Chubb Limited (CB) 10-Q 2 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 18, 2014
Entity Information [Line Items]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'ACE	'
Entity Registrant Name	'ACE Ltd	'
Entity Central Index Key	'0000896159	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	337,700,207

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Investments [Abstract]	'		'
Fixed maturities available for sale, at fair value (amortized cost - $48,282 and $48,406) (includes hybrid financial instruments of $319 and $302)	$49,611		$49,254
Fixed maturities held to maturity, at amortized cost (fair value – $6,080 and $6,263)	5,887		6,098
Equity securities, at fair value (cost – $845 and $841)	851		837
Short-term investments, at fair value and amortized cost	2,526		1,763
Other investments (cost – $2,823 and $2,671)	3,170		2,976
Total investments	62,045		60,928
Cash	847	[1],[2]	579	[1],[3]
Securities lending collateral	1,550		1,632
Accrued investment income	553		556
Insurance and reinsurance balances receivable	4,761		5,026
Reinsurance recoverable on losses and loss expenses	10,755		11,227
Reinsurance recoverable on policy benefits	222		218
Deferred policy acquisition costs	2,402		2,313
Value of business acquired	517		536
Goodwill and other intangible assets	5,382		5,404
Prepaid reinsurance premiums	1,721		1,675
Deferred tax assets	516		616
Investments in partially-owned insurance companies (cost – $463 and $467)	466		470
Other assets	3,442		3,330
Total assets	95,179		94,510
Liabilities	'		'
Unpaid losses and loss expenses	36,866		37,443
Unearned premiums	7,791		7,539
Future policy benefits	4,632		4,615
Insurance and reinsurance balances payable	3,734		3,628
Securities lending payable	1,551		1,633
Accounts payable, accrued expenses, and other liabilities	5,218		4,810
Short-term debt	1,901		1,901
Long-term debt	3,808		3,807
Trust preferred securities	309		309
Total liabilities	65,810		65,685
Commitments and contingencies	'		'
Shareholders’ equity	'		'
Common Shares (CHF 26.59 and CHF 27.04 par value; 342,832,412 shares issued; 337,974,644 and 339,793,935 shares outstanding)	8,724		8,899
Common Shares in treasury (4,857,768 and 3,038,477 shares)	-443		-255
Additional paid-in capital	5,037		5,238
Retained earnings	14,525		13,791
Accumulated other comprehensive income (AOCI)	1,526		1,152
Total shareholders’ equity	29,369		28,825
Total liabilities and shareholders’ equity	$95,179		$94,510
[1]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014 and December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[3]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical)	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2013
In Millions, except Share data, unless otherwise specified	USD ($)	CHF	USD ($)	CHF
Statement of Financial Position [Abstract]	'	'	'	'
Fixed maturities available for sale, at amortized cost	$48,282	'	$48,406	'
Fixed maturities available for sale, hybrid financial instruments	319	'	302	'
Fixed maturities held to maturity, at amortized cost	6,080	'	6,263	'
Equity securities, at cost	845	'	841	'
Other investments, cost	2,823	'	2,671	'
Investments in partially-owned insurance companies, cost	$463	'	$467	'
Common Shares, par value	'	26.59	'	27.04
Common Shares, shares issued	342,832,412	342,832,412	342,832,412	342,832,412
Common Shares, shares outstanding	337,974,644	337,974,644	339,793,935	339,793,935
Common Shares in treasury, shares	4,857,768	4,857,768	3,038,477	3,038,477

Consolidated_Statements_Of_Ope

Consolidated Statements Of Operations and Comprehensive Income (USD $)	3 Months Ended
In Millions, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenues	'	'
Net premiums written	$4,185	$3,798
Increase in unearned premiums	-215	-225
Net premiums earned	3,970	3,573
Net investment income	553	531
Net realized gains (losses):	'	'
Other-than-temporary impairment (OTTI) losses gross	-12	-3
Portion of OTTI losses recognized in other comprehensive income (OCI)	1	0
Net OTTI losses recognized in income	-11	-3
Net realized gains (losses) excluding OTTI losses	-93	209
Total net realized gains (losses)	-104	206
Total revenues	4,419	4,310
Expenses	'	'
Losses and loss expenses	2,161	1,926
Policy benefits	114	131
Policy acquisition costs	728	614
Administrative expenses	535	514
Interest expense	71	60
Other (income) expense	-17	-10
Total expenses	3,592	3,235
Income before income tax	827	1,075
Income tax expense (includes $(3) and $5 income tax (benefit) expense from reclassification of unrealized gains)	93	122
Net income	734	953
Other comprehensive income (loss)	'	'
Unrealized appreciation (depreciation)	519	-116
Reclassification adjustment for net realized gains included in net income	-6	-35
Unrealized appreciation (Depreciation) after reclassification adjustment	513	-151
Change in:	'	'
Cumulative translation adjustment	-33	-211
Pension liability	-8	22
Other comprehensive income (loss), before income tax	472	-340
Income tax (expense) benefit related to OCI items	-98	103
Other comprehensive income (loss)	374	-237
Comprehensive income	1,108	716
Earnings per share	'	'
Basic earnings per share	$2.16	$2.80
Diluted earnings per share	$2.14	$2.77
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]	'	'
Net realized gains (losses):	'	'
Total net realized gains (losses)	6	35
Expenses	'	'
Income tax expense (includes $(3) and $5 income tax (benefit) expense from reclassification of unrealized gains)	($3)	$5

Consolidated_Statements_Of_Ope1

Consolidated Statements Of Operations and Comprehensive Income Consolidated Statements of Operations and Comprehensive Income (Parenthetical) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Net realized gains (losses)	($104)	$206
Income tax expense (benefit)	93	122
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]	'	'
Net realized gains (losses)	6	35
Income tax expense (benefit)	($3)	$5

Consolidated_Statements_Of_Sha

Consolidated Statements Of Shareholders' Equity (USD $)	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Net Unrealized Investment Gain (Loss) [Member]	Accumulated Translation Adjustment [Member]	Accumulated Defined Benefit Plans Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
In Millions
Balance - beginning of period at Dec. 31, 2012	'	$9,591	($159)	$5,179	$10,033	$2,633	$339	($85)	'
Dividends declared on Common Shares – par value reduction	'	-168	'	'	'	'	'	'	'
Common Shares repurchased	'	'	-154	'	'	'	'	'	'
Net shares redeemed under employee share-based compensation plans	'	'	101	-114	'	'	'	'	'
Exercise of stock options	'	'	'	-12	'	'	'	'	'
Share-based compensation expense and other	'	'	'	42	'	'	'	'	'
Funding of dividends declared to Retained earnings	'	'	'	0	'	'	'	'	'
Net income	953	'	'	'	953	'	'	'	'
Funding of dividends declared from Additional paid-in capital	'	'	'	'	0	'	'	'	'
Dividends declared on Common Shares	'	'	'	'	0	'	'	'	'
Change in period, before reclassification from AOCI, net of income tax (expense) benefit of $(90) and $51	'	'	'	'	'	-65	'	'	'
Amounts reclassified from AOCI, net of income tax (expense) benefit of $(3) and $5	'	'	'	'	'	-30	'	'	'
Change in period, net of income tax (expense) benefit of $(93) and $56	'	'	'	'	'	-95	'	'	'
Change in period, net of income tax (expense) benefit of $(8) and $55	'	'	'	'	'	'	-156	'	'
Change in period, net of income tax (expense) benefit of $3 and $(8)	'	'	'	'	'	'	'	14	'
Balance - end of period at Mar. 31, 2013	27,942	9,423	-212	5,095	10,986	2,538	183	-71	2,650
Balance - beginning of period at Dec. 31, 2013	28,825	8,899	-255	5,238	13,791	1,174	63	-85	'
Dividends declared on Common Shares – par value reduction	'	-175	'	'	'	'	'	'	'
Common Shares repurchased	'	'	-332	'	'	'	'	'	'
Net shares redeemed under employee share-based compensation plans	'	'	144	-154	'	'	'	'	'
Exercise of stock options	'	'	'	-18	'	'	'	'	'
Share-based compensation expense and other	'	'	'	52	'	'	'	'	'
Funding of dividends declared to Retained earnings	'	'	'	-81	'	'	'	'	'
Net income	734	'	'	'	734	'	'	'	'
Funding of dividends declared from Additional paid-in capital	'	'	'	'	81	'	'	'	'
Dividends declared on Common Shares	'	'	'	'	-81	'	'	'	'
Change in period, before reclassification from AOCI, net of income tax (expense) benefit of $(90) and $51	'	'	'	'	'	429	'	'	'
Amounts reclassified from AOCI, net of income tax (expense) benefit of $(3) and $5	'	'	'	'	'	-9	'	'	'
Change in period, net of income tax (expense) benefit of $(93) and $56	'	'	'	'	'	420	'	'	'
Change in period, net of income tax (expense) benefit of $(8) and $55	'	'	'	'	'	'	-41	'	'
Change in period, net of income tax (expense) benefit of $3 and $(8)	'	'	'	'	'	'	'	-5	'
Balance - end of period at Mar. 31, 2014	$29,369	$8,724	($443)	$5,037	$14,525	$1,594	$22	($90)	$1,526

Consolidated_Statements_Of_Sha1

Consolidated Statements Of Shareholders' Equity (Parenthetical) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Net unrealized appreciation on investments, Change in period, income tax (expense) benefit	($93)	$56
Cumulative translation adjustment, Change in period, income tax(expense) benefit	-8	55
Pension liability adjustment, Change in period, income tax (expense) benefit	3	-8
Accumulated Net Unrealized Investment Gain (Loss) [Member]	'	'
Unrealized appreciation on investments, Change in period before reclassification to AOCI, income tax (expense) benefit	9	30
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]	'	'
Unrealized appreciation on investments, Change in period before reclassification to AOCI, income tax (expense) benefit	-3	5
Income tax expense from reclassification of unrealized gains	($90)	$51

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Cash flows from operating activities	'		'
Net income	$734		$953
Adjustments to reconcile net income to net cash flows from operating activities	'		'
Net realized (gains) losses	104		-206
Amortization of premiums/discounts on fixed maturities	53		66
Deferred income taxes	0		35
Unpaid losses and loss expenses	-598		-505
Unearned premiums	270		267
Future policy benefits	56		44
Insurance and reinsurance balances payable	112		-41
Accounts payable, accrued expenses, and other liabilities	-64		144
Income taxes payable	15		29
Insurance and reinsurance balances receivable	264		-45
Reinsurance recoverable on losses and loss expenses	478		435
Reinsurance recoverable on policy benefits	-2		10
Deferred policy acquisition costs	-99		-121
Prepaid reinsurance premiums	-52		-58
Other	-21		-94
Net cash flows from operating activities	1,250		913
Cash flows from investing activities	'		'
Purchases of fixed maturities available for sale	-3,522		-5,446
Purchases of to be announced mortgage-backed securities	0		-19
Purchases of fixed maturities held to maturity	-30		-142
Purchases of equity securities	-37		-107
Sales of fixed maturities available for sale	2,208		2,745
Sales of to be announced mortgage-backed securities	0		19
Sales of equity securities	27		31
Maturities and redemptions of fixed maturities available for sale	1,550		2,016
Maturities and redemptions of fixed maturities held to maturity	212		491
Net change in short-term investments	-765		-687
Net derivative instruments settlements	-96		-279
Acquisition of subsidiaries	0		-33
Other	-50		-55
Net cash flows used for investing activities	-503		-1,466
Cash flows from financing activities	'		'
Dividends paid on Common Shares	-214		-2
Common Shares repurchased	-335		-154
Proceeds from issuance of long-term debt	0		947
Proceeds from issuance of short-term debt	426		659
Repayment of short-term debt	-426		-658
Proceeds from share-based compensation plans, including windfall tax benefits	40		21
Other	37		0
Net cash flows (used for) from financing activities	-472		813
Effect of foreign currency rate changes on cash and cash equivalents	-7		-20
Net increase in cash	268		240
Cash – beginning of period	579	[1],[2]	615	[3]
Cash – end of period	847	[2],[4]	855	[3]
Supplemental cash flow information	'		'
Taxes paid	60		43
Interest paid	$51		$31
[1]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014 and December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[3]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2013 and December 31, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[4]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

General

General	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
General	'
	General
	Basis of presentation
	ACE Limited is a holding company incorporated in Zurich, Switzerland. ACE Limited, through its subsidiaries, provides a broad range of insurance and reinsurance products to insureds worldwide. ACE operates through five business segments: Insurance – North American P&C, Insurance – North American Agriculture, Insurance – Overseas General, Global Reinsurance, and Life. Refer to Note 9 for additional information.
	The interim unaudited consolidated financial statements, which include the accounts of ACE Limited and its subsidiaries (collectively, ACE, we, us, or our), have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and, in the opinion of management, reflect all adjustments (consisting of normally recurring accruals) necessary for a fair statement of the results and financial position for such periods. All significant intercompany accounts and transactions have been eliminated.
	The results of operations and cash flows for any interim period are not necessarily indicative of the results for the full year. These consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in our 2013 Form 10-K.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2014
Business Combinations [Abstract]	'
Acquisitions	'
	Acquisitions
	The Siam Commercial Samaggi Insurance PCL
	On April 28, 2014, we and our local partner acquired 60.9 percent of The Siam Commercial Samaggi Insurance PCL (Samaggi), a general insurance company in Thailand, from Siam Commercial Bank.  In compliance with Thai regulations, we and our local partner will make a mandatory tender offer for the remaining 39.1 percent ownership of Samaggi for the same share purchase price during the second quarter of 2014.  The implied purchase price for 100 percent of the company, at current exchange rates, is approximately $190 million in cash.
	Fianzas Monterrey
	On April 1, 2013, we acquired Fianzas Monterrey, a leading surety lines company in Mexico offering administrative performance bonds primarily to clients in the construction and industrial sectors, for approximately $293 million in cash. This acquisition greatly expanded our global franchise in the surety business and enhanced our existing commercial lines and personal accident insurance business in Mexico.
	The acquisition generated $137 million of goodwill, attributable to expected growth and profitability, none of which is expected to be deductible for income tax purposes, and other intangible assets of $73 million, based on ACE's purchase price allocation. The other intangible assets primarily relate to customer lists. Amortization of other intangible assets is included in Other (income) expense in the consolidated statements of operations. Goodwill and other intangible assets arising from this acquisition are included in the Insurance – Overseas General segment.
	ABA Seguros
	On May 2, 2013, we acquired ABA Seguros, a property and casualty insurer in Mexico that provides automobile, homeowners, and small business coverages for approximately $690 million in cash.
	The acquisition generated $285 million of goodwill, attributable to expected growth and profitability, none of which is expected to be deductible for income tax purposes, and other intangible assets of $140 million based on ACE’s purchase price allocation. The other intangible assets primarily relate to distribution channels. Amortization of other intangible assets is included in Other (income) expense in the consolidated statements of operations. Goodwill and other intangible assets arising from this acquisition are included in the Insurance – Overseas General segment.

Investments

Investments	3 Months Ended
	Mar. 31, 2014
Investments, Debt and Equity Securities [Abstract]	'
Investments	'
	Investments
	a) Fixed maturities
	31-Mar-14	Amortized			Gross			Gross			Fair			OTTI Recognized
		Cost			Unrealized			Unrealized			Value			in AOCI
	(in millions of U.S. dollars)				Appreciation			Depreciation
	Available for sale
	U.S. Treasury and agency	$	2,939		$	68		$	(37	)	$	2,970		$	—
	Foreign	14,155			441			(65		)	14,531			(1		)
	Corporate securities	16,873			883			(71		)	17,685			(6		)
	Mortgage-backed securities	10,916			210			(155		)	10,971			(27		)
	States, municipalities, and political subdivisions	3,399			95			(40		)	3,454			—
		$	48,282		$	1,697		$	(368	)	$	49,611		$	(34	)
	Held to maturity
	U.S. Treasury and agency	$	777		$	17		$	(4	)	$	790		$	—
	Foreign	837			37			—			874			—
	Corporate securities	1,876			89			—			1,965			—
	Mortgage-backed securities	1,265			41			—			1,306			—
	States, municipalities, and political subdivisions	1,132			23			(10		)	1,145			—
		$	5,887		$	207		$	(14	)	$	6,080		$	—
	31-Dec-13	Amortized			Gross			Gross			Fair			OTTI Recognized
		Cost			Unrealized			Unrealized			Value			in AOCI
	(in millions of U.S. dollars)				Appreciation			Depreciation
	Available for sale
	U.S. Treasury and agency	$	2,946		$	62		$	(59	)	$	2,949		$	—
	Foreign	14,336			377			(122		)	14,591			—
	Corporate securities	16,825			777			(132		)	17,470			(6		)
	Mortgage-backed securities	10,937			184			(227		)	10,894			(34		)
	States, municipalities, and political subdivisions	3,362			65			(77		)	3,350			—
		$	48,406		$	1,465		$	(617	)	$	49,254		$	(40	)
	Held to maturity
	U.S. Treasury and agency	$	820		$	16		$	(4	)	$	832		$	—
	Foreign	864			33			—			897			—
	Corporate securities	1,922			83			—			2,005			—
	Mortgage-backed securities	1,341			39			(1		)	1,379			—
	States, municipalities, and political subdivisions	1,151			16			(17		)	1,150			—
		$	6,098		$	187		$	(22	)	$	6,263		$	—
	As discussed in Note 3 c), if a credit loss is indicated on an impaired fixed maturity, an OTTI is considered to have occurred and the portion of the impairment not related to credit losses (non-credit OTTI) is recognized in OCI. Included in the “OTTI Recognized in AOCI” columns above are the cumulative amounts of non-credit OTTI recognized in OCI adjusted for subsequent sales, maturities, and redemptions. OTTI recognized in AOCI does not include the impact of subsequent changes in fair value of the related securities. In periods subsequent to a recognition of OTTI in OCI, changes in the fair value of the related fixed maturities are reflected in Unrealized appreciation (depreciation) in the consolidated statement of shareholders’ equity. For the three months ended March 31, 2014 and 2013, $4 million and $24 million, respectively, of net unrealized appreciation related to such securities is included in OCI. At March 31, 2014 and December 31, 2013, AOCI includes cumulative net unrealized depreciation of $2 million and $4 million, respectively, related to securities remaining in the investment portfolio at those dates for which ACE has recognized a non-credit OTTI.
	Mortgage-backed securities (MBS) issued by U.S. government agencies are combined with all other to be announced mortgage derivatives held (refer to Note 6 a) (iv)) and are included in the category, “Mortgage-backed securities”. Approximately 82 percent and 83 percent, of the total mortgage-backed securities at March 31, 2014 and December 31, 2013, respectively, are represented by investments in U.S. government agency bonds. The remainder of the mortgage exposure consists of collateralized mortgage obligations and non-government mortgage-backed securities, the majority of which provide a planned structure for principal and interest payments and carry a rating of AAA by the major credit rating agencies.
	The following table presents fixed maturities by contractual maturity:
					31-Mar						31-Dec
					2014						2013
	(in millions of U.S. dollars)	Amortized Cost			Fair Value			Amortized Cost			Fair Value
	Available for sale
	Due in 1 year or less	$	2,504		$	2,528		$	2,387		$	2,411
	Due after 1 year through 5 years	14,199			14,713			14,139			14,602
	Due after 5 years through 10 years	15,947			16,460			16,200			16,535
	Due after 10 years	4,716			4,939			4,743			4,812
		37,366			38,640			37,469			38,360
	Mortgage-backed securities	10,916			10,971			10,937			10,894
		$	48,282		$	49,611		$	48,406		$	49,254
	Held to maturity
	Due in 1 year or less	$	539		$	547		$	401		$	405
	Due after 1 year through 5 years	2,419			2,503			2,284			2,363
	Due after 5 years through 10 years	1,304			1,345			1,686			1,723
	Due after 10 years	360			379			386			393
		4,622			4,774			4,757			4,884
	Mortgage-backed securities	1,265			1,306			1,341			1,379
		$	5,887		$	6,080		$	6,098		$	6,263
	Expected maturities could differ from contractual maturities because borrowers may have the right to call or prepay obligations, with or without call or prepayment penalties.
	b) Equity securities
		31-Mar			31-Dec
	(in millions of U.S. dollars)	2014			2013
	Cost	$	845		$	841
Gross unrealized appreciation	64			63
Gross unrealized depreciation	(58		)	(67		)
Fair value	$	851		$	837
c) Net realized gains (losses)
In accordance with guidance related to the recognition and presentation of OTTI, when an impairment related to a fixed maturity has occurred, OTTI is required to be recorded in Net income if management has the intent to sell the security or it is more likely than not that we will be required to sell the security before the recovery of its amortized cost. Further, in cases where we do not intend to sell the security and it is more likely than not that we will not be required to sell the security, ACE must evaluate the security to determine the portion of the impairment, if any, related to credit losses. If a credit loss is indicated, an OTTI is considered to have occurred and any portion of the OTTI related to credit losses must be reflected in Net income while the portion of OTTI related to all other factors is recognized in OCI. For fixed maturities held to maturity, OTTI recognized in OCI is accreted from AOCI to the amortized cost of the fixed maturity prospectively over the remaining term of the securities.
Each quarter, securities in an unrealized loss position (impaired securities), including fixed maturities, securities lending collateral, equity securities, and other investments, are reviewed to identify impaired securities to be specifically evaluated for a potential OTTI.
For all non-fixed maturities, OTTI is evaluated based on the following:
•	the amount of time a security has been in a loss position and the magnitude of the loss position;
•	the period in which cost is expected to be recovered, if at all, based on various criteria including economic conditions and other issuer-specific developments; and
•	ACE’s ability and intent to hold the security to the expected recovery period.
As a general rule, we also consider that equity securities in an unrealized loss position for twelve consecutive months are other than temporarily impaired.
We review each fixed maturity in an unrealized loss position to assess whether the security is a candidate for credit loss. Specifically, we consider credit rating, market price, and issuer-specific financial information, among other factors, to assess the likelihood of collection of all principal and interest as contractually due. Securities for which we determine that credit loss is likely are subjected to further analysis to estimate the credit loss recognized in Net income, if any. In general, credit loss recognized in Net income equals the difference between the security’s amortized cost and the net present value of its projected future cash flows discounted at the effective interest rate implicit in the debt security. All significant assumptions used in determining credit losses are subject to change as market conditions evolve.
Projected cash flows for corporate securities (principally senior unsecured bonds) are driven primarily by assumptions regarding probability of default and also the timing and amount of recoveries associated with defaults. ACE developed projected cash flows for corporate securities using market observable data, issuer-specific information, and credit ratings. We use historical default data by Moody’s Investors Service (Moody’s) rating category to calculate a 1-in-100 year probability of default, which results in a default assumption in excess of the historical mean default rate. Consistent with management's approach, ACE assumed a 32 percent recovery rate (the par value of a defaulted security that will be recovered) across all rating categories rather than using Moody's historical mean recovery rate of 42 percent. We believe that use of a default assumption in excess of the historical mean is conservative in light of current market conditions.
For the three months ended March 31, 2014 and 2013, credit losses recognized in Net income for corporate securities were $4 million and $1 million, respectively.
For mortgage-backed securities, credit impairment is assessed using a cash flow model that estimates the cash flows on the underlying mortgages, using the security-specific collateral and transaction structure. The model estimates cash flows from the underlying mortgage loans and distributes those cash flows to various tranches of securities, considering the transaction structure and any subordination and credit enhancements that exist in that structure. The cash flow model incorporates actual cash flows on the mortgage-backed securities through the current period and then projects the remaining cash flows using a number of assumptions, including default rates, prepayment rates, and loss severity rates (the par value of a defaulted security that will not be recovered) on foreclosed properties.
For the three months ended March 31, 2014 and 2013, there were no credit losses recognized in Net income for mortgage-backed securities.
The following table presents the Net realized gains (losses) and the losses included in Net realized gains (losses) and OCI as a result of conditions which caused us to conclude the decline in fair value of certain investments was “other-than-temporary”:
	Three Months Ended
	31-Mar
(in millions of U.S. dollars)	2014			2013
Fixed maturities:
OTTI on fixed maturities, gross	$	(6	)	$	(1	)
OTTI on fixed maturities recognized in OCI (pre-tax)	1			—
OTTI on fixed maturities, net	(5		)	(1		)
Gross realized gains excluding OTTI	36			62
Gross realized losses excluding OTTI	(20		)	(25		)
Total fixed maturities	11			36
Equity securities:
OTTI on equity securities	(6		)	(1		)
Gross realized gains excluding OTTI	2			2
Gross realized losses excluding OTTI	(1		)	(2		)
Total equity securities	(5		)	(1		)
OTTI on other investments	—			(1		)
Foreign exchange gains (losses)	(9		)	76
Investment and embedded derivative instruments	(25		)	18
Fair value adjustments on insurance derivative	(48		)	328
S&P put options and futures	(19		)	(250		)
Other derivative instruments	(2		)	—
Other	(7		)	—
Net realized gains (losses)	$	(104	)	$	206
The following table presents a roll-forward of pre-tax credit losses related to fixed maturities for which a portion of OTTI was recognized in OCI:
	Three Months Ended
	31-Mar
(in millions of U.S. dollars)	2014			2013
Balance of credit losses related to securities still held – beginning of period	$	37		$	43
Additions where no OTTI was previously recorded	2			—
Additions where an OTTI was previously recorded	2			1
Reductions for securities sold during the period	(6		)	(9		)
Balance of credit losses related to securities still held – end of period	$	35		$	35
d) Gross unrealized loss
At March 31, 2014, there were 4,540 fixed maturities out of a total of 24,991 fixed maturities in an unrealized loss position. The largest single unrealized loss in the fixed maturities was $5 million. There were 58 equity securities out of a total of 186 equity securities in an unrealized loss position. The largest single unrealized loss in the equity securities was $54 million. Fixed maturities in an unrealized loss position at March 31, 2014, comprised both investment grade and below investment grade securities for which fair value declined primarily due to widening credit spreads since the date of purchase. Equity securities in an unrealized loss position at March 31, 2014, included foreign fixed income securities held in a commingled fund structure for which fair value declined primarily due to widening credit spreads since the date of purchase.
The following tables present, for all securities in an unrealized loss position (including securities on loan), the aggregate fair value and gross unrealized loss by length of time the security has continuously been in an unrealized loss position:
	0 – 12 Months						Over 12 Months						Total
31-Mar-14	Fair Value			Gross			Fair Value			Gross			Fair Value			Gross
				Unrealized						Unrealized						Unrealized
(in millions of U.S. dollars)				Loss						Loss						Loss
U.S. Treasury and agency	$	1,609		$	(37	)	$	33		$	(4	)	$	1,642		$	(41	)
Foreign	2,988			(56		)	259			(9		)	3,247			(65		)
Corporate securities	2,940			(58		)	211			(13		)	3,151			(71		)
Mortgage-backed securities	4,367			(130		)	398			(25		)	4,765			(155		)
States, municipalities, and political subdivisions	1,575			(39		)	189			(11		)	1,764			(50		)
Total fixed maturities	13,479			(320		)	1,090			(62		)	14,569			(382		)
Equity securities	496			(58		)	—			—			496			(58		)
Other investments	65			(5		)	—			—			65			(5		)
Total	$	14,040		$	(383	)	$	1,090		$	(62	)	$	15,130		$	(445	)
	0 – 12 Months						Over 12 Months						Total
31-Dec-13	Fair Value			Gross			Fair Value			Gross			Fair Value			Gross
				Unrealized						Unrealized						Unrealized
(in millions of U.S. dollars)				Loss						Loss						Loss
U.S. Treasury and agency	$	1,794		$	(57	)	$	31		$	(6	)	$	1,825		$	(63	)
Foreign	4,621			(114		)	201			(8		)	4,822			(122		)
Corporate securities	3,836			(118		)	194			(14		)	4,030			(132		)
Mortgage-backed securities	5,248			(197		)	384			(31		)	5,632			(228		)
States, municipalities, and political subdivisions	2,164			(90		)	84			(4		)	2,248			(94		)
Total fixed maturities	17,663			(576		)	894			(63		)	18,557			(639		)
Equity securities	498			(67		)	—			—			498			(67		)
Other investments	67			(9		)	—			—			67			(9		)
Total	$	18,228		$	(652	)	$	894		$	(63	)	$	19,122		$	(715	)
e) Restricted assets
ACE is required to maintain assets on deposit with various regulatory authorities to support its insurance and reinsurance operations. These requirements are generally promulgated in the statutory regulations of the individual jurisdictions. The assets on deposit are available to settle insurance and reinsurance liabilities. ACE is also required to restrict assets pledged under repurchase agreements. We also use trust funds in certain large reinsurance transactions where the trust funds are set up for the benefit of the ceding companies and generally take the place of letter of credit (LOC) requirements. We also have investments in segregated portfolios primarily to provide collateral or guarantees for LOC and derivative transactions. Included in restricted assets at March 31, 2014 and December 31, 2013, are investments, primarily fixed maturities, totaling $16.5 billion and $16.3 billion, respectively, and cash of $98 million and $162 million, respectively.
The following table presents the components of restricted assets:
	31-Mar			31-Dec
(in millions of U.S. dollars)	2014			2013
Trust funds	$	11,385		$	11,315
Deposits with non-U.S. regulatory authorities	1,962			1,970
Assets pledged under repurchase agreements	1,452			1,435
Deposits with U.S. regulatory authorities	1,334			1,334
Other pledged assets	420			391
	$	16,553		$	16,445

