Information provided in connection with outstanding debt of subsidiaries (Condensed Consolidating Balance Sheet) (Detail) - USD ($) $ in Millions		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Investments		$ 66,251		$ 62,904
Cash		1,775	[1],[2]	655	[1],[3],[4]	$ 579	[3],[5]	$ 615	[5]
Insurance and reinsurance balances receivable		5,323		5,426
Reinsurance recoverable on losses and loss expenses		11,386		11,992
Reinsurance recoverable on policy benefits		187		217
Value of business acquired		395		466
Goodwill and other intangible assets		5,683		5,724
Other assets		11,366		10,864
Total assets		102,366		98,248
Unpaid losses and loss expenses		37,303		38,315		37,443		37,946
Unearned premiums		8,439		8,222
Future policy benefits		4,807		4,754
Bank Overdrafts	[4]			0
Repurchase agreements		1,404		1,402
Short-term debt				1,150
Long-term debt		9,447		3,357
Trust preferred securities		309		309
Other liabilities		11,522		11,152
Total liabilities		73,231		68,661
Total shareholders' equity		29,135		29,587		28,825
Total liabilities and shareholders’ equity		102,366		98,248
ACE limited (Parent Gurantor)
Condensed Financial Statements, Captions [Line Items]
Investments		28		30
Cash		1	[1],[2]	0		0	[5]	103	[5]
Investments in subsidiaries		29,612		29,497
Due from subsidiaries and affiliates, net		644		583
Other assets		8		4
Total assets		30,293		30,114
Bank Overdrafts		882	[2]	246	[4]
Other liabilities		276		281
Total liabilities		1,158		527
Total shareholders' equity		29,135		29,587
Total liabilities and shareholders’ equity		30,293		30,114
ACE INA Holdings Inc. (Subsidiary Issuer)
Condensed Financial Statements, Captions [Line Items]
Investments		7,839		225
Cash		2	[1],[2]	1	[1],[3],[4]	16	[5]	2	[5]
Investments in subsidiaries		18,386		18,762
Due from subsidiaries and affiliates, net		1,800
Other assets		517		295
Total assets		28,544		19,283
Due to subsidiaries and affiliates, net				422
Bank Overdrafts		89	[2]	309	[4]
Short-term debt				1,150
Long-term debt		9,436		3,345
Trust preferred securities		309		309
Other liabilities		1,422		1,404
Total liabilities		11,256		6,939
Total shareholders' equity		17,288		12,344
Total liabilities and shareholders’ equity		28,544		19,283
Other ACE Limited Subsidiaries and Eliminations
Condensed Financial Statements, Captions [Line Items]
Investments		58,384		62,649
Cash		2,743	[1],[2]	1,209	[1],[3],[4]	748	[5]	859	[5]
Insurance and reinsurance balances receivable		6,075		6,178
Reinsurance recoverable on losses and loss expenses		20,124		20,992
Reinsurance recoverable on policy benefits		1,129		1,194
Value of business acquired		395		466
Goodwill and other intangible assets		5,683		5,724
Other assets		14,434		14,196
Total assets		108,967		112,608
Unpaid losses and loss expenses		45,490		46,770
Unearned premiums		10,243		9,958
Future policy benefits		5,749		5,731
Due to subsidiaries and affiliates, net		2,444		161
Repurchase agreements		1,404		1,402
Long-term debt		11		12
Other liabilities		12,916		12,659
Total liabilities		78,257		76,693
Total shareholders' equity		30,710		35,915
Total liabilities and shareholders’ equity		108,967		112,608
Consolidating Adjustments
Condensed Financial Statements, Captions [Line Items]
Cash		(971)	[1],[2]	(555)	[1],[3],[4]	$ (185)	[5]	$ (349)	[5]
Insurance and reinsurance balances receivable		(752)		(752)
Reinsurance recoverable on losses and loss expenses		(8,738)		(9,000)
Reinsurance recoverable on policy benefits		(942)		(977)
Investments in subsidiaries		(47,998)		(48,259)
Due from subsidiaries and affiliates, net		(2,444)		(583)
Other assets		(3,593)		(3,631)
Total assets		(65,438)		(63,757)
Unpaid losses and loss expenses		(8,187)		(8,455)
Unearned premiums		(1,804)		(1,736)
Future policy benefits		(942)		(977)
Due to subsidiaries and affiliates, net		(2,444)		(583)
Bank Overdrafts		(971)	[2]	(555)	[4]
Other liabilities		(3,092)		(3,192)
Total liabilities		(17,440)		(15,498)
Total shareholders' equity		(47,998)		(48,259)
Total liabilities and shareholders’ equity		$ (65,438)		$ (63,757)

[1] Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2015 and 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

[2] Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2015, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

[3] Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2014 and 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

[4] Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2014, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

[5] Chubb maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2013 and 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.