Investments (Activity related to the pretax fixed maturity credit loss component reflected within retained earnings for securities still held for which a portion of an OTTI loss was recognized in OCI) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance of credit losses on fixed maturity securities	$ 41	$ 59	$ 53	$ 62
Reductions for securities sold during the period	(2)	(2)	(14)	(5)
Reductions for securities the Company intends to sell or more likely than not will be required to sell	(1)	0	(1)	0
Ending balance of credit losses on fixed maturity securities	$ 38	$ 57	$ 38	$ 57