Nature Of Operations, Basis of Presentation And Summary Of Significant Accounting Policies (Details) item in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Product Information [Line Items]
Grace Period Expiration (In Days)	10 days
Loans Reported As Delinquent In Days	60 days
Period In Which Loans No Longer Accrue Interest In Days	90 days
Front End Load Annuity Products Assumed Life (In Years)	25 years
Useful Life of Sales Force Intangible Assets (In Years)	25 years
Number Of Scenarios Used Per Policy To Value A Block Of Guarantees	100
Total Scenarios To Value GLB liability | item	49
Dividend Expenses | $	$ 57	$ 59	$ 67
Maximum [Member]
Product Information [Line Items]
Estimated Contract Life UL Policies (In Years)	40 years
Estimated Contract Life VUL Policies (In Years)	40 years
Estimated Contract Life Fixed and Variable Deferred Annuities (In Years)	30 years
Traditional Contract Acquisition Cost Amortization Period (In Years)	30 years
Interest Crediting Rate	10.00	10.00	10.00
Minimum [Member]
Product Information [Line Items]
Estimated Contract Life UL Policies (In Years)	30 years
Estimated Contract Life VUL Policies (In Years)	30 years
Estimated Contract Life Fixed and Variable Deferred Annuities (In Years)	15 years
Interest Crediting Rate	1.00	1.00	1.00
Life Insurance Segment [Member] | Maximum [Member]
Product Information [Line Items]
Investment Yield Assumptions for Traditional Direct Individual Life Reserves	7.75%
Life Insurance Segment [Member] | Minimum [Member]
Product Information [Line Items]
Investment Yield Assumptions for Traditional Direct Individual Life Reserves	2.25%
Annuities Segment [Member] | Maximum [Member]
Product Information [Line Items]
Investment Yield Assumptions for Immediate and Deferred Paid-Up Annuities	12.75%
Annuities Segment [Member] | Minimum [Member]
Product Information [Line Items]
Investment Yield Assumptions for Immediate and Deferred Paid-Up Annuities	1.25%