Fair_value_measurements

Fair value measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair value measurements	'
	Fair value measurements
	a) Fair value hierarchy
	Fair value of financial assets and financial liabilities is estimated based on the framework established in the fair value accounting guidance. The guidance defines fair value as the price to sell an asset or transfer a liability (an exit price) in an orderly transaction between market participants and establishes a three-level valuation hierarchy based on the reliability of the inputs. The fair value hierarchy gives the highest priority to quoted prices in active markets and the lowest priority to unobservable data.
	The three levels of the hierarchy are as follows:
	•	Level 1 – Unadjusted quoted prices for identical assets or liabilities in active markets;
	•	Level 2 – Includes, among other items, inputs other than quoted prices that are observable for the asset or liability such as interest rates and yield curves, quoted prices for similar assets and liabilities in active markets, and quoted prices for identical or similar assets and liabilities in markets that are not active; and
	•	Level 3 – Inputs that are unobservable and reflect management’s judgments about assumptions that market participants would use in pricing an asset or liability.
	We categorize financial instruments within the valuation hierarchy at the balance sheet date based upon the lowest level of inputs that are significant to the fair value measurement. Accordingly, transfers between levels within the valuation hierarchy occur when there are significant changes to the inputs, such as increases or decreases in market activity, changes to the availability of current prices, changes to the transparency to underlying inputs, and whether there are significant variances in quoted prices. Transfers in and/or out of any level are assumed to occur at the end of the period.
	We use pricing services to obtain fair value measurements for the majority of our investment securities. Based on management’s understanding of the methodologies used, these pricing services only produce an estimate of fair value if there is observable market information that would allow them to make a fair value estimate. Based on our understanding of the market inputs used by the pricing services, all applicable investments have been valued in accordance with GAAP. We do not adjust prices obtained from pricing services. The following is a description of the valuation techniques and inputs used to determine fair values for financial instruments carried at fair value, as well as the general classification of such financial instruments pursuant to the valuation hierarchy.
	Fixed maturities
	We use pricing services to estimate fair value measurements for the majority of our fixed maturities. The pricing services use market quotations for fixed maturities that have quoted prices in active markets; such securities are classified within Level 1. For fixed maturities other than U.S. Treasury securities that generally do not trade on a daily basis, the pricing services prepare estimates of fair value measurements using their pricing applications, which include available relevant market information, benchmark curves, benchmarking of like securities, sector groupings, and matrix pricing. Additional valuation factors that can be taken into account are nominal spreads, dollar basis, and liquidity adjustments. The pricing services evaluate each asset class based on relevant market and credit information, perceived market movements, and sector news. The market inputs used in the pricing evaluation, listed in the approximate order of priority include: benchmark yields, reported trades, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, reference data, and industry and economic events. The extent of the use of each input is dependent on the asset class and the market conditions. Given the asset class, the priority of the use of inputs may change, or some market inputs may not be relevant. Additionally, fixed maturities valuation is more subjective when markets are less liquid due to the lack of market based inputs (i.e., stale pricing), which may increase the potential that an investment's estimated fair value is not reflective of the price at which an actual transaction would occur. The overwhelming majority of fixed maturities are classified within Level 2 because the most significant inputs used in the pricing techniques are observable. For a small number of fixed maturities, we obtain a quote from a broker (typically a market maker). Due to the disclaimers on the quotes that indicate that the price is indicative only, we include these fair value estimates in
	Level 3.
	Equity securities
	Equity securities with active markets are classified within Level 1 as fair values are based on quoted market prices. For equity securities in markets which are less active, fair values are based on market valuations and are classified within Level 2. Equity securities for which pricing is unobservable are classified within Level 3.
	Short-term investments
	Short-term investments, which comprise securities due to mature within one year of the date of purchase that are traded in active markets, are classified within Level 1 as fair values are based on quoted market prices. Securities such as commercial paper and discount notes are classified within Level 2 because these securities are typically not actively traded due to their approaching maturity and, as such, their cost approximates fair value. Short-term investments for which pricing is unobservable are classified within Level 3.
	Other investments
	Fair values for the majority of Other investments including investments in partially-owned investment companies, investment funds, and limited partnerships are based on their respective net asset values or equivalent (NAV). The majority of these investments, for which NAV was used as a practical expedient to measure fair value, are classified within Level 3 because either ACE will never have the contractual option to redeem the investments or will not have the contractual option to redeem the investments in the near term. The remainder of such investments is classified within Level 2. Certain of our long-duration contracts are supported by assets that do not qualify for separate account reporting under GAAP. These assets comprise mutual funds classified within Level 1 in the valuation hierarchy on the same basis as other equity securities traded in active markets. Other investments also includes equity securities and fixed maturities held in rabbi trusts maintained by ACE for deferred compensation plans, which are classified within the valuation hierarchy on the same basis as other equity securities and fixed maturities.
	Securities lending collateral
	The underlying assets included in Securities lending collateral in the consolidated balance sheets are fixed maturities which are classified in the valuation hierarchy on the same basis as other fixed maturities. Excluded from the valuation hierarchy is the corresponding liability related to ACE’s obligation to return the collateral plus interest as it is reported at contract value and not fair value in the consolidated balance sheets.
	Investment derivative instruments
	Actively traded investment derivative instruments, including futures, options, and forward contracts are classified within Level 1 as fair values are based on quoted market prices. The fair value of cross-currency swaps are based on market valuations and are classified within Level 2. Investment derivative instruments are recorded in either Other assets or Accounts payable, accrued expenses, and other liabilities in the consolidated balance sheets.
	Other derivative instruments
	We maintain positions in other derivative instruments including exchange-traded equity futures contracts and option contracts designed to limit exposure to a severe equity market decline, which would cause an increase in expected claims and, therefore, reserves for our guaranteed minimum death benefits (GMDB) and guaranteed living benefits (GLB) reinsurance business. Our position in exchange-traded equity futures contracts is classified within Level 1. The fair value of the majority of the remaining positions in other derivative instruments is based on significant observable inputs including equity security and interest rate indices. Accordingly, these are classified within Level 2. Other derivative instruments are recorded in either Other assets or Accounts payable, accrued expenses, and other liabilities in the consolidated balance sheets.
	Separate account assets
	Separate account assets represent segregated funds where investment risks are borne by the customers, except to the extent of certain guarantees made by ACE. Separate account assets comprise mutual funds classified in the valuation hierarchy on the same basis as other equity securities traded in active markets and are classified within Level 1. Separate account assets also include fixed maturities classified within Level 2 because the most significant inputs used in the pricing techniques are observable. Excluded from the valuation hierarchy are the corresponding liabilities as they are reported at contract value and not fair value in the consolidated balance sheets. Separate account assets are recorded in Other assets in the consolidated balance sheets.
	Guaranteed living benefits
	The GLB arises from life reinsurance programs covering living benefit guarantees whereby we assume the risk of guaranteed minimum income benefits (GMIB) and guaranteed minimum accumulation benefits (GMAB) associated with variable annuity contracts. GLB’s are recorded in Accounts payable, accrued expenses, and other liabilities and Future policy benefits in the consolidated balance sheets. For GLB reinsurance, ACE estimates fair value using an internal valuation model which includes current market information and estimates of policyholder behavior. All of the treaties contain claim limits, which are factored into the valuation model. The fair value depends on a number of inputs, including changes in interest rates, changes in equity markets, credit risk, current account value, changes in market volatility, expected annuitization rates, changes in policyholder behavior, and changes in policyholder mortality.
	The most significant policyholder behavior assumptions include lapse rates and the GMIB annuitization rates. Assumptions regarding lapse rates and GMIB annuitization rates differ by treaty, but the underlying methodologies to determine rates applied to each treaty are comparable. The assumptions regarding lapse and GMIB annuitization rates determined for each treaty are based on a dynamic calculation that uses several underlying factors.
	A lapse rate is the percentage of in-force policies surrendered in a given calendar year. All else equal, as lapse rates increase, ultimate claim payments will decrease.
	GMIB annuitization rate is the percentage of policies for which the policyholder will elect to annuitize using the guaranteed benefit provided under the GMIB. All else equal, as GMIB annuitization rates increase, ultimate claim payments will increase, subject to treaty claim limits.
	The effect of changes in key market factors on assumed lapse and annuitization rates reflect emerging trends using data available from cedants. For treaties with limited experience, rates are established in line with data received from other ceding companies adjusted, as appropriate, with industry estimates. The model and related assumptions are continuously re-evaluated by management and enhanced, as appropriate, based upon additional experience obtained related to policyholder behavior and availability of more information, such as market conditions, market participant assumptions, and demographics of in-force annuities. During the three months ended March 31, 2014, no material changes were made to actuarial or behavioral assumptions. We made minor technical refinements to the model with an unfavorable net income impact of approximately $3 million. For detailed information on our lapse and annuitization rate assumptions, refer to Note 4 to the Consolidated Financial Statements of our 2013 Form 10-K.
	We view the variable annuity reinsurance business as having a similar risk profile to that of catastrophe reinsurance, with the probability of a cumulative long-term economic net loss relatively small at the time of pricing. However, adverse changes in market factors and policyholder behavior will have an adverse impact on net income, which may be material. Because of the significant use of unobservable inputs including policyholder behavior, GLB reinsurance is classified within Level 3.
	The following tables present, by valuation hierarchy, the financial instruments measured at fair value on a recurring basis:
	31-Mar-14	Level 1				Level 2				Level 3				Total
	(in millions of U.S. dollars)
	Assets:
	Fixed maturities available for sale
	U.S. Treasury and agency	$	1,709			$	1,261			$	—			$	2,970
	Foreign	233				14,272				26				14,531
	Corporate securities	—				17,534				151				17,685
	Mortgage-backed securities	—				10,963				8				10,971
	States, municipalities, and political subdivisions	—				3,454				—				3,454
		1,942				47,484				185				49,611
	Equity securities	380				469				2				851
	Short-term investments	1,590				936				—				2,526
	Other investments	314				245				2,611				3,170
	Securities lending collateral	—				1,550				—				1,550
	Investment derivative instruments	8				—				—				8
	Other derivative instruments	7				—				—				7
	Separate account assets	1,193				83				—				1,276
	Total assets measured at fair value	$	5,434			$	50,767			$	2,798			$	58,999
	Liabilities:
	Investment derivative instruments	$	6			$	—			$	—			$	6
	Other derivative instruments	12				2				—				14
	GLB(1)	—				—				243				243
	Total liabilities measured at fair value	$	18			$	2			$	243			$	263
	(1)	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.
	December 31, 2013	Level 1				Level 2				Level 3				Total
	(in millions of U.S. dollars)
	Assets:
	Fixed maturities available for sale
	U.S. Treasury and agency	$	1,626			$	1,323			$	—			$	2,949
Foreign	223				14,324				44				14,591
Corporate securities	—				17,304				166				17,470
Mortgage-backed securities	—				10,886				8				10,894
States, municipalities, and political subdivisions	—				3,350				—				3,350
	1,849				47,187				218				49,254
Equity securities	373				460				4				837
Short-term investments	953				803				7				1,763
Other investments	305				231				2,440				2,976
Securities lending collateral	—				1,632				—				1,632
Investment derivative instruments	19				—				—				19
Other derivative instruments	—				6				—				6
Separate account assets	1,145				81				—				1,226
Total assets measured at fair value	$	4,644			$	50,400			$	2,669			$	57,713
Liabilities:
Investment derivative instruments	$	6			$	—			$	—			$	6
Other derivative instruments	60				2				—				62
GLB(1)	—				—				193				193
Total liabilities measured at fair value	$	66			$	2			$	193			$	261
(1)	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.
During the three months ended March 31, 2014, there were no transfers from Level 1 to Level 2 or Level 2 to Level 1.
There were $13 million of transfers from Level 1 to Level 2 and no transfers from Level 2 to Level 1 during the three months ended March 31, 2013.
Fair value of alternative investments
Included in Other investments in the fair value hierarchy at March 31, 2014 and December 31, 2013 are investment funds, limited partnerships, and partially-owned investment companies measured at fair value using NAV as a practical expedient. At March 31, 2014 and December 31, 2013, there were no probable or pending sales related to any of the investments measured at fair value using NAV.
The following table presents, by investment category, the expected liquidation period, fair value, and maximum future funding commitments of alternative investments:
							31-Mar								31-Dec
	Expected						2014								2013
	Liquidation
(in millions of U.S. dollars)	Period of Underlying Assets		Fair				Maximum				Fair				Maximum
			Value				Future Funding				Value				Future Funding
							Commitments								Commitments
Financial	5 to 9 Years		$	271			$	122			$	256			$	129
Real estate	3 to 9 Years		319				63				322				92
Distressed	6 to 9 Years		243				169				180				230
Mezzanine	6 to 9 Years		290				235				276				252
Traditional	3 to 8 Years		882				414				813				456
Vintage	1 to 3 Years		12				—				13				—
Investment funds	Not Applicable		440				—				428				—
			$	2,457			$	1,003			$	2,288			$	1,159
Included in all categories in the above table except for Investment funds are investments for which ACE will never have the contractual option to redeem but receives distributions based on the liquidation of the underlying assets. Further, for all categories except for Investment funds, ACE does not have the ability to sell or transfer the investments without the consent from the general partner of individual funds.
Investment Category		Consists of investments in private equity funds:
Financial		targeting financial services companies such as financial institutions and insurance services worldwide
Real estate		targeting global distress opportunities, value added U.S. properties, and global mezzanine debt securities in the commercial real estate market
Distressed		targeting distressed debt/credit and equity opportunities in the U.S
Mezzanine		targeting private mezzanine debt of large-cap and mid-cap companies in the U.S. and worldwide
Traditional		employing traditional private equity investment strategies such as buyout and venture with different geographical focuses including Brazil, Asia, Europe, and the U.S.
Vintage		made before 2002 and where the funds’ commitment periods had already expired
Investment funds
ACE’s investment funds employ various investment strategies such as long/short equity and arbitrage/distressed. Included in this category are investments for which ACE has the option to redeem at agreed upon value as described in each investment fund’s subscription agreement. Depending on the terms of the various subscription agreements, investment fund investments may be redeemed monthly, quarterly, semi-annually, or annually. If ACE wishes to redeem an investment fund investment, it must first determine if the investment fund is still in a lock-up period (a time when ACE cannot redeem its investment so that the investment fund manager has time to build the portfolio). If the investment fund is no longer in its lock-up period, ACE must then notify the investment fund manager of its intention to redeem by the notification date prescribed by the subscription agreement. Subsequent to notification, the investment fund can redeem ACE’s investment within several months of the notification. Notice periods for redemption of the investment funds range between 5 and 120 days. ACE can redeem its investment funds without consent from the investment fund managers.
Level 3 financial instruments
The fair values of assets and liabilities measured at fair value using significant unobservable inputs (Level 3) consist of various inputs and assumptions that management makes when determining fair value. Management analyzes changes in fair value measurements classified within Level 3 by comparing pricing and returns of our investments to benchmarks, including month-over-month movements, investment credit spreads, interest rate movements, and credit quality of securities.
The following table presents the significant unobservable inputs used in the Level 3 liability valuations. Excluded from the table below are inputs used to determine the fair value of Level 3 assets which are based on single broker quotes or net asset value and contain no quantitative unobservable inputs developed by management.
(in millions of U.S. dollars, except for percentages)	Fair Value								Valuation		Significant		Ranges
	31-Mar-14				31-Dec-13				Technique		Unobservable Inputs
GLB(1)	$	243			$	193			Actuarial model		Lapse rate		1% – 30%
											Annuitization rate		0% – 55%
(1)	Discussion of the most significant inputs used in the fair value measurement of GLB and the sensitivity of those assumptions is included within Note 4 a) Guaranteed living benefits.
The following tables present a reconciliation of the beginning and ending balances of financial instruments measured at fair value using significant unobservable inputs (Level 3):
	Assets																						Liabilities
Three Months Ended	Available-for-Sale Debt Securities												Equity				Short-term investments			Other			GLB(1)
31-Mar-14	Foreign				Corporate				MBS				securities							investments
(in millions of U.S. dollars)					securities
Balance–Beginning of Period	$	44			$	166			$	8			$	4			$	7		$	2,440		$	193
Transfers into Level 3	—				4				—				—				—			—			—
Transfers out of Level 3	(18		)		(22		)		—				(2		)		(7		)	—			—
Change in Net Unrealized Gains (Losses) included in OCI	(1		)		—				—				1				—			41			—
Net Realized Gains/Losses	—				—				—				—				—			—			50
Purchases	2				15				—				1				—			200			—
Sales	(1		)		(6		)		—				(2		)		—			(1		)	—
Settlements	—				(6		)		—				—				—			(69		)	—
Balance–End of Period	$	26			$	151			$	8			$	2			$	—		$	2,611		$	243
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—			$	—			$	—			$	—			$	—		$	—		$	50
(1)	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.
	Assets																			Liabilities
	Available-for-Sale Debt Securities												Equity				Other			GLB(1)
Three Months Ended	Foreign				Corporate				MBS				securities				investments
31-Mar-13					securities
(in millions of U.S. dollars)
Balance–Beginning of Period	$	60			$	102			$	13			$	3			$	2,252		$	1,119
Transfers into Level 3	3				12				—				—				—			—
Transfers out of Level 3	(27		)		(2		)		—				(1		)		—			—
Change in Net Unrealized Gains (Losses) included in OCI	—				1				—				—				22			—
Net Realized Gains/Losses	1				—				—				—				(1		)	(366		)
Purchases	—				10				—				—				136			—
Sales	(1		)		—				—				—				(9		)	—
Settlements	(1		)		(5		)		—				—				(72		)	—
Balance–End of Period	$	35			$	118			$	13			$	2			$	2,328		$	753
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—			$	—			$	—			$	—			$	(1	)	$	(366	)
(1)	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. The liability for GLB reinsurance was $1.0 billion at March 31, 2013, and $1.4 billion at December 31, 2012, which includes a fair value derivative adjustment of $753 million and $1.1 billion, respectively.
b) Financial instruments disclosed, but not measured, at fair value
ACE uses various financial instruments in the normal course of its business. Our insurance contracts are excluded from fair value of financial instruments accounting guidance, and therefore, are not included in the amounts discussed below.
The carrying values of cash, other assets, other liabilities, and other financial instruments not included below approximated their fair values.
Investments in partially-owned insurance companies
Fair values for investments in partially-owned insurance companies are based on ACE’s share of the net assets based on the financial statements provided by those companies.
Short- and long-term debt and trust preferred securities
Where practical, fair values for short-term debt, long-term debt, and trust preferred securities are estimated using discounted cash flow calculations based principally on observable inputs including incremental borrowing rates, which reflect ACE’s credit rating, for similar types of borrowings with maturities consistent with those remaining for the debt being valued.
The following tables present fair value, by valuation hierarchy, and carrying value of the financial instruments not measured at fair value:
31-Mar-14	Fair Value																Carrying Value
(in millions of U.S. dollars)	Level 1				Level 2				Level 3				Total
Assets:
Fixed maturities held to maturity
U.S. Treasury and agency	$	595			$	195			$	—			$	790			$	777
Foreign	—				874				—				874				837
Corporate securities	—				1,949				16				1,965				1,876
Mortgage-backed securities	—				1,306				—				1,306				1,265
States, municipalities, and political subdivisions	—				1,145				—				1,145				1,132
	595				5,469				16				6,080				5,887
Partially-owned insurance companies	—				—				466				466				466
Total assets	$	595			$	5,469			$	482			$	6,546			$	6,353
Liabilities:
Short-term debt	$	—			$	1,907			$	—			$	1,907			$	1,901
Long-term debt	—				4,139				—				4,139				3,808
Trust preferred securities	—				452				—				452				309
Total liabilities	$	—			$	6,498			$	—			$	6,498			$	6,018
31-Dec-13	Fair Value																Carrying Value
(in millions of U.S. dollars)	Level 1				Level 2				Level 3				Total
Assets:
Fixed maturities held to maturity
U.S. Treasury and agency	$	596			$	236			$	—			$	832			$	820
Foreign	—				897				—				897				864
Corporate securities	—				1,990				15				2,005				1,922
Mortgage-backed securities	—				1,379				—				1,379				1,341
States, municipalities, and political subdivisions	—				1,150				—				1,150				1,151
	596				5,652				15				6,263				6,098
Partially-owned insurance companies	—				—				470				470				470
Total assets	$	596			$	5,652			$	485			$	6,733			$	6,568
Liabilities:
Short-term debt	$	—			$	1,913			$	—			$	1,913			$	1,901
Long-term debt	—				4,088				—				4,088				3,807
Trust preferred securities	—				438				—				438				309
Total liabilities	$	—			$	6,439			$	—			$	6,439			$	6,017

