Investments (Details 4) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Unrealized gain on:
Pretax	$ 1,290		$ 902
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(467)		(324)
Net	823	[1]	578	[1]	491	[1]	167
Fixed maturities [Member]
Unrealized gain on:
Pretax	2,035		1,245
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(726)		(444)
Net	1,309		801
Equity securities [Member]
Unrealized gain on:
Pretax	161		184
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(57)		(65)
Net	104		119
Deferred policy acquisition costs [Member]
Unrealized gain on:
Pretax	(710)		(537)
Deferred Tax and Amounts Attributable to Noncontrolling Interests	247		188
Net	(463)		(349)
Annuity benefits accumulated [Member]
Unrealized gain on:
Pretax	(136)		(30)
Deferred Tax and Amounts Attributable to Noncontrolling Interests	48		11
Net	(88)		(19)
Life, accident and health reserves [Member]
Unrealized gain on:
Pretax	(117)
Deferred Tax and Amounts Attributable to Noncontrolling Interests	41
Net	(76)
Other liabilities [Member]
Unrealized gain on:
Pretax	57		40
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(20)		(14)
Net	$ 37		$ 26

[1] Includes net unrealized gains of $33 million at December 31, 2012 compared to net unrealized losses of $16 million and $11 million at December 31, 2011 and 2010, respectively, related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings.