2	1
Preferred stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	23	13
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	3	3
Estimated Fair Value, 12 Months or Longer	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Estimated Fair Value, Total	23	13
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	3	3
Total equity securities available-for-sale [Member]
Schedule of Available-for-sale Securities [Line Items]
Estimated Fair Value, Less than 12 Months	27	16
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	5	4
Estimated Fair Value, 12 Months or Longer	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Estimated Fair Value, Total	27	16
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 5	$ 4

Investments (Activity related t

Investments (Activity related to the pretax fixed maturity credit loss component reflected within retained earnings for securities still held for which a portion of an OTTI loss was recognized in OCI) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance of credit losses on fixed maturity securities	$ 48	$ 61	$ 53	$ 62
Reductions for securities sold during the period	(7)	(2)	(12)	(3)
Ending balance of credit losses on fixed maturity securities	$ 41	$ 59	$ 41	$ 59

Investments (Contractual maturi

Investments (Contractual maturity) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Investments [Abstract]
Due in one year or less, cost or amortized cost	$ 1,817	$ 1,574
Due after one year through five years, cost or amortized cost	8,616	7,721
Due after five years through ten years, cost or amortized cost	14,583	14,652
Due after ten years, cost or amortized cost	12,812	13,303
Total Amortized Cost Basis	37,828	37,250
Due in one year or less, estimated fair value	1,855	1,595
Due after one year through five years, estimated fair value	9,114	8,070
Due after five years through ten years, estimated fair value	15,466	14,915
Due after ten years, estimated fair value	15,412	14,989
Total Estimated Fair Value	$ 41,847	$ 39,569

Fair Value (Assets and liabilit

Fair Value (Assets and liabilities measured at fair value on a recurring basis) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	$ 43,341	$ 41,442
Fair value of liabilities, measured on a recurring basis	8	(5)
Corporate and other bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	19,214	17,760
States, municipalities and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	13,773	13,174
Residential mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	5,189	5,072
Commercial mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	2,163	2,197
Other asset-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	931	921
Total asset-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	8,283	8,190
U.S. Treasury and obligations of government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	92	67
Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	460	346
Redeemable preferred stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	35	35
Fixed maturity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	41,857	39,572
Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	123	197
Other invested assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	5	17
Short term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	1,289	1,582
Life settlement contracts, included in Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	67	74
Embedded Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, measured on a recurring basis	8	(5)
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	569	726
Fair value of liabilities, measured on a recurring basis	0	0
Level 1 [Member] | Corporate and other bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 1 [Member] | States, municipalities and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 1 [Member] | Residential mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 1 [Member] | Commercial mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 1 [Member] | Other asset-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 1 [Member] | Total asset-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 1 [Member] | U.S. Treasury and obligations of government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	91	66
Level 1 [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 1 [Member] | Redeemable preferred stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	35	35
Level 1 [Member] | Fixed maturity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	126	101
Level 1 [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	104	177
Level 1 [Member] | Other invested assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 1 [Member] | Short term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	339	448
Level 1 [Member] | Life settlement contracts, included in Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 1 [Member] | Embedded Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, measured on a recurring basis	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	42,252	40,243
Fair value of liabilities, measured on a recurring basis	8	(5)
Level 2 [Member] | Corporate and other bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	18,972	17,592
Level 2 [Member] | States, municipalities and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	13,771	13,172
Level 2 [Member] | Residential mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	5,055	4,938
Level 2 [Member] | Commercial mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	2,152	2,175
Level 2 [Member] | Other asset-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	886	868
Level 2 [Member] | Total asset-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	8,093	7,981
Level 2 [Member] | U.S. Treasury and obligations of government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	1	1
Level 2 [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	460	346
Level 2 [Member] | Redeemable preferred stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 2 [Member] | Fixed maturity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	41,297	39,092
Level 2 [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 2 [Member] | Other invested assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	5	17
Level 2 [Member] | Short term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	950	1,134
Level 2 [Member] | Life settlement contracts, included in Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 2 [Member] | Embedded Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, measured on a recurring basis	8	(5)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	520	473
Fair value of liabilities, measured on a recurring basis	0	0
Level 3 [Member] | Corporate and other bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	242	168
Level 3 [Member] | States, municipalities and political subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	2	2
Level 3 [Member] | Residential mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	134	134
Level 3 [Member] | Commercial mortgage-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	11	22
Level 3 [Member] | Other asset-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	45	53
Level 3 [Member] | Total asset-backed [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	190	209
Level 3 [Member] | U.S. Treasury and obligations of government-sponsored enterprises [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 3 [Member] | Foreign Government Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 3 [Member] | Redeemable preferred stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 3 [Member] | Fixed maturity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	434	379
Level 3 [Member] | Equity securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	19	20
Level 3 [Member] | Other invested assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 3 [Member] | Short term investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	0	0
Level 3 [Member] | Life settlement contracts, included in Other assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets, measured on a recurring basis	67	74
Level 3 [Member] | Embedded Derivative Financial Instruments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of liabilities, measured on a recurring basis	$ 0	$ 0

