Segment Information (Reconciliation of Assets From Segments to Consolidated Balance Sheet) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total assets	$ 253,377	$ 236,945
Parent Company [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total assets	21,999	20,708
Annuities [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total assets	130,316	120,267
Retirement Plan Services [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total assets	33,678	32,369
Life Insurance [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total assets	70,493	65,639
Group Protection [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total assets	4,238	3,865
Other Operations [Member]
Schedule Of Segment Reporting And Reconcilliation [Line Items]
Total assets	$ 14,652	$ 14,805