Segment Information (Reconciliation of DAC VOBA Amortization From Segments to Consolidated) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	$ 1,167	$ 962	$ 1,172
Annuities Segment [Member]
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	347	402	310
Retirement Plan Services Segment [Member]
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	27	26	27
Life Insurance Segment [Member]
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	701	455	709
Group Protection Segment [Member]
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	$ 92	$ 79	$ 126