Business and Basis of Presentation (Narrative) (Details) $ in Millions |
3 Months Ended | 12 Months Ended | |
|---|---|---|---|
|
Jun. 30, 2016
USD ($)
|
Dec. 31, 2017
segment
division
|
Dec. 31, 2016
USD ($)
|
|
| Error Corrections and Prior Period Adjustments Restatement [Line Items] | |||
| Number of Reportable Segments | segment | 7 | ||
| Number of divisions | division | 5 | ||
| Universal Life | |||
| Error Corrections and Prior Period Adjustments Restatement [Line Items] | |||
| Out of period decrease adjustments | $ (148) | $ (141) | |
| Income From Continuing Operations Before Income Taxes And Equity In Earnings Of Operating Joint Ventures | |||
| Error Corrections and Prior Period Adjustments Restatement [Line Items] | |||
| Out of period decrease adjustments | $ (153) | $ (134) | |