XML 48 R51.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Summary of Significant Accounting Policies (Details) - Credit Losses - USD ($)
$ in Millions
Jan. 01, 2020
Dec. 31, 2017
Retained earnings [Member]    
New Accounting Pronouncements    
Cumulative effect adjustment   $ 22
Subsequent event [Member] | Forecast [Member] | Accounting Standards Update 2016-13 [Member] | Allowance for uncollectible reinsurance [Member]    
New Accounting Pronouncements    
Cumulative effect adjustment $ 43  
Subsequent event [Member] | Forecast [Member] | Accounting Standards Update 2016-13 [Member] | Retained earnings [Member]    
New Accounting Pronouncements    
Cumulative effect adjustment $ (43)