Assumed_life_reinsurance_progr

Assumed life reinsurance programs involving minimum benefit guarantees under annuity contracts	3 Months Ended
	Mar. 31, 2014
Reinsurance Disclosures [Abstract]	'
Assumed life reinsurance programs involving minimum benefit guarantees under annuity contracts	'
	Assumed life reinsurance programs involving minimum benefit guarantees under annuity contracts
	The following table presents income and expenses relating to GMDB and GLB reinsurance. GLBs include GMIBs as well as some GMABs originating in Japan.
			Three Months Ended
			31-Mar
	(in millions of U.S. dollars)		2014			2013
	GMDB
	Net premiums earned		$	19		$	20
	Policy benefits and other reserve adjustments		$	15		$	19
	GLB
	Net premiums earned		$	36		$	39
	Policy benefits and other reserve adjustments		9			9
	Net realized gains (losses)		(50		)	369
	Gain (loss) recognized in income		$	(23	)	$	399
	Net cash received		$	33		$	32
	Net (increase) decrease in liability		$	(56	)	$	367
	At March 31, 2014, reported liabilities for GMDB and GLB reinsurance were $104 million and $483 million, respectively, compared with $100 million and $427 million, respectively, at December 31, 2013. The reported liability for GLB reinsurance of $483 million at March 31, 2014, and $427 million at December 31, 2013, includes a fair value derivative adjustment of $243 million and $193 million, respectively. Included in Net realized gains (losses) in the table above are gains (losses) related to foreign exchange and other fair value derivative adjustments. Reported liabilities for both GMDB and GLB reinsurance are determined using internal valuation models. Such valuations require considerable judgment and are subject to significant uncertainty. The valuation of these products is subject to fluctuations arising from, among other factors, changes in interest rates, changes in equity markets, changes in credit markets, changes in the allocation of the investments underlying annuitants’ account values, and assumptions regarding future policyholder behavior. These models and the related assumptions are continually reviewed by management and enhanced, as appropriate, based upon improvements in modeling assumptions and availability of more information, such as market conditions and demographics of in-force annuities.
	Variable Annuity Net Amount at Risk
	(i) Reinsurance covering the GMDB risk only
	At March 31, 2014 and December 31, 2013, the net amount at risk from reinsurance programs covering the GMDB risk only was $645 million and $586 million, respectively.
	For reinsurance programs covering the GMDB risk only, the net amount at risk is defined as the present value of future claim payments under the following assumptions:
	•	policy account values and guaranteed values are fixed at the valuation date (March 31, 2014 and December 31, 2013, respectively);
	•	there are no lapses or withdrawals;
	•	mortality according to 100 percent of the Annuity 2000 mortality table;
	•	future claims are discounted in line with the discounting assumption used in the calculation of the benefit reserve averaging between 1.5 percent and 2.5 percent; and
	•	reinsurance coverage ends at the earlier of the maturity of the underlying variable annuity policy or the reinsurance treaty.
	The total claim amount payable on reinsurance programs covering the GMDB risk only, if all the cedants’ policyholders were to die immediately at March 31, 2014 was approximately $666 million. This takes into account all applicable reinsurance treaty claim limits.
	(ii) Reinsurance covering the GLB risk only
	At March 31, 2014 and December 31, 2013, the net amount at risk from reinsurance programs covering the GLB risk only was $163 million and $136 million, respectively.
	For reinsurance programs covering the GLB risk only, the net amount at risk is defined as the present value of future claim payments under the following assumptions:
	•	policy account values and guaranteed values are fixed at the valuation date (March 31, 2014 and December 31, 2013, respectively);
	•	there are no deaths, lapses, or withdrawals;
	•	policyholders annuitize at a frequency most disadvantageous to ACE (in other words, annuitization at a level that maximizes claims taking into account the treaty limits) under the terms of the reinsurance contracts;
	•	for annuitizing policyholders, the GMIB claim is calculated using interest rates in line with those used in calculating the reserve;
	•	future claims are discounted in line with the discounting assumption used in the calculation of the benefit reserve averaging between 3.5 percent and 4.5 percent; and
	•	reinsurance coverage ends at the earlier of the maturity of the underlying variable annuity policy or the reinsurance treaty.
	(iii) Reinsurance covering both the GMDB and GLB risks on the same underlying policyholders
	At both March 31, 2014 and December 31, 2013, the GMDB net amount at risk from reinsurance programs covering both the GMDB and GLB risks on the same underlying policyholders was $73 million.
	At March 31, 2014 and December 31, 2013, the GLB net amount at risk from reinsurance programs covering both the GMDB and GLB risks on the same underlying policyholders was $158 million and $141 million, respectively.
	These net amounts at risk reflect the interaction between the two types of benefits on any single policyholder (eliminating double-counting), and therefore the net amounts at risk should be considered additive.
	For reinsurance programs covering both the GMDB and GLB risks on the same underlying policyholders, the net amount at risk is defined as the present value of future claim payments under the following assumptions:
	•	policy account values and guaranteed values are fixed at the valuation date (March 31, 2014 and December 31, 2013, respectively);
	•	there are no lapses, or withdrawals;
	•	mortality according to 100 percent of the Annuity 2000 mortality table;
	•	policyholders annuitize at a frequency most disadvantageous to ACE (in other words, annuitization at a level that maximizes claims taking into account the treaty limits) under the terms of the reinsurance contracts;
	•	for annuitizing policyholders, the GMIB claim is calculated using interest rates in line with those used in calculating the reserve;
	•	future claims are discounted in line with the discounting assumption used in the calculation of the benefit reserve averaging between 3.0 percent and 4.0 percent; and
	•	reinsurance coverage ends at the earlier of the maturity of the underlying variable annuity policy or the reinsurance treaty.
	The total claim amount payable on reinsurance programs covering both the GMDB and GLB risks on the same underlying policyholders, if all of the cedants’ policyholders were to die immediately at March 31, 2014 was approximately $93 million. This takes into account all applicable reinsurance treaty claim limits. Although there would be an increase in death claims resulting from 100 percent immediate mortality of all policyholders, the GLB claims would be zero.
	The average attained age of all policyholders under sections i), ii), and iii) above, weighted by the guaranteed value of each reinsured policy, is approximately 68 years.

Commitments_contingencies_and_

Commitments, contingencies, and guarantees	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments, contingencies, and guarantees	'
	Commitments, contingencies, and guarantees
	a) Derivative instruments
	Derivative instruments employed
	ACE maintains positions in derivative instruments such as futures, options, swaps, and foreign currency forward contracts for which the primary purposes are to manage duration and foreign currency exposure, yield enhancement, or to obtain an exposure to a particular financial market. ACE also maintains positions in convertible bond investments that contain embedded derivatives. These are the most numerous and frequent derivative transactions.
	In addition, ACE from time to time purchases to be announced mortgage-backed securities (TBAs) as part of its investing activities.
	Under reinsurance programs covering GLBs, ACE assumes the risk of GLBs, including GMIB and GMAB, associated with variable annuity contracts. The GMIB risk is triggered if, at the time the contract holder elects to convert the accumulated account value to a periodic payment stream (annuitize), the accumulated account value is not sufficient to provide a guaranteed minimum level of monthly income. The GMAB risk is triggered if, at contract maturity, the contract holder’s account value is less than a guaranteed minimum value. The GLB reinsurance product meets the definition of a derivative instrument. Benefit reserves in respect of GLBs are classified as Future policy benefits (FPB) while the fair value derivative adjustment is classified within Accounts payable, accrued expenses, and other liabilities (AP). ACE also maintains positions in exchange-traded equity futures contracts and options on equity market indices to limit equity exposure in the GMDB and GLB blocks of business.
	In relation to certain debt issuances, ACE from time to time enters into interest rate swap transactions for the purpose of either fixing or reducing borrowing costs. Although the use of these interest rate swaps has the economic effect of fixing or reducing borrowing costs on a net basis, gross interest expense on the related debt issuances is included in Interest expense while the settlements related to the interest rate swaps are reflected in Net realized gains (losses) in the consolidated statements of operations. At March 31, 2014, ACE had no in-force interest rate swaps.
	All derivative instruments are carried at fair value with changes in fair value recorded in Net realized gains (losses) in the consolidated statements of operations. None of the derivative instruments are designated as hedges for accounting purposes.
	The following table presents the balance sheet locations, fair values of derivative instruments in an asset or (liability) position, and notional values/payment provisions of our derivative instruments:
								31-Mar-14							31-Dec-13
		Consolidated		Fair Value							Notional		Fair Value					Notional
		Balance Sheet									Value/							Value/
		Location(1)									Payment							Payment
	(in millions of U.S. dollars)			Derivative Asset				Derivative (Liability)			Provision		Derivative Asset		Derivative (Liability)			Provision
	Investment and embedded derivative instruments
	Foreign currency forward contracts	OA / (AP)		$	2			$	(4	)	$	1,469	$	3	$	(4	)	$	1,202
	Cross-currency swaps	OA / (AP)		—				—			50		—		—			50
	Futures contracts on money market instruments	OA / (AP)		4				—			3,910		3		—			3,910
	Futures contracts on notes and bonds	OA / (AP)		2				(2		)	903		13		(2		)	871
	Convertible bonds	FM AFS		319				—			272		302		—			254
				$	327			$	(6	)	$	6,604	$	321	$	(6	)	$	6,287
	Other derivative instruments
	Futures contracts on equities(2)	OA / (AP)		$	—			$	(12	)	$	1,453	$	—	$	(60	)	$	1,692
	Options on equity market indices(2)	OA / (AP)		—				—			250		6		—			250
	Other	OA / (AP)		7				(2		)	64		—		(2		)	8
				$	7			$	(14	)	$	1,767	$	6	$	(62	)	$	1,950
	GLB(3)	(AP) / (FPB)		$	—			$	(483	)	$	321	$	—	$	(427	)	$	277
	(1)	Other assets (OA), Fixed maturities available for sale (FM AFS)
	(2)	Related to GMDB and GLB blocks of business.
	(3)	Includes both future policy benefits reserves and fair value derivative adjustment. Refer to Note 5 for additional information. Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.
	At March 31, 2014 and December 31, 2013, derivative liabilities of $10 million and $41 million, respectively, included in the table above were subject to a master netting agreement.  The remaining derivatives included in the table above were not subject to a master netting agreement.
	At both March 31, 2014 and December 31, 2013, our repurchase obligations of $1,401 million were fully collateralized.  At March 31, 2014 and December 31, 2013, our securities lending payable was $1,551 million and $1,633 million, respectively, and our securities lending collateral was $1,550 million and $1,632 million, respectively.  The securities lending collateral can only be accessed in the event that the institution borrowing the securities is in default under the lending agreement.  An indemnification agreement with the lending agent protects us in the event a borrower becomes insolvent or fails to return any of the securities on loan.  In contrast to securities lending programs, the use of cash received is not restricted for the repurchase obligations.
	The following table presents net realized gains (losses) related to derivative instrument activity in the consolidated statements of operations:
		Three Months Ended
		31-Mar
	(in millions of U.S. dollars)	2014				2013
	Investment and embedded derivative instruments
	Foreign currency forward contracts	$	(3	)		$	5
	All other futures contracts and options	(22		)		7
	Convertible bonds	—				6
	Total investment and embedded derivative instruments	$	(25	)		$	18
	GLB and other derivative instruments
	GLB(1)	$	(48	)		$	328
	Futures contracts on equities(2)	(17		)		(237		)
	Options on equity market indices(2)	(2		)		(13		)
	Other	(2		)		—
	Total GLB and other derivative instruments	$	(69	)		$	78
		$	(94	)		$	96
	(1)	Excludes foreign exchange gains (losses) related to GLB.
	(2)	Related to GMDB and GLB blocks of business.
	Derivative instrument objectives
	(i) Foreign currency exposure management
	A foreign currency forward contract (forward) is an agreement between participants to exchange specific foreign currencies at a future date. ACE uses forwards to minimize the effect of fluctuating foreign currencies.
	(ii) Duration management and market exposure
	Futures
	Futures contracts give the holder the right and obligation to participate in market movements, determined by the index or underlying security on which the futures contract is based. Settlement is made daily in cash by an amount equal to the change in value of the futures contract times a multiplier that scales the size of the contract. Exchange-traded futures contracts on money market instruments, notes and bonds are used in fixed maturity portfolios to more efficiently manage duration, as substitutes for ownership of the money market instruments, bonds and notes without significantly increasing the risk in the portfolio. Investments in futures contracts may be made only to the extent that there are assets under management not otherwise committed.
	Exchange-traded equity futures contracts are used to limit exposure to a severe equity market decline, which would cause an increase in expected claims and therefore, reserves for GMDB and GLB reinsurance business.
	Options
	An option contract conveys to the holder the right, but not the obligation, to purchase or sell a specified amount or value of an underlying security at a fixed price. Option contracts are used in the investment portfolio as protection against unexpected shifts in interest rates, which would affect the duration of the fixed maturity portfolio. By using options in the portfolio, the overall interest rate sensitivity of the portfolio can be reduced. Option contracts may also be used as an alternative to futures contracts in the synthetic strategy as described above.
	Another use for option contracts is to limit exposure to a severe equity market decline, which would cause an increase in expected claims and therefore, reserves for GMDB and GLB reinsurance business.
	The price of an option is influenced by the underlying security, expected volatility, time to expiration, and supply and demand.
	The credit risk associated with the above derivative financial instruments relates to the potential for non-performance by counterparties. Although non-performance is not anticipated, in order to minimize the risk of loss, management monitors the creditworthiness of its counterparties and obtains collateral. The performance of exchange-traded instruments is guaranteed by the exchange on which they trade. For non-exchange-traded instruments, the counterparties are principally banks which must meet certain criteria according to our investment guidelines.
	Cross-currency swaps
Cross-currency swaps are agreements under which two counterparties exchange interest payments and principal denominated in different currencies at a future date.  We use cross-currency swaps to reduce the foreign currency and interest rate risk by converting cash flows back into local currency.  We invest in foreign currency denominated investments to improve credit diversification and also to obtain better duration matching to our liabilities that is limited in the local currency market.
Other
Included within Other are derivatives intended to reduce potential losses which may arise from certain exposures in our insurance business.  The economic benefit provided by these derivatives is similar to purchased reinsurance.  For example, from time to time ACE may enter into crop derivative contracts to protect underwriting results in the event of a significant decline in commodity prices.  Also included within Other are certain life insurance products that meet the definition of a derivative instrument for accounting purposes.
(iii) Convertible security investments
A convertible bond is a debt instrument that can be converted into a predetermined amount of the issuer’s equity at certain times prior to the bond’s maturity. The convertible option is an embedded derivative within the fixed maturity host instruments which are classified in the investment portfolio as available for sale. ACE purchases convertible bonds for their total return and not specifically for the conversion feature.
(iv) TBA
By acquiring TBAs, we make a commitment to purchase a future issuance of mortgage-backed securities. For the period between purchase of the TBAs and issuance of the underlying security, we account for our position as a derivative in the consolidated financial statements. ACE purchases TBAs both for their total return and for the flexibility they provide related to our mortgage-backed security strategy.
(v) GLB
Under the GLB program, as the assuming entity, ACE is obligated to provide coverage until the expiration or maturity of the underlying deferred annuity contracts or the expiry of the reinsurance treaty. Premiums received under the reinsurance treaties are classified as premium. Expected losses allocated to premiums received are classified as Future policy benefits and valued similar to GMDB reinsurance. Other changes in fair value, principally arising from changes in expected losses allocated to expected future premiums, are classified as Net realized gains (losses). Fair value represents management’s estimate of exit price and thus, includes a risk margin. We may recognize a realized loss for other changes in fair value due to adverse changes in the capital markets (e.g., declining interest rates and/or declining equity markets) and changes in actual or estimated future policyholder behavior (e.g., increased annuitization or decreased lapse rates) although we expect the business to be profitable. We believe this presentation provides the most meaningful disclosure of changes in the underlying risk within the GLB reinsurance programs for a given reporting period.
b) Other investments
At March 31, 2014, included in Other investments in the consolidated balance sheet are investments in limited partnerships and partially-owned investment companies with a carrying value of $2.0 billion. In connection with these investments, we have commitments that may require funding of up to $1.0 billion over the next several years.
c) Taxation
As of March 31, 2014, $26 million of unrecognized tax benefits remains outstanding. It is reasonably possible that over the next twelve months, the amount of unrecognized tax benefits may change resulting from the re-evaluation of unrecognized tax benefits arising from examinations of taxing authorities. With few exceptions, ACE is no longer subject to state and local or non-U.S. income tax examinations for years before 2005.
d) Legal proceedings
Our insurance subsidiaries are subject to claims litigation involving disputed interpretations of policy coverages and, in some jurisdictions, direct actions by allegedly-injured persons seeking damages from policyholders. These lawsuits, involving claims on policies issued by our subsidiaries which are typical to the insurance industry in general and in the normal course of business, are considered in our loss and loss expense reserves. In addition to claims litigation, we are subject to lawsuits and regulatory actions in the normal course of business that do not arise from or directly relate to claims on insurance policies. This category of business litigation typically involves, among other things, allegations of underwriting errors or misconduct, employment claims, regulatory activity, or disputes arising from our business ventures. In the opinion of management, our ultimate liability for these matters could be, but we believe is not likely to be, material to our consolidated financial condition and results of operations.

Shareholders_equity

Shareholders' equity	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
Shareholders' equity	'
	Shareholders’ equity
	All of ACE’s Common Shares are authorized under Swiss corporate law. Though the par value of Common Shares is stated in Swiss francs, ACE continues to use U.S. dollars as its reporting currency for preparing consolidated financial statements. Under Swiss corporate law, dividends, including distributions through a reduction in par value (par value reduction) or from legal reserves, must be stated in Swiss francs though dividend payments are made by ACE in U.S. dollars. At our May 2012 and May 2013 annual general meetings, our shareholders approved a dividend for the following year, respectively, payable in four quarterly installments after the annual general meetings in the form of a distribution by way of a par value reduction. At the January 10, 2014 Extraordinary General Meeting, our shareholders approved a resolution to increase our quarterly dividend from $0.51 per share to $0.63 per share for the final two quarterly installments (made on January 31, 2014 and April 17, 2014) that had been earlier approved at our 2013 annual general meeting. The $0.12 per share increase for each installment was distributed from capital contribution reserves (Additional paid-in capital), a subaccount of legal reserves, and transferred to free reserves (Retained earnings) for payment, while the existing $0.51 per share was distributed by way of a par value reduction.
	For the three months ended March 31, 2014, dividends per Common Share amounted to CHF 0.65 ($0.75), of which CHF 0.45 ($0.51) were distributed by way of a par value reduction and CHF 0.20 ($0.24) were distributed from capital contribution reserves. Par value reductions have been reflected as such through Common Shares in the consolidated statements of shareholders' equity and had the effect of reducing par value per Common Share to CHF 26.59 at March 31, 2014.
	Common Shares in treasury are used principally for issuance upon the exercise of employee stock options, grants of restricted stock, and purchases under the Employee Stock Purchase Plan (ESPP). At March 31, 2014, 4,857,768 Common Shares remain in treasury after net shares redeemed under employee share-based compensation plans.
	ACE Limited securities repurchase authorization
	For the three months ended March 31, 2014, ACE repurchased 3,487,882 Common Shares for a cost of $332 million in a series of open market transactions under the November 2013 Board authorization of a share repurchase program of up to $2.0 billion of ACE's Common Shares through December 31, 2014. At March 31, 2014, $1.61 billion in share repurchase authorization remained through December 31, 2014 pursuant to the Board authorization. For the period April 1, 2014 through May 1, 2014, ACE repurchased 531,000 Common Shares for a total of $53 million in a series of open market transactions. At May 1, 2014, $1.56 billion in share repurchase authorization remained through December 31, 2014.

Sharebased_compensation

Share-based compensation	3 Months Ended
	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Share-based compensation	'
	Share-based compensation
	The ACE Limited 2004 Long-Term Incentive Plan (the 2004 LTIP) permits grants of both incentive and non-qualified stock options principally at an option price per share equal to the grant date fair value of ACE’s Common Shares. Stock options are generally granted with a 3-year vesting period and a 10-year term. Stock options typically vest in equal annual installments over the vesting period, which is also the requisite service period. On February 27, 2014, ACE granted 1,779,074 stock options with a weighted-average grant date fair value of $18.00 each. The fair value of the options issued is estimated on the date of grant using the Black-Scholes option pricing model.
	The 2004 LTIP also permits grants of restricted stock and restricted stock units. ACE generally grants restricted stock and restricted stock units with a 4-year vesting period, based on a graded vesting schedule. The restricted stock is granted at market close price on the grant date. On February 27, 2014, ACE granted 1,492,290 restricted stock awards and 276,992 restricted stock units to employees and officers with a grant date fair value of $96.76 each. Each restricted stock unit represents our obligation to deliver to the holder one Common Share upon vesting.

Segment_information

Segment information	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Segment information	'
	Segment information
	ACE operates through five business segments: Insurance – North American P&C, Insurance – North American Agriculture, Insurance – Overseas General, Global Reinsurance, and Life. These segments distribute their products through various forms of brokers, agencies, and direct marketing programs. All business segments have established relationships with reinsurance intermediaries.
	For segment reporting purposes, certain items have been presented in a different manner below than in the consolidated financial statements. Management uses underwriting income as the main measure of segment performance. ACE calculates underwriting income by subtracting Losses and loss expenses, Policy benefits, Policy acquisition costs, and Administrative expenses from Net premiums earned. For the Insurance – North American Agriculture segment, management includes gains and losses from fair value changes on crop derivatives as a component of underwriting income. For the three months ended March 31, 2014, underwriting loss in our Insurance – North American Agriculture segment was $31 million. This amount includes $2 million of realized losses related to crop derivatives which are included in Net realized gains (losses) below. For the Life segment, management includes Net investment income and (Gains) losses from fair value changes in separate account assets that do not qualify for separate account reporting under GAAP as components of Life underwriting income. For example, for the three months ended March 31, 2014, Life underwriting income of $98 million includes Net investment income of $64 million and losses from fair value changes in separate account assets of $6 million.
	The following tables present the Statement of Operations by segment:
	For the Three Months Ended March 31, 2014	Insurance – North American P&C			Insurance – North American Agriculture			Insurance –			Global			Life			Corporate			ACE
								Overseas			Reinsurance									Consolidated
	(in millions of U.S. dollars)							General
	Net premiums written	$	1,418		$	194		$	1,771		$	308		$	494		$	—		$	4,185
	Net premiums earned	1,487			103			1,612			284			484			—			3,970
	Losses and loss expenses	940			126			817			126			151			1			2,161
	Policy benefits	—			—			—			—			114			—			114
	Policy acquisition costs	159			5			386			67			111			—			728
	Administrative expenses	161			1			250			14			68			41			535
	Underwriting income (loss)	227			(29		)	159			77			40			(42		)	432
	Net investment income	270			7			132			77			64			3			553
	Net realized gains (losses) including OTTI	(9		)	(2		)	(10		)	(8		)	(76		)	1			(104		)
	Interest expense	3			—			1			1			3			63			71
	Other (income) expense:
	(Gains) losses from fair value changes in separate account assets	—			—			—			—			6			—			6
	Other	(20		)	8			(6		)	(19		)	7			7			(23		)
	Income tax expense (benefit)	83			(7		)	37			10			10			(40		)	93
	Net income (loss)	$	422		$	(25	)	$	249		$	154		$	2		$	(68	)	$	734
	For the Three Months Ended March 31, 2013	Insurance – North American P&C			Insurance – North American Agriculture			Insurance –			Global			Life			Corporate			ACE
								Overseas			Reinsurance									Consolidated
	(in millions of U.S. dollars)							General
	Net premiums written	$	1,284		$	113		$	1,620		$	279		$	502		$	—		$	3,798
	Net premiums earned	1,338			52			1,459			247			477			—			3,573
	Losses and loss expenses	878			32			747			106			157			6			1,926
	Policy benefits	—			—			—			—			131			—			131
	Policy acquisition costs	143			4			339			48			80			—			614
	Administrative expenses	125			5			236			12			85			51			514
	Underwriting income (loss)	192			11			137			81			24			(57		)	388
	Net investment income	251			6			132			72			63			7			531
	Net realized gains (losses) including OTTI	26			—			34			20			127			(1		)	206
	Interest (income) expense	(2		)	—			1			1			4			56			60
	Other (income) expense:
	(Gains) losses from fair value changes in separate account assets	—			—			—			—			(4		)	—			(4		)
	Other	(15		)	8			(1		)	(8		)	—			10			(6		)
	Income tax expense (benefit)	94			2			46			8			13			(41		)	122
	Net income (loss)	$	392		$	7		$	257		$	172		$	201		$	(76	)	$	953
	Underwriting assets are reviewed in total by management for purposes of decision-making. Other than goodwill and other intangible assets, ACE does not allocate assets to its segments.
	The following table presents net premiums earned for each segment by product:
	(in millions of U.S. dollars)	Property &			Casualty			Life,			ACE
		All Other						Accident &			Consolidated
	For the Three Months Ended March 31, 2014							Health
	Insurance – North American P&C	$	405		$	981		$	101		$	1,487
	Insurance – North American Agriculture	103			—			—			103
	Insurance – Overseas General	693			369			550			1,612
	Global Reinsurance	154			130			—			284
	Life	—			—			484			484
		$	1,355		$	1,480		$	1,135		$	3,970
	For the Three Months Ended March 31, 2013
	Insurance – North American P&C	$	347		$	902		$	89		$	1,338
	Insurance – North American Agriculture	52			—			—			52
	Insurance – Overseas General	585			339			535			1,459
	Global Reinsurance	135			112			—			247
	Life	—			—			477			477
		$	1,119		$	1,353		$	1,101		$	3,573

Earnings_per_share

Earnings per share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Earnings per share	'
	Earnings per share
		Three Months Ended
		31-Mar
	(in millions of U.S. dollars, except share and per share data)	2014		2013
	Numerator:
	Net income	$	734	$	953
	Denominator:
	Denominator for basic earnings per share:
	Weighted-average shares outstanding	338,869,562		340,778,142
	Denominator for diluted earnings per share:
	Share-based compensation plans	3,171,174		3,128,226
	Weighted-average shares outstanding and assumed conversions	342,040,736		343,906,368
	Basic earnings per share	$	2.16	$	2.8
	Diluted earnings per share	$	2.14	$	2.77
	Potential anti-dilutive share conversions	657,182		634,385
	Excluded from weighted-average shares outstanding and assumed conversions is the impact of securities that would have been anti-dilutive during the respective periods.