Fair Value (Table of reconcilia

Fair Value (Table of reconciliation for assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	$ 491	$ 1,213	$ 473	$ 1,281
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	8	6	12	24
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	4	0	7	7
Purchases	139	56	201	181
Sales	(45)	(90)	(61)	(246)
Settlements	(32)	(45)	(46)	(98)
Transfers into Level 3	3	17	5	54
Transfers out of Level 3	(48)	(56)	(71)	(102)
Balance, Ending, Assets	520	1,101	520	1,101
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	(3)	(5)	(3)	(4)
Corporate and other bonds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	193	186	168	162
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	1	(2)	0	(1)
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	3	(1)	7	(1)
Purchases	94	0	147	12
Sales	(20)	0	(36)	(12)
Settlements	(7)	(7)	(10)	(21)
Transfers into Level 3	0	0	0	37
Transfers out of Level 3	(22)	(35)	(34)	(35)
Balance, Ending, Assets	242	141	242	141
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	(3)	0	(3)
States, municipalities and political subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	2	86	2	94
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	0	0	0	1
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	(1)	0	(10)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, Ending, Assets	2	85	2	85
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Residential mortgage-backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	128	232	134	189
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	1	1	2	2
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	(1)	(2)	(1)	(2)
Purchases	10	0	10	72
Sales	0	0	0	0
Settlements	(4)	(11)	(9)	(21)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	(13)	(2)	(33)
Balance, Ending, Assets	134	207	134	207
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Commercial Mortgage Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	27	64	22	83
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	0	1	0	2
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	0	(1)	0	0
Purchases	0	9	9	15
Sales	0	0	0	0
Settlements	(9)	(1)	(9)	(2)
Transfers into Level 3	3	17	3	17
Transfers out of Level 3	(10)	(2)	(14)	(28)
Balance, Ending, Assets	11	87	11	87
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Other asset-backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	50	553	53	655
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	0	2	0	3
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	2	1	2	10
Purchases	35	47	35	82
Sales	(25)	(90)	(25)	(234)
Settlements	(1)	(17)	(1)	(20)
Transfers into Level 3	0	0	2	0
Transfers out of Level 3	(16)	(6)	(21)	(6)
Balance, Ending, Assets	45	490	45	490
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Total asset-backed [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	205	849	209	927
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	1	4	2	7
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	1	(2)	1	8
Purchases	45	56	54	169
Sales	(25)	(90)	(25)	(234)
Settlements	(14)	(29)	(19)	(43)
Transfers into Level 3	3	17	5	17
Transfers out of Level 3	(26)	(21)	(37)	(67)
Balance, Ending, Assets	190	784	190	784
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Total Fixed maturity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	400	1,121	379	1,183
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	2	2	2	7
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	4	(3)	8	7
Purchases	139	56	201	181
Sales	(45)	(90)	(61)	(246)
Settlements	(21)	(37)	(29)	(74)
Transfers into Level 3	3	17	5	54
Transfers out of Level 3	(48)	(56)	(71)	(102)
Balance, Ending, Assets	434	1,010	434	1,010
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	(3)	0	(3)
Equity securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	19	13	20	16
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	0	0	0	0
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	0	3	(1)	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, Ending, Assets	19	16	19	16
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	0	0	0	0
Life settlement contracts, included in Other assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, Beginning, Assets	72	79	74	82
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss)	6	4	10	17
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Settlements	(11)	(8)	(17)	(24)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance, Ending, Assets	67	75	67	75
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ (3)	$ (2)	$ (3)	$ (1)

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value, Assets, Level 1 to Level 2, Transfers	$ 0	$ 0	$ 0	$ 0
Fair Value, Assets, Level 2 to Level 1, Transfers	0	$ 0	0	$ 0
Other Invested Assets Overseas Deposit	$ 28		$ 28		$ 27

Fair Value (Quantitative inform

Fair Value (Quantitative information about significant unobservable inputs in the fair value measurement of level 3 assets) (Details) - Income Approach Valuation Technique [Member] - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Fixed maturity securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 226	$ 138
Fixed maturity securities [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit Spread	1.00%	3.00%
Fixed maturity securities [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit Spread	40.00%	184.00%
Fixed maturity securities [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Credit Spread	6.00%	6.00%
Life settlement contracts, included in Other assets [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Assets, Fair Value Disclosure	$ 67	$ 74
Life settlement contracts, included in Other assets [Member] | Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality assumption	55.00%	55.00%
Life settlement contracts, included in Other assets [Member] | Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality assumption	1676.00%	1676.00%
Life settlement contracts, included in Other assets [Member] | Weighted Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Mortality assumption	162.00%	164.00%
Life settlement contracts, included in Other assets [Member] | Rate [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate risk premium	9.00%	9.00%

Fair Value (Carrying amount and

Fair Value (Carrying amount and estimated fair value of financial instrument assets and liabilities which are not measured at fair value) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Financial Assets [Abstract]
Mortgage loans	$ 610	$ 678
Financial Liabilities [Abstract]
Short term debt	0	350
Long term debt	2,708	2,210
Carrying Amount [Member]
Financial Assets [Abstract]
Mortgage loans	610	678
Financial Liabilities [Abstract]
Short term debt		350
Long term debt	2,708	2,210
Estimated Fair Value [Member]
Financial Assets [Abstract]
Mortgage loans	638	688
Financial Liabilities [Abstract]
Short term debt		360
Long term debt	3,024	2,433
Level 1 [Member] | Estimated Fair Value [Member]
Financial Assets [Abstract]
Mortgage loans	0	0
Financial Liabilities [Abstract]
Short term debt		0
Long term debt	0	0
Level 2 [Member] | Estimated Fair Value [Member]
Financial Assets [Abstract]
Mortgage loans	0	0
Financial Liabilities [Abstract]
Short term debt		360
Long term debt	3,024	2,433
Level 3 [Member] | Estimated Fair Value [Member]
Financial Assets [Abstract]
Mortgage loans	638	688
Financial Liabilities [Abstract]
Short term debt		0
Long term debt	$ 0	$ 0

