Segment Information (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2018 USD ($) segment	Sep. 30, 2018 USD ($)
Segment Reporting [Abstract]
Number of segments	3	3
Annuities
Segment Reporting Information [Line Items]
Estimated increase (decrease) in total assets due to new methodology	$ 2,000	$ 2,000	$ 2,000
Life
Segment Reporting Information [Line Items]
Estimated increase (decrease) in total assets due to new methodology	3,000	3,000	3,000
Run-off
Segment Reporting Information [Line Items]
Estimated increase (decrease) in total assets due to new methodology	(3,000)	(3,000)	(3,000)
Corporate & Other
Segment Reporting Information [Line Items]
Estimated increase (decrease) in total assets due to new methodology	$ (2,000)	$ (2,000)	(2,000)
Minimum | Life
Segment Reporting Information [Line Items]
Estimated increase (decrease) in adjusted earnings due to new methodology			60
Maximum | Life
Segment Reporting Information [Line Items]
Estimated increase (decrease) in adjusted earnings due to new methodology			$ 75