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		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance of credit losses on fixed maturity securities	$ 48	$ 61	$ 53	$ 62
Reductions for securities sold during the period	(7)	(2)	(12)	(3)
Ending balance of credit losses on fixed maturity securities	$ 41	$ 59	$ 41	$ 59