Claim and Claim Adjustment Ex40

Claim and Claim Adjustment Expense Reserves (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended		48 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2010
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	$ (98)		$ (5)	$ (150)	$ (12)
Catastrophe losses net of reinsurance	85		60	121	89
Specialty [Member]
Favorable development in other professional liability and management liability related to lower than expected severity for professional services primarily in accident years 2010 and prior			38		41
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	(65)		(13)	(99)	(11)
Unfavorable development in other professional liability and management liability related to lower than expected severity for professional services primarily in accident years 2012 through 2014			37		37
Commercial [Member]
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	(18)		16	(32)	11
Loss Portfolio Transfer [Member]
Liability for Asbestos and Environmental Claims, Net								$ 1,600
Aggregate limit under AEP Loss Portfolio Transfer								4,000
Claim And Allocated Claim Adjustment Expense Reserves Under Existing Third Party Reinsurance Contracts								1,200
Reinsurance premium paid to NICO under AEP Loss Portfolio Transfer								2,000
Net reinsurance receivables transferrred to NICO under AEP Loss Portfolio Transfer								215
Total consideration paid to NICO under AEP Loss Portfolio Transfer								$ 2,200
Net AEP adverse development before consideration of LPT	0	$ 200	$ 150	200	$ 150	$ 900
Cumulative amounts ceded under AEP Loss Portfolio Transfer	2,800			2,800			$ 2,600
Deferred reinsurance benefit yet to be recognized	359			359			241
Fair value of collateral trust account established by NICO under AEP Loss Portfolio Transfer	$ 2,600			$ 2,600			$ 2,800

Claim and Claim Adjustment Ex41

Claim and Claim Adjustment Expense Reserves (Net prior year development) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	$ (98)	$ (5)	$ (150)	$ (12)
Pretax (favorable) unfavorable premium development, excluding Life & Group	(8)	(15)	(22)	(6)
Total pretax (favorable) unfavorable net prior year development, excluding Life & Group	(106)	(20)	(172)	(18)
Specialty [Member]
Segment Reporting Information [Line Items]
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	(65)	(13)	(99)	(11)
Pretax (favorable) unfavorable premium development, excluding Life & Group	(7)	(2)	(18)	(8)
Total pretax (favorable) unfavorable net prior year development, excluding Life & Group	(72)	(15)	(117)	(19)
Commercial [Member]
Segment Reporting Information [Line Items]
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	(18)	16	(32)	11
Pretax (favorable) unfavorable premium development, excluding Life & Group	(2)	(11)	(4)	(12)
Total pretax (favorable) unfavorable net prior year development, excluding Life & Group	(20)	5	(36)	(1)
International [Member]
Segment Reporting Information [Line Items]
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	(15)	(8)	(19)	(12)
Pretax (favorable) unfavorable premium development, excluding Life & Group	1	(2)	0	14
Total pretax (favorable) unfavorable net prior year development, excluding Life & Group	(14)	(10)	(19)	2
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	0	0	0	0
Pretax (favorable) unfavorable premium development, excluding Life & Group	0	0	0	0
Total pretax (favorable) unfavorable net prior year development, excluding Life & Group	$ 0	$ 0	$ 0	$ 0

Claim and Claim Adjustment Ex42

Claim and Claim Adjustment Expense Reserves (Net prior year claim and allocated claim adjustment expense reserve development for Specialty segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	$ (98)	$ (5)	$ (150)	$ (12)
Specialty [Member]
Medical Professional Liability	(23)	(6)	(30)	8
Other Professional Liability and Management Liability	(41)	(1)	(50)	(4)
Surety	0	0	0	1
Warranty	3	1	5	1
Other	(4)	(7)	(24)	(17)
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	$ (65)	$ (13)	$ (99)	$ (11)

Claim and Claim Adjustment Ex43

Claim and Claim Adjustment Expense Reserves (Net prior year claim and allocated claim adjustment expense reserve development for Commercial segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	$ (98)	$ (5)	$ (150)	$ (12)
Commercial [Member]
Commercial Auto	(20)	7	(35)	7
General Liability	(37)	1	(52)	5
Workers' Compensation	50	24	54	23
Property and Other	(11)	(16)	1	(24)
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	$ (18)	$ 16	$ (32)	$ 11

