Segment Information (Reconciliation of Amortization of DAC and VOBA, Net of Interest from Segments to Consolidated Net Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	$ 1,283	$ 1,111	$ 931
Annuities Segment [Member]
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	342	362	383
Retirement Plan Services Segment [Member]
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	30	37	48
Life Segment [Member]
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	831	655	447
Group Protection Segment [Member]
Amortization of DAC and VOBA, Net of Interest
Amortization of DAC and VOBA, net of interest	$ 80	$ 57	$ 53