Consolidated Statements Of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Statement Consolidated Statements Of Shareholders Equity [Abstract]
Change in year, before reclassification from AOCI, net of income tax benefit(expense)	$ (559)	$ 102
Income tax benefit (expense) from reclassification of unrealized gains	16	10
Net unrealized appreciation on investments, Change in period, income tax (expense) benefit	(543)	112
Cumulative translation adjustment, Change in period, income tax(expense) benefit	(18)	35
Net income	2,525	2,151
Pension liability adjustment, Change in period, income tax (expense) benefit	$ 0	$ (2)