Consolidated Statements Of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net unrealized appreciation on investments, Change in period, income tax (expense) benefit	$ (233)	$ (83)
Cumulative translation adjustment, Change in period, income tax(expense) benefit	(35)	11
Pension liability adjustment, Change in period, income tax (expense) benefit	(1)	(3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Tax	(234)	(87)
Income tax benefit (expense) from reclassification of unrealized gains	$ 1	$ 4