Derivatives (Changes in Estimated Fair Value Related to Embedded Derivatives) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ 821	$ 229	$ 794	$ 120
Net derivative gains (losses)
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	821	229	794	120
Policyholder benefits and claims
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ (43)	$ 8	$ (19)	$ 23