XML 56 R44.htm IDEA: XBRL DOCUMENT v3.10.0.1
Investments - OTTI OCI (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Other than Temporary Impairment, Recognized in Accumulated Other Comprehensive Income [Roll Forward]        
Balance, beginning $ 5 $ 7 $ 16 $ 9
Additional Credit Impairments [Abstract]        
On securities previously impaired 1 0 1 0
Reductions [Abstract]        
Increase in cash flows 0 0 0 0
Securities sold, matured, prepaid, or paid down 1 0 12 2
Balance, ending $ 5 $ 7 $ 5 $ 7