Goodwill and Specifically Identifiable Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Roll Forward]
Acquisition balance as of beginning-of-year	$ 2,273	$ 3,863
Cumulative impairment as of beginning-of-year	(1,590)	(844)
Impairment	0	(747)
Other	0	1
Balance as of end-of-year	2,273	2,273
Future estimated amortization of specifically identifiable intangible assets [Abstract]
2013	4
2014	4
2015	4
2016	4
2017	4
Annuities Segment [Member]
Goodwill [Roll Forward]
Acquisition balance as of beginning-of-year	440	1,040
Cumulative impairment as of beginning-of-year	(600)	(600)
Impairment	0	0
Other	0	0
Balance as of end-of-year	440	440
Retirement Plan Services Segment [Member]
Goodwill [Roll Forward]
Acquisition balance as of beginning-of-year	20	20
Cumulative impairment as of beginning-of-year	0	0
Impairment	0	0
Other	0	0
Balance as of end-of-year	20	20
Life Segment [Member]
Goodwill [Roll Forward]
Acquisition balance as of beginning-of-year	1,539	2,188
Cumulative impairment as of beginning-of-year	(649)	0
Impairment	0	(650)
Other	0	1
Balance as of end-of-year	1,539	1,539
Group Protection Segment [Member]
Goodwill [Roll Forward]
Acquisition balance as of beginning-of-year	274	274
Cumulative impairment as of beginning-of-year	0	0
Impairment	0	0
Other	0	0
Balance as of end-of-year	274	274
Other Operations [Member]
Goodwill [Roll Forward]
Acquisition balance as of beginning-of-year	0	341
Cumulative impairment as of beginning-of-year	(341)	(244)
Impairment	0	(97)
Other	0	0
Balance as of end-of-year	$ 0	$ 0