Derivatives (Changes in Estimated Fair Value Related to Embedded Derivatives) (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
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ 1,079	$ (1,378)	$ 2,763	$ 446
Net derivatives gains (losses) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	1,079	(1,378)	2,763	446
Policyholder benefits and claims [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ (33)	$ 42	$ (80)	$ (5)