Derivatives (Details 10) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ 1,239	$ (1,284)	$ (387)
Net derivatives gains (losses) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	1,239	(1,284)	(387)
Policyholder benefits and claims [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	$ 75	$ 86	$ 8