Investments (Changes in Net Unrealized Investment Gains Losses) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Changes In Net Unrealized Investment Gains Losses Included In Accumulated Other Comprehensive Loss [Abstract]
Balance, beginning of period	$ 2,449
Fixed maturity securities on which noncredit OTTI losses have been recognized	12
Unrealized investment gains (losses) during the year	(2,519)
Unrealized investment gains (losses) relating to [Abstract]
Insurance liability gain (loss) recognition	537
DAC and VOBA related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(3)
DAC and VOBA	311
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in accumulated other comprehensive income (loss)	(3)
Deferred income tax benefit (expense)	596
Balance,end of period	1,380
Changes in net unrealized investment gains (losses)	$ (1,069)