XML 61 R79.htm IDEA: XBRL DOCUMENT v3.19.3
Fair Value Measurements - Measured Under Certain Conditions (Details) - USD ($)
9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Financing Receivable, Impaired [Line Items]    
Realized investment losses on assets measured at fair value under certain conditions, after-tax $ 0
Realized investment gains on equity securities with no readily determinable fair value $ 0
Maximum [Member]    
Financing Receivable, Impaired [Line Items]    
Assets measured at fair value under certain conditions as a percent of total investments 1.00% 1.00%