Insurance - Net earnings and capital and surplus on a statutory basis for the insurance subsidiaries (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property and casualty companies
Statutory information
Net Earnings	$ 461	$ 408	$ 318
Capital and Surplus	2,939	2,488
Life insurance companies
Statutory information
Net Earnings	167	399	$ 349
Capital and Surplus	$ 1,976	$ 1,721