Information_provided_in_connec

Information provided in connection with outstanding debt of subsidiaries	3 Months Ended
	Mar. 31, 2014
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]	'
Information provided in connection with outstanding debt of subsidiaries	'
	Information provided in connection with outstanding debt of subsidiaries
	The following tables present condensed consolidating financial information at March 31, 2014 and December 31, 2013, and for the three months ended March 31, 2014 and 2013 for ACE Limited (Parent Guarantor) and ACE INA Holdings, Inc. (Subsidiary Issuer). The Subsidiary Issuer is an indirect 100 percent-owned subsidiary of the Parent Guarantor. The Parent Guarantor fully and unconditionally guarantees certain of the debt of the Subsidiary Issuer.
	During the third quarter of 2013, we determined that the Subsidiary Issuer columns presented in the previously issued condensed consolidating financial information should be presented on the equity method of accounting rather than on a consolidated basis. Accordingly, we have revised the disclosure to correct the Condensed Consolidating Statement of Operations and Comprehensive Income and the Condensed Consolidating Statement of Cash Flows for the three months ended March 31, 2013. As a result of this revision to the Subsidiary Issuer condensed consolidating financial information, revenues and expenses and cash flows of the subsidiaries of ACE INA Holdings, Inc. (Subsidiary Issuer) are now presented in the Other ACE Limited Subsidiaries column on a combined basis. In addition, we revised the Consolidating Adjustments and Eliminations column to correctly include all intercompany eliminations. Previously, this column reflected only ACE Limited parent company intercompany eliminations. We also revised the Condensed Consolidating Statement of Cash Flows for the three months ended March 31, 2013 to correct the presentation of negative cash associated with our affiliated notional cash pooling programs (Pools). In addition, certain items in the Condensed Consolidating Statement of Cash Flows for the three months ended March 31, 2013 have been reclassified to conform to current period presentation. Also, the operating cash flows have been corrected to properly reflect certain intercompany transactions previously recorded in financing cash flows for the three months ended March 31, 2013.
	Total shareholders' equity and net income of the Subsidiary Issuer and Parent Guarantor were not impacted as a result of these revisions. The impact of the revisions was not material to the prior period consolidated financial statements taken as a whole. There was no impact on the consolidated amounts previously reported.
	Condensed Consolidating Balance Sheet at March 31, 2014
	(in millions of U.S. dollars)	ACE			ACE INA			Other ACE			Consolidating			ACE Limited
		Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Consolidated
		(Parent			(Subsidiary			Subsidiaries
		Guarantor)			Issuer)
	Assets
	Investments	$	32		$	18		$	61,995		$	—		$	62,045
	Cash(1)	25			1			1,206			(385		)	847
	Insurance and reinsurance balances receivable	—			—			5,540			(779		)	4,761
	Reinsurance recoverable on losses and loss expenses	—			—			19,531			(8,776		)	10,755
	Reinsurance recoverable on policy benefits	—			—			1,210			(988		)	222
	Value of business acquired	—			—			517			—			517
	Goodwill and other intangible assets	—			—			5,382			—			5,382
	Investments in subsidiaries	29,075			18,368			—			(47,443		)	—
	Due from subsidiaries and affiliates, net	487			—			—			(487		)	—
	Other assets	3			256			13,956			(3,565		)	10,650
	Total assets	$	29,622		$	18,643		$	109,337		$	(62,423	)	$	95,179
	Liabilities
	Unpaid losses and loss expenses	$	—		$	—		$	45,173		$	(8,307	)	$	36,866
	Unearned premiums	—			—			9,584			(1,793		)	7,791
	Future policy benefits	—			—			5,620			(988		)	4,632
	Due to (from) subsidiaries and affiliates, net	—			367			120			(487		)	—
	Affiliated notional cash pooling programs(1)	—			385			—			(385		)	—
	Short-term debt	—			500			1,401			—			1,901
	Long-term debt	—			3,795			13			—			3,808
	Trust preferred securities	—			309			—			—			309
	Other liabilities	253			1,343			11,927			(3,020		)	10,503
	Total liabilities	253			6,699			73,838			(14,980		)	65,810
	Total shareholders’ equity	29,369			11,944			35,499			(47,443		)	29,369
	Total liabilities and shareholders’ equity	$	29,622		$	18,643		$	109,337		$	(62,423	)	$	95,179
	(1)	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
	Condensed Consolidating Balance Sheet at December 31, 2013
	(in millions of U.S. dollars)	ACE			ACE INA			Other ACE			Consolidating			ACE Limited
		Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Consolidated
		(Parent			(Subsidiary			Subsidiaries
		Guarantor)			Issuer)
	Assets
	Investments	$	32		$	10		$	60,886		$	—		$	60,928
	Cash(1)	—			16			748			(185		)	579
	Insurance and reinsurance balances receivable	—			—			5,835			(809		)	5,026
	Reinsurance recoverable on losses and loss expenses	—			—			20,057			(8,830		)	11,227
	Reinsurance recoverable on policy benefits	—			—			1,215			(997		)	218
	Value of business acquired	—			—			536			—			536
	Goodwill and other intangible assets	—			—			5,404			—			5,404
	Investments in subsidiaries	28,351			18,105			—			(46,456		)	—
	Due from subsidiaries and affiliates, net	844			—			—			(844		)	—
	Other assets	5			258			13,788			(3,459		)	10,592
	Total assets	$	29,232		$	18,389		$	108,469		$	(61,580	)	$	94,510
	Liabilities
	Unpaid losses and loss expenses	$	—		$	—		$	45,714		$	(8,271	)	$	37,443
	Unearned premiums	—			—			9,242			(1,703		)	7,539
	Future policy benefits	—			—			5,612			(997		)	4,615
	Due to (from) subsidiaries and affiliates, net	—			714			130			(844		)	—
	Affiliated notional cash pooling programs(1)	185			—			—			(185		)	—
	Short-term debt	—			500			1,401			—			1,901
	Long-term debt	—			3,795			12			—			3,807
	Trust preferred securities	—			309			—			—			309
	Other liabilities	222			1,318			11,655			(3,124		)	10,071
	Total liabilities	407			6,636			73,766			(15,124		)	65,685
Total shareholders’ equity	28,825			11,753			34,703			(46,456		)	28,825
Total liabilities and shareholders’ equity	$	29,232		$	18,389		$	108,469		$	(61,580	)	$	94,510
(1)	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
Condensed Consolidating Statements of Operations and Comprehensive Income
For the Three Months Ended March 31, 2014	ACE			ACE INA			Other ACE			Consolidating			ACE
	Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Limited
	(Parent			(Subsidiary			Subsidiaries						Consolidated
(in millions of U.S. dollars)	Guarantor)			Issuer)
Net premiums written	$	—		$	—		$	4,185		$	—		$	4,185
Net premiums earned	—			—			3,970			—			3,970
Net investment income	—			—			553			—			553
Equity in earnings of subsidiaries	702			180			—			(882		)	—
Net realized gains (losses) including OTTI	—			(1		)	(103		)	—			(104		)
Losses and loss expenses	—			—			2,161			—			2,161
Policy benefits	—			—			114			—			114
Policy acquisition costs and administrative expenses	17			6			1,240			—			1,263
Interest (income) expense	(10		)	71			10			—			71
Other (income) expense	(42		)	14			11			—			(17		)
Income tax expense (benefit)	3			(30		)	120			—			93
Net income	$	734		$	118		$	764		$	(882	)	$	734
Comprehensive income	$	1,108		$	266		$	1,138		$	(1,404	)	$	1,108
Condensed Consolidating Statements of Operations and Comprehensive Income (Revised)
For the Three Months Ended March 31, 2013	ACE			ACE INA			Other ACE			Consolidating			ACE
	Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Limited
	(Parent			(Subsidiary			Subsidiaries						Consolidated
(in millions of U.S. dollars)	Guarantor)			Issuer)
Net premiums written	$	—		$	—		$	3,798		$	—		$	3,798
Net premiums earned	—			—			3,573			—			3,573
Net investment income	—			1			530			—			531
Equity in earnings of subsidiaries	914			188			—			(1,102		)	—
Net realized gains (losses) including OTTI	12			—			194			—			206
Losses and loss expenses	—			—			1,926			—			1,926
Policy benefits	—			—			131			—			131
Policy acquisition costs and administrative expenses	15			4			1,109			—			1,128
Interest (income) expense	(7		)	62			5			—			60
Other (income) expense	(38		)	9			19			—			(10		)
Income tax expense (benefit)	3			(33		)	152			—			122
Net income	$	953		$	147		$	955		$	(1,102	)	$	953
Comprehensive income (loss)	$	716		$	(1	)	$	718		$	(717	)	$	716
Condensed Consolidating Statements of Operations and Comprehensive Income (As previously reported)
For the Three Months Ended March 31, 2013	ACE			ACE INA			Other ACE			Consolidating			ACE
	Limited			Holdings Inc.			Limited			Adjustments (2)			Limited
	(Parent			(Subsidiary			Subsidiaries and						Consolidated
(in millions of U.S. dollars)	Guarantor)			Issuer)			Eliminations(1)
Net premiums written	$	—		$	2,082		$	1,716		$	—		$	3,798
Net premiums earned	—			2,006			1,567			—			3,573
Net investment income	—			248			283			—			531
Equity in earnings of subsidiaries	914			—			—			(914		)	—
Net realized gains (losses) including OTTI	12			10			184			—			206
Losses and loss expenses	—			1,253			673			—			1,926
Policy benefits	—			81			50			—			131
Policy acquisition costs and administrative expenses	15			626			487			—			1,128
Interest (income) expense	(7		)	67			—			—			60
Other (income) expense	(38		)	34			(6		)	—			(10		)
Income tax expense	3			56			63			—			122
Net income	$	953		$	147		$	767		$	(914	)	$	953
Comprehensive income (loss)	$	716		$	(1	)	$	915		$	(914	)	$	716
-1	Includes all other subsidiaries of ACE Limited and intercompany eliminations.
-2	Includes ACE Limited parent company eliminations.
Condensed Consolidating Statement of Cash Flows
For the Three Months Ended March 31, 2014	ACE			ACE INA			Other ACE			Consolidating			ACE
	Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Limited
	(Parent			(Subsidiary			Subsidiaries						Consolidated
(in millions of U.S. dollars)	Guarantor)			Issuer)
Net cash flows from (used for) operating activities	$	57		$	(13	)	$	1,206		$	—		$	1,250
Cash flows from investing activities
Purchases of fixed maturities available for sale	—			—			(3,522		)	—			(3,522		)
Purchases of fixed maturities held to maturity	—			—			(30		)	—			(30		)
Purchases of equity securities	—			—			(37		)	—			(37		)
Sales of fixed maturities available for	—			—			2,208			—			2,208
sale
Sales of equity securities	—			—			27			—			27
Maturities and redemptions of fixed maturities available for sale	—			—			1,550			—			1,550
Maturities and redemptions of fixed maturities held to maturity	—			—			212			—			212
Net change in short-term investments	—			(8		)	(757		)	—			(765		)
Net derivative instruments settlements	—			(9		)	(87		)	—			(96		)
Other	—			(3		)	(47		)	—			(50		)
Net cash flows used for investing activities	—			(20		)	(483		)	—			(503		)
Cash flows from financing activities
Dividends paid on Common Shares	(214		)	—			—			—			(214		)
Common Shares repurchased	—			—			(335		)	—			(335		)
Proceeds from share-based compensation plans, including windfall tax benefits	—			—			40			—			40
Advances (to) from affiliates	367			(367		)	—			—			—
Net proceeds from (payments to) affiliated notional cash pooling programs(1)	(185		)	385			—			(200		)	—
Other	—			—			37			—			37
Net cash flows (used for) from financing activities	(32		)	18			(258		)	(200		)	(472		)
Effect of foreign currency rate changes on cash and cash equivalents	—			—			(7		)	—			(7		)
Net increase (decrease) in cash	25			(15		)	458			(200		)	268
Cash – beginning of period(1)	—			16			748			(185		)	579
Cash – end of period(1)	$	25		$	1		$	1,206		$	(385	)	$	847
(1)	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014 and December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
Condensed Consolidating Statement of Cash Flows (Revised)
For the Three Months Ended March 31, 2013	ACE			ACE INA			Other ACE			Consolidating			ACE
	Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Limited
	(Parent			(Subsidiary			Subsidiaries						Consolidated
(in millions of U.S. dollars)	Guarantor)			Issuer)
Net cash flows from (used for) operating activities	$	25		$	(19	)	$	907		$	—		$	913
Cash flows from investing activities
Purchases of fixed maturities available for sale	—			—			(5,568		)	103			(5,465		)
Purchases of fixed maturities held to maturity	—			—			(142		)	—			(142		)
Purchases of equity securities	—			—			(107		)	—			(107		)
Sales of fixed maturities available for sale	—			—			2,867			(103		)	2,764
Sales of equity securities	—			—			31			—			31
Maturities and redemptions of fixed maturities available for sale	—			—			2,016			—			2,016
Maturities and redemptions of fixed maturities held to maturity	—			—			491			—			491
Net change in short-term investments	—			4			(691		)	—			(687		)
Net derivative instruments settlements	—			—			(279		)	—			(279		)
Acquisition of subsidiaries	—			—			(33		)	—			(33		)
Capital contribution	—			(27		)	—			27			—
Other	—			2			(57		)	—			(55		)
Net cash flows used for investing activities	—			(21		)	(1,472		)	27			(1,466		)
Cash flows from financing activities
Dividends paid on Common Shares	(2		)	—			—			—			(2		)
Common Shares repurchased	—			—			(154		)	—			(154		)
Net proceeds from issuance of long-term debt	—			947			—			—			947
Net proceeds from issuance of short-term debt	—			—			1			—			1
Proceeds from share-based compensation plans	—			—			21			—			21
Advances (to) from affiliates	71			(71		)	—			—			—
Dividends to parent company	—			—			—			—			—
Capital contribution	—			—			27			(27		)	—
Net payments to affiliated notional cash pooling programs(1)	—			(349		)	—			349			—
Net cash flows from (used for) financing activities	69			527			(105		)	322			813
Effect of foreign currency rate changes on cash and cash equivalents	—			—			(20		)	—			(20		)
Net increase (decrease) in cash	94			487			(690		)	349			240
Cash – beginning of period(1)	103			2			859			(349		)	615
Cash – end of period(1)	$	197		$	489		$	169		$	—		$	855
(1)	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2013 and December 31, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
Condensed Consolidating Statement of Cash Flows (As previously reported)
For the Three Months Ended March 31, 2013	ACE			ACE INA			Other ACE			Consolidating			ACE
	Limited			Holdings Inc.			Limited			Adjustments(2)			Limited
	(Parent			(Subsidiary			Subsidiaries and						Consolidated
(in millions of U.S. dollars)	Guarantor)			Issuer)			Eliminations(1)
Net cash flows from operating activities	$	53		$	644		$	216		$	—		$	913
Cash flows from investing activities
Purchases of fixed maturities available for sale	—			(3,825		)	(2,327		)	—			(6,152		)
Purchases of fixed maturities held to maturity	—			(137		)	(5		)	—			(142		)
Purchases of equity securities	—			(89		)	(18		)	—			(107		)
Sales of fixed maturities available for sale	—			1,473			1,291			—			2,764
Sales of equity securities	—			25			6			—			31
Maturities and redemptions of fixed maturities available for sale	—			879			1,137			—			2,016
Maturities and redemptions of fixed maturities held to maturity	—			351			140			—			491
Net derivative instruments settlements	—			4			(283		)	—			(279		)
Advances from (to) affiliates	43			—			—			(43		)	—
Acquisition of subsidiaries	—			(33		)	—			—			(33		)
Other	—			(86		)	31			—			(55		)
Net cash flows from (used for) investing activities	43			(1,438		)	(28		)	(43		)	(1,466		)
Cash flows from financing activities
Dividends paid on Common Shares	(2		)	—			—			—			(2		)
Common Shares repurchased	—			—			(154		)	—			(154		)
Net proceeds from issuance of long-term debt	—			947			—			—			947
Net proceeds from issuance of short-term debt	—			—			1			—			1
Proceeds from share-based compensation plans, including windfall tax benefits	—			(8		)	29			—			21
Advances (to) from affiliates	—			(71		)	28			43			—
Net cash flows from (used for) financing activities	(2		)	868			(96		)	43			813
Effect of foreign currency rate changes on cash and cash equivalents	—			(29		)	9			—			(20		)
Net increase in cash	94			45			101			—			240
Cash – beginning of period	103			515			(3		)	—			615
Cash – end of period(3)	$	197		$	560		$	98		$	—		$	855
-1	Includes all other subsidiaries of ACE Limited and intercompany eliminations.
-2	Includes ACE Limited parent company eliminations and certain consolidating adjustments.
-3	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

General_Policies

General (Policies)	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis of presentation	'
	ACE Limited is a holding company incorporated in Zurich, Switzerland. ACE Limited, through its subsidiaries, provides a broad range of insurance and reinsurance products to insureds worldwide. ACE operates through five business segments: Insurance – North American P&C, Insurance – North American Agriculture, Insurance – Overseas General, Global Reinsurance, and Life. Refer to Note 9 for additional information.
	The interim unaudited consolidated financial statements, which include the accounts of ACE Limited and its subsidiaries (collectively, ACE, we, us, or our), have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP) and, in the opinion of management, reflect all adjustments (consisting of normally recurring accruals) necessary for a fair statement of the results and financial position for such periods. All significant intercompany accounts and transactions have been eliminated.
	The results of operations and cash flows for any interim period are not necessarily indicative of the results for the full year. These consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes included in our 2013 Form 10-K.

Investments_Tables

Investments (Tables)	3 Months Ended
	Mar. 31, 2014
Investments, Debt and Equity Securities [Abstract]	'
Schedule Of Amortized Cost And Fair Value Of Fixed Maturities And Related OTTI Recognized In AOCI	'
	31-Mar-14	Amortized			Gross			Gross			Fair			OTTI Recognized
		Cost			Unrealized			Unrealized			Value			in AOCI
	(in millions of U.S. dollars)				Appreciation			Depreciation
	Available for sale
	U.S. Treasury and agency	$	2,939		$	68		$	(37	)	$	2,970		$	—
	Foreign	14,155			441			(65		)	14,531			(1		)
	Corporate securities	16,873			883			(71		)	17,685			(6		)
	Mortgage-backed securities	10,916			210			(155		)	10,971			(27		)
	States, municipalities, and political subdivisions	3,399			95			(40		)	3,454			—
		$	48,282		$	1,697		$	(368	)	$	49,611		$	(34	)
	Held to maturity
	U.S. Treasury and agency	$	777		$	17		$	(4	)	$	790		$	—
	Foreign	837			37			—			874			—
	Corporate securities	1,876			89			—			1,965			—
	Mortgage-backed securities	1,265			41			—			1,306			—
	States, municipalities, and political subdivisions	1,132			23			(10		)	1,145			—
		$	5,887		$	207		$	(14	)	$	6,080		$	—
	31-Dec-13	Amortized			Gross			Gross			Fair			OTTI Recognized
		Cost			Unrealized			Unrealized			Value			in AOCI
	(in millions of U.S. dollars)				Appreciation			Depreciation
	Available for sale
	U.S. Treasury and agency	$	2,946		$	62		$	(59	)	$	2,949		$	—
	Foreign	14,336			377			(122		)	14,591			—
	Corporate securities	16,825			777			(132		)	17,470			(6		)
	Mortgage-backed securities	10,937			184			(227		)	10,894			(34		)
	States, municipalities, and political subdivisions	3,362			65			(77		)	3,350			—
		$	48,406		$	1,465		$	(617	)	$	49,254		$	(40	)
	Held to maturity
	U.S. Treasury and agency	$	820		$	16		$	(4	)	$	832		$	—
	Foreign	864			33			—			897			—
	Corporate securities	1,922			83			—			2,005			—
	Mortgage-backed securities	1,341			39			(1		)	1,379			—
	States, municipalities, and political subdivisions	1,151			16			(17		)	1,150			—
		$	6,098		$	187		$	(22	)	$	6,263		$	—
Schedule Of Fixed Maturities By Contractual Maturity	'
					31-Mar						31-Dec
					2014						2013
	(in millions of U.S. dollars)	Amortized Cost			Fair Value			Amortized Cost			Fair Value
	Available for sale
	Due in 1 year or less	$	2,504		$	2,528		$	2,387		$	2,411
	Due after 1 year through 5 years	14,199			14,713			14,139			14,602
	Due after 5 years through 10 years	15,947			16,460			16,200			16,535
	Due after 10 years	4,716			4,939			4,743			4,812
		37,366			38,640			37,469			38,360
	Mortgage-backed securities	10,916			10,971			10,937			10,894
		$	48,282		$	49,611		$	48,406		$	49,254
	Held to maturity
	Due in 1 year or less	$	539		$	547		$	401		$	405
	Due after 1 year through 5 years	2,419			2,503			2,284			2,363
	Due after 5 years through 10 years	1,304			1,345			1,686			1,723
	Due after 10 years	360			379			386			393
		4,622			4,774			4,757			4,884
	Mortgage-backed securities	1,265			1,306			1,341			1,379
		$	5,887		$	6,080		$	6,098		$	6,263
Schedule Of Cost And Fair Value Of Equity Securities	'
		31-Mar			31-Dec
	(in millions of U.S. dollars)	2014			2013
	Cost	$	845		$	841
	Gross unrealized appreciation	64			63
	Gross unrealized depreciation	(58		)	(67		)
	Fair value	$	851		$	837
Schedule Of Net Realized Gains (Losses) And The Losses Included In Net Realized Gains (Losses) And OCI	'
		Three Months Ended
		31-Mar
	(in millions of U.S. dollars)	2014			2013
	Fixed maturities:
	OTTI on fixed maturities, gross	$	(6	)	$	(1	)
	OTTI on fixed maturities recognized in OCI (pre-tax)	1			—
	OTTI on fixed maturities, net	(5		)	(1		)
	Gross realized gains excluding OTTI	36			62
	Gross realized losses excluding OTTI	(20		)	(25		)
	Total fixed maturities	11			36
	Equity securities:
	OTTI on equity securities	(6		)	(1		)
	Gross realized gains excluding OTTI	2			2
	Gross realized losses excluding OTTI	(1		)	(2		)
	Total equity securities	(5		)	(1		)
	OTTI on other investments	—			(1		)
	Foreign exchange gains (losses)	(9		)	76
	Investment and embedded derivative instruments	(25		)	18
	Fair value adjustments on insurance derivative	(48		)	328
	S&P put options and futures	(19		)	(250		)
	Other derivative instruments	(2		)	—
	Other	(7		)	—
	Net realized gains (losses)	$	(104	)	$	206
Schedule Of Roll-Forward Of Pre-Tax Credit Losses Related To Fixed Maturities For Which A Portion Of OTTI Was Recognized In OCI	'
		Three Months Ended
		31-Mar
	(in millions of U.S. dollars)	2014			2013
	Balance of credit losses related to securities still held – beginning of period	$	37		$	43
	Additions where no OTTI was previously recorded	2			—
	Additions where an OTTI was previously recorded	2			1
	Reductions for securities sold during the period	(6		)	(9		)
	Balance of credit losses related to securities still held – end of period	$	35		$	35
Schedule Of Aggregate Fair Value And Gross Unrealized Loss By Length Of Time The Security Has Continuously Been In An Unrealized Loss Position	'
		0 – 12 Months						Over 12 Months						Total
	31-Mar-14	Fair Value			Gross			Fair Value			Gross			Fair Value			Gross
					Unrealized						Unrealized						Unrealized
	(in millions of U.S. dollars)				Loss						Loss						Loss
	U.S. Treasury and agency	$	1,609		$	(37	)	$	33		$	(4	)	$	1,642		$	(41	)
	Foreign	2,988			(56		)	259			(9		)	3,247			(65		)
	Corporate securities	2,940			(58		)	211			(13		)	3,151			(71		)
	Mortgage-backed securities	4,367			(130		)	398			(25		)	4,765			(155		)
	States, municipalities, and political subdivisions	1,575			(39		)	189			(11		)	1,764			(50		)
	Total fixed maturities	13,479			(320		)	1,090			(62		)	14,569			(382		)
	Equity securities	496			(58		)	—			—			496			(58		)
	Other investments	65			(5		)	—			—			65			(5		)
	Total	$	14,040		$	(383	)	$	1,090		$	(62	)	$	15,130		$	(445	)
		0 – 12 Months						Over 12 Months						Total
	31-Dec-13	Fair Value			Gross			Fair Value			Gross			Fair Value			Gross
					Unrealized						Unrealized						Unrealized
	(in millions of U.S. dollars)				Loss						Loss						Loss
	U.S. Treasury and agency	$	1,794		$	(57	)	$	31		$	(6	)	$	1,825		$	(63	)
	Foreign	4,621			(114		)	201			(8		)	4,822			(122		)
	Corporate securities	3,836			(118		)	194			(14		)	4,030			(132		)
	Mortgage-backed securities	5,248			(197		)	384			(31		)	5,632			(228		)
	States, municipalities, and political subdivisions	2,164			(90		)	84			(4		)	2,248			(94		)
	Total fixed maturities	17,663			(576		)	894			(63		)	18,557			(639		)
	Equity securities	498			(67		)	—			—			498			(67		)
	Other investments	67			(9		)	—			—			67			(9		)
	Total	$	18,228		$	(652	)	$	894		$	(63	)	$	19,122		$	(715	)
Schedule Of Components Of Restricted Assets	'
		31-Mar			31-Dec
	(in millions of U.S. dollars)	2014			2013
	Trust funds	$	11,385		$	11,315
	Deposits with non-U.S. regulatory authorities	1,962			1,970
	Assets pledged under repurchase agreements	1,452			1,435
	Deposits with U.S. regulatory authorities	1,334			1,334
	Other pledged assets	420			391
		$	16,553		$	16,445

