Taxation (Components Of Net Deferred Tax Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets, Gross [Abstract]
Loss reserve discount	$ 663	$ 794
Unearned premium reserve	190	99
Foreign tax credits	969	1,103
Investments	29	9
Provision for uncollectible balances	65	81
Loss carry-forwards	72	40
Compensation related amounts	189	185
Other	65	0
Total deferred tax assets	2,242	2,311
Deferred Tax Liabilities, Gross [Abstract]
Deferred policy acquisition costs	412	213
VOBA and other intangible assets	384	321
Un-remitted foreign earnings	827	939
Unrealized appreciation on investments	195	406
Depreciation	68	77
Deferred Tax Liabilities, Other	0	43
Total deferred tax liabilities	1,886	1,999
Valuation allowance	38	17
Net deferred tax assets	$ 318	$ 295