Reinsurance - Effects of Reinsurance (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Premiums Earned, Net [Abstract]
Ceded	$ 136	$ 130
Premiums Earned Net	7,746	7,402
Reinsurance Recoveries [Abstract]
Reinsurance recoveries	164	159
Individual Life Insurance And Annuity Business Sold [Member]
Premiums Earned, Net [Abstract]
Ceded	41	41
Reinsurance Recoveries [Abstract]
Reinsurance recoveries	68	86
Other Subsegments [Member]
Premiums Earned, Net [Abstract]
Ceded	95	89
Reinsurance Recoveries [Abstract]
Reinsurance recoveries	$ 96	$ 73