Deferred Policy Acquisition Costs, Value of Business Acquired and Other Policy-Related Intangibles (DAC and VOBA by Segment) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
DAC and VOBA	$ 5,274	$ 4,809	$ 4,890
Annuities
Segment Reporting Information [Line Items]
DAC and VOBA	4,521	3,510	3,548
Life
Segment Reporting Information [Line Items]
DAC and VOBA	504	680	680
Run-off
Segment Reporting Information [Line Items]
DAC and VOBA	112	510	601
Corporate & Other
Segment Reporting Information [Line Items]
DAC and VOBA	$ 137	$ 109	$ 61