Schedule II - Condensed Financial Information, Statements of Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating expenses:
Total operating expenses	$ 2,321	$ 2,204
Income before Income Taxes	819	854
Income tax expense (benefit)	305	323
Shareholders' Net Income	519	533
Shareholders' other comprehensive income (loss):
Net unrealized appreciation (depreciation) on securities	173	88
Net unrealized appreciation (depreciation), derivatives	(3)	7
Net translation of foreign currencies	81	(104)
Postretirement benefits liability adjustment	11	11
Shareholders' other comprehensive income (loss)	262	2
Shareholders' comprehensive income (loss)	$ 781	$ 535