Schedule II (STATEMENTS OF CASH FLOWS - Parent Company Only) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net cash flows from operating activities	$ 4,496		$ 4,022		$ 3,995
Purchases of fixed maturities available for sale	(15,553)		(21,340)		(23,572)
Sales of fixed maturities available for sale	7,482		10,355		14,321
Net change in short-term investments	(603)		524		117
Net derivative instruments settlements	(230)		(471)		(281)
Other	274		393		555
Net cash flows used for investing activities	(2,504)		(4,442)		(3,439)
Dividends paid on Common Shares	(862)		(517)		(815)
Proceeds from issuance of short-term debt	1,978		2,572		2,933
Repayments of Short-term Debt	1,977		2,572		2,783
Net proceeds from (payments to) affiliated notional cash pooling programs					0	[1]
Proceeds from share-based compensation plans	127		135		126
Net cash flows (used for) from financing activities	(1,777)		391		(550)
Net increase (decrease) in cash	76		(36)		1
Cash – beginning of year	579	[2],[3],[4]	615	[1],[2]	614	[1]
Cash – end of year	655	[3],[5]	579	[2],[3],[4]	615	[1],[2]
Parent Company Only
Condensed Financial Statements, Captions [Line Items]
Net cash flows from operating activities	541		970		573
Net change in short-term investments	0		(1)		0
Net derivative instruments settlements	0		0		(1)
Capital contributions to subsidiaries	0		(133)		0
Net cash flows used for investing activities	0		(134)		(1)
Dividends paid on Common Shares	(862)		(517)		(815)
Proceeds from issuance of short-term debt					130
Repayments of Short-term Debt					130
Advances (to) from affiliates	260		(621)		206
Net proceeds from (payments to) affiliated notional cash pooling programs	61	[3]	185	[2]	0
Proceeds from share-based compensation plans	0		14		34
Net cash flows (used for) from financing activities	(541)		(939)		(575)
Net increase (decrease) in cash	0		(103)		(3)
Cash – beginning of year	0		103	[1],[2]	106	[1]
Cash – end of year	$ 0	[3],[5]	$ 0		$ 103	[1],[2]

[1] (1)ACE maintains two notional multi-currency cash pools (Pools) with a third-party bank. Refer to Note 1 f) for additional information. At December 31, 2012 and 2011, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.

[2] (1)ACE 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.

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

[5] (1) ACE 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.