Consolidated Statements Of Shareholders' Equity (Parenthetical) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Statement Consolidated Statements Of Shareholders Equity [Abstract]
Change in year, before reclassification from AOCI, net of income tax benefit(expense)	$ (477)	$ 81
Income tax benefit (expense) from reclassification of unrealized gains	5	14
Net unrealized appreciation on investments, Change in period, income tax (expense) benefit	(472)	95
Cumulative translation adjustment, Change in period, income tax(expense) benefit	(11)	7
Net income	1,165	1,623
Pension liability adjustment, Change in period, income tax (expense) benefit	$ 1	$ (2)