Consolidated Statements Of Cash Flows (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011
Cash flows from operating activities
Net income (loss)	$ 1,941		$ 805
Adjustments to reconcile net income to net cash flows from operating activities
Net realized (gains) losses	194		878
Amortization of premiums/discounts on fixed maturities	161		105
Deferred income taxes	46		3
Unpaid losses and loss expenses	430		826
Unearned premiums	708		232
Future policy benefits	109		51
Insurance and reinsurance balances payable	(174)		158
Accounts payable, accrued expenses, and other liabilities	252		508
Income taxes payable	44		74
Insurance and reinsurance balances receivable	(828)		(1,103)
Reinsurance recoverable on losses and loss expenses	606		133
Reinsurance recoverable on policy benefits	47		26
Deferred policy acquisition costs	(260)		(139)
Prepaid reinsurance premiums	(115)		(52)
Other	(136)		493
Net cash flows from operating activities	3,025		2,998
Cash flows from investing activities
Purchases of fixed maturities available for sale	(17,348)		(18,783)
Purchases of to be announced mortgage-backed securities	(308)		(785)
Purchases of fixed maturities held to maturity	(217)		(285)
Purchases of equity securities	(114)		(289)
Sales of fixed maturities available for sale	11,058		13,567
Sales of to be announced mortgage-backed securities	297		756
Sales of equity securities	57		364
Maturities and redemptions of fixed maturities available for sale	3,596		2,603
Maturities and redemptions of fixed maturities held to maturity	1,092		966
Net derivative instruments settlements	(358)		67
Acquisition of subsidiaries (net of cash acquired of $8 and $81)	(98)		(394)
Other	(339)		(317)
Net cash flows from (used for) investing activities	(2,682)		(2,530)
Cash flows from financing activities
Dividends paid on Common Shares	(484)		(342)
Common Shares repurchased	(11)		(168)
Proceeds from issuance of short-term debt	2,083		3,985
Repayment of short-term debt	(1,932)		(4,035)
Proceeds from share-based compensation plans	73		82
Net cash flows (used for) from financing activities	(271)		(478)
Effect of foreign currency rate changes on cash and cash equivalents	4		4
Net (decrease) increase in cash	76		(6)
Cash - beginning of period	614		772	[1]
Cash - end of period	690	[2]	766	[1]
Supplemental cash flow information
Taxes paid	323		306
Interest paid	$ 156		$ 151

[1] ACE maintains two notional multi-currency 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 September 30, 2011 and December 31, 2010, 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 September 30, 2012, the cash balance of one or more entities was negative; however, the overall Pool balances were positive.