Segment Information (Reconciliation Of Income (Loss) From Operations By Segment To Consolidated Net Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations	$ 348	$ 439	$ 398	$ 329					$ 1,514	$ 1,244	$ 1,286
Income (loss) from discontinued operations, after-tax	1								1		27
Net income (loss)	349	439	398	329	351	337	317	239	1,515	1,244	1,313
Annuities [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									925	750	595
Retirement Plan Services [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									160	141	130
Life Insurance [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									612	544	574
Group Protection [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									23	71	72
Other Operations [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									(109)	(122)	(87)
Excluded realized gain (loss), after-tax [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									(106)	(178)	(25)
Gain (loss) on early extinguishment of debt, after-tax [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations											(3)
Income (loss) from reserve changes (net of related amortization) on business sold through reinsurance, after-tax [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									2	2	3
Impairment of intangibles, after-tax, reconciling item [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations											2
Benefit ratio unlocking, after-tax, reconciling item [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations									7	36	25
Parent Company [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)									$ 1,515	$ 1,244	$ 1,313