Schedule II (BALANCE SHEETS - Parent Company Only) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Assets
Short-term investments	$ 2,322		$ 1,763
Other investments	3,346		2,976
Cash	655	[1],[2]	579	[1],[3],[4]	615	[4],[5]	614	[5]
Other assets	3,556		3,330
Total assets	98,248		94,510
Liabilities
Accounts payable, accrued expenses, and other liabilities	5,726		4,810
Bank Overdrafts			0	[3]
Short-term debt	2,552		1,901
Total liabilities	68,661		65,685
Stockholders' Equity Attributable to Parent [Abstract]
Common Shares	8,055		8,899
Common Shares in treasury	(1,448)		(255)
Additional paid-in capital	5,145		5,238
Retained earnings	16,644		13,791
Accumulated other comprehensive income	1,191		1,152
Total liabilities and shareholders’ equity	98,248		94,510
Parent Company Only
Assets
Investments in subsidiaries and affiliates on equity basis	29,497		28,351
Short-term investments	1		2
Other investments	29		30
Total investments	29,527		28,383
Cash	0	[1],[2]	0		103	[4],[5]	106	[5]
Due from subsidiaries and affiliates, net	583		844
Other assets	4		5
Total assets	30,114		29,232
Liabilities
Accounts payable, accrued expenses, and other liabilities	281		222
Bank Overdrafts	246	[2]	185	[3]
Total liabilities	527		407
Stockholders' Equity Attributable to Parent [Abstract]
Common Shares	8,055		8,899
Common Shares in treasury	(1,448)		(255)
Additional paid-in capital	5,145		5,238
Retained earnings	16,644		13,791
Accumulated other comprehensive income	1,191		1,152
Total shareholders' equity	29,587		28,825
Total liabilities and shareholders’ equity	$ 30,114		$ 29,232

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

[2] (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.

[3] (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.

[4] (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.

[5] (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.