Investments (Details 15) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Changes In Net Unrealized Investment Gains Losses Included In Accumulated Other Comprehensive Loss [Abstract]
Balance, beginning of period	$ 1,910
Fixed maturity securities on which noncredit OTTI losses have been recognized	42
Unrealized investment gains (losses) during the year	1,644
Unrealized investment gains (losses) relating to [Abstract]
Insurance liability gain (loss) recognition	(443)
DAC and VOBA related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(2)
DAC and VOBA	(208)
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(14)
Deferred income tax benefit (expense)	(360)
Balance, end of period	2,569
Changes in net unrealized investment gains (losses)	$ 659