Information provided in connection with outstanding debt of subsidiaries (Condensed Consolidating Balance Sheet) (Detail) - USD ($) $ in Millions	Dec. 31, 2016		Jan. 14, 2016	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Debt Instrument, Face Amount	$ 1,000
Investments	99,094			$ 66,251
Cash	985	[1],[2]		1,775	[1],[3],[4]	$ 655	[1],[5]	$ 579	[5]
Insurance and reinsurance balances receivable	8,970			5,323
Reinsurance recoverable on losses and loss expenses	13,577			11,386
Reinsurance recoverable on policy benefits	182			187
Value of business acquired	355			395
Goodwill	22,095			5,683
Other assets	14,528			11,306
Total assets	159,786			102,306
Unpaid losses and loss expenses	60,540			37,303		38,315		37,443
Unearned premiums	14,779			8,439
Future policy benefits	5,036			4,807
Affiliated notional cash pooling program	300			0	[4]
Repurchase agreements	1,403			1,404
Short-term debt	500			0
Long-term debt	12,610			9,389
Trust preferred securities	308			307
Other liabilities	16,335			11,522
Total liabilities	111,511			73,171
Total shareholders' equity	48,275			29,135
Total liabilities and shareholders’ equity	159,786			102,306
Consolidating Adjustments
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Cash	(982)	[1],[2]		(971)	[1],[3],[4]	(555)	[1],[5]	(185)	[5]
Insurance and reinsurance balances receivable	(1,528)			(752)
Reinsurance recoverable on losses and loss expenses	(10,919)			(8,738)
Reinsurance recoverable on policy benefits	(971)			(942)
Investments in subsidiaries	(87,917)			(47,998)
Due from subsidiaries and affiliates, net	(10,482)			(2,444)
Other assets	(4,353)			(3,593)
Total assets	(117,152)			(65,438)
Unpaid losses and loss expenses	(10,143)			(8,187)
Unearned premiums	(3,759)			(1,804)
Future policy benefits	(971)			(942)
Due to subsidiaries and affiliates, net	(10,482)			(2,444)
Affiliated notional cash pooling program	(982)	[2]		(971)	[4]
Repurchase agreements	0			0
Other liabilities	(2,898)			(3,092)
Total liabilities	(29,235)			(17,440)
Total shareholders' equity	(87,917)			(47,998)
Total liabilities and shareholders’ equity	(117,152)			(65,438)
Chubb limited (Parent Guarantor)
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Investments	27			28
Cash	1	[1],[2]		1	[1],[3],[4]	0	[5]	0	[5]
Investments in subsidiaries	38,408			29,612
Due from subsidiaries and affiliates, net	10,482			644
Other assets	3			8
Total assets	48,921			30,293
Affiliated notional cash pooling program	363	[2]		882	[4]
Repurchase agreements	0			0
Other liabilities	283			276
Total liabilities	646			1,158
Total shareholders' equity	48,275			29,135
Total liabilities and shareholders’ equity	48,921			30,293
Chubb INA Holdings Inc. (Subsidiary Issuer)
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Investments	485			7,839
Cash	1	[1],[2]		2	[1],[3],[4]	1	[1],[5]	16	[5]
Investments in subsidiaries	49,509			18,386
Due from subsidiaries and affiliates, net				1,800
Other assets	436			457
Total assets	50,431			28,484
Due to subsidiaries and affiliates, net	10,209
Affiliated notional cash pooling program	619	[2]		89	[4]
Repurchase agreements	0			0
Short-term debt	500
Long-term debt	12,599			9,378
Trust preferred securities	308			307
Other liabilities	1,582			1,422
Total liabilities	25,817			11,196
Total shareholders' equity	24,614			17,288
Total liabilities and shareholders’ equity	50,431			28,484
Other Chubb Limited Subsidiaries and Eliminations
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Investments	98,582			58,384
Cash	1,965	[1],[2]		2,743	[1],[3],[4]	$ 1,209	[5]	$ 748	[5]
Insurance and reinsurance balances receivable	10,498			6,075
Reinsurance recoverable on losses and loss expenses	24,496			20,124
Reinsurance recoverable on policy benefits	1,153			1,129
Value of business acquired	355			395
Goodwill	22,095			5,683
Other assets	18,442			14,434
Total assets	177,586			108,967
Unpaid losses and loss expenses	70,683			45,490
Unearned premiums	18,538			10,243
Future policy benefits	6,007			5,749
Due to subsidiaries and affiliates, net	273			2,444
Repurchase agreements	1,403			1,404
Long-term debt	11			11
Other liabilities	17,368			12,916
Total liabilities	114,283			78,257
Total shareholders' equity	63,303			30,710
Total liabilities and shareholders’ equity	$ 177,586			$ 108,967
The Chubb Corporation [Member]
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Intercompany Loan Agreements			$ 10,000
Long-term Debt, Weighted Average Interest Rate			3.30%
Debt Instrument, Face Amount			$ 3,300
Investments			42,967
Cash			71
Insurance and reinsurance balances receivable			3,095
Unpaid losses and loss expenses			22,923
Unearned premiums			7,011
Long-term debt			$ 3,765
The Chubb Corporation [Member] | Minimum
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			2.30%
The Chubb Corporation [Member] | Maximum
Information Provided In Connection With Outstanding Debt Of Subsidiaries [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			4.35%

[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, 2016 and 2015, 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, 2016, 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, 2015 and 2014, 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, 2015, 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, 2014 and 2013, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.