v3.8.0.1
Goodwill and Other Intangibles (Changes in the Book Value of Goodwill by Segment) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Goodwill [Roll Forward]      
Gross Goodwill, Beginning of the year $ 833 $ 824 $ 831
Accumulated Impairment Losses, Beginning of the year 0 0 0
Net Goodwill, Beginning of the year 833 824 831
Acquisitions 0 0 0
Other 10 9 (7)
Gross Goodwill, End of the year 843 833 824
Accumulated Impairment Losses, End of the year 0 0 0
Net Goodwill, End of the year 843 833 824
Retirement      
Goodwill [Roll Forward]      
Gross Goodwill, Beginning of the year 444 444 444
Accumulated Impairment Losses, Beginning of the year 0 0 0
Net Goodwill, Beginning of the year 444 444 444
Acquisitions 0 0 0
Other 0 0 0
Gross Goodwill, End of the year 444 444 444
Accumulated Impairment Losses, End of the year 0 0 0
Net Goodwill, End of the year 444 444 444
Investment Management      
Goodwill [Roll Forward]      
Gross Goodwill, Beginning of the year 230 231 235
Accumulated Impairment Losses, Beginning of the year 0 0 0
Net Goodwill, Beginning of the year 230 231 235
Acquisitions 0 0 0
Other 5 (1) (4)
Gross Goodwill, End of the year 235 230 231
Accumulated Impairment Losses, End of the year 0 0 0
Net Goodwill, End of the year 235 230 231
International Insurance      
Goodwill [Roll Forward]      
Gross Goodwill, Beginning of the year 159 149 152
Accumulated Impairment Losses, Beginning of the year 0 0 0
Net Goodwill, Beginning of the year 159 149 152
Acquisitions 0 0 0
Other 5 10 (3)
Gross Goodwill, End of the year 164 159 149
Accumulated Impairment Losses, End of the year 0 0 0
Net Goodwill, End of the year $ 164 $ 159 $ 149