Consolidated Statements of Shareholders' Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement Of Comprehensive Income
Shareholders' Net Income	$ 813	$ 510	$ 1,411	$ 1,029
Shareholders' other comprehensive income (loss), net of tax:
Net unrealized appreciation (depreciation) on securities	67	177	74	350
Net unrealized appreciation (depreciation) on derivatives	0	(1)	(3)	(4)
Net translation of foreign currencies	27	(40)	139	41
Postretirement benefits liability adjustment	12	8	26	19
Shareholders' other comprehensive income (loss), net of tax	106	144	236	406
Shareholders' comprehensive income (loss)	$ 919	$ 654	$ 1,647	$ 1,435