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
	Mar. 31, 2016	Mar. 31, 2015
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance of credit losses on fixed maturity securities	$ 53	$ 62
Additional credit losses for securities for which an OTTI loss was previously recognized	0	0
Reductions for securities sold during the period	(5)	(1)
Reductions for securities the Company intends to sell or more likely than not will be required to sell	0	0
Ending balance of credit losses on fixed maturity securities	$ 48	$ 61