Claim and Claim Adjustment Ex44

Claim and Claim Adjustment Expense Reserves Net prior year claim and allocated claim adjustment expense reserve development for International segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	$ (98)	$ (5)	$ (150)	$ (12)
International [Member]
Medical Professional Liability	(1)	0	(1)	0
Other Professional Liability	18	(5)	17	(5)
Liability	(19)	(2)	(19)	(7)
Property & Marine	(3)	(8)	(7)	(14)
Other	(10)	7	(9)	14
Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group	$ (15)	$ (8)	$ (19)	$ (12)

Claim and Claim Adjustment Ex45

Claim and Claim Adjustment Expense Reserves Impact of Loss Portfolio Transfer on the Consolidated Statement of Operations (Details) - Loss Portfolio Transfer [Member] - USD ($) $ in Millions	3 Months Ended			6 Months Ended		48 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2013
Net AEP adverse development before consideration of LPT	$ 0	$ 200	$ 150	$ 200	$ 150	$ 900
Provision for uncollectible third-party reinsurance on AEP	0		0	0	0
Additional amounts ceded under LPT	0		150	200	150
Retroactive reinsurance benefit recognized	(9)		(66)	(82)	(71)
Pretax impact of deferred retroactive reinsurance benefit	$ (9)		$ 84	$ 118	$ 79

Benefit Plans (Components of ne

Benefit Plans (Components of net periodic cost (benefit)) (Details) - Pension Plans, Defined Benefit [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 2	$ 0	$ 4
Interest cost on projected benefit obligation	28	28	56	56
Expected return on plan assets	(40)	(44)	(80)	(87)
Amortization of net actuarial (gain) loss	10	10	19	19
Net periodic (benefit) cost	$ (2)	$ (4)	$ (5)	$ (8)

Benefit Plans (Narrative) (Deta

Benefit Plans (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Defined Benefit Plan, Curtailments	$ 55
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.00%	3.85%

Commitments and Contingencies48

Commitments and Contingencies, and Guarantees (Narrative) (Detail) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Property Lease Guarantee [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 16
Guarantee and Indemnification [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Current Carrying Value	5	$ 5
Guarantee agreement [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	375
Indemnification Agreement [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	259
Guarantee Obligations [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 2,000

Accumulated Other Comprehensi49

Accumulated Other Comprehensive Income (Loss) by Component (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	$ (56)	$ 421	$ (315)	$ 400
Other comprehensive income (loss), before reclassifications	274	(291)	514	(267)
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	8	(13)	(11)	(10)
Other comprehensive income (loss) after tax (expense) benefit	266	(278)	525	(257)
Accumulated other comprehensive income (loss), ending balance	210	143	210	143
Reclassification from AOCI, Current Period, Tax	(3)	9	8	12
Tax (expense) benefit on other comprehensive income (loss)	(159)	160	(281)	95
Net unrealized gains (losses) on investments with OTTI losses [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	32	35	27	36
Other comprehensive income (loss), before reclassifications	(1)	(4)	2	(5)
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	0	0	(2)	0
Other comprehensive income (loss) after tax (expense) benefit	(1)	(4)	4	(5)
Accumulated other comprehensive income (loss), ending balance	31	31	31	31
Reclassification from AOCI, Current Period, Tax	0	0	1	0
Tax (expense) benefit on other comprehensive income (loss)	1	2	(2)	2
Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	624	1,054	390	942
Other comprehensive income (loss), before reclassifications	323	(372)	546	(251)
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	13	(7)	2	2
Other comprehensive income (loss) after tax (expense) benefit	310	(365)	544	(253)
Accumulated other comprehensive income (loss), ending balance	934	689	934	689
Reclassification from AOCI, Current Period, Tax	(6)	5	1	5
Tax (expense) benefit on other comprehensive income (loss)	(157)	181	(273)	119
Pension and postretirement benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(642)	(627)	(648)	(633)
Other comprehensive income (loss), before reclassifications	0	36	0	36
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	(5)	(6)	(11)	(12)
Other comprehensive income (loss) after tax (expense) benefit	5	42	11	48
Accumulated other comprehensive income (loss), ending balance	(637)	(585)	(637)	(585)
Reclassification from AOCI, Current Period, Tax	3	4	6	7
Tax (expense) benefit on other comprehensive income (loss)	(3)	(23)	(6)	(26)
Cumulative foreign currency translation adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss), beginning balance	(70)	(41)	(84)	55
Other comprehensive income (loss), before reclassifications	(48)	49	(34)	(47)
Amounts reclassified from accumulated other comprehensive income (loss) after tax (expense) benefit	0	0	0	0
Other comprehensive income (loss) after tax (expense) benefit	(48)	49	(34)	(47)
Accumulated other comprehensive income (loss), ending balance	(118)	8	(118)	8
Reclassification from AOCI, Current Period, Tax	0	0	0	0
Tax (expense) benefit on other comprehensive income (loss)	$ 0	$ 0	$ 0	$ 0

