Schedule II - Condensed Financial Information, Statements of Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating expenses:
Debt extinguishment costs	$ 321	$ 0	$ 321	$ 0
Total operating expenses	2,696	2,428	7,497	7,038
Income before Income Taxes	824	742	2,848	2,374
Income tax expense (benefit)	262	290	883	905
Shareholders' Net Income	560	456	1,971	1,485
Shareholders' other comprehensive income (loss), net of tax:
Net unrealized appreciation (depreciation) on securities	(22)	66	52	416
Net unrealized appreciation (depreciation) on derivatives	0	(1)	(3)	(5)
Net translation of foreign currencies	34	55	173	96
Postretirement benefits liability adjustment	10	9	36	28
Shareholders' other comprehensive income (loss)	22	129	258	535
Shareholders' comprehensive income (loss)	$ 582	$ 585	$ 2,229	$ 2,020