Investments (Details 4) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Jun. 30, 2012		Dec. 31, 2011		Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Unrealized gain on:
Pretax	$ 1,441				$ 902
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(520)				(324)
Net	921	[1]	771	[1]	578	[1]	588	605	491
Fixed maturities [Member]
Unrealized gain on:
Pretax	1,986				1,245
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(709)				(444)
Net	1,277				801
Equity securities [Member]
Unrealized gain on:
Pretax	206				184
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(74)				(65)
Net	132				119
Deferred policy acquisition costs [Member]
Unrealized gain on:
Pretax	(764)				(537)
Deferred Tax and Amounts Attributable to Noncontrolling Interests	267				188
Net	(497)				(349)
Annuity benefits and other liabilities [Member]
Unrealized gain on:
Pretax	13				10
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(4)				(3)
Net	$ 9				$ 7

[1] Includes net unrealized gains of $23 million at September 30, 2012 compared to net unrealized losses of $1 million at June 30, 2012 and $16 million at December 31, 2011 related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings.