Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Notes to Financial Statements [Abstract]
Federal income tax rate									35.00%
Schedule of Segment Reporting And Reconcilliation [Line Items]
Total revenues	$ 2,964	$ 2,954	$ 2,899	$ 2,715	$ 2,569	$ 2,547	$ 2,807	$ 2,718	$ 11,532	$ 10,641	$ 10,415
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations	320	400	322	244	(541)	158	301	311	1,286	229	873
Income (loss) from discontinued operations, after-tax	0	28	0	(1)	0	(8)	0	0	27	(8)	29
Net income (loss)	320	428	322	243	(541)	150	301	311	1,313	221	902
Net Investment Income [Abstract]
Total net investment income									4,698	4,652	4,541
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest									1,026	846	905
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									282	274	262
Total assets	218,869				201,491				218,869	201,491
Excluded Realized Gain (Loss), After Tax, Reconciling Item [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									(25)	(252)	(93)
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									(14)	(136)	(50)
Gain (loss) on early extinguishment of debt, After Tax, Reconcilling Item [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									(3)	(5)	(3)
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									(2)	(3)	(2)
Income (loss) from reserve changes (net of related amortization) on business sold through reinsurance, After Tax, Reconciling Item [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									3	2	3
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									1	1	1
Impairment of intangibles, After Tax, Reconciling Item [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									2	(747)	0
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									(2)	0	0
Benefit ratio unlocking, After Tax, Reconciling Item [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									25	(15)	11
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									14	(6)	5
Excluded Realized Gain (Loss), Pre Tax, Reconciling Item [Member]
Schedule of Segment Reporting And Reconcilliation [Line Items]
Total revenues									(39)	(388)	(143)
Amortization of Deferred Gains From Reserve Changes On Business Sold Through Reinsurance, Pre Tax, Reconciling Item [Member]
Schedule of Segment Reporting And Reconcilliation [Line Items]
Total revenues									4	2	3
Amortization Income of DFEL Associated With Benefit Ratio Unlocking, Pre Tax, Reconciling Item [Member]
Schedule of Segment Reporting And Reconcilliation [Line Items]
Total revenues									1	0	0
Annuities Segment [Member]
Schedule of Segment Reporting And Reconcilliation [Line Items]
Total revenues									2,975	2,871	2,659
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									595	573	471
Net Investment Income [Abstract]
Total net investment income									1,082	1,106	1,119
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest									321	351	360
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									121	104	97
Total assets	106,906				96,866				106,906	96,866
Retirement Plan Services Segment [Member]
Schedule of Segment Reporting And Reconcilliation [Line Items]
Total revenues									1,024	1,017	988
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									130	163	151
Net Investment Income [Abstract]
Total net investment income									799	792	769
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest									42	33	54
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									38	63	58
Total assets	30,651				28,626				30,651	28,626
Life Segment [Member]
Schedule of Segment Reporting And Reconcilliation [Line Items]
Total revenues									5,053	4,740	4,590
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									574	559	453
Net Investment Income [Abstract]
Total net investment income									2,396	2,294	2,186
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest									614	423	451
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									264	276	222
Total assets	64,115				59,711				64,115	59,711
Group Protection Segment [Member]
Schedule of Segment Reporting And Reconcilliation [Line Items]
Total revenues									2,091	1,938	1,831
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									72	97	68
Net Investment Income [Abstract]
Total net investment income									162	152	141
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest									49	39	40
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									39	52	36
Total assets	3,733				3,429				3,733	3,429
Other Operations [Member]
Schedule of Segment Reporting And Reconcilliation [Line Items]
Total revenues									423	461	487
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									(87)	(146)	(188)
Net Investment Income [Abstract]
Total net investment income									259	308	326
Reconciliation of Federal Income Tax Expense (Benefit) from Segments to Consolidated [Abstract]
Total federal income tax expense (benefit)									(177)	(77)	(105)
Total assets	$ 13,464				$ 12,859				$ 13,464	$ 12,859