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	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance of credit losses on fixed maturity securities	$ 62	$ 74	$ 95
Additional credit losses for securities for which an OTTI loss was previously recognized	0	0	2
Reductions for securities sold during the period	(9)	(9)	(23)
Reductions for securities the Company intends to sell or more likely than not will be required to sell	0	(3)	0
Ending balance of credit losses on fixed maturity securities	$ 53	$ 62	$ 74