Investments (Credit Loss Rollforward) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Balance, beginning of period	$ 359	$ 381	$ 378	$ 392
Additions:
Initial impairments - credit loss OTTI recognized on securities not previously impaired	1	3	1	5
Additional impairments - credit loss OTTI recognized on securities previously impaired	15	23	23	64
Reductions:
Due to sales (maturities, pay downs or prepayments) during the period of securities previously credit loss OTTI impaired	(11)	(21)	(31)	(75)
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Change in Status	0	0	(7)	0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Reductions, Cash Flows	0	(1)	0	(1)
Balance, end of period	$ 364	$ 385	$ 364	$ 385