Reinsurance (Life Insurance Contract Holders' Benefits Incurred On Ceded Business) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net incurred loss and loss expenses	$ 2,808	$ 2,856	$ 2,505
Life Insurance Segment
Direct contract holders' benefits incurred	292	299	266
Ceded contract holders' benefits incurred	(56)	(70)	(62)
Net incurred loss and loss expenses	$ 236	$ 229	$ 204