Investment Securities (Rollforward of Cumulative OTTI Credit Losses Recognized in Earnings) (Details) (USD $)	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 [Line Items]
Beginning balance	$ (1,158,000,000)	$ (1,164,000,000)	$ (1,160,000,000)	$ (1,201,000,000)
Additional loss where credit impairment was previously recognized	(1,000,000)	(2,000,000)	(4,000,000)	(16,000,000)
Reduction due to credit impaired securities sold or matured		7,000,000	5,000,000	58,000,000
Ending balance	$ (1,159,000,000)	$ (1,159,000,000)	$ (1,159,000,000)	$ (1,159,000,000)