Business Segments (Income State

Business Segments (Income Statement Information) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating Revenues
Net earned premiums	$ 1,730	$ 1,735	$ 3,429	$ 3,422
Net investment income	502	500	937	1,058
Other revenues	100	92	197	189
Total operating revenues	2,332	2,327	4,563	4,669
Claims, Benefits and Expenses
Net incurred claims and benefits	1,335	1,466	2,739	2,801
Policyholders' dividends	4	3	8	7
Amortization of deferred acquisition costs	305	314	612	617
Other insurance related expenses	270	259	547	527
Other expenses	146	121	292	250
Total claims, benefits and expenses	2,060	2,163	4,198	4,202
Operating income (loss) before income tax	272	164	365	467
Income tax (expense) benefit on operating income (loss)	(71)	(32)	(73)	(110)
Net operating income (loss)	201	132	292	357
Net realized investment gains (losses), pre-tax	16	0	(20)	10
Income tax (expense) benefit on net realized investment gains (losses)	(8)	6	3	4
Net realized investment gains (losses), after tax	8	6	(17)	14
Net Income (Loss)	209	138	275	371
Specialty [Member]
Operating Revenues
Net earned premiums	702	689	1,384	1,369
Net investment income	133	134	240	289
Other revenues	89	81	176	159
Total operating revenues	924	904	1,800	1,817
Claims, Benefits and Expenses
Net incurred claims and benefits	377	416	767	845
Policyholders' dividends	1	1	2	2
Amortization of deferred acquisition costs	148	146	292	290
Other insurance related expenses	73	66	148	135
Other expenses	79	69	154	136
Total claims, benefits and expenses	678	698	1,363	1,408
Operating income (loss) before income tax	246	206	437	409
Income tax (expense) benefit on operating income (loss)	(82)	(69)	(146)	(137)
Net operating income (loss)	164	137	291	272
Net realized investment gains (losses), pre-tax	4	0	(7)	4
Income tax (expense) benefit on net realized investment gains (losses)	(2)	0	2	(1)
Net realized investment gains (losses), after tax	2	0	(5)	3
Net Income (Loss)	166	137	286	275
Commercial [Member]
Operating Revenues
Net earned premiums	696	703	1,384	1,381
Net investment income	164	169	290	373
Other revenues	8	9	14	18
Total operating revenues	868	881	1,688	1,772
Claims, Benefits and Expenses
Net incurred claims and benefits	469	507	911	961
Policyholders' dividends	3	2	6	5
Amortization of deferred acquisition costs	117	117	233	234
Other insurance related expenses	130	130	271	257
Other expenses	11	5	16	13
Total claims, benefits and expenses	730	761	1,437	1,470
Operating income (loss) before income tax	138	120	251	302
Income tax (expense) benefit on operating income (loss)	(46)	(42)	(85)	(104)
Net operating income (loss)	92	78	166	198
Net realized investment gains (losses), pre-tax	8	2	(10)	6
Income tax (expense) benefit on net realized investment gains (losses)	(3)	2	3	(1)
Net realized investment gains (losses), after tax	5	4	(7)	5
Net Income (Loss)	97	82	159	203
International [Member]
Operating Revenues
Net earned premiums	197	207	395	398
Net investment income	13	13	25	27
Other revenues	0	(1)	1	(1)
Total operating revenues	210	219	421	424
Claims, Benefits and Expenses
Net incurred claims and benefits	157	114	278	230
Policyholders' dividends	0	0	0	0
