Segment Information (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)	Mar. 31, 2018 USD ($) segment	Mar. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of segments	3	3
Life
Segment Reporting Information [Line Items]
Estimated increase (decrease) in total assets due to new methodology	$ 3,000	$ 3,000	$ 3,000
Annuities
Segment Reporting Information [Line Items]
Estimated increase (decrease) in total assets due to new methodology	2,000	2,000	2,000
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			20
Maximum | Life
Segment Reporting Information [Line Items]
Estimated increase (decrease) in adjusted earnings due to new methodology			$ 25