Taxation (Components Of Net Deferred Tax Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Taxation [Abstract]
Loss reserve discount	$ 933	$ 852
Unearned premiums reserve	85	87
Foreign tax credits	1,074	952
Investments	67	51
Provision for uncollectible balances	113	132
Loss carry-forwards	43	57
Other, net	31	114
Cumulative translation adjustment	5	2
Total deferred tax assets	2,351	2,247
Deferred policy acquisition costs	107	100
VOBA and other intangible assets	373	367
Un-remitted foreign earnings	810	718
Unrealized appreciation on investments	392	262
Total deferred tax liabilities	1,682	1,447
Valuation allowance	57	31
Net deferred tax assets	$ 612	$ 769