Amortization of deferred acquisition costs	40	45	87	80
Other insurance related expenses	37	31	65	68
Other expenses	7	(5)	16	0
Total claims, benefits and expenses	241	185	446	378
Operating income (loss) before income tax	(31)	34	(25)	46
Income tax (expense) benefit on operating income (loss)	4	(12)	4	(15)
Net operating income (loss)	(27)	22	(21)	31
Net realized investment gains (losses), pre-tax	4	1	8	2
Income tax (expense) benefit on net realized investment gains (losses)	(1)	(1)	(2)	(1)
Net realized investment gains (losses), after tax	3	0	6	1
Net Income (Loss)	(24)	22	(15)	32
Life and Group Non-Core [Member]
Operating Revenues
Net earned premiums	136	137	267	275
Net investment income	188	179	375	358
Other revenues	3	0	3	9
Total operating revenues	327	316	645	642
Claims, Benefits and Expenses
Net incurred claims and benefits	340	344	663	684
Policyholders' dividends	0	0	0	0
Amortization of deferred acquisition costs	0	6	0	13
Other insurance related expenses	31	34	64	69
Other expenses	2	5	5	9
Total claims, benefits and expenses	373	389	732	775
Operating income (loss) before income tax	(46)	(73)	(87)	(133)
Income tax (expense) benefit on operating income (loss)	42	49	81	92
Net operating income (loss)	(4)	(24)	(6)	(41)
Net realized investment gains (losses), pre-tax	(2)	(5)	(5)	(4)
Income tax (expense) benefit on net realized investment gains (losses)	(3)	6	(3)	8
Net realized investment gains (losses), after tax	(5)	1	(8)	4
Net Income (Loss)	(9)	(23)	(14)	(37)
Corporate and Other Non-Core [Member]
Operating Revenues
Net earned premiums	0	0	0	0
Net investment income	4	5	7	11
Other revenues	0	3	3	5
Total operating revenues	4	8	10	16
Claims, Benefits and Expenses
Net incurred claims and benefits	(8)	85	120	81
Policyholders' dividends	0	0	0	0
Amortization of deferred acquisition costs	0	0	0	0
Other insurance related expenses	0	(1)	0	(1)
Other expenses	47	47	101	93
Total claims, benefits and expenses	39	131	221	173
Operating income (loss) before income tax	(35)	(123)	(211)	(157)
Income tax (expense) benefit on operating income (loss)	11	42	73	54
Net operating income (loss)	(24)	(81)	(138)	(103)
Net realized investment gains (losses), pre-tax	2	2	(6)	2
Income tax (expense) benefit on net realized investment gains (losses)	1	(1)	3	(1)
Net realized investment gains (losses), after tax	3	1	(3)	1
Net Income (Loss)	(21)	(80)	(141)	(102)
Eliminations [Member]
Operating Revenues
Net earned premiums	(1)	(1)	(1)	(1)
Net investment income	0	0	0	0
Other revenues	0	0	0	(1)
Total operating revenues	(1)	(1)	(1)	(2)
Claims, Benefits and Expenses
Net incurred claims and benefits	0	0	0	0
Policyholders' dividends	0	0	0	0
Amortization of deferred acquisition costs	0	0	0	0
Other insurance related expenses	(1)	(1)	(1)	(1)
Other expenses	0	0	0	(1)
Total claims, benefits and expenses	(1)	(1)	(1)	(2)
Operating income (loss) before income tax	0	0	0	0
Income tax (expense) benefit on operating income (loss)	0	0	0	0
Net operating income (loss)	0	0	0	0
Net realized investment gains (losses), pre-tax	0	0	0	0
Income tax (expense) benefit on net realized investment gains (losses)	0	0	0	0
Net realized investment gains (losses), after tax	0	0	0	0
Net Income (Loss)	$ 0	$ 0	$ 0	$ 0

