Derivatives (Changes in Estimated Fair Value Related to Embedded Derivatives) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ 898	$ 227	$ 3,661	$ 673
Net Derivative Gain (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	898	227	3,661	673
Policyholder benefits and claims [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ (30)	$ (4)	$ (110)	$ (9)