Investments (Details 4) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Unrealized gain on:
Pretax	$ 937				$ 1,290
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(337)				(467)
Net	600	[1]	865	[1]	823	[1]	771	705	578
Fixed maturities [Member]
Unrealized gain on:
Pretax	1,295				2,035
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(461)				(726)
Net	834				1,309
Equity securities [Member]
Unrealized gain on:
Pretax	215				161
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(77)				(57)
Net	138				104
Deferred policy acquisition costs [Member]
Unrealized gain on:
Pretax	(438)				(710)
Deferred Tax and Amounts Attributable to Noncontrolling Interests	153				247
Net	(285)				(463)
Annuity benefits and other liabilities [Member]
Unrealized gain on:
Pretax	(87)				(136)
Deferred Tax and Amounts Attributable to Noncontrolling Interests	31				48
Net	(56)				(88)
Life, accident and health reserves [Member]
Unrealized gain on:
Pretax	(81)				(117)
Deferred Tax and Amounts Attributable to Noncontrolling Interests	28				41
Net	(53)				(76)
Other Liabilities [Member]
Unrealized gain on:
Pretax	33				57
Deferred Tax and Amounts Attributable to Noncontrolling Interests	(11)				(20)
Net	$ 22				$ 37

[1] Includes net unrealized gains of $42 million at June 30, 2013, $45 million at March 31, 2013 and $33 million at December 31, 2012 related to securities for which only the credit portion of an other-than-temporary impairment has been recorded in earnings.