Fair_value_measurements_Tables

Fair value measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Financial Instruments Measured At Fair Value On A Recurring Basis	'
	31-Mar-14	Level 1				Level 2				Level 3				Total
	(in millions of U.S. dollars)
	Assets:
	Fixed maturities available for sale
	U.S. Treasury and agency	$	1,709			$	1,261			$	—			$	2,970
	Foreign	233				14,272				26				14,531
	Corporate securities	—				17,534				151				17,685
	Mortgage-backed securities	—				10,963				8				10,971
	States, municipalities, and political subdivisions	—				3,454				—				3,454
		1,942				47,484				185				49,611
	Equity securities	380				469				2				851
	Short-term investments	1,590				936				—				2,526
	Other investments	314				245				2,611				3,170
	Securities lending collateral	—				1,550				—				1,550
	Investment derivative instruments	8				—				—				8
	Other derivative instruments	7				—				—				7
	Separate account assets	1,193				83				—				1,276
	Total assets measured at fair value	$	5,434			$	50,767			$	2,798			$	58,999
	Liabilities:
	Investment derivative instruments	$	6			$	—			$	—			$	6
	Other derivative instruments	12				2				—				14
	GLB(1)	—				—				243				243
	Total liabilities measured at fair value	$	18			$	2			$	243			$	263
	(1)	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.
	December 31, 2013	Level 1				Level 2				Level 3				Total
	(in millions of U.S. dollars)
	Assets:
	Fixed maturities available for sale
	U.S. Treasury and agency	$	1,626			$	1,323			$	—			$	2,949
	Foreign	223				14,324				44				14,591
	Corporate securities	—				17,304				166				17,470
	Mortgage-backed securities	—				10,886				8				10,894
	States, municipalities, and political subdivisions	—				3,350				—				3,350
		1,849				47,187				218				49,254
	Equity securities	373				460				4				837
	Short-term investments	953				803				7				1,763
	Other investments	305				231				2,440				2,976
	Securities lending collateral	—				1,632				—				1,632
	Investment derivative instruments	19				—				—				19
	Other derivative instruments	—				6				—				6
	Separate account assets	1,145				81				—				1,226
	Total assets measured at fair value	$	4,644			$	50,400			$	2,669			$	57,713
	Liabilities:
	Investment derivative instruments	$	6			$	—			$	—			$	6
	Other derivative instruments	60				2				—				62
	GLB(1)	—				—				193				193
	Total liabilities measured at fair value	$	66			$	2			$	193			$	261
	(1)	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.
Fair Value And Maximum Future Funding Commitments Related To Investments	'
								31-Mar								31-Dec
		Expected						2014								2013
		Liquidation
	(in millions of U.S. dollars)	Period of Underlying Assets		Fair				Maximum				Fair				Maximum
				Value				Future Funding				Value				Future Funding
								Commitments								Commitments
	Financial	5 to 9 Years		$	271			$	122			$	256			$	129
	Real estate	3 to 9 Years		319				63				322				92
	Distressed	6 to 9 Years		243				169				180				230
	Mezzanine	6 to 9 Years		290				235				276				252
	Traditional	3 to 8 Years		882				414				813				456
	Vintage	1 to 3 Years		12				—				13				—
	Investment funds	Not Applicable		440				—				428				—
				$	2,457			$	1,003			$	2,288			$	1,159
Schedule Of Significant Unobservable Inputs Used In Level 3 Liability Valuations	'
	(in millions of U.S. dollars, except for percentages)	Fair Value								Valuation		Significant		Ranges
		31-Mar-14				31-Dec-13				Technique		Unobservable Inputs
	GLB(1)	$	243			$	193			Actuarial model		Lapse rate		1% – 30%
												Annuitization rate		0% – 55%
	(1)	Discussion of the most significant inputs used in the fair value measurement of GLB and the sensitivity of those assumptions is included within Note 4 a) Guaranteed living benefits.
Financial Instruments Measured At Fair Value Using Significant Unobservable Inputs	'
		Assets																						Liabilities
	Three Months Ended	Available-for-Sale Debt Securities												Equity				Short-term investments			Other			GLB(1)
	31-Mar-14	Foreign				Corporate				MBS				securities							investments
	(in millions of U.S. dollars)					securities
	Balance–Beginning of Period	$	44			$	166			$	8			$	4			$	7		$	2,440		$	193
	Transfers into Level 3	—				4				—				—				—			—			—
	Transfers out of Level 3	(18		)		(22		)		—				(2		)		(7		)	—			—
	Change in Net Unrealized Gains (Losses) included in OCI	(1		)		—				—				1				—			41			—
	Net Realized Gains/Losses	—				—				—				—				—			—			50
	Purchases	2				15				—				1				—			200			—
	Sales	(1		)		(6		)		—				(2		)		—			(1		)	—
	Settlements	—				(6		)		—				—				—			(69		)	—
	Balance–End of Period	$	26			$	151			$	8			$	2			$	—		$	2,611		$	243
	Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—			$	—			$	—			$	—			$	—		$	—		$	50
	(1)	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.
		Assets																			Liabilities
		Available-for-Sale Debt Securities												Equity				Other			GLB(1)
	Three Months Ended	Foreign				Corporate				MBS				securities				investments
	31-Mar-13					securities
	(in millions of U.S. dollars)
	Balance–Beginning of Period	$	60			$	102			$	13			$	3			$	2,252		$	1,119
	Transfers into Level 3	3				12				—				—				—			—
	Transfers out of Level 3	(27		)		(2		)		—				(1		)		—			—
	Change in Net Unrealized Gains (Losses) included in OCI	—				1				—				—				22			—
	Net Realized Gains/Losses	1				—				—				—				(1		)	(366		)
	Purchases	—				10				—				—				136			—
	Sales	(1		)		—				—				—				(9		)	—
	Settlements	(1		)		(5		)		—				—				(72		)	—
	Balance–End of Period	$	35			$	118			$	13			$	2			$	2,328		$	753
	Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date	$	—			$	—			$	—			$	—			$	(1	)	$	(366	)
	(1)	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. The liability for GLB reinsurance was $1.0 billion at March 31, 2013, and $1.4 billion at December 31, 2012, which includes a fair value derivative adjustment of $753 million and $1.1 billion, respectively.
Carrying Values And Fair Values Of Financial Instruments Not Measured At Fair Value	'
	31-Mar-14	Fair Value																Carrying Value
	(in millions of U.S. dollars)	Level 1				Level 2				Level 3				Total
	Assets:
	Fixed maturities held to maturity
	U.S. Treasury and agency	$	595			$	195			$	—			$	790			$	777
	Foreign	—				874				—				874				837
	Corporate securities	—				1,949				16				1,965				1,876
	Mortgage-backed securities	—				1,306				—				1,306				1,265
	States, municipalities, and political subdivisions	—				1,145				—				1,145				1,132
		595				5,469				16				6,080				5,887
	Partially-owned insurance companies	—				—				466				466				466
	Total assets	$	595			$	5,469			$	482			$	6,546			$	6,353
	Liabilities:
	Short-term debt	$	—			$	1,907			$	—			$	1,907			$	1,901
	Long-term debt	—				4,139				—				4,139				3,808
	Trust preferred securities	—				452				—				452				309
	Total liabilities	$	—			$	6,498			$	—			$	6,498			$	6,018
	31-Dec-13	Fair Value																Carrying Value
	(in millions of U.S. dollars)	Level 1				Level 2				Level 3				Total
	Assets:
	Fixed maturities held to maturity
	U.S. Treasury and agency	$	596			$	236			$	—			$	832			$	820
	Foreign	—				897				—				897				864
	Corporate securities	—				1,990				15				2,005				1,922
	Mortgage-backed securities	—				1,379				—				1,379				1,341
	States, municipalities, and political subdivisions	—				1,150				—				1,150				1,151
		596				5,652				15				6,263				6,098
	Partially-owned insurance companies	—				—				470				470				470
	Total assets	$	596			$	5,652			$	485			$	6,733			$	6,568
	Liabilities:
	Short-term debt	$	—			$	1,913			$	—			$	1,913			$	1,901
	Long-term debt	—				4,088				—				4,088				3,807
	Trust preferred securities	—				438				—				438				309
	Total liabilities	$	—			$	6,439			$	—			$	6,439			$	6,017

Assumed_life_reinsurance_progr1

Assumed life reinsurance programs involving minimum benefit guarantees under annuity contracts (Tables)	3 Months Ended
	Mar. 31, 2014
Reinsurance Disclosures [Abstract]	'
Schedule Of Guaranteed Minimum Death Benefits And Guaranteed Minimum Income Benefits Income And Expense	'
		Three Months Ended
		31-Mar
	(in millions of U.S. dollars)	2014			2013
	GMDB
	Net premiums earned	$	19		$	20
	Policy benefits and other reserve adjustments	$	15		$	19
	GLB
	Net premiums earned	$	36		$	39
	Policy benefits and other reserve adjustments	9			9
	Net realized gains (losses)	(50		)	369
	Gain (loss) recognized in income	$	(23	)	$	399
	Net cash received	$	33		$	32
	Net (increase) decrease in liability	$	(56	)	$	367

Commitments_contingencies_and_1

Commitments, contingencies, and guarantees (Tables)	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Balance Sheet Locations, Fair Values In An Asset Or (Liability) Position, And Notional Values/Payment Provisions Of Derivative Instruments	'
								31-Mar-14							31-Dec-13
		Consolidated		Fair Value							Notional		Fair Value					Notional
		Balance Sheet									Value/							Value/
		Location(1)									Payment							Payment
	(in millions of U.S. dollars)			Derivative Asset				Derivative (Liability)			Provision		Derivative Asset		Derivative (Liability)			Provision
	Investment and embedded derivative instruments
	Foreign currency forward contracts	OA / (AP)		$	2			$	(4	)	$	1,469	$	3	$	(4	)	$	1,202
	Cross-currency swaps	OA / (AP)		—				—			50		—		—			50
	Futures contracts on money market instruments	OA / (AP)		4				—			3,910		3		—			3,910
	Futures contracts on notes and bonds	OA / (AP)		2				(2		)	903		13		(2		)	871
	Convertible bonds	FM AFS		319				—			272		302		—			254
				$	327			$	(6	)	$	6,604	$	321	$	(6	)	$	6,287
	Other derivative instruments
	Futures contracts on equities(2)	OA / (AP)		$	—			$	(12	)	$	1,453	$	—	$	(60	)	$	1,692
	Options on equity market indices(2)	OA / (AP)		—				—			250		6		—			250
	Other	OA / (AP)		7				(2		)	64		—		(2		)	8
				$	7			$	(14	)	$	1,767	$	6	$	(62	)	$	1,950
	GLB(3)	(AP) / (FPB)		$	—			$	(483	)	$	321	$	—	$	(427	)	$	277
	(1)	Other assets (OA), Fixed maturities available for sale (FM AFS)
	(2)	Related to GMDB and GLB blocks of business.
	(3)	Includes both future policy benefits reserves and fair value derivative adjustment. Refer to Note 5 for additional information. Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.
Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations	'
		Three Months Ended
		31-Mar
	(in millions of U.S. dollars)	2014				2013
	Investment and embedded derivative instruments
	Foreign currency forward contracts	$	(3	)		$	5
	All other futures contracts and options	(22		)		7
	Convertible bonds	—				6
	Total investment and embedded derivative instruments	$	(25	)		$	18
	GLB and other derivative instruments
	GLB(1)	$	(48	)		$	328
	Futures contracts on equities(2)	(17		)		(237		)
	Options on equity market indices(2)	(2		)		(13		)
	Other	(2		)		—
	Total GLB and other derivative instruments	$	(69	)		$	78
		$	(94	)		$	96
	(1)	Excludes foreign exchange gains (losses) related to GLB.
	(2)	Related to GMDB and GLB blocks of business.

Segment_information_Tables

Segment information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting [Abstract]	'
Operations By Segment	'
	For the Three Months Ended March 31, 2014	Insurance – North American P&C			Insurance – North American Agriculture			Insurance –			Global			Life			Corporate			ACE
								Overseas			Reinsurance									Consolidated
	(in millions of U.S. dollars)							General
	Net premiums written	$	1,418		$	194		$	1,771		$	308		$	494		$	—		$	4,185
	Net premiums earned	1,487			103			1,612			284			484			—			3,970
	Losses and loss expenses	940			126			817			126			151			1			2,161
	Policy benefits	—			—			—			—			114			—			114
	Policy acquisition costs	159			5			386			67			111			—			728
	Administrative expenses	161			1			250			14			68			41			535
	Underwriting income (loss)	227			(29		)	159			77			40			(42		)	432
	Net investment income	270			7			132			77			64			3			553
	Net realized gains (losses) including OTTI	(9		)	(2		)	(10		)	(8		)	(76		)	1			(104		)
	Interest expense	3			—			1			1			3			63			71
	Other (income) expense:
	(Gains) losses from fair value changes in separate account assets	—			—			—			—			6			—			6
	Other	(20		)	8			(6		)	(19		)	7			7			(23		)
	Income tax expense (benefit)	83			(7		)	37			10			10			(40		)	93
	Net income (loss)	$	422		$	(25	)	$	249		$	154		$	2		$	(68	)	$	734
	For the Three Months Ended March 31, 2013	Insurance – North American P&C			Insurance – North American Agriculture			Insurance –			Global			Life			Corporate			ACE
								Overseas			Reinsurance									Consolidated
	(in millions of U.S. dollars)							General
	Net premiums written	$	1,284		$	113		$	1,620		$	279		$	502		$	—		$	3,798
	Net premiums earned	1,338			52			1,459			247			477			—			3,573
	Losses and loss expenses	878			32			747			106			157			6			1,926
	Policy benefits	—			—			—			—			131			—			131
	Policy acquisition costs	143			4			339			48			80			—			614
	Administrative expenses	125			5			236			12			85			51			514
	Underwriting income (loss)	192			11			137			81			24			(57		)	388
	Net investment income	251			6			132			72			63			7			531
	Net realized gains (losses) including OTTI	26			—			34			20			127			(1		)	206
	Interest (income) expense	(2		)	—			1			1			4			56			60
	Other (income) expense:
	(Gains) losses from fair value changes in separate account assets	—			—			—			—			(4		)	—			(4		)
	Other	(15		)	8			(1		)	(8		)	—			10			(6		)
	Income tax expense (benefit)	94			2			46			8			13			(41		)	122
	Net income (loss)	$	392		$	7		$	257		$	172		$	201		$	(76	)	$	953
Net Premiums Earned For Segment By Product	'
	(in millions of U.S. dollars)	Property &			Casualty			Life,			ACE
		All Other						Accident &			Consolidated
	For the Three Months Ended March 31, 2014							Health
	Insurance – North American P&C	$	405		$	981		$	101		$	1,487
	Insurance – North American Agriculture	103			—			—			103
	Insurance – Overseas General	693			369			550			1,612
	Global Reinsurance	154			130			—			284
	Life	—			—			484			484
		$	1,355		$	1,480		$	1,135		$	3,970
	For the Three Months Ended March 31, 2013
	Insurance – North American P&C	$	347		$	902		$	89		$	1,338
	Insurance – North American Agriculture	52			—			—			52
	Insurance – Overseas General	585			339			535			1,459
	Global Reinsurance	135			112			—			247
	Life	—			—			477			477
		$	1,119		$	1,353		$	1,101		$	3,573

Earnings_per_share_Tables

Earnings per share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Schedule Of Earnings Per Share, Basic And Diluted	'
		Three Months Ended
		31-Mar
	(in millions of U.S. dollars, except share and per share data)	2014		2013
	Numerator:
	Net income	$	734	$	953
	Denominator:
	Denominator for basic earnings per share:
	Weighted-average shares outstanding	338,869,562		340,778,142
	Denominator for diluted earnings per share:
	Share-based compensation plans	3,171,174		3,128,226
	Weighted-average shares outstanding and assumed conversions	342,040,736		343,906,368
	Basic earnings per share	$	2.16	$	2.8
	Diluted earnings per share	$	2.14	$	2.77
	Potential anti-dilutive share conversions	657,182		634,385

Information_provided_in_connec1

Information provided in connection with outstanding debt of subsidiaries (Tables)	3 Months Ended
	Mar. 31, 2014
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Abstract]	'
Condensed Consolidating Balance Sheet	'
	Condensed Consolidating Balance Sheet at March 31, 2014
	(in millions of U.S. dollars)	ACE			ACE INA			Other ACE			Consolidating			ACE Limited
		Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Consolidated
		(Parent			(Subsidiary			Subsidiaries
		Guarantor)			Issuer)
	Assets
	Investments	$	32		$	18		$	61,995		$	—		$	62,045
	Cash(1)	25			1			1,206			(385		)	847
	Insurance and reinsurance balances receivable	—			—			5,540			(779		)	4,761
	Reinsurance recoverable on losses and loss expenses	—			—			19,531			(8,776		)	10,755
	Reinsurance recoverable on policy benefits	—			—			1,210			(988		)	222
	Value of business acquired	—			—			517			—			517
	Goodwill and other intangible assets	—			—			5,382			—			5,382
	Investments in subsidiaries	29,075			18,368			—			(47,443		)	—
	Due from subsidiaries and affiliates, net	487			—			—			(487		)	—
	Other assets	3			256			13,956			(3,565		)	10,650
	Total assets	$	29,622		$	18,643		$	109,337		$	(62,423	)	$	95,179
	Liabilities
	Unpaid losses and loss expenses	$	—		$	—		$	45,173		$	(8,307	)	$	36,866
	Unearned premiums	—			—			9,584			(1,793		)	7,791
	Future policy benefits	—			—			5,620			(988		)	4,632
	Due to (from) subsidiaries and affiliates, net	—			367			120			(487		)	—
	Affiliated notional cash pooling programs(1)	—			385			—			(385		)	—
	Short-term debt	—			500			1,401			—			1,901
	Long-term debt	—			3,795			13			—			3,808
	Trust preferred securities	—			309			—			—			309
	Other liabilities	253			1,343			11,927			(3,020		)	10,503
	Total liabilities	253			6,699			73,838			(14,980		)	65,810
	Total shareholders’ equity	29,369			11,944			35,499			(47,443		)	29,369
	Total liabilities and shareholders’ equity	$	29,622		$	18,643		$	109,337		$	(62,423	)	$	95,179
	(1)	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
	Condensed Consolidating Balance Sheet at December 31, 2013
	(in millions of U.S. dollars)	ACE			ACE INA			Other ACE			Consolidating			ACE Limited
		Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Consolidated
		(Parent			(Subsidiary			Subsidiaries
		Guarantor)			Issuer)
	Assets
	Investments	$	32		$	10		$	60,886		$	—		$	60,928
	Cash(1)	—			16			748			(185		)	579
	Insurance and reinsurance balances receivable	—			—			5,835			(809		)	5,026
	Reinsurance recoverable on losses and loss expenses	—			—			20,057			(8,830		)	11,227
	Reinsurance recoverable on policy benefits	—			—			1,215			(997		)	218
	Value of business acquired	—			—			536			—			536
	Goodwill and other intangible assets	—			—			5,404			—			5,404
	Investments in subsidiaries	28,351			18,105			—			(46,456		)	—
	Due from subsidiaries and affiliates, net	844			—			—			(844		)	—
	Other assets	5			258			13,788			(3,459		)	10,592
	Total assets	$	29,232		$	18,389		$	108,469		$	(61,580	)	$	94,510
	Liabilities
	Unpaid losses and loss expenses	$	—		$	—		$	45,714		$	(8,271	)	$	37,443
	Unearned premiums	—			—			9,242			(1,703		)	7,539
	Future policy benefits	—			—			5,612			(997		)	4,615
	Due to (from) subsidiaries and affiliates, net	—			714			130			(844		)	—
	Affiliated notional cash pooling programs(1)	185			—			—			(185		)	—
	Short-term debt	—			500			1,401			—			1,901
	Long-term debt	—			3,795			12			—			3,807
	Trust preferred securities	—			309			—			—			309
	Other liabilities	222			1,318			11,655			(3,124		)	10,071
	Total liabilities	407			6,636			73,766			(15,124		)	65,685
	Total shareholders’ equity	28,825			11,753			34,703			(46,456		)	28,825
	Total liabilities and shareholders’ equity	$	29,232		$	18,389		$	108,469		$	(61,580	)	$	94,510
	(1)	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
Condensed Consolidating Statement Of Operations and Comprehensive Income	'
	Condensed Consolidating Statements of Operations and Comprehensive Income
	For the Three Months Ended March 31, 2014	ACE			ACE INA			Other ACE			Consolidating			ACE
		Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Limited
		(Parent			(Subsidiary			Subsidiaries						Consolidated
	(in millions of U.S. dollars)	Guarantor)			Issuer)
	Net premiums written	$	—		$	—		$	4,185		$	—		$	4,185
	Net premiums earned	—			—			3,970			—			3,970
	Net investment income	—			—			553			—			553
	Equity in earnings of subsidiaries	702			180			—			(882		)	—
	Net realized gains (losses) including OTTI	—			(1		)	(103		)	—			(104		)
	Losses and loss expenses	—			—			2,161			—			2,161
	Policy benefits	—			—			114			—			114
	Policy acquisition costs and administrative expenses	17			6			1,240			—			1,263
	Interest (income) expense	(10		)	71			10			—			71
	Other (income) expense	(42		)	14			11			—			(17		)
	Income tax expense (benefit)	3			(30		)	120			—			93
	Net income	$	734		$	118		$	764		$	(882	)	$	734
	Comprehensive income	$	1,108		$	266		$	1,138		$	(1,404	)	$	1,108
	Condensed Consolidating Statements of Operations and Comprehensive Income (Revised)
	For the Three Months Ended March 31, 2013	ACE			ACE INA			Other ACE			Consolidating			ACE
		Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Limited
		(Parent			(Subsidiary			Subsidiaries						Consolidated
	(in millions of U.S. dollars)	Guarantor)			Issuer)
	Net premiums written	$	—		$	—		$	3,798		$	—		$	3,798
	Net premiums earned	—			—			3,573			—			3,573
	Net investment income	—			1			530			—			531
	Equity in earnings of subsidiaries	914			188			—			(1,102		)	—
	Net realized gains (losses) including OTTI	12			—			194			—			206
	Losses and loss expenses	—			—			1,926			—			1,926
	Policy benefits	—			—			131			—			131
	Policy acquisition costs and administrative expenses	15			4			1,109			—			1,128
	Interest (income) expense	(7		)	62			5			—			60
	Other (income) expense	(38		)	9			19			—			(10		)
	Income tax expense (benefit)	3			(33		)	152			—			122
	Net income	$	953		$	147		$	955		$	(1,102	)	$	953
	Comprehensive income (loss)	$	716		$	(1	)	$	718		$	(717	)	$	716
	Condensed Consolidating Statements of Operations and Comprehensive Income (As previously reported)
	For the Three Months Ended March 31, 2013	ACE			ACE INA			Other ACE			Consolidating			ACE
		Limited			Holdings Inc.			Limited			Adjustments (2)			Limited
		(Parent			(Subsidiary			Subsidiaries and						Consolidated
	(in millions of U.S. dollars)	Guarantor)			Issuer)			Eliminations(1)
	Net premiums written	$	—		$	2,082		$	1,716		$	—		$	3,798
	Net premiums earned	—			2,006			1,567			—			3,573
	Net investment income	—			248			283			—			531
	Equity in earnings of subsidiaries	914			—			—			(914		)	—
	Net realized gains (losses) including OTTI	12			10			184			—			206
	Losses and loss expenses	—			1,253			673			—			1,926
	Policy benefits	—			81			50			—			131
	Policy acquisition costs and administrative expenses	15			626			487			—			1,128
	Interest (income) expense	(7		)	67			—			—			60
	Other (income) expense	(38		)	34			(6		)	—			(10		)
	Income tax expense	3			56			63			—			122
	Net income	$	953		$	147		$	767		$	(914	)	$	953
	Comprehensive income (loss)	$	716		$	(1	)	$	915		$	(914	)	$	716
	-1	Includes all other subsidiaries of ACE Limited and intercompany eliminations.
	-2	Includes ACE Limited parent company eliminations.
Condensed Consolidating Statement of Cash Flows	'
	Condensed Consolidating Statement of Cash Flows
	For the Three Months Ended March 31, 2014	ACE			ACE INA			Other ACE			Consolidating			ACE
		Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Limited
		(Parent			(Subsidiary			Subsidiaries						Consolidated
	(in millions of U.S. dollars)	Guarantor)			Issuer)
	Net cash flows from (used for) operating activities	$	57		$	(13	)	$	1,206		$	—		$	1,250
	Cash flows from investing activities
	Purchases of fixed maturities available for sale	—			—			(3,522		)	—			(3,522		)
	Purchases of fixed maturities held to maturity	—			—			(30		)	—			(30		)
	Purchases of equity securities	—			—			(37		)	—			(37		)
	Sales of fixed maturities available for	—			—			2,208			—			2,208
	sale
	Sales of equity securities	—			—			27			—			27
	Maturities and redemptions of fixed maturities available for sale	—			—			1,550			—			1,550
	Maturities and redemptions of fixed maturities held to maturity	—			—			212			—			212
	Net change in short-term investments	—			(8		)	(757		)	—			(765		)
	Net derivative instruments settlements	—			(9		)	(87		)	—			(96		)
	Other	—			(3		)	(47		)	—			(50		)
	Net cash flows used for investing activities	—			(20		)	(483		)	—			(503		)
	Cash flows from financing activities
	Dividends paid on Common Shares	(214		)	—			—			—			(214		)
	Common Shares repurchased	—			—			(335		)	—			(335		)
	Proceeds from share-based compensation plans, including windfall tax benefits	—			—			40			—			40
	Advances (to) from affiliates	367			(367		)	—			—			—
	Net proceeds from (payments to) affiliated notional cash pooling programs(1)	(185		)	385			—			(200		)	—
	Other	—			—			37			—			37
	Net cash flows (used for) from financing activities	(32		)	18			(258		)	(200		)	(472		)
	Effect of foreign currency rate changes on cash and cash equivalents	—			—			(7		)	—			(7		)
	Net increase (decrease) in cash	25			(15		)	458			(200		)	268
	Cash – beginning of period(1)	—			16			748			(185		)	579
	Cash – end of period(1)	$	25		$	1		$	1,206		$	(385	)	$	847
	(1)	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014 and December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
	Condensed Consolidating Statement of Cash Flows (Revised)
	For the Three Months Ended March 31, 2013	ACE			ACE INA			Other ACE			Consolidating			ACE
		Limited			Holdings Inc.			Limited			Adjustments and Eliminations			Limited
		(Parent			(Subsidiary			Subsidiaries						Consolidated
	(in millions of U.S. dollars)	Guarantor)			Issuer)
	Net cash flows from (used for) operating activities	$	25		$	(19	)	$	907		$	—		$	913
	Cash flows from investing activities
	Purchases of fixed maturities available for sale	—			—			(5,568		)	103			(5,465		)
	Purchases of fixed maturities held to maturity	—			—			(142		)	—			(142		)
	Purchases of equity securities	—			—			(107		)	—			(107		)
	Sales of fixed maturities available for sale	—			—			2,867			(103		)	2,764
	Sales of equity securities	—			—			31			—			31
	Maturities and redemptions of fixed maturities available for sale	—			—			2,016			—			2,016
	Maturities and redemptions of fixed maturities held to maturity	—			—			491			—			491
	Net change in short-term investments	—			4			(691		)	—			(687		)
	Net derivative instruments settlements	—			—			(279		)	—			(279		)
	Acquisition of subsidiaries	—			—			(33		)	—			(33		)
	Capital contribution	—			(27		)	—			27			—
	Other	—			2			(57		)	—			(55		)
	Net cash flows used for investing activities	—			(21		)	(1,472		)	27			(1,466		)
	Cash flows from financing activities
	Dividends paid on Common Shares	(2		)	—			—			—			(2		)
	Common Shares repurchased	—			—			(154		)	—			(154		)
	Net proceeds from issuance of long-term debt	—			947			—			—			947
	Net proceeds from issuance of short-term debt	—			—			1			—			1
	Proceeds from share-based compensation plans	—			—			21			—			21
	Advances (to) from affiliates	71			(71		)	—			—			—
	Dividends to parent company	—			—			—			—			—
	Capital contribution	—			—			27			(27		)	—
	Net payments to affiliated notional cash pooling programs(1)	—			(349		)	—			349			—
	Net cash flows from (used for) financing activities	69			527			(105		)	322			813
Effect of foreign currency rate changes on cash and cash equivalents	—			—			(20		)	—			(20		)
Net increase (decrease) in cash	94			487			(690		)	349			240
Cash – beginning of period(1)	103			2			859			(349		)	615
Cash – end of period(1)	$	197		$	489		$	169		$	—		$	855
(1)	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2013 and December 31, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
Condensed Consolidating Statement of Cash Flows (As previously reported)
For the Three Months Ended March 31, 2013	ACE			ACE INA			Other ACE			Consolidating			ACE
	Limited			Holdings Inc.			Limited			Adjustments(2)			Limited
	(Parent			(Subsidiary			Subsidiaries and						Consolidated
(in millions of U.S. dollars)	Guarantor)			Issuer)			Eliminations(1)
Net cash flows from operating activities	$	53		$	644		$	216		$	—		$	913
Cash flows from investing activities
Purchases of fixed maturities available for sale	—			(3,825		)	(2,327		)	—			(6,152		)
Purchases of fixed maturities held to maturity	—			(137		)	(5		)	—			(142		)
Purchases of equity securities	—			(89		)	(18		)	—			(107		)
Sales of fixed maturities available for sale	—			1,473			1,291			—			2,764
Sales of equity securities	—			25			6			—			31
Maturities and redemptions of fixed maturities available for sale	—			879			1,137			—			2,016
Maturities and redemptions of fixed maturities held to maturity	—			351			140			—			491
Net derivative instruments settlements	—			4			(283		)	—			(279		)
Advances from (to) affiliates	43			—			—			(43		)	—
Acquisition of subsidiaries	—			(33		)	—			—			(33		)
Other	—			(86		)	31			—			(55		)
Net cash flows from (used for) investing activities	43			(1,438		)	(28		)	(43		)	(1,466		)
Cash flows from financing activities
Dividends paid on Common Shares	(2		)	—			—			—			(2		)
Common Shares repurchased	—			—			(154		)	—			(154		)
Net proceeds from issuance of long-term debt	—			947			—			—			947
Net proceeds from issuance of short-term debt	—			—			1			—			1
Proceeds from share-based compensation plans, including windfall tax benefits	—			(8		)	29			—			21
Advances (to) from affiliates	—			(71		)	28			43			—
Net cash flows from (used for) financing activities	(2		)	868			(96		)	43			813
Effect of foreign currency rate changes on cash and cash equivalents	—			(29		)	9			—			(20		)
Net increase in cash	94			45			101			—			240
Cash – beginning of period	103			515			(3		)	—			615
Cash – end of period(3)	$	197		$	560		$	98		$	—		$	855
-1	Includes all other subsidiaries of ACE Limited and intercompany eliminations.
-2	Includes ACE Limited parent company eliminations and certain consolidating adjustments.
-3	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

Acquisitions_Detail

Acquisitions (Detail) (USD $)	1 Months Ended		1 Months Ended
In Millions, unless otherwise specified	Apr. 30, 2013	Apr. 02, 2013	31-May-13	2-May-13	Apr. 28, 2014	Jan. 12, 2014
	Fianzas Monterrey [Member]	Fianzas Monterrey [Member]	ABA Seguros [Member]	ABA Seguros [Member]	The Siam Commercial Samaggi Insurance PCL [Member]	The Siam Commercial Samaggi Insurance PCL [Member]
					Subsequent Event [Member]	Subsequent Event [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'
Acquisition purchase price	$293	'	$690	'	'	'
Business Acquisition, Percentage of Voting Interests Acquired	'	'	'	'	'	60.90%
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage	'	'	'	'	'	39.10%
Business Acquisition, Purchase Price Allocation, Goodwill Amount	'	137	'	285	'	'
Business Acquisition, Purchase Price Allocation, Intangible Assets Other than Goodwill	'	73	'	140	'	'
Business Acquisition, Cost of Acquired Entity, Expected Cash Consideration	'	'	'	'	$190	'

Investments_Narrative_Detail

Investments (Narrative) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	Security
Investments, Debt and Equity Securities [Abstract]	'	'	'
Net unrealized appreciation (depreciation) included in OCI	$4,000,000	$24,000,000	'
Net unrealized depreciation included in AOCI	2,000,000	'	4,000,000
Percentage of mortgage-backed securities represented by investments in US government agency bonds	82.00%	'	83.00%
Credit losses recognized in net income for corporate securities	4,000,000	1,000,000	'
Credit losses recognized in net income for mortgage-backed securities	0	0	'
Number of fixed maturities in an unrealized loss position	4,540	'	'
Total number of fixed maturities	24,991	'	'
Largest single unrealized loss in the fixed maturities	5,000,000	'	'
Number of equity securities in an unrealized loss position	58	'	'
Total number of equity securities	186	'	'
Largest single unrealized loss in the equity securities	54,000,000	'	'
Restricted assets in fixed maturities and short-term investments	16,500,000,000	'	16,300,000,000
Restricted assets in cash	$98,000,000	'	$162,000,000

Investments_Schedule_Of_Amorti

Investments (Schedule Of Amortized Cost And Fair Value Of Fixed Maturities And Related Other-Than-Temporary Impairment Recognized In Accumulated Other Comprehensive Income) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investment [Line Items]	'	'
Held to maturity, Amortized Cost	$5,887	$6,098
Held to maturity, Gross Unrealized Appreciation	207	187
Held to maturity, Gross Unrealized Depreciation	-14	-22
Held to maturity, Fair Value	6,080	6,263
Held to maturity, OTTI recognized in AOCI	'	'
Available for sale, Amortized Cost	48,282	48,406
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	1,697	1,465
Available for sale, Gross Unrealized Depreciation	-368	-617
Available for sale, Fair Value	49,611	49,254
Available for sale, OTTI recognized in AOCI	-34	-40
U.S. Treasury And Agency [Member]	'	'
Investment [Line Items]	'	'
Held to maturity, Amortized Cost	777	820
Held to maturity, Gross Unrealized Appreciation	17	16
Held to maturity, Gross Unrealized Depreciation	-4	-4
Held to maturity, Fair Value	790	832
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	2,939	2,946
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	68	62
Available for sale, Gross Unrealized Depreciation	-37	-59
Available for sale, Fair Value	2,970	2,949
Available for sale, OTTI recognized in AOCI	0	0
Foreign [Member]	'	'
Investment [Line Items]	'	'
Held to maturity, Amortized Cost	837	864
Held to maturity, Gross Unrealized Appreciation	37	33
Held to maturity, Gross Unrealized Depreciation	0	0
Held to maturity, Fair Value	874	897
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	14,155	14,336
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	441	377
Available for sale, Gross Unrealized Depreciation	-65	-122
Available for sale, Fair Value	14,531	14,591
Available for sale, OTTI recognized in AOCI	-1	0
Corporate Securities [Member]	'	'
Investment [Line Items]	'	'
Held to maturity, Amortized Cost	1,876	1,922
Held to maturity, Gross Unrealized Appreciation	89	83
Held to maturity, Gross Unrealized Depreciation	0	0
Held to maturity, Fair Value	1,965	2,005
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	16,873	16,825
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	883	777
Available for sale, Gross Unrealized Depreciation	-71	-132
Available for sale, Fair Value	17,685	17,470
Available for sale, OTTI recognized in AOCI	-6	-6
Mortgage Backed-Securities [Member]	'	'
Investment [Line Items]	'	'
Held to maturity, Amortized Cost	1,265	1,341
Held to maturity, Gross Unrealized Appreciation	41	39
Held to maturity, Gross Unrealized Depreciation	0	-1
Held to maturity, Fair Value	1,306	1,379
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	10,916	10,937
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	210	184
Available for sale, Gross Unrealized Depreciation	-155	-227
Available for sale, Fair Value	10,971	10,894
Available for sale, OTTI recognized in AOCI	-27	-34
States, Municipalities, And Political Subdivisions [Member]	'	'
Investment [Line Items]	'	'
Held to maturity, Amortized Cost	1,132	1,151
Held to maturity, Gross Unrealized Appreciation	23	16
Held to maturity, Gross Unrealized Depreciation	-10	-17
Held to maturity, Fair Value	1,145	1,150
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	3,399	3,362
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	95	65
Available for sale, Gross Unrealized Depreciation	-40	-77
Available for sale, Fair Value	3,454	3,350
Available for sale, OTTI recognized in AOCI	$0	$0

Investments_Schedule_Of_Fixed_

Investments (Schedule Of Fixed Maturities By Contractual Maturity) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'	'
Available for sale, Due in 1 year or less, Amortized Cost	$2,504	$2,387
Available for sale, Due after 1 year through 5 years, Amortized Cost	14,199	14,139
Available for sale, Due after 5 years though 10 years, Amortized Cost	15,947	16,200
Available for sale, Due after 10 years, Amortized Cost	4,716	4,743
Available for sale, Subtotal, Amortized Cost	37,366	37,469
Available for sale, Mortgage-backed securities, Amortized Cost	10,916	10,937
Available for sale, Amortized Cost	48,282	48,406
Available for sale, Fair Value	49,611	49,254
Held to maturity, Due in 1 year or less, Amortized Cost	539	401
Held to maturity, Due after 1 year through 5 years, Amortized Cost	2,419	2,284
Held to maturity, Due after 5 years through 10 years, Amortized Cost	1,304	1,686
Held to maturity, Due after 10 years, Amortized Cost	360	386
Held to maturity, Subtotal, Amortized Cost	4,622	4,757
Held to maturity, Mortgage backed securities, Amortized Cost	1,265	1,341
Available for sale, Due in 1 year or less, Fair Value	2,528	2,411
Available for sale, Due after 1 year through 5 years, Fair Value	14,713	14,602
Available for sale, Due after 5 years through 10 years, Fair Value	16,460	16,535
Available for sale, Due after 10 years, Fair Value	4,939	4,812
Available for sale, Subtotal, Fair Value	38,640	38,360
Available for sale, Mortgage backed securities, Fair Value	10,971	10,894
Held to maturity, Due in 1 year or less, Fair Value	547	405
Held to maturity, Due after 1 year through 5, Fair Value	2,503	2,363
Held to maturity, Due after 5 years through 10 years, Fair Value	1,345	1,723
Held to maturity, Due after 10 years, Fair Value	379	393
Held to maturity, Subtotal, Fair Value	4,774	4,884
Held to maturity, Mortgage backed securities, Fair Value	1,306	1,379
Held-to-maturity Securities	5,887	6,098
Held to maturity, Fair Value	$6,080	$6,263

Investments_Schedule_Of_Cost_A

Investments (Schedule Of Cost And Fair Value Of Equity Securities) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'	'
Cost	$845	$841
Gross unrealized appreciation	64	63
Gross unrealized depreciation	-58	-67
Fair value	$851	$837

Investments_Net_Realized_Gains

Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Investments, Debt and Equity Securities [Abstract]	'	'
OTTI on fixed maturities, gross	($6)	($1)
OTTI on fixed maturities recognized in OCI (pre-tax)	1	0
OTTI on fixed maturities, net	-5	-1
Fixed maturities, Gross realized gains excluding OTTI	36	62
Fixed maturities, Gross realized losses excluding OTTI	-20	-25
Total fixed maturities	11	36
OTTI on equity securities	-6	-1
Equity securities, Gross realized gains excluding OTTI	2	2
Equity securities, Gross realized losses excluding OTTI	-1	-2
Total equity securities	-5	-1
OTTI on other investments	0	-1
Foreign exchange gains (losses)	-9	76
Investment and embedded derivative instruments	-25	18
Fair value adjustments on insurance derivative	-48	328
S&P put options and futures	-19	-250
Other derivative instruments	-2	0
Other	-7	0
Total net realized gains (losses)	($104)	$206

Investments_RollForward_Of_Pre

Investments (Roll-Forward Of Pre-Tax Credit Losses Related To Fixed Maturities For Which Portion Of Other-Than-Temporary Impairment Was Recognized In Other Comprehensive Income) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Roll-Forward Of Pre-Tax Credit Losses Related To Fixed Maturities For Which Portion Of Other-Than-Temporary Impairment Was Recognized In Other Comprehensive Income [Roll Forward]	'	'
Balance of credit losses related to securities still held – beginning of period	$37	$43
Additions where no OTTI was previously recorded	2	0
Additions where an OTTI was previously recorded	2	1
Reductions for securities sold during the period	-6	-9
Balance of credit losses related to securities still held – end of period	$35	$35

Investments_Aggregate_Fair_Val

Investments (Aggregate Fair Value And Gross Unrealized Loss By Length Of Time Security Has Continuously Been In Unrealized Loss Position) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investment [Line Items]	'	'
Investment securities, Unrealized loss position, 0-12 Months, Fair Value	$14,040	$18,228
Investment securities, Unrealized loss position, 0-12 Months, Gross Unrealized Loss	-383	-652
Investment securities, Unrealized loss position, Over 12 Months, Fair Value	1,090	894
Investment securities, Unrealized loss position, Over 12 Months, Gross Unrealized Loss	-62	-63
Investment securities, Unrealized loss position, Total Fair Value	15,130	19,122
Investment securities, Unrealized loss position, Total Gross Unrealized Loss	-445	-715
US Treasury and Government [Member]	'	'
Investment [Line Items]	'	'
Investment securities, Unrealized loss position, 0-12 Months, Fair Value	1,609	1,794
Investment securities, Unrealized loss position, 0-12 Months, Gross Unrealized Loss	-37	-57
Investment securities, Unrealized loss position, Over 12 Months, Fair Value	33	31
Investment securities, Unrealized loss position, Over 12 Months, Gross Unrealized Loss	-4	-6
Investment securities, Unrealized loss position, Total Fair Value	1,642	1,825
Investment securities, Unrealized loss position, Total Gross Unrealized Loss	-41	-63
Foreign Government Debt Securities [Member]	'	'
Investment [Line Items]	'	'
Investment securities, Unrealized loss position, 0-12 Months, Fair Value	2,988	4,621
Investment securities, Unrealized loss position, 0-12 Months, Gross Unrealized Loss	-56	-114
Investment securities, Unrealized loss position, Over 12 Months, Fair Value	259	201
Investment securities, Unrealized loss position, Over 12 Months, Gross Unrealized Loss	-9	-8
Investment securities, Unrealized loss position, Total Fair Value	3,247	4,822
Investment securities, Unrealized loss position, Total Gross Unrealized Loss	-65	-122
Corporate Securities [Member]	'	'
Investment [Line Items]	'	'
Investment securities, Unrealized loss position, 0-12 Months, Fair Value	2,940	3,836
Investment securities, Unrealized loss position, 0-12 Months, Gross Unrealized Loss	-58	-118
Investment securities, Unrealized loss position, Over 12 Months, Fair Value	211	194
Investment securities, Unrealized loss position, Over 12 Months, Gross Unrealized Loss	-13	-14
Investment securities, Unrealized loss position, Total Fair Value	3,151	4,030
Investment securities, Unrealized loss position, Total Gross Unrealized Loss	-71	-132
Collateralized Mortgage Backed Securities [Member]	'	'
Investment [Line Items]	'	'
Investment securities, Unrealized loss position, 0-12 Months, Fair Value	4,367	5,248
Investment securities, Unrealized loss position, 0-12 Months, Gross Unrealized Loss	-130	-197
Investment securities, Unrealized loss position, Over 12 Months, Fair Value	398	384
Investment securities, Unrealized loss position, Over 12 Months, Gross Unrealized Loss	-25	-31
Investment securities, Unrealized loss position, Total Fair Value	4,765	5,632
Investment securities, Unrealized loss position, Total Gross Unrealized Loss	-155	-228
US States and Political Subdivisions Debt Securities [Member]	'	'
Investment [Line Items]	'	'
Investment securities, Unrealized loss position, 0-12 Months, Fair Value	1,575	2,164
Investment securities, Unrealized loss position, 0-12 Months, Gross Unrealized Loss	-39	-90
Investment securities, Unrealized loss position, Over 12 Months, Fair Value	189	84
Investment securities, Unrealized loss position, Over 12 Months, Gross Unrealized Loss	-11	-4
Investment securities, Unrealized loss position, Total Fair Value	1,764	2,248
Investment securities, Unrealized loss position, Total Gross Unrealized Loss	-50	-94
Fixed Maturities [Member]	'	'
Investment [Line Items]	'	'
Investment securities, Unrealized loss position, 0-12 Months, Fair Value	13,479	17,663
Investment securities, Unrealized loss position, 0-12 Months, Gross Unrealized Loss	-320	-576
Investment securities, Unrealized loss position, Over 12 Months, Fair Value	1,090	894
Investment securities, Unrealized loss position, Over 12 Months, Gross Unrealized Loss	-62	-63
Investment securities, Unrealized loss position, Total Fair Value	14,569	18,557
Investment securities, Unrealized loss position, Total Gross Unrealized Loss	-382	-639
Equity Securities [Member]	'	'
Investment [Line Items]	'	'
Investment securities, Unrealized loss position, 0-12 Months, Fair Value	496	498
Investment securities, Unrealized loss position, 0-12 Months, Gross Unrealized Loss	-58	-67
Investment securities, Unrealized loss position, Over 12 Months, Fair Value	0	0
Investment securities, Unrealized loss position, Over 12 Months, Gross Unrealized Loss	0	0
Investment securities, Unrealized loss position, Total Fair Value	496	498
Investment securities, Unrealized loss position, Total Gross Unrealized Loss	-58	-67
Other Long-term Investments [Member]	'	'
Investment [Line Items]	'	'
Investment securities, Unrealized loss position, 0-12 Months, Fair Value	65	67
Investment securities, Unrealized loss position, 0-12 Months, Gross Unrealized Loss	-5	-9
Investment securities, Unrealized loss position, Over 12 Months, Fair Value	0	0
Investment securities, Unrealized loss position, Over 12 Months, Gross Unrealized Loss	0	0
Investment securities, Unrealized loss position, Total Fair Value	65	67
Investment securities, Unrealized loss position, Total Gross Unrealized Loss	($5)	($9)

Investments_Schedule_Of_Compon

Investments (Schedule Of Components Of Restricted Assets) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]	'	'
Trust funds	$11,385	$11,315
Deposits with non-U.S. regulatory authorities	1,962	1,970
Assets pledged under repurchase agreements	1,452	1,435
Deposits with U.S. regulatory authorities	1,334	1,334
Other pledged assets	420	391
Total restricted assets	$16,553	$16,445

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Fair Value Measurements Of Financial Instruments [Line Items]	'	'
Level 1 to Level 2 Transfers	'	$13
Level 2 to Level 1 Transfers	0	0
Guaranteed Living Benefits, Net Income Impact From Model Refinement	$3	'
Redemption Notice Periods Lower Range [Member]	'	'
Fair Value Measurements Of Financial Instruments [Line Items]	'	'
Notice period for redemption for alternative investments investment funds, days	'5 days	'
Redemption Notice Periods Upper Range [Member]	'	'
Fair Value Measurements Of Financial Instruments [Line Items]	'	'
Notice period for redemption for alternative investments investment funds, days	'120 days	'

Fair_Value_Measurements_Financ

Fair Value Measurements (Financial Instruments Measured At Fair Value On Recurring Basis) (Detail) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	$49,611		$49,254
Equity securities, at fair value	851		837
Short-term investments	2,526		1,763
Other investments	3,170		2,976
Securities lending collateral	1,550		1,632
Fair Value, Inputs, Level 1 [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	1,942		1,849
Equity securities, at fair value	380		373
Short-term investments	1,590		953
Other investments	314		305
Investment derivative instruments, assets	8		19
Other derivative instruments, assets	7		0
Separate account assets	1,193		1,145
Total assets measured at fair value	5,434		4,644
Investment derivative instruments, liabilities	6		6
Other derivative instruments, liability	12		60
GLB	0	[1]	0	[1]
Total liabilities measured at fair value	18		66
Fair Value, Inputs, Level 1 [Member] | U.S. Treasury And Agency [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	1,709		1,626
Fair Value, Inputs, Level 1 [Member] | Foreign [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	233		223
Fair Value, Inputs, Level 1 [Member] | Corporate Securities [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	0		0
Fair Value, Inputs, Level 2 [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	47,484		47,187
Equity securities, at fair value	469		460
Short-term investments	936		803
Other investments	245		231
Securities lending collateral	1,550		1,632
Other derivative instruments, assets	0		6
Separate account assets	83		81
Total assets measured at fair value	50,767		50,400
Investment derivative instruments, liabilities	0		0
Other derivative instruments, liability	2		2
GLB	0	[1]	0	[1]
Total liabilities measured at fair value	2		2
Fair Value, Inputs, Level 2 [Member] | U.S. Treasury And Agency [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	1,261		1,323
Fair Value, Inputs, Level 2 [Member] | Foreign [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	14,272		14,324
Fair Value, Inputs, Level 2 [Member] | Corporate Securities [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	17,534		17,304
Fair Value, Inputs, Level 2 [Member] | Mortgage Backed-Securities [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	10,963		10,886
Fair Value, Inputs, Level 2 [Member] | States, Municipalities, And Political Subdivisions [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	3,454		3,350
Fair Value, Inputs, Level 3 [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	185		218
Equity securities, at fair value	2		4
Short-term investments	0		7
Other investments	2,611		2,440
Other derivative instruments, assets	0		0
Total assets measured at fair value	2,798		2,669
Investment derivative instruments, liabilities	0		0
Other derivative instruments, liability	0		0
GLB	243	[1]	193	[1]
Total liabilities measured at fair value	243		193
Fair Value, Inputs, Level 3 [Member] | U.S. Treasury And Agency [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Foreign [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	26		44
Fair Value, Inputs, Level 3 [Member] | Corporate Securities [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	151		166
Fair Value, Inputs, Level 3 [Member] | Mortgage Backed-Securities [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	8		8
Fair Value, Inputs, Level 3 [Member] | States, Municipalities, And Political Subdivisions [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	0		0
Estimate of Fair Value, Fair Value Disclosure [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	49,611		49,254
Equity securities, at fair value	851		837
Short-term investments	2,526		1,763
Other investments	3,170		2,976
Securities lending collateral	1,550		1,632
Investment derivative instruments, assets	8		19
Other derivative instruments, assets	7		6
Separate account assets	1,276		1,226
Total assets measured at fair value	58,999		57,713
Investment derivative instruments, liabilities	6		6
Other derivative instruments, liability	14		62
GLB	243	[1]	193	[1]
Total liabilities measured at fair value	263		261
Estimate of Fair Value, Fair Value Disclosure [Member] | U.S. Treasury And Agency [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	2,970		2,949
Estimate of Fair Value, Fair Value Disclosure [Member] | Foreign [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	14,531		14,591
Estimate of Fair Value, Fair Value Disclosure [Member] | Corporate Securities [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	17,685		17,470
Estimate of Fair Value, Fair Value Disclosure [Member] | Mortgage Backed-Securities [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	10,971		10,894
Estimate of Fair Value, Fair Value Disclosure [Member] | States, Municipalities, And Political Subdivisions [Member]	'		'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'		'
Fixed maturities available for sale at fair value	$3,454		$3,350
[1]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.

Fair_Value_Measurements_Fair_V

Fair Value Measurements (Fair Value And Maximum Future Funding Commitments Related To Investments) (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fair Value [Member]	'	'
Fair Value And Maximum Future Funding Commitments Related To Investments [Line Items]	'	'
Financial	271	256
Real estate	319	322
Distressed	243	180
Mezzanine	290	276
Traditional	882	813
Vintage	12	13
Investment funds	440	428
Total of alternative investments	2,457	2,288
Maximum Future Funding Commitments [Member]	'	'
Fair Value And Maximum Future Funding Commitments Related To Investments [Line Items]	'	'
Financial	122	129
Real estate	63	92
Distressed	169	230
Mezzanine	235	252
Traditional	414	456
Vintage	0	0
Total of alternative investments	1,003	1,159
Expected Liquidation Period Lower Range [Member]	'	'
Fair Value And Maximum Future Funding Commitments Related To Investments [Line Items]	'	'
Liquidation period for financial alternative investments (in years)	'5 years	'5 years
Liquidation period for real estate alternative investments (in years)	'3 years	'3 years
Liquidation period for distressed alternative investments (in years)	'6 years	'6 years
Liquidation period for mezzanine alternative investments (in years)	'6 years	'6 years
Liquidation period for traditional alternative investments (in years)	'3 years	'3 years
Liquidation period for vintage alternative investments (in years)	'1 year	'1 year
Expected Liquidation Period Upper Range [Member]	'	'
Fair Value And Maximum Future Funding Commitments Related To Investments [Line Items]	'	'
Liquidation period for financial alternative investments (in years)	'9 years	'9 years
Liquidation period for real estate alternative investments (in years)	'9 years	'9 years
Liquidation period for distressed alternative investments (in years)	'9 years	'9 years
Liquidation period for mezzanine alternative investments (in years)	'9 years	'9 years
Liquidation period for traditional alternative investments (in years)	'8 years	'8 years
Liquidation period for vintage alternative investments (in years)	'3 years	'3 years

Fair_Value_Measurements_Schedu

Fair Value Measurements (Schedule Of Significant Unobservable Inputs Used In Level 3 Liability Valuations) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013		Dec. 31, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'		'		'		'
Valuation Technique	'Actuarial model	[1]	'		'		'
Minimum [Member]	'		'		'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'		'		'		'
Significant Unobservable Inputs Lapse rate	1.00%	[1]	'		'		'
Significant Unobservable Inputs Annuitization rate	0.00%	[1]	'		'		'
Maximum [Member]	'		'		'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'		'		'		'
Significant Unobservable Inputs Lapse rate	30.00%	[1]	'		'		'
Significant Unobservable Inputs Annuitization rate	50.00%	[1]	'		'		'
Guaranteed Minimum Income Benefit [Member]	'		'		'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'		'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	$243	[2]	$753	[2]	$193	[2]	$1,119	[2]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	50	[2]	-366	[2]	'		'
Fair Value	243	[1]	'		193		'
Short-term Investments [Member]	'		'		'		'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'		'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	0		'		7		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	$0		'		'		'
[1]	Discussion of the most significant inputs used in the fair value measurement of GLB and the sensitivity of those assumptions is included within Note 4 a) Guaranteed living benefits.
[2]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.

Fair_Value_Measurements_Financ1

Fair Value Measurements (Financial Instruments Measured At Fair Value Using Significant Unobservable Inputs) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013		Dec. 31, 2012
Equity Securities [Member]	'		'		'		'
Schedule Of Fair Value Measurements [Line Items]	'		'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	$0		$0		'		'
Balance- Beginning of Period, Assets	4		3		'		'
Transfers out of Level 3, Assets	-2		-1		'		'
Change in Net Unrealized Gains (Losses) included in OCI, Assets	1		0		'		'
Net Realized Gains/Losses, Assets	'		0		'		'
Purchases, Assets	1		0		'		'
Sales, Assets	-2		0		'		'
Settlements, Assets	'		0		'		'
Balance-End of Period, Assets	2		2		'		'
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	'		0		'		'
Short-term Investments [Member]	'		'		'		'
Schedule Of Fair Value Measurements [Line Items]	'		'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		'		'		'
Balance- Beginning of Period, Assets	7		'		'		'
Transfers out of Level 3, Assets	-7		'		'		'
Purchases, Assets	0		'		'		'
Balance-End of Period, Assets	0		'		'		'
Other Long-term Investments [Member]	'		'		'		'
Schedule Of Fair Value Measurements [Line Items]	'		'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0		'		'
Balance- Beginning of Period, Assets	2,440		2,252		'		'
Transfers out of Level 3, Assets	'		0		'		'
Change in Net Unrealized Gains (Losses) included in OCI, Assets	41		22		'		'
Net Realized Gains/Losses, Assets	0		-1		'		'
Purchases, Assets	200		136		'		'
Sales, Assets	-1		-9		'		'
Settlements, Assets	-69		-72		'		'
Balance-End of Period, Assets	2,611		2,328		'		'
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	0		-1		'		'
Available-for-sale Securities [Member] | Foreign [Member]	'		'		'		'
Schedule Of Fair Value Measurements [Line Items]	'		'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		3		'		'
Balance- Beginning of Period, Assets	44		60		'		'
Transfers out of Level 3, Assets	-18		-27		'		'
Change in Net Unrealized Gains (Losses) included in OCI, Assets	-1		0		'		'
Net Realized Gains/Losses, Assets	0		1		'		'
Purchases, Assets	2		0		'		'
Sales, Assets	-1		-1		'		'
Settlements, Assets	0		-1		'		'
Balance-End of Period, Assets	26		35		'		'
Available-for-sale Securities [Member] | Corporate Debt Securities [Member]	'		'		'		'
Schedule Of Fair Value Measurements [Line Items]	'		'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	4		12		'		'
Balance- Beginning of Period, Assets	166		102		'		'
Transfers out of Level 3, Assets	-22		-2		'		'
Change in Net Unrealized Gains (Losses) included in OCI, Assets	0		1		'		'
Net Realized Gains/Losses, Assets	0		0		'		'
Purchases, Assets	15		10		'		'
Sales, Assets	-6		0		'		'
Settlements, Assets	-6		-5		'		'
Balance-End of Period, Assets	151		118		'		'
Available-for-sale Securities [Member] | Mortgage Backed-Securities [Member]	'		'		'		'
Schedule Of Fair Value Measurements [Line Items]	'		'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0		'		'
Balance- Beginning of Period, Assets	8		13		'		'
Transfers out of Level 3, Assets	0		0		'		'
Change in Net Unrealized Gains (Losses) included in OCI, Assets	'		0		'		'
Net Realized Gains/Losses, Assets	'		0		'		'
Purchases, Assets	0		0		'		'
Sales, Assets	0		0		'		'
Settlements, Assets	0		0		'		'
Balance-End of Period, Assets	8		13		'		'
Guaranteed Minimum Income Benefit [Member]	'		'		'		'
Schedule Of Fair Value Measurements [Line Items]	'		'		'		'
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	243	[1]	753	[1]	193	[1]	1,119	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	50	[1]	-366	[1]	'		'
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Liabilities	50		-366		'		'
Reported liabilities	$483		$1,000		$427		$1,400
[1]	Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.

Fair_Value_Measurements_Carryi

Fair Value Measurements (Carrying Values And Fair Values Of Financial Instruments Not Measured At Fair Value) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Financial Instruments Fair Value [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	$6,080	$6,263
Partially-owned insurance companies	466	470
Total assets	6,546	6,733
Short-term debt	1,907	1,913
Long-term debt	4,139	4,088
Trust preferred securities	452	438
Total liabilities	6,498	6,439
Financial Instruments Fair Value [Member] | U.S. Treasury And Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	790	832
Financial Instruments Fair Value [Member] | Foreign [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	874	897
Financial Instruments Fair Value [Member] | Corporate Debt Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	1,965	2,005
Financial Instruments Fair Value [Member] | Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	1,306	1,379
Financial Instruments Fair Value [Member] | US States and Political Subdivisions Debt Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	1,145	1,150
Fair Value, Inputs, Level 1 [Member] | Financial Instruments Fair Value [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	595	596
Total assets	595	596
Fair Value, Inputs, Level 1 [Member] | Financial Instruments Fair Value [Member] | U.S. Treasury And Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	595	596
Fair Value, Inputs, Level 2 [Member] | Financial Instruments Fair Value [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	5,469	5,652
Total assets	5,469	5,652
Short-term debt	1,907	1,913
Long-term debt	4,139	4,088
Trust preferred securities	452	438
Total liabilities	6,498	6,439
Fair Value, Inputs, Level 2 [Member] | Financial Instruments Fair Value [Member] | U.S. Treasury And Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	195	236
Fair Value, Inputs, Level 2 [Member] | Financial Instruments Fair Value [Member] | Foreign [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	874	897
Fair Value, Inputs, Level 2 [Member] | Financial Instruments Fair Value [Member] | Corporate Debt Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	1,949	1,990
Fair Value, Inputs, Level 2 [Member] | Financial Instruments Fair Value [Member] | Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	1,306	1,379
Fair Value, Inputs, Level 2 [Member] | Financial Instruments Fair Value [Member] | US States and Political Subdivisions Debt Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	1,145	1,150
Fair Value, Inputs, Level 3 [Member] | Financial Instruments Fair Value [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	16	15
Partially-owned insurance companies	466	470
Total assets	482	485
Fair Value, Inputs, Level 3 [Member] | Financial Instruments Fair Value [Member] | U.S. Treasury And Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	0	0
Fair Value, Inputs, Level 3 [Member] | Financial Instruments Fair Value [Member] | Corporate Debt Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	16	15
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Financial Instruments Carrying Value [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	5,887	6,098
Partially-owned insurance companies	466	470
Total assets	6,353	6,568
Short-term debt	1,901	1,901
Long-term debt	3,808	3,807
Trust preferred securities	309	309
Total liabilities	6,018	6,017
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Financial Instruments Carrying Value [Member] | U.S. Treasury And Agency [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	777	820
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Financial Instruments Carrying Value [Member] | Foreign [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	837	864
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Financial Instruments Carrying Value [Member] | Corporate Debt Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	1,876	1,922
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Financial Instruments Carrying Value [Member] | Collateralized Mortgage Backed Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	1,265	1,341
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Financial Instruments Carrying Value [Member] | US States and Political Subdivisions Debt Securities [Member]	'	'
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'
Total Fixed maturities held to maturity	$1,132	$1,151

Recovered_Sheet1

Assumed Life Reinsurance Programs Involving Minimum Benefit Guarantees Under Annuity Contracts (Schedule Of Guaranteed Minimum Benefits Income And Expense) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Guaranteed Minimum Benefits [Line Items]	'	'
Net premiums earned	$3,970	$3,573
Policy benefits and other reserve adjustments	114	131
Net realized gains (losses)	-104	206
Guaranteed Minimum Death Benefit [Member]	'	'
Guaranteed Minimum Benefits [Line Items]	'	'
Net premiums earned	19	20
Policy benefits and other reserve adjustments	15	19
Guaranteed Minimum Income Benefit [Member]	'	'
Guaranteed Minimum Benefits [Line Items]	'	'
Net premiums earned	36	39
Policy benefits and other reserve adjustments	9	9
Net realized gains (losses)	-50	369
Gain (loss) recognized in income	-23	399
Net cash received	33	32
Net (increase) decrease in liability	($56)	$367

Recovered_Sheet2

Assumed Life Reinsurance Programs Involving Minimum Benefit Guarantees Under Annuity Contracts (Narrative) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013
		Guaranteed Minimum Death Benefit [Member]	Guaranteed Minimum Death Benefit [Member]	Guaranteed Minimum Income Benefit [Member]	Guaranteed Minimum Income Benefit [Member]	Guaranteed Minimum Income Benefit [Member]	Guaranteed Minimum Income Benefit [Member]	Guaranteed Minimum Deaths Benefits And Guaranteed Living Benefits [Member]	Guaranteed Minimum Deaths Benefits And Guaranteed Living Benefits [Member]	Guaranteed Living Benefits [Member]	Guaranteed Living Benefits [Member]
Guaranteed Minimum Benefits [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Reported liabilities	'	$104	$100	$483	$427	$1,000	$1,400	'	'	'	'
Fair value derivative adjustment in liability	'	'	'	243	193	'	'	'	'	'	'
Net amount at risk	'	645	586	'	'	'	'	'	'	163	136
Mortality percentage according to Annuity 2000 mortality table	'	'	'	'	'	'	'	'	'	100.00%	'
Discounting assumption used in the calculation of the benefit reserve averaging - lower range	'	1.50%	'	'	'	'	'	3.00%	'	3.50%	'
Discounting assumption used in the calculation of the benefit reserve averaging - upper range	'	2.50%	'	'	'	'	'	4.00%	'	4.50%	'
Total claim amount payable, if all of the Company's cedants' policyholders covered were to die immediately	'	666	'	'	'	'	'	93	'	'	'
GMBD net amount of risk	'	'	'	'	'	'	'	73	'	'	'
GLB net amount of risk	'	'	'	'	'	'	'	$158	$141	'	'
Average attained age of all policyholders under all benefits reinsured, years	'68 years	'	'	'	'	'	'	'	'	'	'

Recovered_Sheet3

Commitments, Contingencies, And Guarantees (Balance Sheet Locations, Fair Values In Asset Or (Liability) Position, And Notional Values/Payment Provisions Of Derivative Instruments) (Detail) (USD $)	Mar. 31, 2014		Dec. 31, 2013
In Millions, unless otherwise specified
Foreign Exchange Future [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Notional Value/Payment Provision	$1,469		$1,202
Cross Currency Swap [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Notional Value/Payment Provision	50		50
Futures Contracts On Money Market Instruments [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Notional Value/Payment Provision	3,910		3,910
Futures contracts on notes and bonds [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Notional Value/Payment Provision	903		871
Convertibles and Bonds with Warrants Attached [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Notional Value/Payment Provision	272		254
Investment And Embedded Derivative Instruments [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	327		321
Notional Value/Payment Provision	6,604		6,287
Single-Stock Future [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	'		0	[1]
Notional Value/Payment Provision	1,453	[1]	1,692	[1]
Options On Equity Market Indices [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	'		6	[1]
Notional Value/Payment Provision	250	[1]	250	[1]
Other Derivatives [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Notional Value/Payment Provision	64		8
Other Derivative Instruments [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Notional Value/Payment Provision	1,767		1,950
Guaranteed Living Benefits [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	'		0	[2]
Notional Value/Payment Provision	321	[2]	277	[2]
Other Assets [Member] | Foreign Exchange Future [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	2		3
Other Assets [Member] | Futures Contracts On Money Market Instruments [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	4		3
Other Assets [Member] | Futures contracts on notes and bonds [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	2		13
Other Assets [Member] | Single-Stock Future [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	0	[1]	'
Other Assets [Member] | Options On Equity Market Indices [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	0	[1]	'
Other Assets [Member] | Other Derivatives [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	7		'
Other Assets [Member] | Other Derivative Instruments [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	7		6
Other Assets [Member] | Guaranteed Living Benefits [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	0	[2]	'
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Foreign Exchange Future [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	-4		-4
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Futures Contracts On Money Market Instruments [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	0		0
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Futures contracts on notes and bonds [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	-2		-2
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Investment And Embedded Derivative Instruments [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	-6		-6
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Single-Stock Future [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	-12	[1]	-60	[1]
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Options On Equity Market Indices [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	0	[1]	0	[1]
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivatives [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	-2		-2
Accounts Payable, Accrued Expenses, And Other Liabilities [Member] | Other Derivative Instruments [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	-14		-62
Fixed Maturities Available For Sale [Member] | Convertibles and Bonds with Warrants Attached [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	319		302
Accounts Payable Future Policy Benefits [Member] | Guaranteed Living Benefits [Member]	'		'
Derivatives, Fair Value [Line Items]	'		'
Fair Value	($483)	[2]	($427)	[2]
[1]	(2) Related to GMDB and GLB blocks of business.
[2]	(3) Includes both future policy benefits reserves and fair value derivative adjustment. Refer to Note 5 for additional information. Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.

Recovered_Sheet4

Commitments, Contingencies, And Guarantees (Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Net realized gains (losses)	($94)		$96		'
Foreign Exchange Future [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Notional Value Payment Provision	1,469		'		1,202
Net realized gains (losses)	-3		5		'
All Other Futures Contracts And Options [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Net realized gains (losses)	-22		7		'
Convertibles and Bonds with Warrants Attached [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Notional Value Payment Provision	272		'		254
Net realized gains (losses)	0		6		'
Investment And Embedded Derivative Instruments [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	327		'		321
Derivative Instruments Notional Value Payment Provision	6,604		'		6,287
Net realized gains (losses)	-25		18		'
Guaranteed Living Benefits [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	'		'		0	[1]
Derivative Instruments Notional Value Payment Provision	321	[1]	'		277	[1]
Net realized gains (losses)	-48	[2]	328	[2]	'
Single-Stock Future [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	'		'		0	[3]
Derivative Instruments Notional Value Payment Provision	1,453	[3]	'		1,692	[3]
Net realized gains (losses)	-17	[4]	-237	[4]	'
Options On Equity Market Indices [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	'		'		6	[3]
Derivative Instruments Notional Value Payment Provision	250	[3]	'		250	[3]
Net realized gains (losses)	-2	[4]	-13	[4]	'
Guaranteed Living Benefit And Other Derivative Instruments [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Net realized gains (losses)	-69		78		'
Other Derivatives [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Notional Value Payment Provision	64		'		8
Net realized gains (losses)	-2		0		'
Balance Sheet Location Fixed Maturities Available For Sale [Member] | Convertibles and Bonds with Warrants Attached [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	319		'		302
Balance Sheet Location Accounts Payable [Member] | Foreign Exchange Future [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	-4		'		-4
Balance Sheet Location Accounts Payable [Member] | Investment And Embedded Derivative Instruments [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	-6		'		-6
Balance Sheet Location Accounts Payable [Member] | Single-Stock Future [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	-12	[3]	'		-60	[3]
Balance Sheet Location Accounts Payable [Member] | Options On Equity Market Indices [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	0	[3]	'		0	[3]
Balance Sheet Location Accounts Payable [Member] | Other Derivatives [Member]	'		'		'
Commitments Contingencies And Guarantees [Line Items]	'		'		'
Derivative Instruments Fair Value	($2)		'		($2)
[1]	(3) Includes both future policy benefits reserves and fair value derivative adjustment. Refer to Note 5 for additional information. Note that the payment provision related to GLB is the net amount at risk. The concept of a notional value does not apply to the GLB reinsurance contracts.
[2]	Excludes foreign exchange gains (losses) related to GLB.
[3]	(2) Related to GMDB and GLB blocks of business.
[4]	Related to GMDB and GLB blocks of business.

Commitments_Contingencies_And_2

Commitments, Contingencies, And Guarantees (Narrative) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'	'
Carrying value of limited partnerships and partially-owned investment companies included in other investments	$2,000,000,000	'
Funding commitments relating to limited partnerships and partially-owned investment companies	1,000,000,000	'
Derivative asset subject to a master netting agreement	10,000,000	41,000,000
Repurchase obligations	1,401,000,000	1,401,000,000
Securities lending payable	1,551,000,000	1,633,000,000
Securities lending collateral	1,550,000,000	1,632,000,000
Unrecognized tax benefits	$26,000,000	'

Shareholders_Equity_Detail

Shareholders' Equity (Detail)	3 Months Ended			1 Months Ended	3 Months Ended	1 Months Ended
	Mar. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Nov. 30, 2013	Mar. 31, 2014	1-May-14
	USD ($)	CHF	CHF	November 2013 Stock Repurchase Plan [Member]	November 2013 Stock Repurchase Plan [Member]	November 2013 Stock Repurchase Plan [Member]
				USD ($)	USD ($)	Subsequent Event [Member]
						USD ($)
Equity, Class of Treasury Stock [Line Items]	'	'	'	'	'	'
Share repurchase amount	'	'	'	'	$332,000,000	$53,000,000
Repurchase of outstanding common shares, shares	'	'	'	'	3,487,882	531,000
Share repurchase authorization remains	'	'	'	'	1,610,000,000	1,560,000,000
Common Shares in treasury, shares	4,857,768	4,857,768	3,038,477	'	'	'
Stock repurchase program, authorized amount	'	'	'	$2,000,000,000	'	'
Increase to dividend approved by shareholders in January	$0.12	'	'	'	'	'
Dividends declared per common share	$0.75	0.65	'	'	'	'
Par Value Reduction	$0.51	0.45	'	'	'	'
Common Shares, par value	'	26.59	27.04	'	'	'

ShareBased_Compensation_Detail

Share-Based Compensation (Detail) (USD $)	3 Months Ended	0 Months Ended
	Mar. 31, 2014	Feb. 27, 2014	Feb. 27, 2014	Feb. 27, 2014
		Stock Options [Member]	Restricted Stock [Member]	Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Stock option vesting period in years	'3 years	'	'	'
Stock option term in years	'10 years	'	'	'
Stock options granted	'	1,779,074	'	'
Weighted-average grant date fair value for stock options granted	'	$18	'	'
Restricted stock award and units vesting period in years	'4 years	'	'	'
Restricted stock awards granted to employees and officers of the company	'	'	1,492,290	'
Restricted stock units awarded to employees and officers of the company	'	'	'	276,992
Grant date fair value of awards except for options granted to employees and officers of the company	'	'	$96.76	$96.76

Segment_Information_Operations

Segment Information (Operations By Segment) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Net premiums written	$4,185	$3,798
Net premiums earned	3,970	3,573
Losses and loss expenses	2,161	1,926
Policy benefits	114	131
Policy acquisition costs	728	614
Administrative expenses	535	514
Underwriting income (loss)	432	388
Net investment income	553	531
Net realized gains (losses) including OTTI	-104	206
Interest expense	71	60
(Gains) losses from fair value changes in separate account assets	6	-4
Other	-23	-6
Other (income) expense	-17	-10
Income tax expense (benefit)	93	122
Net income (loss)	734	953
Insurance - North American P&C [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Net premiums written	1,418	1,284
Net premiums earned	1,487	1,338
Losses and loss expenses	940	878
Policy acquisition costs	159	143
Administrative expenses	161	125
Underwriting income (loss)	227	192
Net investment income	270	251
Net realized gains (losses) including OTTI	-9	26
Interest expense	3	-2
Other	-20	-15
Income tax expense (benefit)	83	94
Net income (loss)	422	392
Insurance - North American Agriculture [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Underwriting Income Including Losses Related to Crop Derivatives	-31	'
Net premiums written	194	113
Net premiums earned	103	52
Losses and loss expenses	126	32
Policy acquisition costs	5	4
Administrative expenses	1	5
Underwriting income (loss)	-29	11
Net investment income	7	6
Net realized gains (losses) including OTTI	-2	0
Interest expense	0	0
Other	8	8
Income tax expense (benefit)	-7	2
Net income (loss)	-25	7
Crop Derivative Reclassification	2	'
Insurance - Overseas General [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Net premiums written	1,771	1,620
Net premiums earned	1,612	1,459
Losses and loss expenses	817	747
Policy acquisition costs	386	339
Administrative expenses	250	236
Underwriting income (loss)	159	137
Net investment income	132	132
Net realized gains (losses) including OTTI	-10	34
Interest expense	1	1
Other	-6	-1
Income tax expense (benefit)	37	46
Net income (loss)	249	257
Global Reinsurance [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Net premiums written	308	279
Net premiums earned	284	247
Losses and loss expenses	126	106
Policy acquisition costs	67	48
Administrative expenses	14	12
Underwriting income (loss)	77	81
Net investment income	77	72
Net realized gains (losses) including OTTI	-8	20
Interest expense	1	1
Other	-19	-8
Income tax expense (benefit)	10	8
Net income (loss)	154	172
Life [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Life underwriting income	98	'
Net premiums written	494	502
Net premiums earned	484	477
Losses and loss expenses	151	157
Policy benefits	114	131
Policy acquisition costs	111	80
Administrative expenses	68	85
Underwriting income (loss)	40	24
Net investment income	64	63
Net realized gains (losses) including OTTI	-76	127
Interest expense	3	4
(Gains) losses from fair value changes in separate account assets	6	-4
Other	7	0
Income tax expense (benefit)	10	13
Net income (loss)	2	201
Corporate And Other [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Losses and loss expenses	1	6
Policy acquisition costs	'	0
Administrative expenses	41	51
Underwriting income (loss)	-42	-57
Net investment income	3	7
Net realized gains (losses) including OTTI	1	-1
Interest expense	63	56
Other	7	10
Income tax expense (benefit)	-40	-41
Net income (loss)	($68)	($76)

Segment_Information_Net_Premiu

Segment Information (Net Premiums Earned For Segment By Product) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting Information [Line Items]	'	'
Property & All Other	$1,355	$1,119
Casualty	1,480	1,353
Life, Accident & Health	1,135	1,101
Net premiums earned	3,970	3,573
Insurance - North American P&C [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property & All Other	405	347
Casualty	981	902
Life, Accident & Health	101	89
Net premiums earned	1,487	1,338
Insurance - North American Agriculture [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property & All Other	103	52
Casualty	0	0
Life, Accident & Health	0	0
Net premiums earned	103	52
Insurance - Overseas General [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property & All Other	693	585
Casualty	369	339
Life, Accident & Health	550	535
Net premiums earned	1,612	1,459
Global Reinsurance [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Property & All Other	154	135
Casualty	130	112
Net premiums earned	284	247
Life [Member]	'	'
Segment Reporting Information [Line Items]	'	'
Life, Accident & Health	484	477
Net premiums earned	$484	$477

Earnings_Per_Share_Detail

Earnings Per Share (Detail) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]	'	'
Net income	$734	$953
Weighted-average shares outstanding	338,869,562	340,778,142
Share-based compensation plans	3,171,174	3,128,226
Adjusted weighted-average shares outstanding and assumed conversions	342,040,736	343,906,368
Basic earnings per share (US$ per share)	$2.16	$2.80
Diluted earnings per share (US$ per share)	$2.14	$2.77
Potential anti-dilutive share conversions	657,182	634,385

Recovered_Sheet5

Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Balance Sheet) (Detail) (USD $)	Mar. 31, 2014		Dec. 31, 2013		Mar. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Investments	$62,045		$60,928		'		'
Insurance and reinsurance balances receivable	4,761		5,026		'		'
Reinsurance recoverable on losses and loss expenses	10,755		11,227		'		'
Reinsurance recoverable on policy benefits	222		218		'		'
Value of business acquired	517		536		'		'
Goodwill and other intangible assets	5,382		5,404		'		'
Other assets	10,650		10,592		'		'
Total assets	95,179		94,510		'		'
Unpaid losses and loss expenses	36,866		37,443		'		'
Unearned premiums	7,791		7,539		'		'
Future policy benefits	4,632		4,615		'		'
Short-term debt	1,901		1,901		'		'
Long-term debt	3,808		3,807		'		'
Trust preferred securities	309		309		'		'
Other liabilities	10,503		10,071		'		'
Total liabilities	65,810		65,685		'		'
Total shareholders' equity	29,369		28,825		27,942		'
Total liabilities and shareholders’ equity	95,179		94,510		'		'
Cash	847	[1],[2]	579	[2],[3]	855	[4]	615	[4]
Scenario, Previously Reported [Member]	'		'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Cash	'		'		855	[5]	615
ACE Limited (Parent Guarantor)	'		'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Investments	32		32		'		'
Investments in subsidiaries	29,075		28,351		'		'
Due from subsidiaries and affiliates, net	487		844		'		'
Other assets	3		5		'		'
Total assets	29,622		29,232		'		'
Affiliated notional cash pooling programs	0	[1]	185	[1]	'		'
Trust preferred securities	'		0		'		'
Other liabilities	253		222		'		'
Total liabilities	253		407		'		'
Total shareholders' equity	29,369		28,825		'		'
Total liabilities and shareholders’ equity	29,622		29,232		'		'
Cash	25	[1],[2]	0	[2],[3]	197	[4]	103	[4]
ACE Limited (Parent Guarantor) | Scenario, Previously Reported [Member]	'		'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Cash	'		'		197	[5]	103
ACE INA Holdings Inc (Subsidiary Issuer)	'		'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Investments	18		10		'		'
Insurance and reinsurance balances receivable	0		0		'		'
Reinsurance recoverable on losses and loss expenses	0		0		'		'
Reinsurance recoverable on policy benefits	0		0		'		'
Value of business acquired	0		0		'		'
Goodwill and other intangible assets	0		0		'		'
Investments in subsidiaries	18,368		18,105		'		'
Other assets	256		258		'		'
Total assets	18,643		18,389		'		'
Unpaid losses and loss expenses	0		0		'		'
Unearned premiums	0		0		'		'
Future policy benefits	0		0		'		'
Due to subsidiaries and affiliates, net	367		714		'		'
Short-term debt	500		500		'		'
Affiliated notional cash pooling programs	385	[1]	0	[1]	'		'
Long-term debt	3,795		3,795		'		'
Trust preferred securities	309		309		'		'
Other liabilities	1,343		1,318		'		'
Total liabilities	6,699		6,636		'		'
Total shareholders' equity	11,944		11,753		'		'
Total liabilities and shareholders’ equity	18,643		18,389		'		'
Cash	1	[1],[2]	16	[2],[3]	489	[4]	2	[4]
ACE INA Holdings Inc (Subsidiary Issuer) | Scenario, Previously Reported [Member]	'		'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Cash	'		'		560	[5]	515
Other ACE Limited Subsidiaries	'		'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Investments	61,995		60,886		'		'
Insurance and reinsurance balances receivable	5,540		5,835		'		'
Reinsurance recoverable on losses and loss expenses	19,531		20,057		'		'
Reinsurance recoverable on policy benefits	1,210		1,215		'		'
Value of business acquired	517		536		'		'
Goodwill and other intangible assets	5,382		5,404		'		'
Other assets	13,956		13,788		'		'
Total assets	109,337		108,469		'		'
Unpaid losses and loss expenses	45,173		45,714		'		'
Unearned premiums	9,584		9,242		'		'
Future policy benefits	5,620		5,612		'		'
Due to subsidiaries and affiliates, net	120		130		'		'
Short-term debt	1,401		1,401		'		'
Affiliated notional cash pooling programs	0	[1]	0	[1]	'		'
Long-term debt	13		12		'		'
Trust preferred securities	'		0		'		'
Other liabilities	11,927		11,655		'		'
Total liabilities	73,838		73,766		'		'
Total shareholders' equity	35,499		34,703		'		'
Total liabilities and shareholders’ equity	109,337		108,469		'		'
Cash	1,206	[1],[2]	748	[2],[3]	169	[4]	859	[4]
Other ACE Limited Subsidiaries | Scenario, Previously Reported [Member]	'		'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Cash	'		'		98	[5],[6]	-3	[6]
Consolidating Adjustments and Eliminations	'		'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Investments	0		0		'		'
Insurance and reinsurance balances receivable	-779		-809		'		'
Reinsurance recoverable on losses and loss expenses	-8,776		-8,830		'		'
Reinsurance recoverable on policy benefits	-988		-997		'		'
Value of business acquired	0		0		'		'
Goodwill and other intangible assets	0		0		'		'
Investments in subsidiaries	-47,443		-46,456		'		'
Due from subsidiaries and affiliates, net	-487		-844		'		'
Other assets	-3,565		-3,459		'		'
Total assets	-62,423		-61,580		'		'
Unpaid losses and loss expenses	-8,307		-8,271		'		'
Unearned premiums	-1,793		-1,703		'		'
Future policy benefits	-988		-997		'		'
Due to subsidiaries and affiliates, net	-487		-844		'		'
Short-term debt	0		0		'		'
Affiliated notional cash pooling programs	-385	[1]	-185	[1]	'		'
Long-term debt	'		0		'		'
Trust preferred securities	'		0		'		'
Other liabilities	-3,020		-3,124		'		'
Total liabilities	-14,980		-15,124		'		'
Total shareholders' equity	-47,443		-46,456		'		'
Total liabilities and shareholders’ equity	-62,423		-61,580		'		'
Cash	-385	[1],[2]	-185	[2],[3]	0	[4]	-349	[4]
Consolidating Adjustments and Eliminations | Scenario, Previously Reported [Member]	'		'		'		'
Condensed Financial Statements, Captions [Line Items]	'		'		'		'
Cash	'		'		$0	[5],[7]	$0	[7]
[1]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014 and December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[3]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[4]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2013 and December 31, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[5]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[6]	Includes all other subsidiaries of ACE Limited and intercompany eliminations.
[7]	Includes ACE Limited parent company eliminations and certain consolidating adjustments.

Recovered_Sheet6

Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Operations) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Net premiums written	$4,185	$3,798
Net premiums earned	3,970	3,573
Net investment income	553	531
Net realized gains (losses) including OTTI	-104	206
Losses and loss expenses	2,161	1,926
Policy benefits	114	131
Policy acquisition costs and administrative expenses	1,263	1,128
Interest (income) expense	71	60
Other (income) expense	-17	-10
Income tax expense (benefit)	93	122
Net income (loss)	734	953
Comprehensive income (loss)	1,108	716
ACE Limited (Parent Guarantor)	'	'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Net investment income	0	0
Equity in earnings of subsidiaries	702	914
Net realized gains (losses) including OTTI	0	12
Policy acquisition costs and administrative expenses	17	15
Interest (income) expense	-10	-7
Other (income) expense	-42	-38
Income tax expense (benefit)	3	3
Net income (loss)	734	953
Comprehensive income (loss)	1,108	716
ACE INA Holdings Inc (Subsidiary Issuer)	'	'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Net premiums written	0	0
Net premiums earned	0	0
Net investment income	0	1
Equity in earnings of subsidiaries	180	188
Net realized gains (losses) including OTTI	-1	0
Losses and loss expenses	0	0
Policy benefits	0	0
Policy acquisition costs and administrative expenses	6	4
Interest (income) expense	71	62
Other (income) expense	14	9
Income tax expense (benefit)	-30	-33
Net income (loss)	118	147
Comprehensive income (loss)	266	-1
Other ACE Limited Subsidiaries	'	'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Net premiums written	4,185	3,798
Net premiums earned	3,970	3,573
Net investment income	553	530
Net realized gains (losses) including OTTI	-103	194
Losses and loss expenses	2,161	1,926
Policy benefits	114	131
Policy acquisition costs and administrative expenses	1,240	1,109
Interest (income) expense	10	5
Other (income) expense	11	19
Income tax expense (benefit)	120	152
Net income (loss)	764	955
Comprehensive income (loss)	1,138	718
Consolidating Adjustments and Eliminations	'	'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Equity in earnings of subsidiaries	-882	-1,102
Net income (loss)	-882	-1,102
Comprehensive income (loss)	-1,404	-717
Scenario, Previously Reported [Member]	'	'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Net premiums written	'	3,798
Net premiums earned	'	3,573
Net investment income	'	531
Net realized gains (losses) including OTTI	'	206
Losses and loss expenses	'	1,926
Policy benefits	'	131
Policy acquisition costs and administrative expenses	'	1,128
Interest (income) expense	'	60
Other (income) expense	'	-10
Income tax expense (benefit)	'	122
Net income (loss)	'	953
Comprehensive income (loss)	'	716
Scenario, Previously Reported [Member] | ACE Limited (Parent Guarantor)	'	'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Net investment income	'	0
Equity in earnings of subsidiaries	'	914
Net realized gains (losses) including OTTI	'	12
Policy acquisition costs and administrative expenses	'	15
Interest (income) expense	'	-7
Other (income) expense	'	-38
Income tax expense (benefit)	'	3
Net income (loss)	'	953
Comprehensive income (loss)	'	716
Scenario, Previously Reported [Member] | ACE INA Holdings Inc (Subsidiary Issuer)	'	'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Net premiums written	'	2,082
Net premiums earned	'	2,006
Net investment income	'	248
Equity in earnings of subsidiaries	'	0
Net realized gains (losses) including OTTI	'	10
Losses and loss expenses	'	1,253
Policy benefits	'	81
Policy acquisition costs and administrative expenses	'	626
Interest (income) expense	'	67
Other (income) expense	'	34
Income tax expense (benefit)	'	56
Net income (loss)	'	147
Comprehensive income (loss)	'	-1
Scenario, Previously Reported [Member] | Other ACE Limited Subsidiaries	'	'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Net premiums written	'	1,716	[1]
Net premiums earned	'	1,567	[1]
Net investment income	'	283	[1]
Net realized gains (losses) including OTTI	'	184	[1]
Losses and loss expenses	'	673	[1]
Policy benefits	'	50	[1]
Policy acquisition costs and administrative expenses	'	487	[1]
Interest (income) expense	'	0	[1]
Other (income) expense	'	-6	[1]
Income tax expense (benefit)	'	63	[1]
Net income (loss)	'	767	[1]
Comprehensive income (loss)	'	915	[1]
Scenario, Previously Reported [Member] | Consolidating Adjustments and Eliminations	'	'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'	'
Equity in earnings of subsidiaries	'	-914	[2]
Net income (loss)	'	-914	[2]
Comprehensive income (loss)	'	($914)	[2]
[1]	Includes all other subsidiaries of ACE Limited and intercompany eliminations.
[2]	Includes ACE Limited parent company eliminations.

Information_Provided_In_Connec2

Information Provided In Connection With Outstanding Debt Of Subsidiaries (Condensed Consolidating Statement Of Cash Flows) (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	$1,250		$913
Purchases of fixed maturities available for sale	-3,522		-5,465
Purchases of fixed maturities held to maturity	-30		-142
Purchases of equity securities	-37		-107
Sales of fixed maturities available for sale	2,208		2,764
Sales of equity securities	27		31
Maturities and redemptions of fixed maturities available for sale	1,550		2,016
Maturities and redemptions of fixed maturities held to maturity	212		491
Payments to Acquire Short-term Investments	-765		-687
Net derivative instruments settlements	-96		-279
Acquisition of subsidiaries	0		-33
Other	-50		-55
Net cash flows used for investing activities	-503		-1,466
Dividends paid on Common Shares	-214		-2
Common Shares repurchased	-335		-154
Proceeds from issuance of long-term debt	0		947
Net proceeds from (repayments) issuance of short-term debt	'		1
Proceeds from share-based compensation plans, including windfall tax benefits	40		21
Other	37		0
Net cash flows (used for) from financing activities	-472		813
Effect of foreign currency rate changes on cash and cash equivalents	-7		-20
Net increase in cash	268		240
Cash – beginning of period	579	[1],[2]	615	[3]
Cash – end of period	847	[1],[4]	855	[3]
ACE Limited (Parent Guarantor)	'		'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	57		25
Sales of fixed maturities available for sale	'		0
Net derivative instruments settlements	0		0
Net cash flows used for investing activities	0		0
Dividends paid on Common Shares	-214		-2
Net proceeds from (repayments) issuance of short-term debt	'		0
Proceeds from share-based compensation plans, including windfall tax benefits	0		0
Advances (to) from affiliates	367		71
Net proceeds from (payments to) affiliated notional cash pooling program	-185	[1]	0	[3]
Net cash flows (used for) from financing activities	-32		69
Net increase in cash	25		94
Cash – beginning of period	0	[1],[2]	103	[3]
Cash – end of period	25	[1],[4]	197	[3]
ACE INA Holdings Inc (Subsidiary Issuer)	'		'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	-13		-19
Purchases of fixed maturities available for sale	0		0
Purchases of fixed maturities held to maturity	0		0
Purchases of equity securities	0		0
Sales of fixed maturities available for sale	0		0
Sales of equity securities	0		0
Maturities and redemptions of fixed maturities available for sale	0		0
Maturities and redemptions of fixed maturities held to maturity	0		0
Proceeds from Sale of Short-term Investments	'		4
Payments to Acquire Short-term Investments	-8		'
Net derivative instruments settlements	-9		0
Acquisition of subsidiaries	'		0
Payment Of Contributions To Subsidiary	'		-27
Other	-3		2
Net cash flows used for investing activities	-20		-21
Proceeds from issuance of long-term debt	'		947
Net proceeds from (repayments) issuance of short-term debt	'		0
Proceeds from share-based compensation plans, including windfall tax benefits	0		'
Advances (to) from affiliates	-367		-71
Capital contribution	'		0
Net proceeds from (payments to) affiliated notional cash pooling program	385	[1]	-349	[3]
Other	0		'
Net cash flows (used for) from financing activities	18		527
Effect of foreign currency rate changes on cash and cash equivalents	0		0
Net increase in cash	-15		487
Cash – beginning of period	16	[1],[2]	2	[3]
Cash – end of period	1	[1],[4]	489	[3]
Other ACE Limited Subsidiaries	'		'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	1,206		907
Purchases of fixed maturities available for sale	-3,522		-5,568
Purchases of fixed maturities held to maturity	-30		-142
Purchases of equity securities	-37		-107
Sales of fixed maturities available for sale	2,208		2,867
Sales of equity securities	27		31
Maturities and redemptions of fixed maturities available for sale	1,550		2,016
Maturities and redemptions of fixed maturities held to maturity	212		491
Payments to Acquire Short-term Investments	-757		-691
Net derivative instruments settlements	-87		-279
Acquisition of subsidiaries	'		-33
Payment Of Contributions To Subsidiary	'		0
Other	-47		-57
Net cash flows used for investing activities	-483		-1,472
Dividends paid on Common Shares	0		'
Common Shares repurchased	-335		-154
Net proceeds from (repayments) issuance of short-term debt	'		1
Proceeds from share-based compensation plans, including windfall tax benefits	40		21
Advances (to) from affiliates	0		0
Cash Dividends Paid to Parent Company	'		0
Capital contribution	'		27
Net proceeds from (payments to) affiliated notional cash pooling program	0	[1]	0	[3]
Other	37		'
Net cash flows (used for) from financing activities	-258		-105
Effect of foreign currency rate changes on cash and cash equivalents	-7		-20
Net increase in cash	458		-690
Cash – beginning of period	748	[1],[2]	859	[3]
Cash – end of period	1,206	[1],[4]	169	[3]
Consolidating Adjustments and Eliminations	'		'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	0		0
Purchases of fixed maturities available for sale	0		103
Purchases of fixed maturities held to maturity	0		0
Purchases of equity securities	0		0
Sales of fixed maturities available for sale	0		-103
Sales of equity securities	0		0
Maturities and redemptions of fixed maturities available for sale	0		0
Maturities and redemptions of fixed maturities held to maturity	0		0
Net derivative instruments settlements	0		0
Acquisition of subsidiaries	'		0
Payment Of Contributions To Subsidiary	'		27
Other	0		0
Net cash flows used for investing activities	0		27
Dividends paid on Common Shares	0		'
Common Shares repurchased	0		0
Net proceeds from (repayments) issuance of short-term debt	'		0
Proceeds from share-based compensation plans, including windfall tax benefits	0		0
Advances (to) from affiliates	0		0
Cash Dividends Paid to Parent Company	'		0
Capital contribution	'		-27
Net proceeds from (payments to) affiliated notional cash pooling program	-200	[1]	349	[3]
Net cash flows (used for) from financing activities	-200		322
Effect of foreign currency rate changes on cash and cash equivalents	0		0
Net increase in cash	-200		349
Cash – beginning of period	-185	[1],[2]	-349	[3]
Cash – end of period	-385	[1],[4]	0	[3]
Scenario, Previously Reported [Member]	'		'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	'		913
Purchases of fixed maturities available for sale	'		-6,152
Purchases of fixed maturities held to maturity	'		-142
Purchases of equity securities	'		-107
Sales of fixed maturities available for sale	'		2,764
Sales of equity securities	'		31
Maturities and redemptions of fixed maturities available for sale	'		2,016
Maturities and redemptions of fixed maturities held to maturity	'		491
Net derivative instruments settlements	'		-279
Acquisition of subsidiaries	'		-33
Other	'		-55
Net cash flows used for investing activities	'		-1,466
Dividends paid on Common Shares	'		-2
Common Shares repurchased	'		-154
Proceeds from issuance of long-term debt	'		947
Net proceeds from (repayments) issuance of short-term debt	'		1
Proceeds from share-based compensation plans, including windfall tax benefits	'		21
Net cash flows (used for) from financing activities	'		813
Effect of foreign currency rate changes on cash and cash equivalents	'		-20
Net increase in cash	'		240
Cash – beginning of period	'		615
Cash – end of period	'		855	[5]
Scenario, Previously Reported [Member] | ACE Limited (Parent Guarantor)	'		'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	'		53
Sales of fixed maturities available for sale	'		0
Net derivative instruments settlements	'		0
Payments To From Affiliates	'		43
Net cash flows used for investing activities	'		43
Dividends paid on Common Shares	'		-2
Net proceeds from (repayments) issuance of short-term debt	'		0
Proceeds from share-based compensation plans, including windfall tax benefits	'		0
Advances (to) from affiliates	'		0
Net cash flows (used for) from financing activities	'		-2
Net increase in cash	'		94
Cash – beginning of period	'		103
Cash – end of period	'		197	[5]
Scenario, Previously Reported [Member] | ACE INA Holdings Inc (Subsidiary Issuer)	'		'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	'		644
Purchases of fixed maturities available for sale	'		-3,825
Purchases of fixed maturities held to maturity	'		-137
Purchases of equity securities	'		-89
Sales of fixed maturities available for sale	'		1,473
Sales of equity securities	'		25
Maturities and redemptions of fixed maturities available for sale	'		879
Maturities and redemptions of fixed maturities held to maturity	'		351
Net derivative instruments settlements	'		4
Acquisition of subsidiaries	'		-33
Other	'		-86
Net cash flows used for investing activities	'		-1,438
Proceeds from issuance of long-term debt	'		947
Net proceeds from (repayments) issuance of short-term debt	'		0
Proceeds from share-based compensation plans, including windfall tax benefits	'		-8
Advances (to) from affiliates	'		-71
Net cash flows (used for) from financing activities	'		868
Effect of foreign currency rate changes on cash and cash equivalents	'		-29
Net increase in cash	'		45
Cash – beginning of period	'		515
Cash – end of period	'		560	[5]
Scenario, Previously Reported [Member] | Other ACE Limited Subsidiaries	'		'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	'		216	[6]
Purchases of fixed maturities available for sale	'		-2,327	[6]
Purchases of fixed maturities held to maturity	'		-5	[6]
Purchases of equity securities	'		-18	[6]
Sales of fixed maturities available for sale	'		1,291	[6]
Sales of equity securities	'		6	[6]
Maturities and redemptions of fixed maturities available for sale	'		1,137	[6]
Maturities and redemptions of fixed maturities held to maturity	'		140	[6]
Net derivative instruments settlements	'		-283	[6]
Acquisition of subsidiaries	'		0	[6]
Other	'		31	[6]
Net cash flows used for investing activities	'		-28	[6]
Common Shares repurchased	'		-154	[6]
Net proceeds from (repayments) issuance of short-term debt	'		1	[6]
Proceeds from share-based compensation plans, including windfall tax benefits	'		29	[6]
Advances (to) from affiliates	'		28	[6]
Net cash flows (used for) from financing activities	'		-96	[6]
Effect of foreign currency rate changes on cash and cash equivalents	'		9	[6]
Net increase in cash	'		101	[6]
Cash – beginning of period	'		-3	[6]
Cash – end of period	'		98	[5],[6]
Scenario, Previously Reported [Member] | Consolidating Adjustments and Eliminations	'		'
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]	'		'
Net cash flows from operating activities	'		0	[7]
Purchases of fixed maturities available for sale	'		0	[7]
Purchases of fixed maturities held to maturity	'		0	[7]
Purchases of equity securities	'		0	[7]
Sales of fixed maturities available for sale	'		0	[7]
Sales of equity securities	'		0	[7]
Maturities and redemptions of fixed maturities available for sale	'		0	[7]
Maturities and redemptions of fixed maturities held to maturity	'		0	[7]
Net derivative instruments settlements	'		0	[7]
Payments To From Affiliates	'		-43	[7]
Acquisition of subsidiaries	'		0	[7]
Other	'		0	[7]
Net cash flows used for investing activities	'		-43	[7]
Common Shares repurchased	'		0	[7]
Net proceeds from (repayments) issuance of short-term debt	'		0	[7]
Proceeds from share-based compensation plans, including windfall tax benefits	'		0	[7]
Advances (to) from affiliates	'		43	[7]
Net cash flows (used for) from financing activities	'		43	[7]
Effect of foreign currency rate changes on cash and cash equivalents	'		0	[7]
Net increase in cash	'		0	[7]
Cash – beginning of period	'		0	[7]
Cash – end of period	'		$0	[5],[7]
[1]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014 and December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[2]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[3]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2013 and December 31, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[4]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At March 31, 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[5]	ACE maintains two notional multicurrency cash pools (Pools) with a third-party bank. Various ACE entities participate in one or the other of the Pools, pursuant to which credit and debit balances in individual ACE accounts are translated daily into a single currency and pooled on a notional basis. Individual ACE entities are permitted to overdraw on their individual accounts provided the overall Pool balances do not fall below zero. At December 31, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.
[6]	Includes all other subsidiaries of ACE Limited and intercompany eliminations.
[7]	Includes ACE Limited parent company eliminations and certain consolidating adjustments.