Taxation (Reconciliation Of The Difference Between The Provision for Income Taxes and the Expected Tax Provision at Swiss Statutory Income Tax Rate) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Income Tax Disclosure [Abstract]
Expected tax provision at Swiss statutory rate		$ 273		$ 331		$ 233
Taxes on earnings subject to rates other that Swiss statutory rate		224		124		129
Income Tax Reconciliation, Change To Deferred Taxes Related To Unrealized Foreign Exchange		139	[1]	0	[1]	0	[1]
Tax exempt interest and dividends received deduction, net of proration		(33)		(27)		(24)
Net witholding taxes		33		27		23
Favorable resolution of prior years' tax matters and closing of statutes of limitations		(1)		(5)		(124)
Change in valuation allowance		(20)		4		4
Other		19		26		29
Provision for income taxes		634		480		270
Income Tax Reconciliation, Change To Deferred Taxes Related to Unrealized Foreign Exchange Net	$ 89	$ 71

[1] (1) Includes charge to deferred taxes related to non-recognition of foreign tax credits related to unrealized foreign exchange losses. Includes $71 million of net charges related to income taxes to correct prior periods. Such amounts are not material to any period presented.