Business Segments (Balance Shee

Business Segments (Balance Sheet Information) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Reinsurance receivables	$ 4,720	$ 4,491
Insurance receivables	2,413	2,129
Deferred acquisition costs	620	598
Goodwill	147	150
Insurance reserves
Claim and claim adjustment expenses	22,975	22,663
Unearned premiums	3,865	3,671
Future policy benefits	11,140	10,152
Specialty [Member]
Segment Reporting Information [Line Items]
Reinsurance receivables	856	724
Insurance receivables	1,005	890
Deferred acquisition costs	308	307
Goodwill	117	117
Insurance reserves
Claim and claim adjustment expenses	6,414	6,269
Unearned premiums	1,871	1,839
Future policy benefits	0	0
Commercial [Member]
Segment Reporting Information [Line Items]
Reinsurance receivables	621	639
Insurance receivables	1,120	993
Deferred acquisition costs	228	213
Goodwill	0	0
Insurance reserves
Claim and claim adjustment expenses	8,973	9,183
Unearned premiums	1,417	1,297
Future policy benefits	0	0
International [Member]
Segment Reporting Information [Line Items]
Reinsurance receivables	128	144
Insurance receivables	274	233
Deferred acquisition costs	84	78
Goodwill	30	33
Insurance reserves
Claim and claim adjustment expenses	1,409	1,347
Unearned premiums	450	415
Future policy benefits	0	0
Life and Group Non-Core [Member]
Segment Reporting Information [Line Items]
Reinsurance receivables	492	497
Insurance receivables	11	11
Deferred acquisition costs	0	0
Goodwill	0	0
Insurance reserves
Claim and claim adjustment expenses	3,382	3,220
Unearned premiums	128	120
Future policy benefits	11,140	10,152
Corporate and Other Non-Core [Member]
Segment Reporting Information [Line Items]
Reinsurance receivables	2,623	2,487
Insurance receivables	3	2
Deferred acquisition costs	0	0
Goodwill	0	0
Insurance reserves
Claim and claim adjustment expenses	2,797	2,644
Unearned premiums	0	0
Future policy benefits	0	0
Eliminations [Member]
Segment Reporting Information [Line Items]
Reinsurance receivables	0	0
Insurance receivables	0	0
Deferred acquisition costs	0	0
Goodwill	0	0
Insurance reserves
Claim and claim adjustment expenses	0	0
Unearned premiums	(1)	0
Future policy benefits	$ 0	$ 0

Business Segments (Revenues by

Business Segments (Revenues by Line of Business) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues	$ 2,348	$ 2,327	$ 4,543	$ 4,679
Specialty [Domain]
Revenues	928	904	1,793	1,821
Management & Professional Liability [Member]
Revenues	659	674	1,277	1,371
Surety [Member]
Revenues	133	125	260	245
Warranty & Alternative Risks [Member]
Revenues	136	105	256	205
Commercial [Domain]
Revenues	876	883	1,678	1,778
Middle Markets [Member]
Revenues	434	412	835	821
Small Business [Member]
Revenues	151	158	294	323
Other Commercial Insurance [Member]
Revenues	291	313	549	634
International [Domain]
Revenues	214	220	429	426
Canada [Member]
Revenues	51	54	101	109
CNA Europe [Member]
Revenues	81	77	159	154
Hardy [Member]
Revenues	82	89	169	163
Life and Group Non-Core [Member]
Revenues	325	311	640	638
Corporate and Other Non-Core [Member]
Revenues	6	10	4	18
Eliminations [Member]
Revenues	$ (1)	$ (1)	$ (1)	$ (2)