Schedule II (STATEMENTS OF CASH FLOWS - Parent Company Only) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Net cash flows used for investing activities		$ (2,935)		$ (2,422)		$ (5,322)
Dividends paid on Common Shares		(1,337)		(1,308)		(1,173)
Net proceeds from (payments to) affiliated notional cash pooling programs		0		0	[1]	0
Cash and restricted cash – beginning of year		728	[2]	985
Cash and restricted cash – end of year		1,247	[3]	728	[2]	985
Chubb limited (Parent Guarantor)
Condensed Financial Statements, Captions [Line Items]
Net cash flows from operating activities	[4]	256		781		3,618
Capital contributions to subsidiaries		(1,475)		0		(2,330)
Net cash flows used for investing activities		(1,475)		0		(2,330)
Dividends paid on Common Shares		(1,337)		(1,308)		(1,173)
Payments To From Affiliates		2,519		892		404
Net proceeds from (payments to) affiliated notional cash pooling programs	[5]	35		(363)		(519)
Net cash flows (used for) from financing activities		1,217		(779)		(1,288)
Net increase (decrease) in cash and restricted cash		(2)		2		0
Cash and restricted cash – beginning of year		3	[2]	1		1
Cash and restricted cash – end of year		1	[3]	3	[2]	1
Cash dividend paid by Affiliates		$ 75		$ 450		$ 3,400

[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, 2017 and 2016, 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, 2017, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

[3] Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2018, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

[4] Includes cash dividends received from subsidiaries of $75 million, $450 million, and $3.4 billion in 2018, 2017, and 2016, respectively.

[5] Chubb maintains two notional multicurrency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information.