Segment Information (Reconciliation Of Income (Loss) From Operations By Segment To Consolidated Net Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended												12 Months Ended
	Dec. 31, 2016	[1]	Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations													$ 1,192	$ 1,154	$ 1,514
Income (loss) from discontinued operations, after-tax															1
Net income (loss)	$ 189		$ 467		$ 325		$ 211		$ 283	$ 227	$ 344	$ 300	1,192	1,154	1,515
Annuities Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations													935	996	925
Retirement Plan Services Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations													127	140	160
Life Insurance Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations													515	370	612
Group Protection Segment [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations													65	43	23
Other Operations [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations													(102)	(154)	(109)
Excluded realized gain (loss), after-tax [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations													(337)	(214)	(106)
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													(41)
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	2
Benefit ratio unlocking, after-tax [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Income (loss) from continuing operations													28	(29)	7
Parent Company [Member]
Reconciliation of Net Income (Loss) from Segments to Consolidated [Abstract]
Net income (loss)													$ 1,192	$ 1,154	$ 1,515

[1] Effective October 1, 2016, we early adopted ASU 2016-09, Improvements to Employee Share-Based Payment Accounting. We have updated certain previously reported interim results and metrics as of January 1, 2016, in accordance with the new guidance. For more information, see Note 2.