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, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Beginning balance of credit losses on fixed maturity securities	$ 92	$ 100	$ 95	$ 92
Additional credit losses for securities for which an OTTI loss was previously recognized	1	10	1	21
Credit losses for securities for which an OTTI loss was not previously recognized		1		2
Reductions for securities sold during the period	(4)	(4)	(7)	(8)
Reductions for securities the Company intends to sell or more likely than not will be required to sell		(8)		(8)
Ending balance of credit losses on fixed maturity securities	$ 89	$ 99	$ 89	$ 99